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Eric Page
07-27-2020, 07:54 PM
OK, it was in a semi trailer, not a barn, but I figure that I'm allowed a little creative license!

I'll start with thanks to each of you who responded to my threads about evaluating the project before I bought it, and finding the serial number once I did. I'm grateful for your help, and I'm excited to see what else I'll learn from everyone here.

So, once I got the project home, I started by putting a 2x6 spine and some caster wheels under the wing cradles so I could move them around easily by myself. With that done, I rearranged my garage extensively. I was able to get everything in there, including my car, but I've decided that I need a garden shed, so that's near the top of my to-do list. The shed will swallow most of the contents of my garage that aren't airplane related, so I'll have a lot more room to work. My garage is insulated, so it will be livable year-round; today's high was 95°, but the garage never got over 80°!

Last week, after removing the shoulder harnesses to find the serial number, I completed removing the belts. The anchor bolts were grossly over-torqued (I almost needed a pipe on the wrench!), so they'll be scrapped and replaced. I soaked the belts in a bucket of hot water and car wash soap. They came out looking great, apart from a tiny bit of rust pitting on the chromed anchors. I'll clean that and apply a coat of clear to prevent any more rust.

I removed the fiberglass seat pan, gave it a good scrubbing and set it aside in a corner of the spare bedroom, along with the windscreen.

Next to come off was the engine mount (for a Rotax 912). That was only loosely held in place, but the hardware has some surface corrosion and will also be replaced. I also removed the coolant catch can bracket. Its tiny little fasteners were so tight that the head popped off one of the screws when I tried to loosen the nut (are you seeing a theme developing?). Finally, I disconnected the brake lines and removed the brake fluid reservoir. This left the firewall held in place by two clecos and the brake lines that were held captive by their compression fittings.

A couple of days ago a neighbor who's an experienced builder (he's currently scratch-building a heavily modified PA-12 clone) came by to look at the Kitfox. As I expected, he told me he didn't think the covering job was airworthy, and he agreed with me that everything should be stripped and the fuselage should be completely disassembled (the wings were factory quick-build).

Somehow it seems like a REALLY big step to cut the fabric off of the plane, but the longer I wait, the later my first flight will be. So, this evening I'm headed to the garage with a razor blade.

I've attached some photos that show what kind of shape my poor plane was in when I received it. I don't have a photo of the firewall, but it's also a mess. The upper right corner is bent, there are tool marks from someone trying to straighten it, and it has several holes in odd places (some of them patched with blobs of Hysol!). Also, the elevator control is very tight; it's obviously binding somewhere.

Most worrisome is the damage to the flaperon skins (last two photos). Any opinions on the repairability of this damage would be welcome.

rv9ralph
07-28-2020, 08:03 AM
Your pictures and descriptions show poor technique... which will require a complete inspection of everything done by the previous builder. As a suggestion, due to age replace all elastic stop nuts and inspect the rest of the AN hardware.

Good luck with it. Think of it as a restoration, you start by going backward until everything is solid, the go forward doing everything properly. In the end you will have the plane you want.

Ralph

alexM
07-28-2020, 09:43 AM
Eric,
Glad you started a restoration/build thread. Maybe I could fly down to Toledo and look it over with you. That elevator push pull tube is concerning. There's supposed to be a plastic bushing in there, very similar to the rudder pedal and flaperon bushings but larger. I know because I just bought one. That dent is concerning and if it were me I would plan on replacing that tube.

I would get that covering off for sure. All of it.

Eric Page
07-28-2020, 12:40 PM
Your pictures and descriptions show poor technique... which will require a complete inspection of everything done by the previous builder. As a suggestion, due to age replace all elastic stop nuts and inspect the rest of the AN hardware.
I agree. It's all coming apart. Much of the remaining hardware has surface corrosion, and the stuff that was used appears to have been universally over-torqued, so I'm planning to buy all new.

-=-=-=-=-=-


Maybe I could fly down to Toledo and look it over with you.
Yes, please do. I'll be here the rest of this week, except 11a-3p on Wed, then away Aug 1-4.


That elevator push pull tube is concerning. There's supposed to be a plastic bushing in there, very similar to the rudder pedal and flaperon bushings but larger. I know because I just bought one. That dent is concerning and if it were me I would plan on replacing that tube.
The bushing is present. I didn't think so at first because of the appearance of the tube -- it looked to me like the aluminum was wearing to powder on the steel support ring -- but it appears that the black smears are from whatever the bushing is made of. I agree on the dent, and replacing the tube.


I would get that covering off for sure. All of it.
I didn't get it done last night, but I'm definitely pulling fabric off the fuselage this afternoon.

avidflyer
07-28-2020, 04:20 PM
When it comes to removing the fabric, it's just like the song that goes ' the first cut is the deepest' Hard to put the knife to the fabric, but once the first cut happens, you just keep going. Remember watching a friend who was about to rebuild his Chief aircraft. He had the hardest time making that first cut. I finally handed him the knife, and said "cut" Pretty soon after that it was naked.... JImChuk

PS, I don't think I would worry to much about the flaperons, as long as the hinges and the main tube are good, and the damage shown is the worst of it.

Eric Page
07-28-2020, 07:23 PM
PS, I don't think I would worry to much about the flaperons, as long as the hinges and the main tube are good, and the damage shown is the worst of it.
Thanks, avidflyer. I was thinking about this today...

Does anyone know what alloy the flaperon skins are made from? If there were markings on mine, they've been removed. I'm guessing 2024, in which case stitch-welding isn't an option.

My initial repair idea is this: Stop-drill the cut in the skin (the hole would be barely around the leading edge, just on the opposite side). Using a wooden buck that matches the airfoil shape, fabricate a patch from 0.020 sheet just large enough to extend about an inch beyond the damage in each direction, with the slot shape pre-formed in the patch. Finally, bond and rivet the patch over the damaged area so that the patch aligns with, and reestablishes the end of, the bracket slot.

For the deep scratch in the other flaperon, stop-drill both ends of the sharp crease, use a dab of Hysol to fill the holes and crease, then use body filler and sanding to smooth out the rest of the dent.

Any other suggestions are welcome.

109JB
07-28-2020, 08:08 PM
On the Kitfox IV speedster, the flaperon skin is cut all the way around making a 1/4" gap at each hinge location. At these points the trailing edge is connected with a small metal tab. The 1/4 gap is covered with fabric. Was supposedly done this way to prevent flaperon binding during high g maneuvers. If I remember I'll post the directions for this from the builder manual. Bottom line is that a little cut in the flaperon skin isn't much to be worried about.

PapuaPilot
07-28-2020, 08:19 PM
My initial repair idea is this: Stop-drill the cut in the skin (the hole would be barely around the leading edge, just on the opposite side). Using a wooden buck that matches the airfoil shape, fabricate a patch from 0.020 sheet just large enough to extend about an inch beyond the damage in each direction, with the slot shape pre-formed in the patch. Finally, bond and rivet the patch over the damaged area so that the patch aligns with, and reestablishes the end of, the bracket slot.

For the deep scratch in the other flaperon, stop-drill both ends of the sharp crease, use a dab of Hysol to fill the holes and crease, then use body filler and sanding to smooth out the rest of the dent.

Your repairs for the flaperons seem good. AC43.13 would be the best guide, which has you use the same thickness of sheet metal as the original material. I am pretty sure that the flaperons are made from 2024-T3 aluminum.

Eric Page
07-29-2020, 11:26 PM
Thanks, guys. I appreciate the info. I'll check 43.13 before I proceed. I'm a long way from needing the flaperons, so they can wait until I'm stuck waiting for parts on something else.

-=-=-=-=-=-

I made some progress the last couple of days. I got the fuselage and vertical stabilizer stripped of fabric, and I'm glad I did. The Poly-Tack application was pretty inconsistent, so the fabric wasn't uniformly stuck to the structure. In some places it came off easily, and in others I had to pick at it with a knife blade to get an edge up that I could get ahold of.

With the tail open I can see how the ribs were done. It looks like Hysol was applied with a kitchen spatula on the end of a broom handle (it ain't pretty!), but the ribs appear to be straight and structurally sound.

Once it was stripped, I got started on removing everything. The doors came off first, then I dove into the flight control system. In all of the controls, there was ONE nut and bolt that didn't fight me. All the rest were either torqued way too tight, or had surface corrosion that made them difficult to remove, or both. I'm REALLY glad I'm taking it apart.

The rudder torque tube assembly is a mess. The pilot's left pedal and the copilot's right pedal are very tight and hard to move. It looks like the nuts holding them to the mounting brackets are too tight, so the tubes are bound up on their bushings. Unfortunately, there doesn't appear to be any way to fix it without drilling out the rivets and separating the torque tubes. The nuts holding them in the brackets just spin their bolts and won't come loose, and the bolt heads are inside the tubes and inaccessible. At least the whole assembly is off the fuselage so I can put it on the bench.

I just need to get some cable cutters and I'll be able to finish the fuselage disassembly. The rudder pedal adjustment handles are trapped because the bolts that hold the cable ends are stuck in the handle tubes, and the cables are captive in the fuselage due to Nicopress sleeves. I have an idea how to get the bolts out using some wood blocks and the bench vise, but I've got to get them free of the fuselage first.

PapuaPilot
07-30-2020, 07:35 AM
I'm REALLY glad I'm taking it apart.


That is what you want to say after wondering if total disassembly was the right thing to do.

As far as you rudder pedal issue I would search the forum on this subject. Look especially for the people who did a build log. This is a known problem and it usually takes us several days of work to align, trim, shim, and mount the rudder pedals and get them free from binding. There is a good chance this wasn't done properly at the original build. Now is the time to take care of it.

Eric Page
07-30-2020, 09:52 AM
As far as you rudder pedal issue I would search the forum on this subject. Look especially for the people who did a build log. This is a known problem and it usually takes us several days of work to align, trim, shim, and mount the rudder pedals and get them free from binding. There is a good chance this wasn't done properly at the original build. Now is the time to take care of it.
When I discovered the problem I thought it must be a misalignment in the way the brackets were mounted to the fuselage, but the assembly is still very stiff even after it's removed. I need to look at the assembly and fitting procedure in the manual to understand how it's supposed to work, but it sure looks like the bolts/nuts that attach the torque tubes to the brackets are too tight.

Like the flaperons, fixing this will wait awhile. Primary focus for now is getting the fuselage ready to go to the welder for tail reinforcement and additional mounting tabs for avionics and antennas. The disassembled rudder torque tubes will go as well, for gusseting.

Dave S
07-30-2020, 11:23 AM
Eric,

It is not that rare that people have some fitment issues with the torque tube mounting. If the original builder did not remove enough material from the hard plastic bearing that could be the issue.

Your comments about encountering bolts that were over tightened may be an issue; but, realizing that the bearings are inserted after the bolts are tightened to the mounting part would seem to indicate that the bigger problem with them sticking may be the fit in the first place.

If a person follows the procedure in the build manual for turning/filing/sanding the bearings down to fit that should alleviate the problem. I found that mounting the bearing on a bolt chucked into the drill press made it easy to turn them down. I also found that working the bearing into a slight barrel shape by taking a bit more off the ends of the bearing while keeping the fitment at the center very close helps a lot with whatever misalignment may be present.

It is not beyond possibilities that if the assembly sat for a while there may be some light surface rust inside the torque tube at the bearing end that may be interfering.

You'll get it figured out.:)

alexM
07-30-2020, 01:35 PM
Yes, those outboard bearings with the hidden bolt heads should pull right out of the tubes. The bolt isn't some kind of chinese finger puzzle.

Eric Page
07-30-2020, 11:12 PM
Excellent, thanks for the tip, Alex. I'll give that a try tomorrow and see if the bearings will pull out of the torque tubes. And Dave, I appreciate the tip on fitting the bearings for smooth operation. I'll refer back to this when the time comes.

-=-=-=-=-=-

I finished disassembly of the fuselage today, after having the light bulb come on over my head with the idea that I didn't need cable cutters to get the control cables out -- I could use the Dremel! The cable made short work of the first cutting disc, so I switched to a 4-1/2" angle grinder, which did the trick. That freed the rudder pedal adjustment handles, which had bolts holding the cables in place that were stuck. I put them in the padded vise jaws, applied a little penetrating oil and gave them a few taps with The Persuader, which broke them loose.

I also removed the flap handle and center console, which completed disassembly of the flight controls.

Finally, I pulled off the brake calipers and found that they had significant surface corrosion, some of which appears to extend into the cylinders. If anyone has an idea how to get the pistons out of these things, I'd be thrilled to hear it. I want to check the cylinder bores and pistons, and at a minimum, replace the o-rings.

Dave S
07-31-2020, 06:47 AM
Eric,

The calipers are pretty expensive so it pays to go slow and get it right the first time.

WORD OF CAUTION - FIRST

The normal way of getting the pistons out carries with it a risk of creating a 40 millimeter cannon which you don't want to have any body parts in the way as well as some risk of damaging the parts if done incorrectly.

So we do it carefully.

Applying air pressure to the line going into the fluid chamber is how these things are normally removed. USE ONLY VERY LOW AIR PRESSURE APPLIED WITH AN AIR GUN - no more than 5 psi at first and only increase a little at a time as needed to get it to move.

1) Have some type of retaining clamp (C clamps often used) to prevent the piston from getting away but you need some give in it so use some foam, rag or similar between the clamp and back side of the caliper - doesn't have to be tight but you need to assure the thing doesn't come flying out. The clamp is loosened as the piston comes out.

2) Since there is some surface corrosion that may interfere with smooth extraction - its good to remove what corrosion you can first - then be prepared to alternately apply air pressure and press the piston in to work it loose. This may be your biggest test of patience.

3) If the piston comes out part way and seems to stick - do not be tempted to grab it with a pliers! Just keep pushing it in and out with you fingers and air pressure to work the gunk out and allow the piston to come out.

Normally the pistons come out with very little problem and just a little air pressure. The corrosion may make them a bit sticky.

Good luck and be careful.

Eric Page
07-31-2020, 08:29 PM
Thanks again, Dave. I'll try your method next time I'm working on it. I'll be away for a few days, but should be back at it by the middle of next week.

-=-=-=-=-=-

I had a nice visit this morning from fellow Series 5 builder Alex (alexM of Project 5), who flew down with his son in his Citabria. He gave my project a good look-over and offered some valuable advice on a couple of things. He also generously gave me his eight leftover rudder torque tube gussets, so I won't have to fabricate those. Thanks, Alex!

Today I re-built a couple of sawhorses from the remains I got with my kit, then put the fuselage on them and removed the landing gear and tailwheel. I found two of the four landing gear bolts missing cotter pins, and a third that was installed but not bent around the nut.

I drilled out the rivets in one end of my dented elevator push-pull tube, which freed it from the fuselage. On Alex's advice, I used some heat to try to remove the reducer from the end of the tube. I kept increasing the temperature until I had the heat gun on maximum and the adhesive began to change color, but it wouldn't budge. When it got to the point that I was damaging the reducer in the attempt, I gave up. Alex mentioned that SkyStar used to use another (3M?) adhesive that doesn't soften with heat before later switching to Hysol, so maybe that's what I've got. Anyway, I'm sure Kitfox will be happy to sell me two new push-pull tube reducers. The rod end bearings look new, so I'll keep those.

While Alex was here, he showed me how the bearings in the rudder torque tube come apart (we tried briefly to pull them out, but couldn't do it). I put them in the bench vise and tried to pull, then knock them out, but all I was doing was dragging the bench away from the wall! The original builder must have pressed them in (I did see a hydraulic press in the trailer with the plane). I had to resort to using a flat blade screwdriver and a rubber mallet. Three out of four came out cleanly, but one was damaged around the flanged end, and I found a Grade 5 hardware store bolt and nut holding one of them to its bracket. Have I mentioned how happy I am that I decided to disassemble this thing?

Now for the bad news: I found that two of the lower fuselage tubes are bent. They're both at the same "station" in the plane, between 30" and 51" aft of the wing strut attach point. The bends are pretty gradual, over several inches and without any kinks, so I think they're fixable. It looks like the original builder must have let the plane sit (or drop!) on a sawhorse in the middle of the tubes' span. I'll have to build a straightening tool like what 109JB used, here (https://teamkitfox.com/Forums/threads/10554-109JB-s-Kitfox-IV-rebuild?p=90923&viewfull=1#post90923). I also plan to go through the entire plane with a straight edge to be sure there aren't any more surprises!

avidflyer
07-31-2020, 08:52 PM
Earlier Kitfoxes used Scotch weld 2216 epoxy instead of the Hysol. It's a nice epoxy, it seems to last forever, but the mix is 5 parts to 7 by weight, so maybe not as convenient as the 1-1 mix of the Hysol. Not sure if it takes more heat to soften it up, but as the aluminum tube is shot anyway, you could carefully cut it off the steel end. Also, it should be real easy to straighten those longerons. JImChuk

alexM
08-01-2020, 10:38 AM
Agree those tubes should be easy to straighten. At one point when I was looking over your fuselage something caught my eye that seemed not quite right (only because I've stared at my own enough), but I got distracted and couldn't find it again. It must have been those tubes and it is understandable why that didn't jump out when you first saw it.
Let me know if you want an extra hand when you put them back in shape.

Eric Page
08-01-2020, 01:11 PM
Thanks, Alex. I'm mulling over in my head what I can build as a straightener with the lumber and other junk that's knocking around in my garage. Stay tuned.

Eric Page
08-01-2020, 07:42 PM
Well, I guess either no one wants to fly yet, or my employer doesn't want me back. My entire 4-day trip was cancelled, so I went back to work on the Kitfox!

With full credit to John Brannen (109JB) for the design (https://teamkitfox.com/Forums/threads/10554-109JB-s-Kitfox-IV-rebuild?p=90923&viewfull=1#post90923), I made a blatant copy of his tube straightening tool. It's ugly, but it works.

The wood parts are a leftover chunk of oak from some long forgotten wood butchery and the red steel part was something I found laying around (I think it's the locking bar from an old toolbox I don't have any more). Getting the steel bent required a vise, a hammer, a propane torch, and some very amateurish blacksmithing over the course of two hours, but it finally assumed the desired shape, more or less.

The bottom of the steel "U" is drilled and tapped (at a funny angle; I don't have a drill press) for the 4-inch 1/4-20 bolt. The small section of steel cut off in the second photo got a centering dimple drilled in it that keeps the tip of the bolt from wandering and protects the wood spine. I use a socket wrench to tighten the bolt.

The white guides holding the red steel "U" in the last photo were added on both sides to keep things in alignment during use. The non-perpendicularity of the bolt thread made it wander without reinforcement. The guides are short sections of steel cleat left over from hanging a closet system in my master bedroom walk-in. Never throw anything away!

I got the right side longeron about 90% straight, but the tool doesn't quite have enough travel to get the last 10%. I was tired, hot and sweaty, so I called it quits. Tomorrow I'll make a shim to go under the wood spine that will give me another 1/2" of thread on the bolt.

Oh, and I found two more lower longerons, aft of the first two, that are also bent. They're not as bad, but they're bent. I'm developing a fondness for this plane due to pity!

jrevens
08-02-2020, 09:43 AM
... I'm developing a fondness for this plane due to pity!

That made me laugh! Good report, Eric!

Eric Page
08-07-2020, 10:18 PM
I had to go to Philly on Sunday (got out Monday morning before the storm arrived), then had a couple days of computer work planning avionics and wiring, but I finally got back out to the garage today.

I put a 1/2" shim in my tubing straightener so it would pull a bit farther, then finished straightening the bent lower longerons. I had to also use a ratchet strap on the left side, as that one had a funny S-bend in it, but it all worked out fine. The other tubes that I thought were bent, aren't (well, they actually are, but it's intentional; they form the curved shape of the lower fuselage).

Next I stripped the covering off of the tail surfaces. The fabric I removed weighed in at 2 lbs 15.6 oz, and that's without paint and doesn't include the glue that's still stuck to the structure. That seems heavy to me, but the Poly-Brush had been applied with a pretty heavy hand.

The organic vapor respirator cartridges I ordered finally arrived today, so I'll be able to get started on cleaning Poly-Tack and -Brush off of everything. Might make some progress on that tomorrow. I have a truckload of nursery stock coming in the morning, so I might end up putting some of that in the ground instead.

I have some high shelves in my garage that I use to store leftover 12' trim boards from my house. By rearranging that stuff a bit I was able to make a perfect storage spot for the flaperons until I need them. They had been laying on furniture blankets on the floor. I had nearly stepped on them twice, and the neighbor's 110# golden lab walked on them once (no more damage, thankfully). I also hung up a 12' extension ladder that's been under foot for too long; that made room for the wing cradle, so I can finally get my car in the garage again.

No photos today; I couldn't be bothered to take any!

Eric Page
08-08-2020, 04:29 PM
Today I suited up in nitrile gloves and a respirator, and started cleaning the fuselage tubes. While acetone does soften -- and with sufficient rubbing, remove -- Poly-Brush and Poly-Tack, it's a LOT of work. I spent the better part of two hours to clean a few feet of tube. At that rate, the job would take a month. The real time eater is the areas where the Poly-goop is thick (which it just about everywhere); you have to hold an acetone-soaked rag on them for awhile to soften the stuff, then rub, and rub, and rub. I tried dipping a Scotch-Brite pad in acetone, and that works a bit faster, but the pad quickly becomes saturated with adhesive and difficult to use. Plus, it dulls the finish on the powder coat.

I searched my toolbox and found a small blunt scraper, which, when held at the right angle, will scrape off Poly-goop. I'll still need to go back over it to wipe away the remains with acetone, but it's a lot faster. Like the Scotch-Brite pad, it ruins the gloss finish on the powder coat, but I'm only using this technique on areas that will be covered again, so I'm not really bothered about it. The powder coat is remarkably tough, so it doesn't go through to bare metal, even with aggressive picking or scraping. The big advantage of this method is that it doesn't require the respirator!

Anyway, I got about half of one side done, so it would appear that the whole fuselage will take about a week. Then there's the tail parts to clean. Then the wings. What on earth have I gotten myself into?!?!

It's funny the things you don't notice until you're perched on a shop stool, inches from the frame. The first builder used so much adhesive to install the aluminum longeron down the side of the fuselage that there were blobs of it on the outside radius of the tube, right were the fabric was. I used a small file to remove enough of it that the new fabric will have a smooth surface to lay across. There were also two small gouges and burrs in the aluminum tube at the forward end. I cleaned those up with the file as well, and since it's not structural, I'll fill them with something and sand it smooth before covering.

Break's over. Back to work.

alexM
08-08-2020, 05:59 PM
Damn that sounds like a lot of work. Glad the scraper works. I was going to suggest the Napa gasket remover stuff I've seen suggested but I'm pretty sure it will do a number on the powder coating.
For the acetone (or MEK) I've read suggestions to wrap the soaked rag around the tube and then we plastic so it doesn't evaporate.

Eric Page
08-08-2020, 09:47 PM
For the acetone (or MEK) I've read suggestions to wrap the soaked rag around the tube and then we plastic so it doesn't evaporate.
I actually thought about that, but I lack the patience!

-=-=-=-=-=-

I'm constantly in disbelief at the way this plane was put together the first time. There were lumps under the fabric around the door frames and rear side windows, but I couldn't figure out what was causing them. Once the fabric was off it became clear: the builder hadn't bothered to clean up the glue squeeze-out from installing the aluminum door and window frames. He just left blobs of it to cure in place, then put the fabric right over it!

I've scraped it all away, and plan to do a little "body work" at the joints between aluminum pieces so the fabric lays down smoothly next time.

I made a surprising amount of progress on the frame clean-up today. The right side of the fuselage and ~2/3 of the vertical stab are done, and the remainder of the vertical and ~3/4 of the left side have been scraped. I should be able to finish the fuselage in one more solid day of work.

My plan for the next step is to use some scrap pieces of insulation foam to make crude mock-ups of the remote avionics boxes so I can plan out where I want to mount them. Since the fuselage will be going to a welder for the tail reinforcement and rudder gussets, I might as well have him add any additional mounting tabs that I'll need for avionics and antennas. Then once the fuselage is in the welder's shop, I can turn my attention to cleaning up the tail frames and stripping the wings.

alexM
08-08-2020, 10:39 PM
I forget, what are you planning for a panel?

bbs428
08-09-2020, 12:21 AM
Ugg! Unbelievable what you found under the fabric. Lol. Your plane will be lbs lighter and look sharp!

My 1st rc plane was lumpy and bumpy cause I didn't go over the structure sanding and filling. I just rushed into it, wanting it done. If you can feel it now, you'll see it later. 90% of the labor is in the prep for a sharp looking finish. Thankfully my original builder only made it to page 30 before quitting! Less work for me! :D

Keep on keeping on and when in doubt, build it light!

Eric Page
08-09-2020, 04:40 PM
I forget, what are you planning for a panel?
One 10" Dynon HDX, ADS-B in/out, Dynon com radio and a couple of AP servos, because they're relatively cheap and I dig gadgets. I'll get the USB WiFi dongle for the HDX as well, so it can talk to my iPad. I don't think I want to cut the panel for an iPad mount, but I'm sure RAM makes something that will work.


Ugg! Unbelievable what you found under the fabric. Lol. Your plane will be lbs lighter and look sharp!

My 1st rc plane was lumpy and bumpy cause I didn't go over the structure sanding and filling. I just rushed into it, wanting it done. If you can feel it now, you'll see it later. 90% of the labor is in the prep for a sharp looking finish. Thankfully my original builder only made it to page 30 before quitting! Less work for me! :D

Keep on keeping on and when in doubt, build it light!
Man, I wish my guy had only made it to page 30. I also wish he hadn't lost his build manual, and that he'd been just a tiny bit organized so I'd have some idea what I've got and what I need to order.

Agree completely on keeping it light, especially since this is an early Series 5 with 1,400# MGW. For that reason (and speed of construction) I'm leaning toward covering with Oratex. And, as much as I would love to strap a 150HP turbo conversion to the nose, for the same reasons I'll probably use a 912iS and a 2-blade carbon prop; they're known quantities with lots of support, they don't weigh a ton and they're good performers at reasonable cost.

-=-=-=-=-=-

No airplane progress to report. I got a load of nursery stock delivered yesterday, so I spent today slaving in the sun (with help from my parents and, for an hour, my neighbor) to get some of them planted. Got about thirty done, out of ~150.

To those of you in parts of the country with nice soil, that probably doesn't sound like much progress for a day's work. Here in the Pacific NW, we're cursed with glacial till (https://www.nps.gov/articles/glacialtillandglacialflour.htm) and lots of clay, which are a ***** to dig in, require sifting to remove rocks and amendment with manure to make anything grow.

I had one unfortunate interruption today. One of my neighbors bought a nice 182RG about a month ago. He was flying this morning and when he came home he put it down without benefit of landing gear. The engine was running, so the prop is destroyed (bent tips and loose in the bub) and the engine will need a tear-down. I didn't get a look at the belly, but I'm sure it's a mess too. It stayed on the pavement and upright, so no wingtip damage. He owns a forklift (because you do, right?!), so we put a strap around the nose at the firewall and picked it up far enough to get some dollies under it, then we were able to tow it back to his hangar. Much to my neighbor's chagrin, it was a nice day, so there were plenty of people at the airport to stand around and watch.

alexM
08-09-2020, 06:29 PM
See that's why I want to live next to an airfield.

I forgot to tell you, when we left your place on our visit. We checked out the twin beech there and as we walk away, off out over the tree line I see what looks like a dude with a wing suit descending rapidly.

Knowing that TDO is a sky diving place I naturally think that is what's going on.
But as I point it out to my son I see it go down behind the tree line and think "huh, pretty sure a wing suit guy has to end jump under a parachute" and this guy showed no signs of that.
Now, the noise in the background didn't make sense because it was the sound of an electric r/c plane, and I had seen an r/c field when I was on the 45.
Pretty creative r/c "aircraft".

Eric Page
08-09-2020, 10:09 PM
I forgot to tell you, when we left your place on our visit. We checked out the twin beech there and as we walk away, off out over the tree line I see what looks like a dude with a wing suit descending rapidly.
That's funny! Yeah, it's an odd place for it, but there is an RC field about a third of a mile S of the approach end of Rwy 6. They seem to be a good bunch of people; I've never heard of a problem.

Eric Page
08-16-2020, 10:55 AM
Made a little progress this week. Using Dave's advice I used compressed air to force the brake pistons out of the calipers. I started with 5 psi and worked upward from there. It got scary before they came apart. In the end I had them face down on the garage floor, on a furniture blanket, with my foot on them. It took 120 psi before they popped out! The pistons have a little discoloration from corrosion, but they should be perfectly usable. The cylinder bores (the most expensive part, naturally) are probably a write-off. I can feel significant roughness in the area where the o-ring rests, so I'll be very surprised if they don't spray brake fluid all over the rotors.

After a few days doing landscaping, I got back to scraping Poly-Tack and Poly-Brush from the fuselage. Apart from some small areas where the frame is sitting on the saw horses, the scraping is mostly done. Next step will be to wipe it all down with acetone to remove any remaining residue. Once that's done, I'll need to inspect every inch to find places where bare metal might be exposed, either from inadequate powder coating from the factory, damage during storage or transport, or my own ham-fisted scraping efforts. Those spots will need to be cleaned of any corrosion, roughed up with light sanding, then sealed with fresh epoxy paint.

Kitfox Pilot
08-16-2020, 11:20 AM
Thanks for this idea Eric. I have glue all over me by the time I get a job done. That should help. Harlan
https://teamkitfox.com/Forums/images/misc/paperclip.png Attached Imageshttps://teamkitfox.com/Forums/attachment.php?attachmentid=25381&stc=1&d=1597599475
Thanks for this idea Eric.

rv9ralph
08-16-2020, 07:05 PM
M The cylinder bores (the most expensive part, naturally) are probably a write-off. I can feel significant roughness in the area where the o-ring rests.

You may be able to hone the roughness off, it may just be residue from the decaying O rings.


Next step will be to wipe it all down with acetone to remove any remaining residue. Once that's done, I'll need to inspect every inch to find places where bare metal might be exposed, either from inadequate powder c

You might try MEK, if you can still find it. If I remember correctly, the Poly-Fiber products are thinned with MEK.

Ralph

efwd
08-17-2020, 05:43 AM
MEK also makes short work of the powder coat as well.

Eric Page
08-18-2020, 05:07 PM
You may be able to hone the roughness off, it may just be residue from the decaying O rings.
I plan to try that before I buy replacements. I hope you're right, but it sure looks like corrosion on the aluminum.


You might try MEK, if you can still find it. If I remember correctly, the Poly-Fiber products are thinned with MEK.
Indeed they are, but I can't find any locally. I exchanged a few emails with someone at Poly-Fiber and they said acetone works too. It does, but boy do you go through the paper towels. They quickly get loaded up with Poly-Tack residue, and you end up just smearing that around. It's a messy and frustrating process.


MEK also makes short work of the powder coat as well.
Good to know. That would be a blue air moment for sure.

Eric Page
08-18-2020, 05:28 PM
Re attached photo: this, boys and girls, is why we don't use Teflon tape on our fuel fittings!

I completely disassembled the header tank. Out of 13 threaded joints, six (where brass reducers were threaded into the tank) had what appeared to be dried, crumbly plumber's putty, and seven (where AN fittings there threaded into the reducers) had Teflon tape. The tank contained plastic swarf from when the bosses were tapped at the factory, and bits of dried putty. I had to chase the tank threads with a pick to clean out the remaining gunk, and clean all of the fittings with a wire brush. I don't have any of the specified Permatex thread sealant, so I bagged up all the fittings for later reassembly, and I'll need to rinse out the thank, obviously.

Speaking of header tanks, I have the polyethylene tank. I seem to recall reading something about leaks with this tank. Can anyone provide details on this issue? Do the tanks crack, or do the threads weep, or something else? I'd like to avoid spending $335 for the aluminum tank kit if I can avoid it.

I also finished scraping Ploy-goop from the fuselage structure and wiped everything with acetone to remove any remaining residue. I still need to go over it with a damp cloth to get 25 years worth of dust off of everything, but the fuselage is almost ready to go to the welder for the tail reinforcement and other mods.

Today I gave the rudder structure the same treatment: scrape off Poly-goop, then wipe with acetone. I didn't want to scrape the fiberglass leading edge, so I sanded that with 120 grit, which worked great and left a nice, smooth surface for the fabric. Once that was done, a quick blow-out with shop air and another acetone wipe cleaned it up nicely. The previous builder made one extra slot in the fiberglass within 1/4" of the correct slot, and the fiberglass between the slots has cracked through, so I'll need to bond in a reinforcement to the back side before covering. Fortunately, there's plenty of the fiberglass material left over. I'll be able to reshape the rudder horn opening at the same time, as his cut-out was a bit rough in that area.

PapuaPilot
08-18-2020, 05:56 PM
Good find on all of the fuel fittings! Use the right type sealant on them.

For the header tank just throw it away the plastic one. I haven't heard of anyone who had long term success with the poly tank. Bite the bullet and get the aluminum one. I went through the same thoughts with the poly tank that come with my 1999 kit (in 2013) and ended up buying the aluminum one. No regrets.

Keep plugging away. The best way to do things is right the first time.

Eric Page
08-18-2020, 08:54 PM
What's the issue with the poly header tanks? I'll buy the new one if I have to, but I'd like to know what problem my money is fixing.

PapuaPilot
08-18-2020, 09:21 PM
Here are some suggestions for this topic.

1. Check out this thread: Replacing original header tank with aluminum SS7 (https://teamkitfox.com/Forums/threads/8007-Replacing-original-header-tank-with-aluminum-SS7)

2. Do a search on the forum about "header tanks". You will find several about the poly header tanks.

3. Call the factory.

L (https://teamkitfox.com/Forums/threads/8007-Replacing-original-header-tank-with-aluminum-SS7)et us know what you decide after doing a little research.

alexM
08-19-2020, 05:32 PM
What's the issue with the poly header tanks? I'll buy the new one if I have to, but I'd like to know what problem my money is fixing.

I sold my NOS plastic tank to someone on this forum since my project came with an aluminum and the original plastic. I should stop selling my surplus parts until you've had a chance to pick through them.

Shortly after selling the one I had someone told me the plastic tanks all split with out much provocation. I don't think I need fuel spilling under the seats in flight.

Hoping to see pics of the welding soon. You've got some catching up to do!

Eric Page
08-19-2020, 09:14 PM
I should stop selling my surplus parts until you've had a chance to pick through them.
Yeah, there's a more than even chance that I'm missing anything you've got extra.


Hoping to see pics of the welding soon. You've got some catching up to do!
I'll definitely post pics of the process and I'll probably come knocking on your hangar door, begging to use your rudder torque tube straightening jig.

Starting Sep 1st my full time job will be Kitfox building, so enjoy your lead while it lasts!

bbs428
08-20-2020, 04:50 AM
Nice find on the fuel fittings. Keep on finding and fixing! Soon you'll be in new territory, building the way you want. ;)

Eric Page
08-20-2020, 07:29 PM
Thanks, Brett. I'm definitely looking forward to being done moving backwards.

-=-=-=-=-=-

Spent a few hours today scraping Poly-goop from the horizontal stab. It was put on really thick here for some reason, and it seems to have adhered more aggressively that it did on the fuselage. It's looking like a 2 or 3 day job, all in.

Eric Page
08-22-2020, 11:11 PM
Today I finished scraping adhesives from the horizontal stabilizer. Almost every joint where a rib meets a tube had a glob of epoxy that made a lump higher than the rib that would show through fabric covering. Many ribs also had epoxy drips on their edges, which also would have shown through. With 64 joints to scrape, plus all the tubes and rib edges, I think I've got twelve hours just in cleaning the horizontal stab. One of the photos below is a before-and-after showing one of the joints. Not all were this bad, but many were.

I also found a couple of places where the ribs have some issues that I'll correct by bonding small doublers to their sides. Another photo shows one of these places; I have no idea what happened there, but it's an unacceptable mess. I plan to cut out the errant piece of plywood and sandwich the gap between two small pieces of plywood that overlap the rib by 1/2" or so on both sides of the gap.

It still needs a good wipe-down with acetone, and there are a few of the rib-to-tube joints that would benefit from a little Superfil and sanding before re-covering.

This evening I dug out some scrap pieces of 1-1/2" rigid insulation foam and cut them up with a miter saw to make mock-ups of all the Dynon remote avionics boxes (last photo). Since I'm taking the fuselage to a welder anyway, I might as well figure out where everything is going to mount first, then I can specify locations for additional welded mounting tabs.

Eric Page
09-27-2020, 06:27 PM
You're not going to believe this, but I got sidetracked from the project for a few weeks.

I had to get ~6,500 sq ft of landscaping done before the fall rains began and turned the place into a mud hole. I put ~130 plants in the ground, spread 30 cu yds of bark mulch, laid 137 ft of edging brick, excavated a walkway, back-filled and compacted it with 3/4-minus gravel, then topped it with 30 bags of marble chips. It wore me out!

With that done, I finally got back to the Kitfox, but I did a little more shop preparation first. I cleaned out my garage and moved a bunch of auto and power equipment supplies onto some empty shelves in a spare bedroom closet. That cleared a shelving unit in the garage to get airplane parts off the floor. I also moved bulky airplane parts (tail sections, landing gear, windshield, cowling halves, etc.) into the spare bedroom for storage (being a single guy has one or two advantages...).

Next I built a workbench to hold a 6" vise and bench grinder that I got for a song at an industrial auction, as well as a new drill press and disc/belt sander (cheapie Chinese, but surprisingly well built). The bench is made from 2x4s held together with Simpson Strong-Tie brackets, which produced a remarkably solid frame. The top is a layer of 3/4" particle board and a layer of 3/4" melamine; the lower shelf is just melamine. I bolted the tools down so they don't walk around, and mounted a box with 4-way receptacle under the top to plug the tools into. An old extension cord with the female end chopped off lets me plug in the whole table. Finally, I put retractable caster wheels (from Amazon) on the legs so it can be rolled around, but sits solidly when in use.

[Note, if you're in the market for a disc/belt sander: apart from some plastic parts being orange instead of green, the WEN sander that I bought is identical to the Ryobi unit sold at Home Depot, but is ~$50 cheaper on Amazon.]

With that done, I used some rough-cut lumber that I got free from a friend in the timber business to build wing rotisseries. They're loosely based on the EAA design I posted recently, except I didn't like the widely spaced legs (they looked like a tripping hazard), so mine have a single, central leg. I also didn't see the point of using cable stays to brace the upright, so I used scrap pieces of melamine from the workbench to make gussets instead. My upright posts are 4x4s fabricated from two 2x4s and a piece of 1/2" plywood sandwiched together. I like the EAA design's pivot system, so I'll stick with that. The rotisseries aren't 100% done, as I'm not ready to mount a wing yet; I'll finish them when I do that.

Finally, some progress on airplane parts: I used the new drill press and a #30 drill to remove all of the rivets from the rudder torque tubes. Unsurprisingly, I found that two of the four plastic bushings are unusable due to the first builder ruining them. With the tubes apart, I used a wire wheel and wire cup to remove powder coat from the tube parts in preparation for welding on gussets. I still need to get the tail wheel mount down to bare metal but I'm still on the fence about how to proceed, since the bottom rear half-rib is already bonded in, as is the fiberglass rudder post fairing.

I also spent an hour or so getting one of the brake calipers cleaned up. Fortunately, it looks (and feels) like the cylinder bores cleaned up well enough to make a seal with new o-rings on the pistons. The outside of the caliper bodies are pretty badly pitted, but I think they can be rescued with some chemical cleaning, followed by body filler and silver paint. Perhaps I'll send them to be powder coated, for the sake of durability. TBD...

Today I went up to Tacoma to see Alex's "Project 5" (he's doing very nice work, and coming up with some neat ways to do things), then we both went to visit with Nate to see the AeroMomentum AM15 (117hp) installation in his SS7. I was leaning in that direction before the visit, and I was pretty impressed with what I saw. The engine looks very well put together, and Nate sounds happy with it after ~22 hours of flying.

Nate is the Kitfox beta tester for the AM15, and he's only had a couple of small problems. One was a failed radiator that was attributed to the mounting method, but AeroMomentum provided him with an aluminum cage to mount the replacement, and that feels very solid. The second failure was the loss of a tooth on the crank position sensor reluctor. AeroMomentum said they had never seen one fail before and suspected that the part may have been dropped at some point before installation in Nate's engine. They sent him a new one at no cost. Nate said he's had good support from the factory and joked that if he had called them right then (a Sunday afternoon), they would have answered. Performance-wise, Nate said he's seeing ~2,000 fpm initial climb with his 3-blade Luga pitched at 15.5°.

Alright, time for dinner then back to work!

bbs428
09-28-2020, 06:37 AM
Top notch result on the rotisserie and bench! Mine works well but falls way short in the "looks" dept. Lol. I made mine from the "possible's pile" of metal, lumber and such in back of the shop. Also known as the junk yard. :o

Nice find on the bushings and getting the brakes cleaned up!

Shadowrider
09-28-2020, 07:31 AM
Looking good! Good idea on gusseting those rudder pedals!

alexM
09-28-2020, 09:50 AM
I'm envious of that bench. If I had it in my garage I would have to push my plane outside. I have used my drill press a few times and have had a bench grinder on my list, but have used my Milwaukee 12V angle and straight grinders (several times per day actually) and find them indispensable for cutting, shaping, deburring, etc.

Kitfox Pilot
09-28-2020, 04:09 PM
Looking good Eric, looks like you have the build headed your way now.

Eric Page
09-28-2020, 08:13 PM
Top notch result on the rotisserie and bench! Mine works well but falls way short in the "looks" dept. Lol. I made mine from the "possible's pile" of metal, lumber and such in back of the shop. Also known as the junk yard. :o
Yeah, that's pretty much what mine was made from. The lumber was useless for anything else and had been cluttering up my garage since the house was finished over a year ago. I had three sticks left that I cut into pieces and gave to my next door neighbor for his fire pit!


I'm envious of that bench. If I had it in my garage I would have to push my plane outside. I have used my drill press a few times and have had a bench grinder on my list, but have used my Milwaukee 12V angle and straight grinders (several times per day actually) and find them indispensable for cutting, shaping, deburring, etc.
The drill press was really handy for removing the powder coat. I just put a small wire wheel in the chuck and that let me use both hands to control the parts; much easier than holding the part in one hand and a drill in the other. I haven't found a use for my angle grinder yet (apart from building the tube straightener), but I did buy a finger sander, which I figured would be handy for cleaning up the plates where the rudder torque tubes mount.

Eric Page
10-09-2020, 10:37 PM
With the last of this year's landscaping done, I'm finally going to be concentrating on the Kitfox. Here's the latest progress.

25743

I used an oscillating tool to slice the outer edges of the tail post fairing about 4" above the tail wheel mounting plate, then it just peeled off of the Scotch Weld with surprising ease. That gets it out of the way for the tail reinforcement, and it can even be re-used (which saved me $60+ for a new one).

25746 25744 25745

With that done, I busted up and removed the bottom rib in the tail. I really only needed to remove the rear half, but the forward half was glued in crooked, and since I have a new rib on order, I'll have material to replace it, so it might was well come out. Once the fairing and rib were out, I used a power file to remove powder coat from the area around and above the tail wheel mounting plate, so a reinforcing gusset can be welded on. If you don't own a power file, I can highly recommend it. It fits in tight spaces, it's easy to control, and it makes short work of paint and corrosion.

25749

The last sanding job on the frame was to remove powder coat from the rudder torque tube bracket mounting plates in the forward fuselage. The holes drilled by the first builder weren't quite in the right place, which may have been a contributor to the rudder pedals being very difficult to move. So, I'm going to have the holes plug welded, and I'll drill them again when I get to reassembly. You can't tell from this photo, but the powder coat is removed on the underside as well. That's where the power file was a Godsend; the tip of it fit into the U-channel with about 1/8" to spare, so each plate took about 30-40 seconds to clean up. That power file is becoming my favorite tool.

25747 25748

You may remember that my brake calipers were in quite a state. Using both the power file and my 4x36 belt sander, I was able to remove virtually all of the corrosion and pitting on the calipers, leaving a bright, shiny surface, ready for a new coating. I'll probably Alodine them to start with, and eventually paint them to match the overall color scheme.

By carefully scrubbing the calipers' cylinder bores with a maroon Scotchbrite pad, I was able to remove all of the roughness left by the old o-rings. There's still some black staining on the aluminum but the bores are nice and smooth, so I think they'll make a good seal with new o-rings on the pistons. That's a huge relief, and I'm keeping my fingers crossed, because replacements are very expensive. Plus, I've got a lot of time into them now!

Finally, I spent about an hour getting my wing rotisseries closer to finished. The first builder had fabricated some PVC tees to mount the wings, which I cut apart to scavenge several ~12" pieces of 2" Sch 40 pipe. I also cut two 36" pieces of 2x4 and bored three holes in each to receive the PVC pipes. Those will be the rotating assembly. The holes need a little sanding to fit the pipes, so I'm waiting on a kit of sanding drums from Amazon. I should be able to get the rotisseries done in another hour or so, then I'll finally be able to start stripping the wings.

It looks like my adaptation of the EAA rotisserie design that I posted a few weeks ago should work well. I'll be able to lock the wing in any position by tightening an iron pipe cap. Hard to explain, but I'll post photos when it's done.

efwd
10-10-2020, 07:06 AM
Looks like your moving right along Eric. I have an air driven sander like yours that I bought cheep at HF. It made my cowl work so much more enjoyable. Most people find the engine cowl work the most unpleasant so anything to lessen that was much appreciated.

alexM
10-10-2020, 08:35 AM
I've spent most of my career in machine shops and have never seen a power file. Looks handy, and will be even more handy cleaning up those welds from the bottom side of those channels. I'm going to have to look that tool up. On my plane the rudder pedal bracket holes in the center were correct, so I didn't need to weld those up. It made the rest of the job less vague.

Having just bonded those bottom tail ribs in the other night I can say they would be easy to get in crooked. They can ride up on the weld bead at the ends and judging what to do around that cross tube takes some time. I also found the tubing isn't perfectly square to the world down there. I tacked mine in place while laying under the tail with good light

Mostly I'm trying to figure out what the heck the covering is supposed to do down there where the steel tubes converge to a point and the bottom wood rib diverges to the fiberglass fairing. It seems to me like a place we need to do more foam/balsa and filler like the tips if the stabs, fin and elevator. But if you do that and carry it too far back you won't be able to access the hardware on that tail wheel platform you're beefing up.

Eric Page
10-10-2020, 11:53 AM
On my plane the rudder pedal bracket holes in the center were correct, so I didn't need to weld those up. It made the rest of the job less vague.
To be honest, I don't know which of the bracket holes are misplaced on mine; I just know it was tweaked enough that it didn't work right, so I'm going to weld them all and start over. I like your idea to use nut plates, so there's a little wiggle room until you torque down the screws.


Mostly I'm trying to figure out what the heck the covering is supposed to do down there where the steel tubes converge to a point and the bottom wood rib diverges to the fiberglass fairing.
I've looked at that and wondered the same thing. I'm sure someone on here will be able to post photos and suggest a procedure.

jiott
10-10-2020, 12:46 PM
Here's how I finished my fabric in the lower tail area:
25751

efwd
10-10-2020, 01:35 PM
Mine looks like Jims, only in Oratex.

Eric Page
10-10-2020, 01:36 PM
See, Alex? These guys are great!

alexM
10-10-2020, 01:44 PM
Here's how I finished my fabric in the lower tail area:
25751
That looks better than I was imagining, thanks for posting that. Next question. How do you reach the nut for the front end of the tail wheel when the plane is covered. It looks like reaching it would be nearly impossible.

Eric Page
10-10-2020, 02:39 PM
I'm going to guess there's an inspection cover on the other side. Either that, or every socket extension in the neighborhood.

efwd
10-10-2020, 06:25 PM
I did just that at 25hrs. I put a T3 on. I just used a ratchet in my hand and reached down through the horizontal passthrough and held the bolt. Of course the elevator has to be trimmed all the way up. I did consider putting an access hole in but decided it just wasn't necessary. Even as easy is that task would be with Oratex as I have, I chose to keep it clean.

jiott
10-10-2020, 07:26 PM
I do have an inspection cover on the other side, but I have never cut them out; they are for if I ever have to remove/reinstall the trim jackscrew.
I reach the front tailwheel spring nut by coming down from above and using "every socket extension". Actually it is very easy; I can even get a torque wrench on it.

Eric Page
10-15-2020, 04:49 PM
More progress today. After finishing my rotisserie (see my post here (https://teamkitfox.com/Forums/threads/11005-EAA-Wing-Rotisserie-Plans?p=94882&viewfull=1#post94882) about that), I got the right wing mounted and within an hour I had all of the fabric removed. It's a little hard on the fingers, but the Poly-Fiber makes a very satisfying sound when you rip it! If you ever have to do this, I recommend eye protection; little bits of adhesive pop off as you pull the fabric loose, and they have an uncanny ability to track direct to your eyeballs.

In the first photo the wing is mounted on the rotisserie, in the second it's partially stripped, and in the third it's a bare skeleton.

25795 25796 25794

In case anyone is interested, the weight of material removed was 4 lbs, 14.6 oz. The weight of fabric removed from the horizontal stabilizer and rudder was 2 lbs, 15.6 oz. I forgot to weigh the fabric from the fuselage, but it would probably be similar to a wing. None of the stuff I weighed had Poly-Spray on it; just a heavy brushed-on coating of Poly-Brush.

I was happy to find that the neatly made adhesive fillets and perfectly spaced and set rivets inside the wing support the first builder's claim that it was a quick-build wing. You can definitely tell where the factory work ends and the first builder's begins. There are two 3-conductor cables running from root to tip for lights. For reasons known only to him, the first builder glued the cables to the neck of the fuel quick-drain with some sort of brittle, clear, amber colored glue. He also managed to get a bunch of it on the quick-drain, so it wouldn't open all the way. I removed the drain and cleaned it up to restore proper function and to get rid of the inappropriate (and probably ineffective) gunk that he used to seal the threads. Note to self: buy new o-rings for the quick-drains.

I got a surprisingly decent photo of the inside of my fuel tank, but I'll post that elsewhere to seek opinions on whether it's already been sealed and if I can move ahead with no further action inside the tanks.

I'm finally on the welder's calendar for next Sat, 10/24, to get the tail reinforcement and rudder torque tube gussets done, along with plug welding a few holes where the rudder brackets mount to the fuselage. Then I can prime, paint and begin reassembly.

Kitfox sent me the Series 5 build manual on a USB stick, so once I get the other wing stripped, I'll sit down and go through it page-by-page to work up a hardware order. I didn't get inventory sheets when I bought the project, so I'll have to figure it out the hard way!

bbs428
10-15-2020, 05:07 PM
Not a huge shock there was no Poly-Spray but still... :eek: The weight of the covering was interesting.

Eric Page
10-15-2020, 07:28 PM
BTW, I forgot to mention that I spoke to Debra McBean about my airplane recently, and it turns out that there was not a clean break between the 1,400# airplanes and the 1,550# airplanes. There were several kits that got the heavier wing spars but lacked other upgrades that were part of the higher gross weight improvement. Sadly, mine is one of those kits; it missed the cut for 1,550# MGW by six serial numbers.

alexM
10-16-2020, 10:21 AM
Those wings actually look great! Weird on the MGTOW. 150 lbs is "real money". I don't suppose Deb gave details of the differences in the fuselage that might possibly be updated as long as you're hanging out with the welder guy?

Eric Page
10-16-2020, 05:52 PM
No, Debra didn't tell me what the other changes were, but I'm very tempted to give them a call again and see if I can find out. As you say, if it's something the welder can fix, it'd be well worth the extra expense. That said, I'll be surprised if it doesn't take new wing struts.

Yeah, I'm pretty happy about the state of the wings. They're going to take quite a bit of sanding to get the leftover adhesive knocked down to a smooth surface for re-covering, but the bones are definitely healthy. I knocked one false rib loose while removing the fabric, but I tagged it with a zip tie so I'll remember to re-glue it when I break out the Hysol.

Speaking of sanding, today I made the mistake of being cheap by buying a triangular rubber hook-and-loop sanding pad for this tool (https://www.homedepot.com/p/309250506), along with a package of six assorted pieces of sandpaper for it. It took about 60 seconds for the heat generated by the oscillations to melt the tip of the rubber pad (which I discovered when I blistered my index finger on it!), and under an hour to destroy all six pieces of sandpaper. It's a fantastic cutting tool, but not a great sander. I guess I'll have to break down and buy an R.O. sander, because I'm sure as heck not doing it all by hand and I don't think my Grandpa's old belt sander is the right tool either!

bbs428
10-16-2020, 11:14 PM
I found this tool to come in handy for the frame. Gets into some tight spots.
Buy the HD belts as they last a lot longer. For some reason they were in another
section of the Chi-Com tool store. I had to ask to find them.

DesertFox4
10-17-2020, 08:44 AM
Brett, that sander came in handy throughout my build. Made shaping my acrylic windshield a pretty simple process also.

Eric Page
10-17-2020, 10:36 AM
Yep, I've got one. Great tool, but not suitable for flat surfaces of the wing skeleton.

Eric Page
10-17-2020, 05:45 PM
Today I swapped wings in the rotisserie and stripped the fabric from the left wing (this time it weighed 4 lbs, 10.4 oz). My neighbor kindly loaned me a random orbit sander, which I used to sand the bottom of the wing smooth. There was considerable glue and Poly-Brush left on the ribs and trailing edge, so the sander took that down to a smooth surface. I'll need to re-varnish the cap strips, but it's a lot smoother now and should result in a nice finish when the plane is re-covered. The sanding took about two hours, so I think I should be able to have both wings completely cleaned up with another day's worth of work.

I need to get an order going from Aircraft Spruce, as I'm going to need the pitot tube mast, the Dynon plumbing kit, and a lot of AN hardware very soon. I also need to order the Oratex that I plan to use for covering the plane, as I'm getting pretty close to putting fabric back on some parts.

No photos today; it looks just like yesterday!

alexM
10-18-2020, 09:07 AM
No, Debra didn't tell me what the other changes were, but I'm very tempted to give them a call again and see if I can find out. As you say, if it's something the welder can fix, it'd be well worth the extra expense. That said, I'll be surprised if it doesn't take new wing struts.

Yeah, I'm pretty happy about the state of the wings. They're going to take quite a bit of sanding to get the leftover adhesive knocked down to a smooth surface for re-covering, but the bones are definitely healthy. I knocked one false rib loose while removing the fabric, but I tagged it with a zip tie so I'll remember to re-glue it when I break out the Hysol.

Speaking of sanding, today I made the mistake of being cheap by buying a triangular rubber hook-and-loop sanding pad for this tool (https://www.homedepot.com/p/309250506), along with a package of six assorted pieces of sandpaper for it. It took about 60 seconds for the heat generated by the oscillations to melt the tip of the rubber pad (which I discovered when I blistered my index finger on it!), and under an hour to destroy all six pieces of sandpaper. It's a fantastic cutting tool, but not a great sander. I guess I'll have to break down and buy an R.O. sander, because I'm sure as heck not doing it all by hand and I don't think my Grandpa's old belt sander is the right tool either!

That's strange about the sander pad getting hot. The triangle head (detail sander) for my HF unit is basically thick foam rubber and I have never experienced it getting too hot.

It's great you got that wing covering off without damaging wood.

Regarding fuselage differences between 1400 and 1550, you can always drag your fuselage up here and we can compare them side by side. I think since we met Nate we know where to look.

Eric Page
10-18-2020, 10:04 AM
That's strange about the sander pad getting hot. The triangle head (detail sander) for my HF unit is basically thick foam rubber and I have never experienced it getting too hot.
I think there must be a significant difference in the action of a tool designed to be a sander -vs- the oscillating cutter I was using. Even before the cutting tool melted the pad, it wasn't doing a very good job of sanding. The RO sander I borrowed from my neighbor did a much better job.

Eric Page
10-25-2020, 09:19 PM
A couple of days ago I finished sanding the first wing, then swapped them between the cradle and rotisserie again and got about 1/3 of one side sanded on the other wing.

Yesterday was a big day -- finally a step forward on the project! But first...

I spent all day Friday thinking it was Thursday, so I made no preparations for the events scheduled to happen on Saturday. I woke up Saturday morning, my phone reminded me that I was supposed to be taking my plane to the welder that day, then I realized that I had made no arrangements to get it there! Fortunately I have great neighbors and one of them loaned me his flatbed trailer and his pickup, for most of the day, on zero notice.

With help from another neighbor, I got the fuselage loaded up and strapped down, then I hauled it ~20 miles to Experimental Aircraft Metal Fabrication (https://super-12.com/). The owner, Steve Furjesi [fur-jessy], has a modestly sized shop that's stuffed with everything from a 1940's punch press to modern CNC machining centers. He's a salt-of-the-earth guy and judging by the work I saw, a very talented fabricator and welder. His shop produces (probably all of the) weldments for Van's Aircraft, as well as some machined parts, and he's in the middle of restoring his own Stinson 108-3.

Anyway, we got my fuselage off the trailer and into the shop, then got started on the tail post base reinforcement. I showed Steve a photo of a new Kitfox tail post, and he was off to the races. He found a perfect little hank of 4130 sheet in the scrap bin, shaped it, gave it a 90° bend, welded it on, and within 30 minutes the first job was done.

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Next up were the rudder pedal torque tube gussets. Forum member alexM generously gave me a set of gussets, but on two of the four tubes they would have interfered with existing rivet holes that I would like to re-use. I showed Steve the SkyStar service bulletin, and he came up with a way to reinforce my tubes that's very similar to the SB procedure, except welded instead of bonded and riveted.

First, he cut a strip of thin 4130 into four pieces about 1" wide by 5" long, rounded the ends, then used an absurdly oversized press to form a 1" diameter, ~120° bend in the middle of each piece. This was the result (please ignore the misaligned rivet hole -- not my work!).

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Next he centered the straps on the tubes and tacked them in place.

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Next step was to peen the edges of the straps so that they conformed to the shape of the tubes.

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And to finish them up, they were fully welded. I don't think Godzilla could break them now.

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Steve thought it likely that the parts didn't warp, since they were equally welded on all four quadrants of the upright tube. I'll find out for sure when it comes to reassembly. Fingers crossed for now.

Finally, Steve plug welded eleven holes in the forward fuselage, on the plates where the rudder torque tube brackets are mounted.

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With all of that done we put the plane back on the trailer, strapped it down again, and I headed for home.

alexM
10-26-2020, 09:39 AM
Wow that is some beautiful welding. Looking forward to doing business with him on my engine mount. His method of reinforcement on those rudder pedal torque tubes echoes what any skilled welder says about the design, so you did good.

I only "lost" two holes by going with the triangle gussets (the ones between the triangles and nearest the upright tube) and drilled new ones after.

I've been going to the annual fly in BBQ events at Curtis for the past three years (excluding 2020 of course) and one year I did a double take by his shop when I saw a Lamborghini Diablo in among the machinery and projects.

bbs428
10-27-2020, 06:49 AM
Elegant solution on the rudder pedal reinforcement. Tail wheel as well. Nice looking work.

Eric Page
10-27-2020, 09:02 AM
I did a double take by his shop when I saw a Lamborghini Diablo in among the machinery and projects.
Yikes, I didn't see anything like that!

Eric Page
10-31-2020, 07:11 PM
Had to take another couple of days off from the Kitfox to install a check valve in the footing drain pipe from my house, and install a sump pump in the crawl space. Sadly, the pump had to go at the opposite end of the house from the crawl space entrance, and the soil under my house is sticky, wet clay. Not a fun project!

Over the last couple of days, I finished sanding the adhesive and fabric coatings off of the wing skeletons. After finishing the first wing without any damage, I managed to break the tip off of one false rib (in my defense, it had already been broken and glued once before), as well as breaking loose the adhesive bond where three false ribs attach to the front spar. No pictures today; just imagine two clean, smooth wings!

Eric Page
12-03-2020, 07:53 PM
Hard to believe it's been more than a month. The delay involved a failed sump pump (during a rainstorm, of course) and badly rat-damaged HVAC ducting and insulation in my parents' home. My advice: if you have seed feeders in your yard to attract birds, get rid of them. They're rat-magnets.

Anyway, you might disagree, but I'm calling this progress:

Today I removed a false rib that was broken by the first builder, then sanded the mounting spots smooth in preparation for fitting a replacement (which I have three of thanks to forum member "Porky" -- thanks!). There will be two more to replace on the other wing, eventually.

Then I changed the oil/filter on the lawn tractor, completely rearranged the garage to make room to park it out of my way, stacked all the other yard tools in a corner, swept out the garage, and turned the shipping crate from my new S7 elevator frame into a 10 ft x 3-1/2 ft work table.

With that done, I cleaned the rudder torque tube parts with acetone in preparation for primer. That will have to wait for my next session; since I had the garage doors open, it was far too cold in there to spray primer this evening.

The last few weeks haven't been a total loss. I spent an alarming amount of money on airplane parts and hardware from Kitfox and Spruce, as well as a big, long box from Germany with my Oratex in it. Hopefully I can get at least one part covered before my glue goes bad. It didn't occur to me that I might be ordering it too soon. I'm storing it in a warm spot, shaking the bottles weekly and keeping my fingers crossed.

I also bought a bore scope camera with the intent of inspecting the inside of anything it will fit into, including the wing spars, wing struts and fuel tanks. More to come on the results of that.

Kitfox Pilot
12-03-2020, 08:23 PM
Eric, Nice to see you getting a little work done. I'm covering right now with oratex and I was surprised at the short shelf life on the glue too.

bbs428
12-04-2020, 05:44 AM
"I also bought a bore scope camera with the intent of inspecting the inside of anything it will fit into, including the wing spars, wing struts and fuel tanks. More to come on the results of that."

​Which system did you go with Eric? It might be prudent to do the same here. In my case, the lift struts. My spars cleaned up nicely with vinegar followed by the alodine treatment. It was a low weight option compared to the two part epoxy coating.

Depending on the results of your tank inspections, maybe two new resin formula tanks from Kitfox might be the way to go?

"Hard to believe it's been more than a month. The delay involved a failed sump pump (during a rainstorm, of course) and badly rat-damaged HVAC ducting and insulation in my parents' home."

Lol. I'm chuckling at what life throws at all of us on our journey. In my case a roof repair - found some rotten plywood while cleaning the gutters and a bathroom remodel - the last one thankfully! Looking forward to a day of nothing but Kitfox! ;)

alexM
12-04-2020, 09:33 AM
I'm curious about the bore scope too.

I've only attended a few of the EAA meetings in Puyallup but that chapter has a very nice unit which is pretty amazing. You can stick in through a spark plug hole and then control the camera so well you can turn it around and inspect the valves.

A few years ago I bought an eBay item referred to as an endoscope, and I'm old enough to know what that is. The camera portion was easy to set up and drive from a beater laptop but the cord is just a floppy wire like a USB cable.
I didn't intended to use it as the name implies (I was trying to get a look at some very remotely mounted turbochargers). In order to get it to look where I needed it to I had to tape it to a stiff piece of wire and it took several tries to get the view I needed. It was cheap and I still have it but man that one the Puyallup chapter has would be the shiz.

Eric Page
12-04-2020, 08:36 PM
Which system did you go with Eric?
I bought a cheap unit from AliExpress, not expecting much, but it's actually not half bad. It creates a WiFi hotspot that I connect my iPad to, then run an app to display the images, take still photos or record videos. Here's a link (https://www.aliexpress.com/item/32923426024.html) to the unit I bought. I got the 3.5-meter cable.


Depending on the results of your tank inspections, maybe two new resin formula tanks from Kitfox might be the way to go?
Perhaps, but I'd really like to avoid that if possible. Removing tanks, waiting for replacements and installing new ones would be a big delay that I don't want to endure. Fingers crossed.

Eric Page
12-04-2020, 08:40 PM
A few years ago I bought an eBay item referred to as an endoscope, and I'm old enough to know what that is. The camera portion was easy to set up and drive from a beater laptop but the cord is just a floppy wire like a USB cable.
Yeah, that's what this one was called. They come with either "soft" or "hard" cables; I got the hard one and it's plenty stiff to put it where you want it, within reason. It doesn't have any ability to steer the camera precisely, and I don't think you'd be able to use it to inspect valves unless you rigged up some kind of tiny mirror (it comes with a mirror attachment, but it only shifts the angle of view by 90 deg).

airlina
12-05-2020, 04:46 AM
After reading about it in several aviation maintenance articles authored by Mike Busch and Dave Prizio, I bought the Vividia VA-400 Ablescope (just checked on amazon , $250) . What I like about it is the articulating head that allows you to curl the head 180 degrees once it is, lets say placed in a spark plug hole that allows me to check valve condition etc. It plugs in to a cheapo tablet I have for viewing (theres an app for that) . Recently had to install a new wall mounted light in my house and was struggling with fishing the romex wire thru the wall. Out came the boroscope to show me the plumbing obstructions in the wall that allowed me to get the wire thru. So its use full for more than airplane stuff (thats how I justified buying it), heck I do colonoscopy's on the side so if any of you guys are due......... Dr. Bruce N199CL

bbs428
12-05-2020, 05:10 AM
"So its use full for more than airplane stuff (thats how I justified buying it), heck I do colonoscopy's on the side so if any of you guys are due......... Dr. Bruce N199CL"


Roflmao! :D:o:D

Kitfox Pilot
12-05-2020, 06:47 AM
[QUOTE=bbs428;95980]" heck I do colonoscopy's on the side so if any of you guys are due......... Dr. Bruce N199CL"



About spit my breakfast on the screen, LOL

Eric Page
12-05-2020, 08:02 PM
I turn 50 next year, Bruce; I'll be in touch. I just hope you're in-network... :o


I made some good progress today, and stunk up my house real good in the process. It's too cold to open the garage door while painting and the air handler is in the garage, so the result was entirely predictable!

I started by working on the rudder torque tube parts. I sanded down a couple of sharp spots on the welds, then scuffed them up with a Scotch-Brite pad and wiped them down twice with acetone. I sprayed three light coats of self-etching primer, with about ten minutes and some mild heat gun assistance between coats. While I waited for that to flash off, I moved to the fuselage.

26338

There were a number of plug welds just behind the firewall that needed to be sanded flat, top and bottom, then scuffed and cleaned the same way.

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With that done, I moved upward to the cross tubes right behind the windshield. There was a spot on both of them where something had scratched the powder coat down to steel and a little surface rust had started. I sanded that lightly with 220-grit to get shiny metal, then scuffed and cleaned. I repeated the same process of sanding, scuffing and cleaning on the top tube of the truss at the front of the seat pan, where something had made four equally spaced scratches.

With all of the forward problem spots dealt with, I moved aft, prepping the welds at the tail post reinforcement, and the tubes forward of that area (I made a big mess of the powder coat there while removing Poly-Tack), for prime and paint.

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Next I got a bucket of hot soapy water and wiped down the whole fuselage frame. It had gotten really dirty during years of storage and because of the dust from my wing sanding, so it was in need of a good cleaning. Once that was done I went over the bare metal areas again with acetone, then laid down three light primer coats just like before.

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While I waited for the primer on the fuselage to cure, I went back to the rudder torque tubes. They were completely dry, so I gave one side its first coat of gloss black enamel. I'm no pro with a rattle can (is that an oxymoron?), but I think it turned out pretty well. Resisting the urge to lay paint on thick seems to be the key to success. I've had lots of runs with spray paint cans in the past, but this time it went on very well.

26349

Back to the fuselage, the primer was dry, so I went right to paint, laying down the first coat. Again, it went on smooth and shiny, so if I can repeat that performance with the second coat, I'll be very happy.

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I'm planning to get the painting finished on the rudder torque tubes and fuselage tomorrow, and hopefully get the flight control parts cleaned up and inspected as well. I haven't looked at those parts since I removed them a couple months ago, so I'd like to determine if they need any touch-ups.

Eric Page
12-06-2020, 10:03 PM
Today I put a second coat of paint on the fuselage touch-ups and got the rudder torque tube parts to within one spray of being done.

Between those events, I cleaned up the notch in the wing where the replacement false rib will go. I started with a thin hacksaw blade to remove enough material that I could get a thin needle file into the notch, then I used the file to remove the rest of the material. It produced a loose fit on the rib, which should leave a bit of space for Hysol. Please ignore the extra, shallow notch; that's compliments of the first builder.

26370

Next I started working on the brackets that mount the rudder torque tube to the fuselage. The first builder made them from scratch, and he couldn't be bothered to deburr any of the holes, sand the marks left by the band saw blade, or deburr any of the edges. He did coat them with some kind of primer, but apparently didn't bother to clean the parts before coating them, as it was flaking off. Several weeks ago I put them in a Ziploc baggie with paint stripper overnight, which removed virtually all of the primer.

I mounted a fine sanding drum in my drill press, turned the speed up, and started smoothing the rough edges. These two photos are typical before-and-after comparisons between the parts.

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With that done I moved to the bench grinder, where I deburred all the edges and polished the surfaces I could reach using a Scotch-Brite wheel. The parts still aren't perfect, and there's an extra hole in one of them (less weight!), but they're a lot nicer than they were and they'll do their job just fine.

26373

Next I got out the Alumiprep and Alodine. I've never used these chemicals before and the Technical Process Bulletins for them are a little thin on details beyond the dilution ratios, so I just winged it, and my first try was a failure. I put the parts in the Alumiprep for about 3 minutes, rinsed them off, then put them in the Alodine. I kept sloshing them around and checking them periodically, but they weren't changing color. I finally gave up and fished them out at the 10 minute mark.

I figured that I probably didn't let them fizz long enough in the Alumiprep so I put them back in for another session, this time for about 15 minutes. When I got them out they definitely looked brighter, so I figured I was onto something. I rinsed them thoroughly, kept them underwater, then dunked them in the Alodine tub for about 5 minutes. This time they came out looking like a million bucks, with that nice, satisfying straw color.

26374

Today I made some progress, used some tools and learned a new skill. Winning!

alexM
12-07-2020, 12:26 AM
Those look like they've been transformed into airplane parts!

airlina
12-07-2020, 03:43 AM
Nice job Eric, you are turning this once forlorn build into something special by your attention to detail and craftsmanship. I suspect you will really enjoy the finished product, been flying my Series 5 Outback since 2003 , and its been a great airplane . Bruce N199CL

bbs428
12-07-2020, 07:05 AM
Had to do much the same on my build including the joystick torque tube supports and bearing. Build quality is something that cannot be ignored. Time well spent.

Eric Page
12-07-2020, 09:49 PM
Thanks, gents. I really appreciate the kind words. Being a rookie builder, it's hard to accept my work being called "craftsmanship," but I'm trying!


Today I spent an unbelievable amount of time cleaning a pile of really filthy parts. They had been laying on a furniture blanket on the garage floor collecting dust since I removed them from the fuselage several months ago.

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Another bucket of hot, soapy water and a rag made easy work of the dust and grime, but it quickly became apparent that I needed to disassemble every single item down to its constituent parts, because many assemblies weren't moving smoothly. I also found more hardware store fasteners, some mismatched hardware, and most alarming, three rod end bearings assembled without washers!

Luckily I found all of the rod end bearings in acceptable condition. A couple were a bit stiff, but some cleaning and a drop of Tri-Flow got them swiveling like new.

There are a few items that I need some advice on. The first relates to the four control stick pivot bearings that are pressed and Loctited into either end of the control column weldment.

26387

I think these four bearings in my assembly are shot. They weren't seized, but if I stick the rubber tip from an air gun into them to rotate the bearings, they feel like they have detents. I'm assuming there's corrosion inside their races. I tried to drift one out by hammering on it with a socket and nut driver, but it won't budge.

If I torque the nut on the pivot assembly just tight enough to make it turn on the bearings only, it feels pretty bad, but if I loosen it slightly so that the pivot rotates on the bolt, it's like butter. So, I could leave the crappy bearings in place and get an acceptable control feel, but I'm guessing the bearings are there for a reason, and it's not just to locate the bolt.

The other issue is that the flanges that carry the bearings at the left end are too far apart. When I torque the nut on the bearing races, it bends the flanges inward at a slight angle so that the ID of the bearings aren't in alignment. I've got the pivot out of the assembly and I don't see any way to get a washer in there to take up the space.

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So, three questions:


Is there an easy way to get the pivot bearings out without cooking the powder coat with a torch?
Does anyone know the generic part number for that size/style of bearing?
Is there a solution to the spacing issue on the bearing carrier flanges?

Anyway, here's the final beauty shot, with a table of clean parts, mostly ready to go back together. There's a Spruce box elsewhere in the garage with bags of new hardware, waiting for its place in the project.

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Finally, the aileron bellcrank and flap bellcrank assembly feels a little bit stiffer than it should be, given that the two parts are free to rotate on two greased clevis pins. I'm considering taking this apart to clean it and apply new grease. It will require drilling out four 1/8" stainless rivets that hold the pin retaining straps in place.

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This looks pretty straightforward, but if anyone has done it and has any advice to offer so I don't screw it up, I'd be grateful.

Eric Page
12-07-2020, 11:49 PM
And the hits just keep on comin'...

I realized that I hadn't removed the control column braket assembly from the fuselage frame, and it needed to come off due to flaking primer and some black overspray, so I got to work taking it out. The two nuts/bolts in the rectangular part of the bracket came out fine, but the two through the L angle on the right side were a real pain. Here's the forward nut, from underneath (I cleaned up the Poly-Brush while I was under there!).

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As you can see, the first builder made a real mess of the nut because there's no room between the nut and the fuselage tube to get a socket or a box-end wrench onto the nut. The welds holding the tabs on get in the way too. There might have been room for an open end wrench, but whatever the first builder used to tighten the nuts chewed them up so badly that my wrench wouldn't go over them.

In the end I had to roll the fuselage onto its side in order to have any leverage, then grab the nuts with a pair of duck bill pliers and turn them in multiple 10° rotations to get them off. By the time I got them free, this is what they looked like.

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Obviously I don't want a repeat of that performance when I reassemble. So, how the h*** do you get a nut onto those two bolts, and get them torqued properly, when you can't get a socket onto them because of interference from the tube and the tab weld?

alexM
12-08-2020, 12:31 AM
Those nuts on the underside of the right control column end can be a b****. Sockets need not apply because the nuts are so close to the fuselage tube there. Being AN364 nuts makes it even more challenging since there is less to grab on to. I think I can barely get a box end wrench on one of mine but on the other I'm laying under the plane very carefully using an open end and getting 10-15 degrees per cycle. I'm a german car owner so stuff like this seems normal.

Just go with new hardware and take your time, working from the bottom side so you can see the wrench on the nut.

On your other situation (Question 3.3) with the control column, you're aware of the "L" washers right? You should have AN960-10 and -10L. L is supposed to be "light" but it really means thin. There are plenty of places in the control system (especially when it comes to brake master cylinders and rudder pedal cables) where you'll be stacking different combinations of washers to make up a gap.

efwd
12-08-2020, 09:33 AM
Click Bond Nut Plates.

jrevens
12-08-2020, 11:02 AM
Hi Eric,

You’re doing good work! I have just a couple of comments that might be helpful (or not). First, yes you’ll probably have to use heat to break the Loctite bond on the bearings. Definitely don’t want to be spinning on the bolt. Just touch up with some black paint afterwards. Sorry I don’t know the numbers on the bearings, but they’re nothing very special. Kitfox can tell you. About the clearance problem with the nuts and tubes/tabs, you might consider using MS21042 all-metal locknuts. They have equivalent strength but are lighter & have a smaller hex head. You should have plenty of clearance for a socket then. Get the ones with dry lube (gray color). I think they have an “L” in the part number. Aircraft Spruce will have them.

Eric Page
12-08-2020, 11:37 AM
Just go with new hardware and take your time, working from the bottom side so you can see the wrench on the nut.
Yes, and I think I'll get that part re-installed ASAP, while the fuselage is still laying on its side. The part is sitting in a paint stripper bath at the moment, to get the failing primer off of it. I'll Alodine it once that's done cooking, then reinstall.


...you're aware of the "L" washers right?
I have a bag of them. It didn't appear to me that there would be enough room between the ends of the pivot arms and the inside face of the bearing to fit the OD of a -10 washer, but I'll definitely give it a try. If they fit, that'll solve the problem.


Click Bond Nut Plates.
That might work, but I very much doubt there's enough space on those two little tabs to center a nut plate. There's barely room for the diameter of an AN364 nut. Given that this is a part that's very unlikely to ever be removed, I'm not willing to use four $7 fasteners anyway. I'm cheap enough to endure 30 minutes of frustration to save $28!


First, yes you’ll probably have to use heat to break the Loctite bond on the bearings. Definitely don’t want to be spinning on the bolt. Just touch up with some black paint afterwards. Sorry I don’t know the numbers on the bearings, but they’re nothing very special.
That's kinda what I figured. There's a PA-12 replica builder a few minutes away who has a very well-equipped shop; I'll take my torch over there and see if he has a press I can borrow. Once I have the bearings out and can measure them, I'm sure I'll find a suitable replacement.


...you might consider using MS21042 all-metal locknuts. They have equivalent strength but are lighter & have a smaller hex head. You should have plenty of clearance for a socket then. Get the ones with dry lube (gray color). I think they have an “L” in the part number.
Now that's a good idea right there! There might not be enough depth available in that spot for a standard height nut (Kitfox specifies an AN364), or enough bolt length to get a couple threads' worth of protrusion, but I'll put a couple in my next Spruce order and give them a try. Thanks.

jrevens
12-08-2020, 11:45 AM
. ... Now that's a good idea right there! There might not be enough depth available in that spot for a standard height nut (Kitfox specifies an AN364), or enough bolt length to get a couple threads' worth of protrusion, but I'll put a couple in my next Spruce order and give them a try. Thanks.


The nuts are also shorter... you don’t have the extra height that houses the nylon locking material. They should work.

efwd
12-08-2020, 11:56 AM
I have sacrificed a 3/8" socket once by grinding the the socket to a very thin wall. The torque on those is minimal.

Eric Page
12-08-2020, 02:20 PM
The nuts are also shorter... you don’t have the extra height that houses the nylon locking material. They should work.
Excellent, thanks.


I have sacrificed a 3/8" socket once by grinding the the socket to a very thin wall. The torque on those is minimal.
Hmmm, good idea. There happens to be a new Harbor Freight store nearby. Sounds like a good use for one of their tools!

Eric Page
12-08-2020, 11:39 PM
Today I worked on getting the rudder torque tube assembly put back together properly. I didn't get a photo of them, but the inner torque tubes were in quite a state. It appeared that the first builder adjusted fitment of the outer tubes by scraping the powder coat on the inner tubes. It was anything but smooth, and before I disassembled them they were very difficult to move. The copilot side was so stiff that it could actually hold position against the return springs.

So, I had some work to do. I started by sanding the powder coat on the inner tubes axially until I achieved a smooth surface that allowed the larger outer tubes to slide on easily.

This also required smoothing the inside bore of the large outer tubes. I found a suitable length of aluminum rod in the servo mounting kit, wrapped some 220 grit around it, chucked it in the drill press and went to work removing quite a bit of powder coat overspray from inside the tube.

26397

I then started work on fitting the bearings. I ordered new bearings from Kitfox because the originals were in very poor condition. The build manual says to cut them so you can get them over the tube, but I didn't really see the point since they slid on from the end with a little bit of twisting. I fine-tuned the powder coat on the inner tubes until the bearings spun smoothly with light fingertip pressure, then tried the whole assembly to check for smooth rotation. It took several iterations of sanding, assembly, testing, disassembly, sanding, etc., but I got a nice buttery action on both sides.

One of the outer tubes had a very slight bend to it. I'm not sure if it was like this from the factory, or if it happened during welding. Fortunately the bend was so slight that I was able to get it to fit nicely by sanding powder coat on opposite sides at each end.

During all of this work I discovered that the new bearings have a thicker flange than the originals from 1995.

26395

This meant that not only did I not have the required 1/32" of play on the large outer tubes, I couldn't even get the rivet holes to line up. So, I went after the bearing flanges with some 120 grit on a piece of plywood. More sand, assemble, test, disassemble, sand...

26396

In the end I got a very nice fit-up on both sides, with no resistance to rotation with the assemblies clecoed together. I wish the parts looked better, but overall I'm very happy with the result.

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I'll be in town tomorrow, so I'll grab a tub of grease for the bearings, then I'll be able to pull my first rivet in anger!

airlina
12-09-2020, 04:16 AM
The true test at this stage comes when you mount that assembly and hope for that smooth operation that you worked so hard to achieve. can't tell you how many times I had to pull them in and out for more sanding after bolt down in the footwells. This is a common occurrence so keep your fingers crossed. Still remember this from my build 20 years ago as a frustrating part of the process. Bruce N199CL

alexM
12-09-2020, 09:55 AM
The true test at this stage comes when you mount that assembly and hope for that smooth operation that you worked so hard to achieve. can't tell you how many times I had to pull them in and out for more sanding after bolt down in the footwells. This is a common occurrence so keep your fingers crossed. Still remember this from my build 20 years ago as a frustrating part of the process. Bruce N199CL
Agreed. It ain't over until they're torqued in place in the plane.

Eric Page
12-09-2020, 11:26 AM
The true test at this stage comes when you mount that assembly and hope for that smooth operation that you worked so hard to achieve. can't tell you how many times I had to pull them in and out for more sanding after bolt down in the footwells. This is a common occurrence so keep your fingers crossed. Still remember this from my build 20 years ago as a frustrating part of the process. Bruce N199CL


Agreed. It ain't over until they're torqued in place in the plane.
Where is the additional sanding going to take place? Should I not rivet these assemblies together until I fit them in the plane, or does the additional sanding happen on the mounting channels in the fuselage?

I am planning to use the floating nut plates like you did, Alex, which I presume eases alignment to some degree.

alexM
12-09-2020, 01:50 PM
Where is the additional sanding going to take place? Should I not rivet these assemblies together until I fit them in the plane, or does the additional sanding happen on the mounting channels in the fuselage?

I am planning to use the floating nut plates like you did, Alex, which I presume eases alignment to some degree.

Well you're doing it in the right order. Obviously if they don't move freely on your bench they won't cure themselves when installed in the plane. One of the previous builders had sanded on my plastic bearings some, but there isn't much you can sand before they're paper thin.

The problem as I see it is that the two ends of each pair of rudder pedal assemblies are not co-axial (a theoretical line through one bolt should pass exactly through the middle axis of the bolt in the other bearing). In my case it was clearly because the welding of the reinforcement gussets caused the tubes to curve. You'll recall my fixture to show them some love and straighten them out.

Other aggravating conditions are the plywood floor included in the stack up and of course variations in the welded fuselage and the builder's ability to drill perfect holes. Those will become obvious when you install the assemblies in the plane. They may pivot fine but bind up as you torque the fasteners.

I'm not going to say it's a bad design because clearly every builder gets through it (even this knuckle dragger), but at one point I did some bar napkin sketches that would use a spherical bearing on one end. It would be tolerant of variation and eliminate the need for several install/check/remove/fiddle, rinse/repeat cycles.

The floating nutplates I installed don't really reduce the variation from the above conditions. They can make up for a (very) little error in drilling the holes in the fuselage, and assure that you don't cross thread a fastener when installing them. I chose them primarily eliminate the need to mess with the cowl, firewall with the flap that extends back under the rudder pedals, etc if the pedals have to come out for any reason.

EDIT: I actually need to clarify something. Those thin bearings that you noted are supposed to be split can be worked out on the bench and allow you to rivet the inner torque tubes in place. It is the ends of the entire assembly which will bind when you install in the plane. Once I sanded the powder coating from inside the ends of the tubes, the only place left to get freedom of motion is to sand the end bearings (the fat plugs with a bolt through them).

Use the trick where you chuck them up in your fancy drill press and sand the OD until they slip inside the tubes. Pro tip, those things expand like a chinese finger puzzle when torqued. So torque them to spec with the bolt going through them, and chuck that assembly up in your drill press to sand them down. Once those spin freely in the pedal assemblies, then you're ready to fit them in the plane.

Eric Page
12-09-2020, 06:23 PM
Well you're doing it in the right order. Obviously if they don't move freely on your bench they won't cure themselves when installed in the plane. One of the previous builders had sanded on my plastic bearings some, but there isn't much you can sand before they're paper thin.
Indeed. Two of the originals had been sanded to the point that they had holes in them. Meanwhile, there was still ample rough powder coat on the metal parts. I didn't actually have to remove any​ material from the OD of the new bearings.


Other aggravating conditions are the plywood floor included in the stack up and of course variations in the welded fuselage and the builder's ability to drill perfect holes. Those will become obvious when you install the assemblies in the plane. They may pivot fine but bind up as you torque the fasteners.
Got it. If the mounting tabs aren't at exactly the same height, or there's variation in the thickness of the plywood or varnish, or the holes in the mounting brackets aren't at exactly the same height, then the bolts won't be axially aligned, and hey presto: binding.


...at one point I did some bar napkin sketches that would use a spherical bearing on one end.
Hell, I'd buy one of those, and I'm a real cheapskate!


The floating nutplates I installed don't really reduce the variation from the above conditions.
Yeah, I see that now. They just reduce criticality of hole location a bit and ease maintenance in the future.


Use the trick where you chuck them up in your fancy drill press and sand the OD until they slip inside the tubes. Pro tip, those things expand like a chinese finger puzzle when torqued. So torque them to spec with the bolt going through them, and chuck that assembly up in your drill press to sand them down. Once those spin freely in the pedal assemblies, then you're ready to fit them in the plane.
Now that's a useful piece of consumer advice. It wouldn't have occurred to me to torque them to spec before sanding, but it's obvious if you think about it. I'll definitely keep that in mind. Thanks, Alex.

109JB
12-09-2020, 07:10 PM
I'll start by saying that I'm not exactly sure how it is done on newer model Kitfoxes, so what I did may be totally not applicable. That said, working on my Kitfox 4 project I too was unhappy with the freedom with which the rudder pedals moved. The method used on the K4 is like the top sketch in the attached picture. It sounds like the newer model Kifoxes are at least similar. I dorked around with the stock setup for a while and couldn't get it working to my satisfaction so I did the modification in the lower sketch. Basically I took a piece of 5/16" x 0.035 wall 4130 tube (green in sketch) and cut it to length to make an axle for the pedals. I reamed the ends slightly to 1/4" ID, and took a couple bolts and cut the heads off (blue) and rosette welded them at the white dot into the reamed 5/16" tube. I then bored out the stock plastic bearings (Orange) for a good bearing fit on the 5/16" tube and voila. Now I just bolt it in, tighten everything as tight as I want and the pedals still move very freely, falling under their own weight but with no slop to speak of.

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Eric Page
12-09-2020, 07:23 PM
Wow, that's a really clever idea, John. I'll give mine a try as-is just to see if I'm lucky that day, but if I start having problems I'll come back to your method for sure. Thank you!

Eric Page
12-10-2020, 09:58 PM
Today I started by getting the control column mounting block out of the paint stripper and cleaning it up. I soon discovered that it wasn't going to come clean without complete disassembly, so I drilled out four rivets and knocked it apart. The two smaller aluminum parts went back in the stripper bath, and I set about making the large part look presentable. I did some hand work with 220-grit sandpaper, then used the Scotch-Brite wheel to smooth it out as much as I could. It still has some scratches that I can't remove without deep sanding, so they'll just have to stay. Since it's not a structural part, I'm not going to lose any sleep over it.

The doors for my plane had already been assembled and installed by the first builder, but I wasn't happy with their appearance. A few of the rivets didn't line up with the others or weren't spaced evenly, the window plastic was scratched and yellowed, and I wasn't happy with having half the door covered in fiberglass (particularly since the knucklehead riveted Lexan over the edge of it before it was painted!).

Don't be fooled by my reflection in the Lexan; the windows don't bear close scrutiny.

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So, I ordered bubble doors from Kitfox. They arrived (along with a new windshield; that's a mess too) a couple of days ago, minus the frames. I contacted Kitfox and was somewhat disappointed to learn that the bubble doors I thought were a complete kit are in fact only the plastic bubbles.

With that knowledge in hand, and a quote of $490 delivered for two new frames, I contacted the guy who did the welding on my fuselage and rudder tubes. He said he wouldn't charge more than $100 to plug weld all the rivet holes in my door frames, so today's next project was drilling 89 rivets out of the first door. That removed the Lexan and fiberglass panels, as well as the small aluminum hinge mounting plates on the top rail.

Since the door latch bracket was also held on with Scotch-Weld, I first attacked it with a cutting disc on my angle grinder to get rid of the protruding parts, then switched to a grinding disc. My plan was to carefully grind it off the frame, but I got lucky: the heat of grinding made the powder coat under the Scotch-Weld boil, so it pulled off easily!

I was about to celebrate when I realized that I now had a door frame full of rivet stems. Fortunately, I just had to open up two rivet holes to 1/4", shake the frame vigorously for a couple of minutes, and they all fell out. This left me with a bare door frame that looks pretty second hand.

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I'll need a fine grit flap disc to clean up the remaining Scotch-Weld and remove powder coat in preparation for welding. Finally, I cleaned up the edges of the hinge mounting plates, put them and the control column block through the Alumiprep/Alodine treatment and called it a night.

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Tomorrow should see the other parts for the control column block cleaned, Alodined and reassembled, and the other door frame stripped. I forgot to buy grease yesterday, so I couldn't rivet the rudder torque tubes back together yet. I'll get that done early next week.

bbs428
12-11-2020, 05:35 AM
Some serious elbow grease being applied there Eric. :D

Those used parts are looking great!

Eric Page
12-11-2020, 11:13 PM
Thanks, Brett!


I started off today by getting the second door stripped of fiberglass, Lexan and its latch bracket. Since I learned yesterday that a #28 drill does a nice job separating the head of a 1/8" rivet, that process went a lot faster. Removing the latch bracket was quicker as well, since I didn't bother with the grinder and went straight for a propane torch. Heating the bracket for about 20 seconds boiled the powder coat under it and it knocked off easily. Another two 1/4" holes and a couple of minutes' shaking got the rivet stems out, so I just need to strip the powder coat and they'll be ready for welding.

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Next on the agenda was getting the small parts of the control column mounting block out of the paint stripper and cleaning them up. When I dry fit the parts together I discovered that the spacer and mounting flange were different shapes, which wasn't going to satisfy my pilot brain, so I took them to the belt sander and with them clecoed together, sanded them to match one another. Some surface sanding and Scotch-Brite buffing got them ready for Alumiprep and Alodine (along with the hinge plates from the second door), then I pulled my first rivets and was rewarded with a rehabilitated assembly, ready for installation!

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Next up was getting the rudder torque tube assemblies riveted together. I ducked into town for a pot of bearing grease, smeared a modest amount on the inside and outside of the four PVC bearings, slid the tubes together and riveted them in place. Having no experience with such things, I was impressed with the smoothness added by the greased bearings; it's a noticeable difference from the dry parts. I just wonder how many years the grease will last before I'm drilling out 24 rivets to reapply.

I figured I might as well finish prepping the rudder tubes for installation, so I started work on the four outer bearings. Two of the originals were ruined in disassembly, so I had two fresh ones from Kitfox and was anticipating a lot of sanding to get a good fit. They must be smaller diameter than the originals, because they were a perfect fit right out of the box. I had to run a 1/4" drill through the bore to get the AN4 bolts through, and I shortened them slightly so I'd have a couple of threads outside the nut. The two usable old bearings were still too big, so I sanded their ODs for a smooth fit as well, and ended up with the whole mess ready to go into the fuselage.

26423

The final task for today revealed a bit of a problem. I removed the pin retaining straps from the control mixer, extracted the pins and pulled the assembly apart. The reason it was so stiff became immediately obvious: the -416L washers had been embedded in powder coat and the whole thing seemed to have been assembled without lubrication.

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I used the Scotch-Brite wheel to remove powder coat from the mating surfaces and to clean the pins (I'll use new ones for final assembly), then tried a dry-fit to check for better movement. I had a very difficult time getting it back together, as even with the powder coat removed there's only room for a washer at one end. I was only able to get the second washer installed my really gritting my teeth, and once together it didn't move much easier than it had in the first place.

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As you can see from the second photo, I need about half a light washer thickness, plus a few thou for grease. Is this lack of space a common problem in the control mixer? Are builders removing a few thou of steel from each of the four mating surfaces to make room?

Finally, a couple of questions about rudder pedals:

1. The flanges on all four of mine are not bent to a 90° angle, so the bolt and nut have to pull the flanges inward when they're tightened, creating drag on the pedal's rotation. Should I compress them in a vise to achieve a full 90° bend before assembly, or is this normal and acceptable?

2. The plastic bearings that run through the "tee" at the top of the pedal tube are very tight on the long AN3 bolt. I have to apply a lot of pressure to get the bolt to go through, so it doesn't rotate after assembly; the bearing isn't functioning as a bearing. Do I need to run a #12 (0.189") drill through them to open them up a tad, then apply grease?

alexM
12-12-2020, 12:37 AM
A 3/16" reamer should be all that is needed there

Bend the pedals to 90 and mess with washers to shim as needed.

Looking great!

PapuaPilot
12-12-2020, 08:42 AM
FYI the correct size drill bit for doing 1/8" rivets is a #30. It's best to use the #30 for removal of rivet heads too. Using a #28 drill bit would make a larger hole that could lead to loose rivets if you are using the holes again. I think you said you were going to have a welder fill these hole, so this isn't a problem in this case.

Use a reamer, avoid the temptation to use a drill bit to finish any bushings.

alexM
12-12-2020, 11:14 AM
FYI the correct size drill bit for doing 1/8" rivets is a #30. It's best to use the #30 for removal of rivet heads too. Using a #28 drill bit would make a larger hole that could lead to loose rivets if you are using the holes again. I think you said you were going to have a welder fill these hole, so this isn't a problem in this case.

Use a reamer, avoid the temptation to use a drill bit to finish any bushings.

I was going to say that also. #30 is a bit you already have (a few of probably), will cut the rivet head off perfectly and have zero risk of oversizing the hole.

Eric Page
12-12-2020, 11:46 AM
FYI the correct size drill bit for doing 1/8" rivets is a #30. It's best to use the #30 for removal of rivet heads too. Using a #28 drill bit would make a larger hole that could lead to loose rivets if you are using the holes again. I think you said you were going to have a welder fill these hole, so this isn't a problem in this case.

I was going to say that also. #30 is a bit you already have (a few of probably), will cut the rivet head off perfectly and have zero risk of oversizing the hole.
Sorry guys, I should have mentioned that I know better. In this case the material immediately under the rivet heads was scrap, so I just wanted to shear the heads off as quickly as possible. In any case, I didn't push the bit all the way through the hole. I pulled off the fiberglass and Lexan, used a punch to tap the stems through the holes, then shook them out through an enlarged hole.


Use a reamer, avoid the temptation to use a drill bit to finish any bushings.
Yeah, probably a good idea. That's what I get for posting updates at 10pm after standing in a cold garage all day.

Eric Page
12-12-2020, 08:18 PM
Today didn't seem very productive. It was cold and foggy all day, and I couldn't seem to get the garage warm enough. Anyway, excuses...

I started with the control mixer. I put a fine sanding disc on the die grinder and slowly sanded the bearing surfaces I mentioned yesterday, just until I had room for the second -416L washer. Once that was done, I cleaned out the pin bores with acetone and cotton swabs, greased the new hardware and the bearing surfaces, and reassembled. It's not what I'd call floppy loose but there's not enough friction to hold up its own weight, and it's very smooth.

26431 26432

Next I made a start on removing powder coat from the door frames. My compressor can't keep up with the die grinder long enough to do that job, so I put the Scotch-Brite pad in a cordless drill instead. I burned through one slightly used battery just doing one side of the bottom rail, so it's going to be quite a project. No pictures yet.

Finally, I went over to a friend's shop and pressed the four bearings out of the control column weldment. Two felt like they had fine sand in them and the other two felt like they had stones in them. Two had obvious corrosion on the races and seals (naturally, the side facing the table in this photo; sorry!), so SkyStar clearly didn't supply stainless bearings. This would be something to check on an annual inspection if you have a plane of this vintage.

26436

For anyone who's interested, they're marked 7R4 and they measure 0.250" ID x 0.625" OD x 0.196" wide. I found double-sealed stainless steel replacements at Fastenal. Part number 4126716 (https://www.fastenal.com/products/details/4126716).

I wish the control mixer used those instead of washers and pins...

Eric Page
12-18-2020, 10:42 PM
The new bearings arrived a couple of days ago. They look great, feel smooth and (with some work on the control column) fit perfectly.

26506

The sockets they press into were a bit of a mess (sigh...). The first builder seems to have pressed the original bearings into place without removing any powder coat, which had two effects: 1. the bearings didn't seat all the way, so the control stick pivots had room to move fore and aft on the axle bolt; and, 2. the bearings raised a lip of powder coat and steel in the bottom of each socket, preventing the new bearings from seating all the way either.

I had to clean out that lip with a small burr in the Dremel tool, then I used a sanding drum to open the ID of each socket just a smidgen until the bearings had a good, snug fit. That allowed the bearing to seat fully, but there was still a little slop with the pivots installed. I found that putting a -10 washer in one side and a -10L in the other takes up the slack, giving a nice fit-up.

There was some missing powder coat in a couple of places and some rust had started in the area around the bearing sockets. I removed the rust and scuffed the surrounding areas with Scotch-Brite, then primed and painted. Here it is, with new hardware, ready to assemble tomorrow when the paint is completely dry.

26509

Over the last two days, I've spent several hours at a friend's shop, using his sandblasting pot to remove powder coat from my door frames. What a miserable job! It's been chilly and windy here lately, with on-and-off rain. Running a sandblaster in 45° weather, with a 20mph wind, is not my idea of a good time. By the time I was done I had gone through about 130# of sand, and I was freezing to death. Then I realized my car had been parked downwind the whole time, so I got to hose that off when I got home (remember the wind?). Anyway, the door frames are ready to go to the welder to have all of the rivet holes closed up.

26510

I tried to reinstall the control column mounting block in the fuselage yesterday, without success. The holes in the angle piece are too close to the bend radius to allow the bolt head to sit tight against the flat part of the "L" and the holes in the fuselage tabs are too close to the welds to allow any nut to thread on. Being as careful as possible, I still managed to butcher a nut. I also noticed that the tabs are welded to the fuselage tube too low, so there's a gap between the bottom surface of the "L" and the tabs.

I had a good think about the whole problem and decided to try something a bit different. I'm going to take up the space between the "L" and the tabs with washers, then I plan to secure the joints using 3/16" steel pop rivets instead of AN3 bolts. I can grind a little bit from one edge of each rivet head if needed to make it sit flat on the "L" and the mushroom underneath will form itself to the surface it finds, so the weld radius won't interfere.

Given that the whole assembly is very rigid already with just the two AN3 bolts through the rectangular section, I'm comfortable that the rivets will be adequate to provide whatever additional stability it requires. Can anyone think of a good reason not to do this, apart from, "the manual says to use a bolt?"

jiott
12-19-2020, 11:08 AM
Eric, I am afraid that welding up all those rivet holes on the same side will cause massive warping of the frames unless some kind of precaution is taken.

Eric Page
12-19-2020, 11:42 AM
I have that fear as well, Jim, but the guy I'm taking them to is an artist with a TIG torch, so I'm cautiously hopeful that he can overcome physics.

alexM
12-19-2020, 12:07 PM
Eric, I am afraid that welding up all those rivet holes on the same side will cause massive warping of the frames unless some kind of precaution is taken.

I tend to agree with this. I only have my own doors to compare with, and I need to revisit them because I see the lexan material sitting smooth one day and serious puckers on other days - and that's just sitting on the shelf in my hangar. My doors have what looks like black 3M VHB which would cover all those "lightening holes" you have now.

I'm real sure VHB would be the wrong material to use since it would defeat the oversize holes in the lexan to allow for expansion/contraction, but some kind of gasket material still seems in order.

Anyway as long as you don't figure 8 one of those existing holes I think they could be ignored.

As for your control column piece I know the spot you're referring to all too well. Mine is just barely doable as is and it is obvious that a hole drilled even 1/16" off could result in the condition you're experiencing.

Eric Page
12-19-2020, 09:03 PM
I tend to agree with this. I only have my own doors to compare with, and I need to revisit them because I see the lexan material sitting smooth one day and serious puckers on other days - and that's just sitting on the shelf in my hangar. My doors have what looks like black 3M VHB which would cover all those "lightening holes" you have now.

I'm real sure VHB would be the wrong material to use since it would defeat the oversize holes in the lexan to allow for expansion/contraction, but some kind of gasket material still seems in order.
I'm so glad you posted this. It made me go back and look at the bubble door installation instructions (which I had only briefly skimmed), and I found that it calls for using 3M 06382 Acrylic Plus attachment tape. That will cover virtually all of the excess holes, so I really only need to get a few on the back side and on the top and bottom of a couple tubes welded closed. Thank you!!


As for your control column piece I know the spot you're referring to all too well. Mine is just barely doable as is and it is obvious that a hole drilled even 1/16" off could result in the condition you're experiencing.
Yeah, I've wracked my brain and I can't think of another way to get a bolt and nut on there, so I'm going to try the rivets. I ordered a couple of different grip lengths, so I'll just use whatever seems to fit the best.

Eric Page
12-19-2020, 10:03 PM
I discovered today that the little red bottle I had pictured in my head, which I thought was Loctite, was actually lubricant. Probably not the best thing to secure bearings in their sockets, so I ordered a couple bottles of different formulas from Amazon. They'll be here Monday, then I can get back to the control column assembly.

With that on hold, I moved to fabricating a new elevator push-pull tube (the original was badly dented). The raw tube comes from Kitfox at 121". The manual calls for a length of 115-3/4" for a taildragger, so I set up my miter saw, made the cut, then used a file to lightly deburr the ends of the tube, inside and out.

Next I fixtured the bushing adapters with a 1/4" bolt and nut so that I could chuck them in the drill press to sand their OD to fit the ID of the tube. That went smoothly (no pun intended) and I got a nice fit at both ends, with no wiggle.

Next step is to drill the tube and adapters for rivets. It was at about this point that I realized that what I thought were male rod end bearings were actually female, and the threads are separate parts of the assembly that are also riveted to the bushing adapters. My originals are Scotch-Welded to the old adapters and I neglected to order new ones, so... Aircraft Spruce to the rescue! Those will be here Christmas Eve.

Moving on... I'm sure there are lots of ways to drill the center of a tube, but here's what I did. First I cut a small piece of wood (very dense old-growth Douglas Fir, in this case; left over from building my house) to just over 1" in width, then sanded it to exactly 1" (to match the tube's OD).

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Then I sprayed the top of it with primer (because it dries fast) and used the primer as a machinist would use layout fluid to mark the block at 3/8" from the end (the bushing adapters go 3/4" into the tubes) and at the 1/2" centerline.

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Using that crosshair target, I first punched the spot with an ice pick, then drilled it through with a #30, giving me a drill guide the same width as the tube, with a hole exactly in the center and correctly spaced from the end.

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My machine vise is only a thin hair over 1" deep, so I used two brake pads as straight edges to fixture the whole mess at the drill press (I did put the bushing adapter in the tube before drilling; thank you for asking).

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That produced a perfectly centered hole.

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With a cleco in the first hole, I could turn the tube over, putting the cleco straight down through the center hole in the drill press table, re-fixture the tube and guide block, drill the second hole and add another cleco. The third and fourth holes were made by laying the two cleco bodies on the top surface of the machine vise and otherwise proceeding as before.

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This process was repeated at the other end, then I deburred the holes, lightly sanded the whole tube with 220-grit, wiped it down twice with acetone and sprayed it with self-etching primer. Later I'll strategically remove primer and apply grease where it goes through the mid-fuselage support bushing.

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The last task today was to deburr the holes in the bushing adapters, wipe them with acetone, then run them through the Alumiprep/Alodine process. (Yes, I know... I realized as I was rinsing them that I still need to drill three holes in each for the threaded rod ends. Doh!)

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jrevens
12-19-2020, 10:15 PM
Hi Eric,

Just a quick comment... A 3/16" steel pulled ("pop") rivet doesn't have the strength, neither in shear nor tension, that an AN3 bolt and nut has. Does it have sufficient strength for what you're proposing? I'm not sure. You might consider running that one by the factory to see what they think.

Eric Page
12-20-2020, 10:42 AM
A 3/16" steel pulled ("pop") rivet doesn't have the strength, neither in shear nor tension, that an AN3 bolt and nut has. Does it have sufficient strength for what you're proposing? I'm not sure. You might consider running that one by the factory to see what they think.
Indeed, it does not, and I wouldn't dream of using one in place of a bolt in any structural application. In this case, all it's doing is adding a little lateral stability to the control column mounting block. Frankly, I'd happily fly a plane that had been built with the shim and "L" angle pieces omitted, as it's very sturdy with just the two AN3 bolts through the rectangular tube section.

All this assembly does is position and hold a bearing for the end of the control column to rotate on. There's virtually no load on it; certainly nothing that approaches the limits of two AN3 bolts, let alone four. Let's also remember that the "L" angle I'm talking about is attached to the rectangular block with...

...two 1/8" steel rivets.

Dave S
12-20-2020, 02:20 PM
Eric,

Just some engineering food for thought on the rivets vs the bolts per John's comments. Please bear with me.

The control column is held in place by two AN3 bolts on the pilot's side and 4 AN3 bolts on the copilot's side.

On the Pilot's side there there are no stops so there is no vertical push/pull on the two bolts so no stress on the two tabs the bolts are affixed through.

On the copilot's side, that is where the control column stops are and they are pinned to the bracket on that side. What this means is that during operation, the stick will come to rest on the rear stop on landing (at least it should!) which will place a rotating force on the bracket and a consequent push/pull through the bolts on the two tabs securing the rectangular part of the bracket to the fuselage as well as the second pair of bolts holding the L shaped part of the bracket.

The upshot is that the bracket not only locates the bearing for the column to rotate on but it also takes the forces of the stick contacting the stops transmitting that force through the bolts and the tabs which are securing the bracket.

Depending on how hard a person reefs on the stick after contacting the stops, the bracket end with the tabs needs to hold up against the considerable mechanical advantage the pilot has. Since the tabs are flat with the bottom of the bracket, they are somewhat susceptible to fatigue from bending and having 4 secure bolts between 4 tabs and the bracket might be a bit stronger than two rivets and two bolts.

The 4 bolts create a redundancy for the stops not necessarily called for on the pilot's side which has no stops.

Just a thought.

BTW I like your work on the new push pull tube:)

Eric Page
12-20-2020, 06:37 PM
Thanks, Dave. That's why this forum is so great; someone always thinks of something you didn't, or has another way to do something.

What you say makes sense, but there are two things that I think argue against it. First, the "L" is held to the rectangular part with two 1/8" rivets, so rivets (smaller than the ones I'm proposing) are already the weak point in the assembly. If that were a problem, wouldn't they have been assembled with two more bolts? Second, if someone is pulling on the stick hard enough to damage something, I'd bet a paycheck that the thin-wall aluminum stick would bend (probably right at the top of the steel pivot tube) long before an AN3 bolt/nut would give way, or the welds on the steel C-channel that the mounting block is attached to would fail.

jrevens
12-20-2020, 10:59 PM
Thanks, Dave. That's why this forum is so great; someone always thinks of something you didn't, or has another way to do something.

What you say makes sense, but there are two things that I think argue against it. First, the "L" is held to the rectangular part with two 1/8" rivets, so rivets (smaller than the ones I'm proposing) are already the weak point in the assembly. If that were a problem, wouldn't they have been assembled with two more bolts? Second, if someone is pulling on the stick hard enough to damage something, I'd bet a paycheck that the thin-wall aluminum stick would bend (probably right at the top of the steel pivot tube) long before an AN3 bolt/nut would give way, or the welds on the steel C-channel that the mounting block is attached to would fail.

Eric,

The 1/8" rivets carry little, if any, load. They are just there to align & locate the 3 separate aluminum components of that assembly. The principal loads are carried thru the bronze bushings and the angle carries its portion of the forces. The angle is very important, and provides needed additional stiffness to counteract, especially, left and right forces. There is nothing at the left (pilot's) end of the control "walking beam" assembly that does that.

Eric Page
12-21-2020, 06:57 PM
OK, I can see that. Given what everyone has said, the consensus seems to be that substituting rivets for bolts on the control column mounting block "L" angle creates a danger of failure in the pitch/roll control system.

If so, them I'm faced with a serious problem, as I can see no way to install bolts in my installation; there simply isn't room. I have no idea how the first builder accomplished it, but I can assure you that he made a mess of the fasteners and scored the aluminum "L" (I've smoothed that out).

How about turning the holes into short slots in order to move the bolt head and nut just far enough away from the interfering structure?

jrevens
12-21-2020, 07:34 PM
Is it possible you could use something like these, Eric?

MS16998 (NAS1351-3) & MS21042

PapuaPilot
12-21-2020, 07:38 PM
The AN525 pan-head screw is also a structural screw that could be used with the low profile nuts.

You could also use clevis pins with a washer and cotter pins.

https://cdn11.bigcommerce.com/s-scmrv6kkrz/images/stencil/500x659/products/204212/176722/no-8-32-x-3-8-cross-recessed-washer-head-structural-machine-screw-cadmium-plated-an525832r6__10642.1568390739.jpg?c=2

jrevens
12-21-2020, 07:46 PM
Good thinking Eric... Just my opinion, but I think that slotting those particular holes would be fine. It wouldn't hurt to run that by Kitfox for their opinion also. Heck, they might even say that rivets are OK, but if it was my airplane I'd want the bolts.

Eric Page
12-21-2020, 08:43 PM
Is it possible you could use something like these, Eric?

MS16998 (NAS1351-3) & MS21042
See below.


The AN525 pan-head screw is also a structural screw that could be used with the low profile nuts.

You could also use clevis pins with a washer and cotter pins.
I'm not sure that clevis and cotter pins would be any stronger than a steel rivet. Probably less...


Good thinking Eric... Just my opinion, but I think that slotting those particular holes would be fine. It wouldn't hurt to run that by Kitfox for their opinion also. Heck, they might even say that rivets are OK, but if it was my airplane I'd want the bolts.
I can certainly check with the factory. Who should I try to reach? John or Brandon?

I grabbed one of the socket head cap screws from the control column stops and put it through the "L" to show what I'm up against. That's probably the fastener with the smallest head diameter, and even it won't sit down flush.

26556

Underneath, you can see that the weld radius is right next to the bolt threads (for scale, that's a 10-32 bolt).

26557

It looks like I have enough edge margin on the fuselage tab to slot the hole a little bit. I could also grind a tiny bit of the weld away; just enough to give it a square edge that could stop a nut from rotating, then I could tighten it from above. What do you guys think?

109JB
12-21-2020, 08:45 PM
Make a radiused washer.

On the bottom a short piece of bushing stock.

Eric Page
12-21-2020, 09:36 PM
Today I started out by test fitting a bubble to a door frame, to confirm @alexM's idea that mounting tape will cover most of the holes. Indeed, the bubble contacts the door frame all the way around the perimeter, leaving only the holes in the center bar needing to be welded (plus the holes from the original latch bracket).

26558

With that knowledge in hand, I took the frames over to the welder's shop and dropped them off with marks showing which holes to weld and which to ignore. I don't have an ETA for their return, but I won't need them for quite awhile.

When I got back, I masked off the brake calipers, cleaned them with acetone and gave them a shot of primer. Later, when that was dry, I painted them to match the rest of the airframe. The only reason I did this is because I had to sand them quite aggressively to remove corrosion pitting, so they looked pretty rough, with only small areas of their original finish intact and mostly bare metal showing.

26559 26560

I put the new elevator push-pull tube next to the old one, and using the fret marks from the mid-fuselage bushing as a guide, I masked an area on the new tube about 2" longer than those marks, then used acetone to remove primer in that area.

26561


With the bearing area laid bare, I used the brush-on method to Alumiprep/Alodine that ~6" area. I didn't get any photos of that due to the need to work quickly. With that done, I reversed the masking so that the bare area was covered, sprayed primer up to the tape line (and on a few other spots that got scratched during all this futzing around), and set it aside to dry.


Having discovered that primer is pretty delicate stuff and easy to scratch, once the tube was dry I painted it gloss black like everything else. So, I'm left with a tube that matches the fuselage and other control hardware, but with a bare, Alodined section (which will be greased) where it will slide through the mid-fuselage bushing.

26562

Some reamers have arrived in the last couple of days, so I went back to the plastic "bearings" in the rudder pedal mounting tubes. I managed to get a good fit in fairly short order, except for one of them that seems to have been warped during welding. In the end the bolts all rotate easily and don't wobble.

For the life of me, I can't fathom why that assembly was designed with that ridiculous 4" plastic bearing. If the tube gets warped a bit during welding (as one of mine did), it bends the plastic bearing along its length, making it extremely difficult to ream to a straight bore. It's a silly PITA that could easily be eliminated by putting a short 3/16" ID Oilite bronze bushing at each end of the pedal mounting tube. Sand the OD of the bushing to fit the tube, assemble, done.

Anyway, the rudder pedal section is ready to reinstall, once I get the front floorboard rehabilitated (rough varnish job and some mold spots).

Eric Page
12-21-2020, 09:38 PM
Make a radiused washer.

On the bottom a short piece of bushing stock.
Yeah, that could definitely work too. I'll have a good think about it. Either way it means ordering hardware...

alexM
12-21-2020, 10:28 PM
Make a radiused washer.

On the bottom a short piece of bushing stock.
This. Eric I'm looking at your image and if you can use a socket head cap screw and grind a radius on one edge of a washer so it lays in the radius you wont be the first guy that did that. But that only solves the top side.

On the bottom side? That's a lot of damn weld bead but I cringe at the idea of grinding a weld down. I tend to agree with the slot suggestion. That way you retain the full strength of the AN3 bolts in most directions, which seems better than hollow rivets.

rv9ralph
12-22-2020, 07:15 PM
Ok, I'm going to weigh in on the suggestions to correct the issue to attach the angle support on the right end of the control mechanism.

On the bottom side where the weld makes using a nut difficult. You could make a sleve out of 4130 about a quarter inch long to slip over a longer AN3 bolt to allow enough room to fit a nut/washer.

On the top side, fabricate a new angle for the end bracket, drilling the holes further out on the flange of the angle to allow a nut and washer for the AN4 pivot bolt.

Just my $.02.

Ralph

jrevens
12-22-2020, 08:15 PM
I think the sleeve idea is a good possibility too, and it's also been suggested by 109JB. It could probably be shorter than 1/4". Relocating the holes in a new angle piece won't work unless the spacer in the middle of the assembly of 3 pieces can possibly be eliminated or a thinner one used. Spot facing those holes on the existing angle with a small counterbore would work also.

Eric Page
12-23-2020, 05:06 PM
Thanks, guys. I really appreciate all the helpful suggestions on this. Based on all the input, here's what I'm thinking:

I have a friend nearby with a shop that's well-equipped with metal working tools. How about I take the assembly over there and put it on his mill. Using an endmill a hair larger than the diameter of an AN3 bolt head, I'll create two flats on top of the "L" angle, centered on the bolt holes, so the bolts can sit flush (this should remove a very small amount of aluminum from the inside bend radius of the angle, only where the bolts are located). When that's done, I can smooth the edges of the cut with a small grinding stone in the Dremel.

On the bottom, under the welded tabs, I'll use short steel spacers made from 3/16" ID 4130 tube to gain enough clearance from the weld radii to install washers and AN364 nuts. If necessary, I can put a small chamfer on the spacers to clear the weld, leaving sufficient end surface that it will sit flat and not tend to tip under nut tension.

Kind of like this, except perhaps only 1/3 of the circumference, but probably a bit past the inside diameter. Essentially an inclined plane bisecting a "corner" of one end at a 45 deg angle.

26568

Thoughts?

Eric Page
12-25-2020, 01:02 AM
Low effort day today, but progress was made. More of fixing the first builder's messes, sadly. This time I broke out the random orbit sander again and cleaned up the floor boards in preparation for re-varnishing the wood and subsequent installation of the rudder pedal assembly. The floor boards were quite rough (not sanded before varnishing?), they had significant mold staining, the varnish had runs in it, and there were drops of Poly-Tack in many places. Typical before and after pictures follow.

2657426575

Once I have the bottom rib in the tail replaced (it was removed for welding the tail post reinforcement), the new elevator ribs installed and the pitot mount figured out, then the woodworking will be finished and I can varnish everything at once.

Merry Christmas, everyone!

alexM
12-25-2020, 11:27 AM
Looks like you're bringing those back from the dead. The instructions I'm using tells you to sand them with 150 grit between coats. Two coats for proper protection and a third coat if you want it to look beautiful. I'm doing a third coat on the very bottom rib near the tail wheel because it's the lowest point.

When I started my first batches of Hysol I was mixing up too much and wasting quite a bit. I've got that dialed perfectly now and get very close to full utilization.

But with the Epoxy varnish I'm still wasting about 50% it seems. When reduced it is very thin and a little goes a long ways. You can't really come back for a second coat with a given batch (my experience). The current layer is already curing and when you try to brush more on it gets clumpy and doesn't flow. Looks terrible.

Since my first batch where I let it cook for an hour I've dialed it back to 40-45 minutes with good results (humid and cold here currently). It still only gives me about 30 minutes before the varnish in the cup starts to gel slightly, at which point it stops flowing well and brush marks start showing up in your work. Then everything left in the cup is worthless.

Eric Page
12-25-2020, 04:17 PM
That's really good intel; thanks. At some point I scribbled out a note to myself with instructions that said to let it cook 30 min, but I'll go with 40 based on your experience.

I've got the following recipe:

Combine 2 parts EV-400 varnish + 1 part EV-410 catalyst
Rest 40 min
Filter through 60x48 fine mesh paint filter
Combine 2 parts catalyzed varnish + 1 part E-500 reducer

Does that match what you've been doing?

Eric Page
12-27-2020, 07:18 PM
Nothing to report for today, but yesterday...

I started by putting new, lightly greased o-rings onto the brake pistons and reinstalling them in the cylinder bores. They felt nice and smooth going in, so I'm optimistic about having serviceable brakes.

26600

Question: what are y'all using for sealant on the threads of brake fittings? I've got Permatex 85420 Permashield Fuel Resistant Gasket Dressing and Sealant that I bought for fuel fittings. Does that work for brakes as well?

Next I sliced the new bottom tail rib in half and fit it to the fuselage. I had to fiddle with the aft section quite a bit to get it to fit around the new reinforcement gusset, but I ended up with a good fit-up, and unlike the original, the sides line up from forward to aft sections (or at least they will if I glue them properly).

26601

I had a number of control system parts laying on the bench, ready to go, so I finally installed some parts in the airplane for the first time! I'm not going to look up the name of each of them, but I'm sure you'll recognize them. I don't trust anything done by the first builder, so as I reinstall these parts I'm winding every threaded rod end all the way in so I'm forced to set them up again from scratch.

26602 26603
26604 26605

The flap handle was a real bugger. Since the mounting tab on the right side was bent just a tiny bit, the hole in it didn't align with the short piece of 3/16" ID tube on the left. I had an awful time trying to get the bolt through until I realized what the problem was and straightened the tab, then it went right in. Go figure.

I also had some issues with the flaperon mixer, but soon realized that you-know-who didn't ream the bolt holes, so they were still full of powder coat and a little excess metal. It's amazing how much better a bolt fits when the hole is the correct diameter. I think I've reached the fourth stage of grief on this project; I just shake my head now when I find things like that.

By the way, I did wipe the careless paint overspray off of those plastic cable guides in the flap handle picture.

jrevens
12-27-2020, 09:16 PM
That's looking good, Eric! I really like the Permatex High Temp Thread Sealant. Good for up to 400 F. Parts can be repositioned up to 4 hours after application. Full cure takes about 3 days.

alexM
12-28-2020, 09:28 AM
Looks great. I went through every single fastener in my control system too. Not just for the presence of the correct hardware but for orientation and torque. I didn't find anything horrific but there were a couple of places I made corrections. The "five" manual has you set the length of the the push pull tubes and tells you to leave the jam nuts backed off so you know visually that they still need some love.

It also says to leave them until after the plane is covered and you will rig all the flight controls then. I decided early on that I would at least rig my elevator. My 7 manual has a pre-covering checklist and it instructs you to rig everything before covering, so I did. Everything except the very aft end of the elevator push-pull tube is set, jam nuts tight and decorated with torque seal. I've already had the stab/elevator on and off enough times to know there is no variation.

All of my aileron controls still have the jam nuts backed off since my wings are just fiction at this point.

Eric Page
12-28-2020, 11:00 AM
I really like the Permatex High Temp Thread Sealant. Good for up to 400 F. Parts can be repositioned up to 4 hours after application. Full cure takes about 3 days.
Great, thanks John. I just ordered a tube.

Eric Page
12-28-2020, 11:05 AM
Looks great. I went through every single fastener in my control system too. Not just for the presence of the correct hardware but for orientation and torque. I didn't find anything horrific but there were a couple of places I made corrections.
You're lucky. I've found plenty of horror in mine!


My 7 manual has a pre-covering checklist and it instructs you to rig everything before covering, so I did. Everything except the very aft end of the elevator push-pull tube is set, jam nuts tight and decorated with torque seal.
Beauty. I haven't read that far ahead in either manual yet, but I'll plan to do similar. Thanks.

PapuaPilot
12-28-2020, 12:14 PM
I completely rigged my rudder, elevator and cabin aileron/mixer before covering. There really isn't much that can change. I tightened everything I could and marked them with torque seal. If you need to make any adjustments think about the rod end that is easiest to get to and leave the jam nut loose or marked somehow.

Check and double check everything: travel direction and limits, rod end centering on both ends, proper thread engagement/witness holes, no rubbing or interference and smoothness of travel.

Eric Page
12-28-2020, 05:47 PM
Sounds like good advice, Phil. Thank you.





Today I figured I had enough stuff to glue that it was worth burning the Hysol I would lose in a discarded mixing nozzle. I started by drilling the rivet holes in the elevator push-pull bushing adapters to attach the male threaded rod ends, deburring, cleaning, applying Hysol, pulling two rivets, then panicking when I realized that the 1/8" x 1/4" rivets called out in the manual interfere with each other in the ID of the rod end. I was able to drill them out and clean up the Hysol before it set, then experiment with 1/8" x 3/16" rivets instead. Those had plenty of grip length and didn't foul on each other, so I reapplied Hysol, pulled six rivets and ended up with one of these on each end of the tube.

26617


Next up was gluing in a new false rib in one of the wings. I also re-glued four other false ribs that had been knocked loose at some point, but I only took photos of the new one.

26620 26621


While the Hysol gun was at hand, I glued down the protruding ends of the aluminum "Z" pieces around the door opening, at the aft end of each door. That required some creative clamping that taping to (hopefully) hold the ends down tight. It remains to be seen whether it'll be successful.

26612 26614

Finally, I glued the new bottom rib pieces into the base of the tail.

26615 26616

Frontier Fox
12-28-2020, 08:23 PM
Nice work. I too did all of my rigging before covering. Make sure when you set up the elevator to allow for seat upholstery (bottom cushion and stick cover) otherwise you will have to redo the rigging to get 39 +/- 1 degree on the elevator up position like I had to do.

alexM
12-29-2020, 02:28 PM
That all looks really nice. A syringe is a game changer but that mixing gun is even better. I'm probably going to break down and buy one for my wing ribs, since I'll have no difficulty using up an entire set of tubes.

Nice save on riveting that push-pull tube. I think I was in a near panic when I mixed my first few batches of Hysol. I've gotten better about making sure everything is absolutely ready before mixing, and I've also learned that I don't need to be in that big of a hurry with it.

Eric Page
12-29-2020, 03:19 PM
A syringe is a game changer but that mixing gun is even better. I'm probably going to break down and buy one for my wing ribs, since I'll have no difficulty using up an entire set of tubes.
Amazon has the best price (https://smile.amazon.com/gp/product/B000WSKPL4/) I've found for the 50g dual cartridges of Hysol (when it's in stock...), but it's still far more expensive per gram than the cans. The only reason I'm using them is that my wings are already built and I didn't expect to need very much. I bought two cartridges, and got two more with a couple of the parts kits I bought from Kitfox.

It would be an expensive proposition to build a set of wings at $15.69 per 50g cartridge; I'd be surprised if you could get more than two ribs out of each one. Discounting waste, I probably used ~1/3 of one just gluing the few parts I did yesterday.

If you do buy a mixing gun, you'll find that there are many brands, with plungers for many mixing ratios. Now that I have the gun in front of me, it doesn't appear that it would make any difference which ratio plunger you use, as long as the business end of it fits into the Hysol cartridge. Both plungers are ganged together and move forward in unison, so the followers in both tubes of the cartridge are pushed equally regardless of plunger diameter.

The gun I bought (https://smile.amazon.com/gp/product/B01D4681G6/) is listed as working for 1:1 or 2:1 ratios and it came with a 2:1 plunger. The "2" side fits the Hysol cartridge tube perfectly and the "1" side is a little more than 1/2 the tube diameter, but since both move forward at the same rate and the cartridge tubes are the same diameter, it works as a 1:1 dispenser. I suspect that 2:1 epoxies must come in cartridges with different diameter tubes. Anyway, it feels nicely made and works well.

Eric Page
12-29-2020, 10:11 PM
I started today inspecting the outcome of my gluing work yesterday. The bottom rib in the tail is solid and straight, and the false ribs are back in business. The door trim angle on the right side worked out fine...

26632

...but the left side, not so much. My clamp slipped off, so the Hysol cured with the gap open. Fortunately, I think I can get a small hacksaw blade in there to remove the Hysol for another try. Some other day...

26633

Next on the agenda was working on the rib reinforcements for the flaperon hinge brackets. I didn't want to mess with the Series 5 brackets, so I purchased the new ones from Kitfox. I started by making a drill template (https://teamkitfox.com/Forums/threads/11254-Flaperon-Hinge-Bracket-Rivets?p=96642&viewfull=1#post96642) for the brackets, so I could get them to come out more or less the same.

[Permit me a brief digression: Why in God's name does Kitfox show the hole locations in these brackets to three decimal places? Without a precision machined fixture it's impossible to locate a hole 0.438" x 1.188" from the corner of a part, and in any case, it makes ZERO difference if these holes are accurately located! Thank you; now back to our regularly scheduled programming...]

I taped the template to each part in turn, then used a punch and hammer to mark the hole locations.

26634 26635

With the locations marked, I first drilled them with a #45 (for no particular reason, other than it was the first small drill bit I grabbed), then up-drilled to #30 and deburred.

26636 26637

Next I test fit a left and right bracket to rib #9 and had my daily moment of panic. The flange of the brackets sits against an aluminum doubler under the cap strip, but that doubler isn't long enough to reach all the way to the forward end of the bracket. The first photo shows the doubler; the second shows the gap between the bracket and cap strip where the doubler ends.

26638 26639

I figured I might as well take a step ahead and see how bad the problem really is, so I grabbed a hinge bracket, clamped it to the trailing edge, and voilá! The hinge bracket isn't long enough for the gap to matter; all the rivets will go through the doubler and the reinforcing bracket.

26640

So, with disaster averted, I match-drilled the holes through to the other side, and repeated for the other four ribs, being careful to mark each pair of brackets for the wing and rib they now matched. There was one tiny problem, which you'll see in a minute...

26641

With all the holes drilled, I deburred, cleaned, and performed the usual alchemy to turn them into golden airplane parts.

26642

The sharp eyed among you will have noticed the extra holes in the "R3" brackets. There was just enough space at the trailing edge for the right side bracket to slide a bit further aft than the left side, which I didn't notice, so the forward-most hole ended up with virtually no edge margin. Since I was still feeling righteously indignant about the three-decimal-place hole locations, I just punched another one nearby. I'll rivet all four, and no one will ever see them again!

rv9ralph
12-29-2020, 10:33 PM
Permit me a brief digression: Why in God's name does Kitfox show the hole locations in these brackets to three decimal places? Without a precision machined fixture it's impossible to locate a hole 0.438" x 1.188" from the corner of a part, and in any case, it makes ZERO difference if these holes are accurately located! Thank you; now back to our regularly scheduled programming...]


I agree with your reasoning. When I was building an RV I thought a callout for 2 23/64 was odd, seeing that my ability to achieve this accuracy was challenging. I then realized why they had such detailed callouts for holes and cutting dimensions.... it was drawn with CAD and they took the dimensions called out in the drawings.

Ralph

jiott
12-29-2020, 11:22 PM
Those 3-place decimals are merely fractional conversions to decimals (7/16=0.438, 3/16=0.188); no need to get your panties in a wad Eric.:)

jrevens
12-29-2020, 11:40 PM
Yeah, what Jim said! I composed a verbose, overly complicated explanation but deleted it now. It’s kinda late and time for bed.

Eric Page
12-30-2020, 10:54 AM
Yeah, OK, that's all true, but come on... If they meant 7/16 x 1-3/16, then they should have annotated it that way. Expressing a dimension as 0.438 x 1.188 has meaning, and it doesn't mean, "punch a hole roughly as shown."

Thanks, guys. As usual around here, voices of reason prevail!

[/RANT] [/PANTYWAD]

jiott
12-30-2020, 11:46 AM
I don't mean to belabor this discussion, but feel I should point out that the tolerances for measurement in the Kitfox build manual have nothing to do with how many decimal places are shown on the drawings. The tolerances are spelled out in the first section of the manual, I believe its called Builder's Tips, where there is a section on measurement accuracy. If my memory is right I believe it says +or- 1/32" is acceptable, except of course drilled or reamed holes. This is also true in the world of engineering drawings; the general tolerances are spelled out in the title block of the drawing and specific tolerances as a +- number after the dimension. If the title block says 4 place decimals are +or- 0.001 then that is what you do. Our Kitfox project "title block" is the first section of the manual. Sorry for the blather.

You're doing a great job Eric, taking everything seriously, which is much better than the alternate.

rv9ralph
12-30-2020, 06:08 PM
Yup, measure with a micrometer, mark with a dull sharpie, cut with a chainsaw.

Ralph

alexM
12-30-2020, 07:22 PM
As a guy who has designed thousands of aircraft parts I might be guilty of some pretty screwy numbers. If I'm designing a flange on a sheet metal part I start by sketching lines that give me sufficient edge margin. That takes care of my first and last hole on the flange. If it looks like five holes will be spaced about right, then I space the rest evenly with no regard for what the dimension will be. Once I'm looking at the holes on screen I make sure the spacing is to the design specs of my employer, adjust if necessary and "send it". It's going to be a machine that punches or drills it, and that machine doesn't care.

I'm sympathetic that those numbers you reference look screwy but what jiott said is absolutely correct. I have worked in almost zero machine chops that use fractions (I'm talking with a "/" here), but all read .187 (or .188) and say 3/16" (or read .312 and say 5/16) like it was natural.

Get to where they drill a lot of holes and the phrase "a 1/4 inch hole" could mean a .246 reamer to one guy or a .257 drill to another, and they'll just nod and go do it. Depends on whether you want to press a 1/4 dowel into a hole or be able to bolt something together.

bbs428
12-31-2020, 05:53 AM
Yup, measure with a micrometer, mark with a dull sharpie, cut with a chainsaw.

Ralph

Got a chuckle out of that Ralph. So true! Lol. :D:D

Eric Page
01-01-2021, 10:22 PM
I know real men don't cry, but I was nearly reduced to tears by the task of assembling the control column. The first builder made a mess of the bearing sockets, and one of them was misshapen such that the bearing would sit crooked when the nut was torqued down causing the stick pivot to bind. I must have taken that pivot assembly apart and put it back together a dozen times before I finally removed the right molecule of steel (purely by accident, I might add) to make the bearing sit square in the socket. I may have uttered a few words that would have alarmed my mother, but I did end up with a very smooth, free-moving assembly. It still isn't pretty, but nothing short of a full strip and re-coat would fix that. It's safe, the sticks are parallel and it works well.

26659

Since I still haven't resolved the control column pivot block mounting, and I haven't re-varnished the floor boards, there wasn't much more I could do with flight controls, so I moved to fabricating a pitot tube mounting plate for the left wing. My wing has the original 90s-era plastic fitting to accept a bent aluminum pitot tube, and it's mounted on a triangular plywood gusset (right side of photo, below). Since I don't relish the idea of removing that gusset and damaging wing structure in the process, I'm planning to put my Dynon pitot tube on the outboard side of the same rib (left side of photo).

26660

I bought the pre-drilled Gretz Aero pitot mount from Spruce. It's clearly intended to be used on metal airplanes (RVs, specifically), but I see no reason it can't be mounted through a plywood panel and stick through a reinforced bit of wing fabric. I plan to put the bracket's tube through an airfoil shaped hole in the plywood, then sandwich the wood with the supplied aluminum reinforcing plate. Conveniently, Gretz also supply a "washer plate," which, once it's reduced in size somewhat, should make a perfect reinforcement when bonded to the back side of the fabric. At least that's how it works in my head...

Building all of this began with cutting a piece of 1/8" plywood into three pieces, roughly 4" x 5-1/2", and one piece of aerospace tongue depressor,
4" x 1/4".


26661

The small piece is needed to take up a bit of extra space between the rib cap strip and the lower stringer (indicated by the arrow in the first photo).

26663 26664

Next I got out most of the clamps I own and did the first two of three glue-ups, laminating two of the larger pieces together and attaching the small piece to the top edge of the third larger one. Once that cures, the pair will be laminated to the single, butted up against the 1/4" strip. It's probably hard to picture, but I'll post more photos as it comes together. If it comes together; I've never done this before...

26665 26666

Eric Page
01-02-2021, 11:21 PM
Today's efforts started with a "Doh!" moment, when I realized that my beautiful new bottom tail rib was installed before match drilling the tailwheel mounting holes through the new gusset that was welded to base of the tail post. With the rib in place, access to the gusset was blocked. To get around this, I drilled two 1/2-inch "lightening holes" in the rib, then drilled through the gusset with a #13 (0.185") bit, and followed that with a 3/16" reamer.

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Next was the third glue-up on the pitot tube mounting plate, which created a lamination three boards thick. It's very stiff, and I think it'll be plenty strong enough for the job.

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Once that cured, I trimmed it to final size on the miter saw, sanded the edges and corners smooth, and test fit it in the wing.

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I decided it would benefit from a gusset to brace the outboard front corner (lower left corner in the photo above), so I cut two identical rectangles of plywood to size and glued them together in a two-sheet lamination. This piece will be bonded to the mounting plate and span upward where it will attach to the top stringer.

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While that cured, I used one of the metal plates that came with the Gretz bracket to mark my wood mounting plate (incorrectly the first time!), then I pecked at it with a step drill until I had removed most of the material from the airfoil area. Interesting fact: you can use the side of a step drill as a make-shift nibbler (at least you can with wood). The line at the bottom will be the final cut for length.

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After about 20 minutes of filing and test fitting, I had a hole just the right size and shape for the Gretz bracket to slip through with a tight fit.

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I was having so much fun learning woodworking that I made a start on mounting my communications antenna. I decided to use the Advanced Aircraft Electronics VHF-5T (https://www.aircraftspruce.com/catalog/avpages/antennasystems.php), which Delta Whiskey used successfully (https://teamkitfox.com/Forums/threads/9648-bbs428-Build?p=96315&viewfull=1#post96315) in his build. I shamelessly ripped off his mounting location and method, with a few modifications. I started out by straightening the antenna, which comes curled up in the box. I tried curling it the other way for awhile without much success, then I found that holding it at one end and applying gentle heat from a heat gun makes it relax.

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To attach the top end of the antenna to the top rib in the vertical stab, I cut a short piece of 1x2 with one end angled to match the forward rake of the antenna, then nibbled a 1/8" wide x 1" long x 1/2" deep slot in the square end to accommodate the upper end of the antenna, where it will be glued in place (probably with silicone rather than Hysol).

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I mocked this up in the tail with painters tape, marked the ribs where the antenna would need to go, then used a Roto-Zip tool with a spiral wood cutting bit to cut a slot in each rib for the antenna to pass through. The slots were then cleaned up with flat and round files.

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I've hit the photo limit; more to follow...

Eric Page
01-02-2021, 11:35 PM
Here's what it looks like in place. A couple small dabs of silicone at each rib pass-through will hold it in place and prevent chafing. I haven't quite worked out how I'll anchor it at the bottom, but I'm thinking about two wood blocks with thin rubber bonded to them, pinching the end of the antenna between them when a couple of screws are tightened.

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It just occurred to me that I need to verify that this doesn't interfere with the trim position sensor before I finalize the bottom end...

The feed point at the center of the antenna falls conveniently between ribs, right where there's a tube to clamp the coaxial cable for strain relief.

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Finally today, for your amusement, some first-builder tricks. Here's a 5-second video showing the side-to-side play in the forward end of my horizontal stab. If you felt this during a pre-flight, would you fly the plane? Also, see if you can find any problems with the hardware used to mount the nylon blocks (hint: look at the screw heads).



https://drive.google.com/file/d/1qwUN4OE4PJdRLcEuzsaEZ3cNzSq40VdU/view?usp=drivesdk

airlina
01-03-2021, 05:01 AM
See what you mean about those messed up screw heads, but that gives you the opportunity to pull it all apart and put in new screws and sliders because no I would not fly mine with that much play. Bruce N199CL

alexM
01-03-2021, 11:51 AM
My horizontal stab doesn't have anything like that amount of play to it. Seems like you could spin one of those blocks around and might even need to file it a bit to get it to slide nicely. That guy was quite a craftsman. No doubt you saved his life.

Following your antenna install for sure. It's been on my want list for a while.

jiott
01-03-2021, 11:57 AM
Eric, something seems wrong about that bottom tail rib. Even with the access holes, how are you going to access the top side of that rib with the fabric on? The bottom rib shouldn't be that close to the tailwheel mounting bracket. There should be space between the bracket and the bottom of the rib to get the nut on.
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efwd
01-03-2021, 12:01 PM
Hi Eric. I would aim for a tighter fit. Having said that, I have play in mine right now. I would say mine is about 3/4 of that that you have. It didn't start this way and I aim to tighten it up. It is 15-20 degrees cooler now than it was only 4 weeks ago. It has seemed to make my gap bigger. Not to mention 280hrs of use in the past 20 months. Im with Jim on the bottom rib.

Eric Page
01-03-2021, 10:38 PM
My horizontal stab doesn't have anything like that amount of play to it. Seems like you could spin one of those blocks around and might even need to file it a bit to get it to slide nicely.
I thought about that, but only one of them looks wide enough to take up the slack if it's turned around, and I'm afraid that would push the stab out of square with the fuselage centerline (one side farther forward than the other). I'll have to try it and see. I'm sure eBay will have a dozen sellers offering UHMW bar...


Eric, something seems wrong about that bottom tail rib. Even with the access holes, how are you going to access the top side of that rib with the fabric on? The bottom rib shouldn't be that close to the tailwheel mounting bracket. There should be space between the bracket and the bottom of the rib to get the nut on.
I think my photos exaggerated how close the rib is to the bracket. Here's a side view; there's about 1/2" of space for the nut. Tight, certainly, but it should be enough.

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Eric Page
01-07-2021, 08:57 PM
I spent this morning reading the forum and AC43.13-1b, trying to figure out (https://teamkitfox.com/Forums/threads/4445-Repairing-flaperons?p=96863&viewfull=1#post96863) how to repair my flaperons. [If you know anything about patching airplane skins, please take a look at that link.]

I also spent some time drawing a skin patch, but that was more as a Solidworks exercise than anything productive. I've been trying to teach myself Solidworks lately, so I've been drawing anything that catches my eye.

The rivets I needed for the flaperon hinge brackets in the wing ribs arrived yesterday, so after lunch I got out to the garage and installed them in the right wing. It was pretty straightforward, apart from accidentally putting one of them into rib #4 instead of rib #5 (right after buttering it liberally with Hysol, of course!). All of the rivet holes lined up as expected, so I must not have mixed up any of the brackets.

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Hysol is pretty awful stuff, but I'm proud to say that I got through my first large-scale application of it without getting any on my clothes or beyond the first knuckles on my fingers.

Tomorrow I'm headed to a friend's shop to put the control column mounting bracket on his mill. I plan to remove a tiny bit of the inside radius on the "L" angle at both bolt locations so that the bolt heads will sit flush. He's pretty well stocked with 4130 tube, so I'll probably come away with the 1/4" spacers I need to get the nuts on, as well. If all of that works out, I'll be able to get back to installing control parts.

I also need to get one of my neighbors over here to help me swap wings between the cradle and the rotisserie so I can install the hinge brackets and pitot tube mounting plate in the left wing.

Eric Page
01-08-2021, 05:13 PM
Boy, it sure is nice to have a friend five minutes away who has a machine shop in his hangar! I went over there this morning and he modified the control column mounting block so that a washer would sit flat against the top surface at the bolt locations.

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Then we scrounged a piece of 4130 tube, drilled the ID to slightly over 3/16", and he parted off two 1/4" spacers for me.

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Back home, I found that the spacers were a tad long, so I held them with needle nose pliers and shortened them on the disc sander. I also ground a chamfer on each one so it would clear the weld bead under each of the mounting tabs on the fuselage.

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Then I was finally able to reinstall the bracket, with just enough clearance that fabric won't touch the end of the bolt.

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Now that I look at that last photo up close, it appears the spacer on the aft (left) bolt rotated under the nut; perhaps that one didn't need the chamfer after all...

I had to use longer bolts to account for the spacers, and the only ones I had are too long, so I'll need to order some. For now, it's a festival of washers!

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I figured I might as well press on, so I installed the control column also. I don't remember how it was done by the first builder, but I do remember it was quite tight, so I presume he didn't fiddle with it to get a smooth action. I found that the plastic bearing block on the left side pulled the column down too far, causing the axle bolt on the right to bind in the bronze bushings. Not wanting the washer festival to end, I put five -10 washers on each bolt between the plastic block and the mounting tabs to get the block high enough that the column rotated fore/aft with just a light touch. Before you shout at your screen, read on...

[NOTE: The plastic bearing block is installed temporarily for now.]

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Since I didn't fabricate the plastic bearing block, I don't know what the dimensions of the supplied material were. If someone has one that hasn't been touched yet, could you measure it? I'm curious to know if the first builder cut it down too far, or if it was provided this size.

It could be that the welded tabs for the aluminum bushing block on the right side cause it to angle upwards slightly. I'm considering putting a -10 washer into the stack-up under the "L" angle so that the whole block is angled downward to the left a few degrees, then I could probably remove two or three washers from under the plastic block at the other end. There's already one washer on the aft tab, as there was a gap to fill. If I move one more washer from each bolt head to the space between the "L" and the tab, I'll only have two under each bolt head. That, I can live with. Thoughts?

jrevens
01-08-2021, 05:28 PM
Boy, it sure is nice to have a friend five minutes away who has a machine shop in his hangar! I went over there this morning and he modified the control column mounting block so that a washer would sit flat against the top surface at the bolt locations.

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Glad to see that worked, Eric. That's exactly what I suggested in my reply (#138)... he spot-faced those holes with a counterbore.
You're gettin' there!

Eric Page
01-08-2021, 05:36 PM
That's exactly what I suggested in my reply (#138)... he spot-faced those holes with a counterbore. You're gettin' there!
Yep, and I meant to thank you for the idea -- cheers!

Eric Page
01-10-2021, 12:25 PM
Yesterday I started by tripping over something and hitting my head, so I spent nearly three hours completely rearranging my shop/garage, blowing off all the airplane parts, sweeping out an alarming amount of dust and swapping the wings between the cradle and rotisserie.

Feeling righteously smug about the shop, I got to work on the actual plane. Since I now had the left wing in the rotisserie, I took a look at how I was going to remove the original pitot tubing (it's being replaced with new tubing from the Dynon installation kit). The first builder routed it through a hole drilled in the aft spar, then encapsulated the pass-through in Scotch-Weld. I got extraordinarily lucky on that mark, as the Scotch-Weld didn't adhere to the plastic tubing. A gentle tug pulled it loose, and I was able to withdraw the entire length through the hole. I also removed the fitting where the pitot tube would have gone, which left me with this.

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I'm thinking that I should probably cut/grind the Scotch-Weld back a bit, then plug that hole with a good dollop of Hysol. I might as well remove that triangle mounting gusset as well; it's just dead weight.

Moving to the fuselage, I took the control column out and started over, using the idea I mentioned in my last update about moving washers around to angle the aluminum bushing block down toward the left. With one washer on each of the outer welded mounting tabs, I was able to remove six washers from under the plastic bearing block (three forward, three aft). That makes for a much neater looking installation and it resulted in even smoother movement at the sticks. Plus, I no longer have to order longer bolts for the plastic block.

As soon as that was done I started installing push rods, and ran into a problem. The ears on the control column for the forward elevator push rod were welded about 1/16" too far to the right, so the rod fouled on one of the bars in the truss structure. The only way I could see to solve this was to insert a -416 washer on the control column axle bolt, between the right end of the column and the inner bronze bushing in the aluminum block. That pushed the whole column to the left a tad, which made room for the push rod.

I also installed the aileron push rod, during which I discovered that I apparently misinterpreted a drawing in the manual and put the wrong shorty rod-end assembly on the 90° pivot arm at the left end of the truss (I confused it with the slightly longer one that goes on the mixer assembly). With that sorted out, I also installed the flap push rod. All of these are temporary for now (I didn't even install nuts on many of them) because I purposely loosened all of the rod end bearings and wound them shorter so I'd be forced to re-rig everything; I'm assuming it was done wrong, because, well, you know why by now...

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That's where my good luck for the day ran out. When I removed the dented rear elevator push pull tube from the fuselage several months ago, it came out through the mid-fuselage bearing ring without removing the rivets. I don't know how that happened, but I didn't note any difficulty that would have given me a clue about building the new one. You probably know what's coming. When I tried to install my new one, the outside diameter of the rivet heads is too large to fit through the bearing ring. AAAAARGH!!

There's zero chance that bearing is going to come out, so I see two options: 1. grind/sand the bearing back to the steel ring, install the push rod, then fit a new bearing around it; or, 2. drill out the rivets in the aft end of the push rod, install the rod, then pull new rivets. I prefer the latter option, except that it leaves four rivet stems rattling around inside the tube. I think I can solve that by drilling one additional hole just past the end of the reducer bushing, injecting some glue to capture the rivet stems, and plugging the hole with one additional rivet.

If anyone has another idea, I'd love to hear it!

alexM
01-10-2021, 01:43 PM
Drill out the rivets in the elevator push-pull tube. Install new ones after your tube is in place.

You won't be able to do anything about the little pieces rattling around inside but at least our planes will match in that regard.
I suppose you could heat up the Hysol to Tg, remove one end and do the job again if you really want to.

Eric Page
01-10-2021, 11:28 PM
Drill out the rivets in the elevator push-pull tube. Install new ones after your tube is in place.

You won't be able to do anything about the little pieces rattling around inside...
Yep, I think that's what I'm going to do. A new #40 hole should be big enough to inject some adhesive that will capture the rivet stems and keep them from rattling around. Shouldn't take much, then the hole can be plugged with a 3/32 rivet.


Today I got a couple of add-in kits installed, starting with the Trim Assist Kit.

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The instructions mention that in the case of an early Series 5, which I have, the horn on the mixer assembly for the flap push rod doesn't have lightening holes, so you have to enlarge the second hole to 3/16. I drilled it to 0.185 then followed with a 3/16 reamer.

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The other consequence of not having the lightening holes is that later kits can use a supplied nylon bearing on the eye bolt that's mounted in that hole, allowing it to rotate. To achieve more or less the same thing without the bearing, I greased the eye bolt's shaft and both fender washers, tightened the nut just until it began to bind, then backed it off a tiny smidge. The bolt rotates easily with no side-to-side play.

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Next is installing the spring anchor bracket onto the idler bell crank for the elevator push/pull tubes. The instructions show and explain that the bracket has two holes, which are used to adjust the amount of pull force exerted by the spring...

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...but the bracket that came with mine has only a narrow tab with a single hole. Anyway, installation is pretty straightforward. Rough up the powder coat, clean both surfaces, butter the bracket with Hysol, pre-position the hose clamps (they have to be completely opened to get them on the bell crank; remember to raise one clamp above the bracket before sticking it in place), hold the bracket where you want it and tighten the hose clamps.

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The last step is to install the spring, which is easier said than done. I'm not a physical specimen so I wasn't able to bare-hand the spring, but a pair of pliers helped it into place.

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I'm somewhat surprised at the amount of force that the spring exerts on the controls. I certainly hope that it balances out a lot better when the whole system is installed and rigged, and when the weight of the elevator is acting against it, because it's pretty alarming as it is now.

Next I wanted to get the Trim Position Sensor Kit brackets installed so I could be sure there wouldn't be any interference with my comm antenna installation (there isn't). That kit is pretty simple and quick as well. Just two brackets to bond in place; one on the aft elevator tube and one on the horizontal frame member that runs fore/aft just above the horizontal stab.

The first bracket is the one that pushes on the potentiometer's plunger, and it's supposed to be bonded in place so that it's parallel to the chord of the stab. Unfortunately, the half-round part of the bracket is too long on one side, so the bracket is unable to sit parallel due to interference with the welded tube that carries the bushing that mounts the stab.

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A little work on the belt sander removed enough material that it could be rotated forward into the correct orientation, so I roughed up the powder coat, cleaned everything, applied Hysol, and clamped it in place.

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The other bracket holds the potentiometer in a vertical orientation, pointing down. The instructions want the vertical tab to be 1-1/2" forward of the mounting boss for the horizontal stab. The bracket was 1-3/8" on each side of the vertical tab, and the weld bead on the boss occupied about 1/8", so it positioned itself correctly without modification.

It did require a minor clean-up on the inside of the half-round where the weld penetrated through and left two little bumps. Those came off with a burr in the Dremel.

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I just had to chip away a few Scotch-Weld drips from the fuselage tube, then roughen, clean and it was ready to Hysol in place.

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While I was looking at the back end of the plane, I recalled that I still needed to reinstall the small section of fiberglass fairing that I cut away prior to having the tail post reinforcement welded.

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I wanted a way to attach it not only to the tail post and the bottom rib, but also to the rest of the fairing above. I had a couple of small pieces of thin wood sitting on the bench that were left over from assembling the pitot mounting plate. They were the perfect size, so I lightly sanded the inside of the fairing on the plane, cleaned the surfaces, smeared the last of my batch of Hysol on them and clamped them in place. The ends sticking out will be bonded to the offcut piece when I reinstall that.

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Last for today, I cleaned up some Hysol squeeze-out under the left wing cap strips on ribs 1, 3, 5, 7 and 9, then match drilled the flaperon hinge bracket reinforcing plates. They can be Alodined and installed tomorrow.

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Eric Page
01-11-2021, 10:40 PM
I started out today doing a little bit more prep work on the pitot tube mounting plate. I made the final cuts to size, and to align the edge that will be against the rib with the fore/aft axis of the Gretz tube. This resulted in one side looking a bit crooked but it's straight when it's held in place in the wing, and crucially, the pitot tube will point straight ahead.

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I also match drilled the holes for mounting screws and added a thin strip of aluminum to the little stepped edge at the top in the second photo, as I needed to take up a bit more space between the plate and the bottom stringer; I didn't get a picture of that.

Next up was a bit of work on the bottom mount for the comm antenna, now that I know it won't interfere with the trim position sensor. I found a length of leftover maple trim from my kitchen cabinets, cut about 6" from the end of it, held it up to the fuselage and marked what I needed, then cut it to size and smoothed the corners. It's an oddly shaped piece, but it fits the spot. The black tape under my thumb in the second photo is the bottom of the antenna.

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I also cut a small block 1-1/2" long that will serve as a clamp. I intend to put two tee nuts into the outside face of the larger block and use a couple of small screws to pull the clamp piece tight against it. I'll bond a strip of rubber to the inner face of both parts so there's plenty of friction to hold the antenna in place. To remove the horizontal stab, I'll just have to back off the screws and the end of the antenna will slide out. I finished that for today by painting the parts black to match the frame.

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I put the flaperon hinge reinforcement brackets through Alodine, then bonded and riveted them in place in the left wing. My luck with Hysol ran out, and I ended up with it all over my hands and even on the garage floor.

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In between batches in the Alodine tank, I started test fitting the rudder pedal assembly. I can see now why this task is such a notorious pain. Stupidly, I put it in directly on the frame at first, then wasted half an hour fiddling with it before it occurred to me that nothing I was doing mattered one bit since the final fitment had to include the floor board.

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It's just as well I had to take it all out and start over, as the pilot's left pedal would only rotate smoothly with three washers worth of shim under the left-hand bracket.

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I started planning a wooden spacer in my head when I finally woke up and decided to test it with the floor board. Lo and behold, it works fine without any shimming at all. Unfortunately, I'm not out of the woods, as the lateral fit isn't working.

With the right bracket centered over its C-channel in the fuselage...

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...the middle bracket (its sidewall is highlighted in red) is pushed about 1/8" too far to the left...

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...and the left bracket is pushed about 3/16" too far to the left.

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I might be able to gain 1/16" by sanding a couple of the plastic bearing flanges a bit thinner, but it's not going to be enough. The only other way I can see to get the brackets lined up over the C-channels is to shorten the right side torque tube by about 1/8" and the left side torque tube by about 1/16". What have others done in this situation?

Eric Page
01-12-2021, 11:50 PM
I started today's effort by mixing up some Hysol (I'm still using the 50 ml cartridges but for larger amounts I find it easier to dispense what I need into a cup, mix it by hand and spread it with the stir stick).

First to get glued was the fiberglass fairing at the base of the tail post. It was a bear to fixture due to its odd shape and flexibility, but I think I got enough tape on it to hold it in place. It'll need a couple small beads on the inside where it meets the bottom rib, but I can do that another day, when I'm using a mixing nozzle.

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Next was the pitot tube mounting plate, which went in easily and was a cinch to clamp. I decided to leave the triangular gusset where the old pitot would have mounted. It's negligible weight and it'll strengthen the rib where my new pitot is mounted. I will clean up all the old glue and Poly-Brush.

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I had just enough Hysol left to re-glue the end of an aluminum angle behind the left door where my clamping failed last time. I drew a thin hacksaw blade through the opening to remove the last batch of Hysol, followed by the acetone-soaked edge of a rag to clean out the dust. I used the stir stick as a spatula to apply some Hysol into the void, then clamped it with a block of wood and two lengths of duct tape. Tomorrow will tell whether I've glued a 2x3 block of 3/4" maple to the side of my plane.

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Frankly I'm sick and tired of fixing problems and I wanted to do something with the flavor of a new kit, so I put some fresh Kraft paper on my table and unwrapped my new elevator (there's nothing unairworthy about the old one; I just wanted to switch to the longer Series 7 surface). First I put the 3/16" reamer to work again opening up the mounting lugs and control horn, which went surprisingly easy.

I was mildly amazed to find that the hinge lugs on my 2020-built elevator match perfectly with the bushing bosses on my 1994-built horizontal stab. I had visions of 1/16" misalignment and another trip to the welder.

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I found that the Series 5 manual and my 2006 Series 7 manual both show ten ribs in each side of the horizontal stab, but only six in each side of the elevator, while the current Series 7 manual on the Kitfox website shows ten and eight, respectively. Since I bought a new elevator, I have eight, but there's one spot on each side, at the outboard ends, where there's a rib in the stab but none behind it in the elevator (the -302 rib in this image).

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This offends my sense of order, and I imagine it will be noticeable after covering, so I elected to make two more ribs. I traced the profile of the small end onto the table, measured the required distance between tubes, traced the large end at that distance, then connected the dots. Confident that it would work, I copied the layout onto plywood and cut the blank with my miter saw (right at the limit of its reach!).

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I used the belt sander to bring the width down to the line, then a sanding drum in the drill press to shape the large end and a tiny burr in the Dremel (held in the bench vise) for the small end.

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After a little back-and-forth to dial in the fit, I had a new rib.

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Flush with the glow of success, I traced that shape onto the plywood and cut another blank, repeated the shaping process and ended up with a pair.

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I still need to adjust fit on the factory ribs, but the sanding drum makes it a pretty quick process, so it shouldn't take too long. I should also mention that my rib locations bear almost no relation to the measurements shown in the manual. I laid it out on the Kraft paper as shown in the manual, then held my horizontal stab up to the elevator and realized that none of the ribs match those locations (here we go again...). So, I'm just going to roll my eyes and match the horizontal stab locations. Thank goodness they're not structural.

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Eric Page
01-15-2021, 12:11 AM
Just a short update for today, starting with yesterday. All I managed to do on Wed was pick up my doors from the welder. I ended up having him just close the holes that would be visible after mounting the new bubble acrylic, which eliminated any concerns about warping the doors by welding many holes on one side. I didn't take any photos. The welder gave me a line on a local powder coater he uses, so that'll be their next stop.

Today I removed the clamps from all of Tuesday's glue-ups, with good results. The tail post fairing will still need a couple small beads of Hysol at the bottom inside edges, the wood reinforcements will need varnish, and some gaps need filled with Poly-whatever-it-is, but it feels good and solid even now.

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The left door trim glued down the way I wanted it to this time, so it'll just need some body work with Poly-blue-goo to make it disappear.

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My fabricated pitot mounting plate is very solidly glued in place, and I cleaned up the old gusset of glue and Poly-Brush. This still needs a stabilizing brace on the lower right corner of the first photo, which I'll install next time I'm playing with Hysol.

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Most of today's effort was directed at fitting the ribs to the new elevator. I got them all done, and I think they fit pretty well. I gone one about 1/32" too short, but it's nothing a bit of extra Hysol won't solve. Since these ribs don't match the factory-specified locations, many don't lay beside tubes, so they'll need narrow chord-wise braces glued to them for stiffness. I'll probably apply those separately, out of the structure, then install them in the elevator. For now, it looks pretty good!

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Eric Page
01-15-2021, 10:06 PM
Today I started out with more woodworking. Since my elevator ribs don't follow the factory spacing, only two on each side are adjacent to steel tubes. As a result the rest are a bit floppy, so I fabricated stiffeners for them from 1/8" plywood, which I attached to the ribs with a bead of Hysol.

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While I had some Hysol mixed, I permanently attached the top anchor block for the comm antenna. It moved a bit on me while I was taping it in place, which explains the smear of Hysol behind it in the photo. Oops.

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Next to get Hysol was a reinforcing piece for the previously unsupported corner of the pitot tube mounting plate. (Yes, there's still room for the pitot tube's base flange.)

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After lunch I re-attacked the rudder torque tube assembly mounting. Having heard no complaints about my plan to shorten the tubes slightly, that's what I did. I ended up only having to take a bit less than 1/8" from the inside end of the right-hand tube, which made each bracket line up perfectly over its respective C-channel. This photo is the left bracket.

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Some of the existing holes in the floor board don't line up with the new bracket positions, but they'll all be hidden under the brackets. I drilled new holes, but it took some considerable effort. Apparently Harbor Freight drill bits aren't the best for drilling through weld-hardened steel. I got it done, but I'll definitely be stopping in town for some good bits before I try to drill the holes for the brake master cylinder brackets.

Taking an idea from alexM, I drilled the holes oversize, and I intend to use floating nut plates to secure the brackets with screws from above. My effort to get the brackets centered will pay dividends when I mount those in the C-channels.

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With everything tightened down I had some tightness return to the torque tubes, but I used a suggestion from the forum (I'm sorry, I can't remember who suggested it) to sand the bearings in a slight barrel shape to allow some wiggle for misalignment. That worked beautifully, and I've got almost no drag on their movement at all now. It feels really good to have that bug-bear behind me and know that they're ready to be greased, installed and rigged.

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Eric Page
01-20-2021, 12:04 PM
The lack of updates is a consequence of the last few days being very frustrating. With every airplane item I picked up, I lacked either the hardware or the tool I needed to work on it. Then I'd order some stuff from Spruce, go back to the garage, and within two hours have another list of stuff to order. Three orders in three days, plus one from Yardstore (https://www.yardstore.com/) (cool place worth looking at if you haven't seen it before; great prices and very reasonable shipping), and I already have two items on the list for my next order.

Anyway, I did get a few things done over the last several days. First up was securing the comm antenna in its mounting block and tacking each rib pass-through against vibration. I used bathtub caulk so that it would be held securely but could be removed in the future if necessary.

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Sticking with the antenna, I marked and drilled #10 clearance holes in the bottom mounting block, then counterbored the back side for two #10-32 tee nuts.

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With the tee nuts pounded into place, I did a test fit-up. The green stuff sticking out of the clamp is a short length of rubber (cut from the end of a mil-spec exercise band) that provides some friction between the clamp and antenna. Seems to work well. The bolts will be replaced with drilled head versions (on the way), which I'll safety wire so they can't get into the tail controls.

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Satisfied that it would work as intended, I cleaned up the tubes, mixed some Hysol and secured it in place.

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I'm getting near to installing the center console, so I made a start on getting that assembled. The original was in an appalling state, so I ordered a new one with the notched brackets. However, I neglected to get new spacers for the brackets, so I had to disassemble the old console and clean up the spacers from that one.

I found screws that appear to be from an electrical box or light fixture, and a lot of green muck that was slathered on way too thick, apparently over dirty parts.

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After drilling out some rivets and using a punch to remove the bolts...

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...I ended up with ugly spacers.

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Wash, rinse, repeat, and add some Dremel cutting (easier than drilling out two dozen rivets)…

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...then after a night in paint stripper and a pass on the Scotch-Brite wheel, I had these.

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Next I deburred the brackets on the Scotch-Brite wheel, put them through Alodine treatment, then discovered that I'm two short on AN3-11A bolts (they're on the way too).

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If Amazon delivers on time, I should have some thick CA glue today and can get back to fitting elevator ribs.

Eric Page
01-21-2021, 11:19 PM
Since the flap handle is already installed, I decided to press on with the center console. I found that the trim assist spring made it almost impossible to fixture the notched bracket for the flap handle, so the spring had to come off. I'll reconnect it just before covering. With that removed, I clamped the center console in place, determined where the bracket needed to be, marked its position, then removed everything and clamped the bracket in place.

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Actually, it wasn't quite that easy. I had to remove the flap handle from the fuselage and swap a thin washer from its right side to its left in order for the handle to be centered properly in the console slot. That meant removing a cotter pin in a spot that wasn't easily accessible with the control column in the way. One step forward...

I started match drilling the bracket holes to 3/32, but ran into a problem with the holes next to the taller part of the bracket. My drill bit isn't long enough, and even a 1" diameter chuck wouldn't fit with the drill standing upright. The only thing I had that would center properly in the holes was the drill bit itself, so I gave it a gentle tap in each location, then removed the bracket and made a usable mark with a proper punch.

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With that done all the holes could be drilled to 3/32, then the bracket clecoed back on and everything up-drilled to #30. I deburred all the holes and cleaned up a few scratches that the bracket had made on the console while I was fitting it in the fuselage.

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I don't think I'm going to try to Alodine the console, but I will spray the underside with etching primer just before I rivet the brackets in place.

Returning to the brackets, I realized that I had assembled them with the spacers in bare steel, so I took them apart, masked the ends of the spacers and shot them with primer. Once that was dry I reassembled. I'm still one bolt short, but it'll be here soon.

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My thick CA glue came yesterday, so I got to work tacking the elevator ribs in place. My plan was to use the ribs in the stab as sort of a template, with a yardstick against their sides as a location guide in the elevator. I laid out both surfaces on my table, carefully measuring to be sure they were square to one another and equidistant from a reference at one end. It all looked great until I realized that half the ribs in the stab aren't straight (admit it, you knew that going in, right?).

In the end I just measured the distance between the trailing edges of the ribs in the stab and matched those measurements in the elevator so the ribs would line up from one surface to the other, except this time the ribs are square to the spar tube. I had to refine the length of a few ribs for proper fit, and one was a bit looser than I would have liked, but the thick CA glue (and a spritz of accelerator) made positioning it pretty easy and the Hysol will do the rest. After a couple of hours, they were all in!

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I followed up with an acetone wipe-down, then put a mixing nozzle on a Hysol cartridge and got busy bonding the ribs in for good. I can't say enough about how easy those fine-tip mixing nozzles make it to achieve nice results. I went along with the Hysol gun, applying adhesive to each location, then came back with the side of my pinkie finger to make a nice fillet. I just wiped my finger off on a paper towel between each one. This process went surprisingly smooth and after about 45 minutes, voilá!

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While I had the mixing nozzle in action, I applied the missing Hysol to the inside of the lower section of fiberglass tail post fairing.

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With the elevator ribs done I think I'm finished with woodworking, so I guess a major task in the near future will be applying varnish to the sanded cap strips in the wings, the new bottom rib in the tail, the comm antenna mounting block, the floor boards and the elevator ribs. Then I'll need to shape the tips on the stab and elevator and they'll be ready to cover.

jiott
01-22-2021, 11:12 AM
Forgive me if I keep harping on this, but I believe you will be very happy later on if you put a set of notches at the 3/4 flap position. It is much, much easier to do it now before the flap bracket is permanently installed. Half flaps are used regularly but full flaps are not nearly as useable; a 3/4 flap setting would be perfect. FWIW, the factory built SLSA has the full flap position about where I am suggesting a 3/4 flap position on the W/AB kit. Don't ask me why the SLSA and the E/AB kit flap brackets are different, but call John McB if you don't believe me.

Eric Page
01-22-2021, 02:09 PM
Forgive me if I keep harping on this, but I believe you will be very happy later on if you put a set of notches at the 3/4 flap position.
No forgiveness necessary, Jim. I'm happy to have all the advice and reminders I can get. I'm new to this airplane building lark, and I have a limited ability to organize and recall all of the good info I get from this forum.

I do remember seeing this advice previously, now that you mention it. I have a friend nearby with machine tools in his hangar, so I should be able to get this done.

While I'm at it, is there any benefit to adding a 1/4 position along with 3/4? After all, every extra notch makes the plane lighter!

DesertFox4
01-22-2021, 06:15 PM
Myself and several local builders added a 1/4 notch. Nice when flying with slower aircraft. Didn’t add the 3/4 notch. Rarely use over half flaps.

jiott
01-22-2021, 08:50 PM
Sure, a 1/4 flaps notch might be useful to some folks; however, I personally would have no use for one, nor do I know any of my Kitfox friends who have wished for one. It can't hurt anything and you wouldn't need to use it. My only thought as a reason NOT to put it in is this: The 1/2 flaps is used most of the time and I would not want to confuse the 1/2 or 1/4 notch and have to look down or feel for it when setting up for landing. Just my 2 cents.

Eric Page
01-23-2021, 12:25 AM
I wish I knew more about flying the Kitfox, then I'd have a better idea how my skills and preferences translate to the machine. Sadly, I've only ever sat in one for a few minutes and never even had a flight!

Anyway, thanks for the input, guys. Much appreciated, and I'm glad this is one of those "no wrong answer" items.

Eric Page
01-25-2021, 08:01 PM
Well, I ended up adding both the 1/4 and 3/4 notches to my flap handle detent brackets. We first found the arc of the circle that describes the outside edge of the existing notches, then scribed marks 1/8" inside that line (the notches are 1/4"). Next we drilled 1/4" holes on those marks, centered between the existing 0, 1/2 and full notches. Then it was just a matter of using a hacksaw to remove the remaining web of material and a couple of files to clean up the edges. The second photo shows the bracket installed with clecoes, with the handle in the new 1/4 position.

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With all of that done, I re-Alodined the parts and reassembled for good.

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USPS brought me some presents on Saturday, so I set up my new countersink cage and prepared the holes in the center console for flush rivets.

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The feed point in the middle of the comm antenna seemed like it might wobble around and vibrate a bit more than I'd like, so I glued in a stick of plywood between ribs. Like the other spots on the antenna, the feed point is "glued" to the plywood with a dab of bathtub caulk.

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When I removed the rod end bearings that mount the rudder, they were hard to get out, so I feared that the first builder had cross-threaded them. My gift from USPS also contained a 1/4-28 tap, so I chased the threads in the tail post and got out a bunch of powder coat that you-know-who didn't bother to remove.

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One of the old rudder bearings wouldn't loosen up no matter what I did, and the threads on all of them were a little buggered, so I ordered new ones. They'll go in later, with new jam nuts.

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I finally decided to bite the bullet and drill out the rivets that were preventing me from installing my beautiful new elevator push-pull tube. This obviously left four rivet bodies inside the tube, so I shook them down to the forward end and drilled a #40 hole a little past the end of the reducer bushing.

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I stood the tube up on end, and using a Luer lock syringe with a blunt needle, injected about 2 cc of white glue into the tube. This immediately stopped the rivets from rattling around, so I'm confident that once it dries, the problem will be permanently solved. I plugged the hole with a 3/32 aluminum rivet. Since there wasn't enough material for the rivet's 1/8" grip length, the stem broke off a bit proud of the head, but it took all of 5 seconds with a Dremel to knock it down.

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I wish I hadn't had to do that, but I can certainly live with the outcome.

Eric Page
01-26-2021, 09:15 PM
I'm not sure what the first builder of my plane was trying to achieve at the tips of the stabilizers and control surfaces, but they were a mess. This is the top of the vertical stab, where he appears to have used styrofoam to form a roughly "V" shape.

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I didn't see any point in removing the styrofoam since it's light weight and it fills the space, but I definitely wanted a better shape. I started with a scrap of rigid insulation foam of about the right size, then put a sheet of sand paper over the existing tip so I could sand the new block to fit it.

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After about ten minutes, I had the new block notched out so that it fit over the existing tip, so I Hysol'ed it in place.

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Once that was set up enough not to move around, I roughly shaped it with a rasp, then dialed it in with 120 grit, then smoothed it with 320 grit (probably an unnecessary step).

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After testing a few grams and finding that it still sets up hard as a rock, I found a use for my cans of ten-year-expired Hysol. It makes good filler and strengthener for these tips. I mixed up about 20 grams of it and slathered it on as neatly as I could manage. One benefit to the old Hysol is that it has thickened considerably, so it's easy to shape and doesn't slump at all.

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It'll definitely take another application at the leading edge to build a nice taper into the leading edge tube, and probably another coat over all of it to fill low spots. We'll see tomorrow.


The tips of the horizontal stab were in equally poor condition, although in fairness, the overall shape isn't too bad. Hysol was applied (again, over styrofoam) but not sanded and with no attempt to fill low spots. I just can't imagine doing it this way and finding it acceptable. The workmanship in this poor plane is just mind-boggling.

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Anyway, I sanded them down with 100 grit to give the next layer of Hysol something to bite into, wiped with acetone to remove all the dust, mixed up another 20-ish grams of expired Hysol and tried to make a smooth application.


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More sanding and Hysol tomorrow, and I'll try to make a start on fixing the rudder tip as well. Then I'll have the new elevator tips to shape from scratch.

Jcard
01-27-2021, 09:00 PM
Thanks for the post on extra flap notches.
Kicking around the same thing for the 7.
If you get over to Wyoming, you can check out the model V.

bbs428
01-28-2021, 07:47 AM
Much better result on your "tips" than you had before. I went thru much of the same with my 5.

Never ceases to amaze me what poor workmanship is tolerated in a machine that literally has your life dependent on said workmanship. Luckily for me my guy stopped on page 30... Lol.

Going thru everything with a fine tooth comb will pay off handsomely Eric. ;)

Eric Page
01-28-2021, 09:51 AM
Holy cow. That photo is a horror show; it makes my builder-fabbed parts look like Boeing spec!

Jerrytex
01-28-2021, 02:31 PM
Wow! "Hmm.... sure wish I had a hacksaw and a file......guess this machete will have to do....."

Eric Page
01-29-2021, 11:27 AM
Had a couple days of distraction, but got back to the plane last evening. I sanded down the Hysol on the tips of the vertical and horizontal stabs. The vertical ended up looking very smooth and had a nice shape, but the Hysol was thin enough that it felt a bit softer than I would like.

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I didn't take photos, but after the sanding I applied another slathering of Hysol to hopefully give it a harder shell.

The tips of the horizontal still had significant low spots after sanding...

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...so I also put another coat of Hysol on them and will sand again once it cures. If I had any brains, I'd use SuperFil. Big if...

jrevens
01-29-2021, 12:04 PM
FWIW, I made all of my tips completely out of Hysol or West System epoxy with a LOT of micro balloons. Light, easy to sand & very strong. Touched-up as necessary with SuperFil.

Eric Page
01-29-2021, 07:36 PM
I was expecting to do some more Hysol sanding today, but with my garage being so cold overnight, the Hysol didn't feel quite fully cured. I took the horizontal stab inside so it would be warm overnight tonight, then moved on to other things.

I started by installing the elevator push-pull tube, pulling four new rivets in the aft reducer bushing and greasing the area that passes through the mid-fuselage bushing. I was pleased to find that my measurements for the bare area were spot on; the paint gets to within 1/2" on both ends of its travel.

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I stole an idea from alexM to use nut plates below the rudder torque tube brackets. I was going to use Click Bonds like he did but I just can't stomach their price, so I opted for F2000 and F5000 floating anchor nuts mounted with 3/32 stainless steel flush pop rivets. I started by using a dab of CA glue to fix the plates under the C-channel with the nuts centered under the 1/4" holes.

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Using the plate holes as a guide, I drilled the C-channels for rivets, then set up my countersink cage and countersunk the holes on the top side. Before installing the plates for good, I popped them off, cleaned the C-channel with a wipe of acetone and shot them again with primer, then paint.

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Finally, I installed the anchor plates with rivets.

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Since I was in a riveting frame of mind, I also installed the flap handle detent bracket in the center console. My next door neighbor's 6 y/o daughter has expressed interest in the project, so I invited him to bring her over to pull the rivets. Unfortunately, she had been outside for awhile (launching model rockets!) and was cold. It was a choice between the funny guy next door who hangs out in his garage all day, or Mom and hot chocolate. Needless to say, I had to pull my own rivets. So, working alone, I prepped with Scotch-Brite and acetone, applied Hysol, clecoed the bracket in place and pulled the rivets.

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More Hysol sanding tomorrow.

avidflyer
01-29-2021, 08:40 PM
Interesting thing in your post about greasing the part of the elevator push pull tube. Some have said that should not be greased but rather left dry, as the bushing is slick enough on it's own. Another argument is that the grease can pick up dirt which causes wear. Don't remember if the manual addresses this or not. There was a post on FB, and the person's bushing had slid out. His elevator tube was greased as well. So for the other half of the discussion, it may be a good idea to make very good and sure that the bushing can't come out. I had grease on mine in the Kitfox 4, and a few weeks ago when it was about 5 above, my bushing slid out as well. I put a rag on a stick, and was able to wash off all the grease with gas on the rag and a bunch of rubbing. Sure wish I could get back in there and put a real short screw through the bushing holder into the bushing, but there is no way I'd ever fit in there. So far the bushing is staying in place, and yesterday I was flying in about +10 or so temps. JImChuk

109JB
01-29-2021, 09:04 PM
Interesting thing in your post about greasing the part of the elevator push pull tube. Some have said that should not be greased but rather left dry, as the bushing is slick enough on it's own. Another argument is that the grease can pick up dirt which causes wear. Don't remember if the manual addresses this or not. There was a post on FB, and the person's bushing had slid out. His elevator tube was greased as well. So for the other half of the discussion, it may be a good idea to make very good and sure that the bushing can't come out. I had grease on mine in the Kitfox 4, and a few weeks ago when it was about 5 above, my bushing slid out as well. I put a rag on a stick, and was able to wash off all the grease with gas on the rag and a bunch of rubbing. Sure wish I could get back in there and put a real short screw through the bushing holder into the bushing, but there is no way I'd ever fit in there. So far the bushing is staying in place, and yesterday I was flying in about +10 or so temps. JImChuk

To support what Jim is talking about, the Kitfox 4 I'm working on now had grease on that bushing too and it was pretty gummed up. I washed all the grease off and now it is greaseless and will stay that way. Don't know that the bushing ever came out, but I see no reason to lube a plastic bushing.

As a matter of fact, My Sonerai has a similar arrangement, except it has a steel tube pushrod instead of aluminum, and that steel tube runs in a steel bushing welded to the fuselage much like the tube that holds the bushing on the kitfox, except there isn't any plastic in it. Its not lubed either but I did make sure to smooth the ends and bore of the bushing tube.

alexM
01-29-2021, 09:36 PM
You need to get back to your day job so I can keep up. Looking great Eric.

I'm not planning on greasing my elevator push-pull tube bearing at all, and if I do it will be some sort of dry film lube.

I can't con any kids into pulling rivets either, so I bought a Milwaukee 12V rivet gun. Damn near 100 stainless rivets just getting the inserts in my spars and over a 100 more to go.

When you're sanding Hysol and it seems even a tiny bit gummy, walk way and leave it for another day. Same is true with SuperFil. When I did the top of my vertical fin I was meticulous with the balsa piece. After just one coat of Smurf poo it looked great, so I did one thin layer of Hysol over that and declared victory. With the horizontal stab and elevator I did some approximations with balsa wood and slapped on enough adhesive that I figured it would be smooth after one sanding. Not so much. I think it took three layers before all the little voids were filled in.

Eric Page
01-30-2021, 10:22 AM
Interesting info, guys. The original tube that I removed had black dust smearing where it passed through the bearing, which looked to me like the result of aluminum fretting. This is why I lubed the replacement. However, I'm sure you're all correct that the grease will attract dust/dirt and eventually turn into grinding paste (given the dust in my garage, this will probably happen before covering). I'll remove the grease. I suppose that means drilling out the rivets again...

Re riveting, I've got one of those Harbor Freight air-powered rivet guns that works surprisingly well. Listening to my little compressor in a closed garage is no fun, but there aren't many rivets left to pull. I also have a drill attachment that's supposed to pull rivets. I should dig that out and see if it works.

You'll pass me soon, Alex. I got a recall notice last week; I'm going back to work sometime in March.

avidflyer
01-30-2021, 11:39 AM
I wouldn't think you need to pull the rivets. I would just wash off all the grease I could, move the tube, and do it again. Keep at it till the grease is gone. I think I would make some provision so that the bushing can't move out of it's location. JImChuk

Eric Page
01-30-2021, 01:26 PM
Sorry, Jim, I saw your comment about the bearing coming out and forgot to respond. I don't think mine is going anywhere, as it was installed with Scotch-Weld. I've tried shifting that stuff with everything up to a propane torch and had no luck.

Eric Page
02-01-2021, 05:45 PM
Well, a couple more days of life happened. I spent one of them under my parents' house, repairing HVAC ducts that were chewed up by rats. If they can get to warm air, they'll chew a hole big enough to put your fist through. This is an 18" trunk line coming out of the furnace manifold, and the amount of hot air being lost into the crawlspace was impressive.

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Check your crawlspace vent screens, people!
Anyway, this isn't a pest control forum...

I did another day of work sanding and filling the horizontal and vertical stab tips. I started out with this.

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Then I formed it with a wood rasp to get this.

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Then I sanded it with 100-grit to remove the rasp marks.

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And finally sanded with 320 grit to eliminate the scratches.

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There were still a few small divots and scratches left, so I mixed and applied a coat of SuperFil.

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I'm not 100% certain, but I'm pretty sure I screwed up the SuperFil mix. The first batch I neglected to stir up the gunk at the bottom of the jar that had precipitated out of the hardener, and the second batch I think I mixed at 1:1 instead of 1:2. Good thing this stuff is only cosmetic! In any case, both batches have hardened just fine.

On the vertical, I followed the same procedure of rasp shaping, sanding and SuperFil.

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While I had the SuperFil out, I took care of the areas around the door openings and rear quarter windows where the aluminum angle overlaps itself and leaves a small step edge, or where there were small voids.

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Next up I got started on tips for the new elevator. I began by cutting two pieces of rigid insulation foam a bit wider and a few inches longer than needed.

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Then I used 100-grit wrapped around the handle of a small pair of pliers to sand a channel in the foam to receive the steel end tube of the elevator, and cut away a bit of foam at one end to make room for the end of the elevator's spar tube.

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Finally, I mixed up some Hysol and glued the foam blocks to the ends of the elevator.

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bbs428
02-01-2021, 06:33 PM
LOL - yes life happens and critters can do a lot of damage! :p

Tips are looking good!

Eric Page
02-02-2021, 12:30 AM
Had my FAA medical today. I made it to one week short of my 50th before I got stuck with, "Must wear corrective lenses." Grrrr!!!

Another round of sanding this evening. The horizontal and vertical stab tips are getting close.

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It's hard to tell from these photos, but this one is a little lopsided; the lower half is a bit "fuller" than the upper half. I did another layer of SuperFil (mixed 2:1 this time!) there to see if I can get a more uniform shape.

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Both ends of the horizontal also got more SuperFil around the leading edges. I'm hoping to get a better transition from the tube to the end rib.

I'm quite happy with the shape of the vertical tip. Like the horizontal, it needs some work at the leading edges, as well as the right side of the trailing edge. I applied more SuperFil there as well.

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Finally, I sanded the areas around the doors and rear windows where I had applied SuperFil. They mostly turned out fine, but I added a bit more in a few places to smooth out some rivets that were set a little poorly.

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jiott
02-02-2021, 11:21 AM
You guys are doing a fantastic job on smoothing those tips. Just in the interest of saving some of your time may I say that all those areas that get covered with fabric, most get 3 layers, are far less needful of perfectly smooth (paint grade) finish than say a fiberglass or aluminum area that gets painted only. Scratches and small pits will never show thru all that fabric. I am not suggesting poor workmanship by any means, just maybe a little time-saving realism. That said, I also was caught up in obsessive perfectionism on my project just because it felt good on my baby. Of course it is better to overdo something than just let it slide by. Looking good guys!

Eric Page
02-02-2021, 04:36 PM
That would have been great advice three days ago, Jim! Just kidding -- I figured that was probably the case, but I think I'm doing it just to prove to myself that the first builder could have done it right but just chose not to. Anyway, I'm nearly done with the stabs and should be able to finish up the elevator within a couple of days.

Eric Page
02-02-2021, 08:17 PM
More work on the vertical and horizontal stab tips today. I'm mostly happy with the vertical; it just needed another dab of filler on the right side to get the transition I want from the forward tube.

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The horizontal tips are now dialed in just how I wanted them. The first photo looks a little lopsided, but that's due to camera angle.

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The aluminum angles around the door openings and rear windows are getting really close. The right side is good, and I smeared a bit more SuperFil on the left side.

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I got to work on the elevator tips next. First I used a utility knife to cut away most of the rigid foam, leaving a very rough shape, then used a block with 100-grit to shape it closer to what I wanted. This left some voids at the leading and trailing edges, but those were easily filled with a few grams of SuperFil while I was coating the rest of the foam. These will get sanded (and probably coated again) tomorrow.

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Some hardware arrived a couple days ago from Spruce, so I finished assembly of the notched rudder pedal adjustment brackets.

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I really wanted to keep moving on installing the controls, but I'm stuck until I get the floorboards re-varnished. I did get the rudder pedal adjustment handles fitted, which required relieving a little metal from the bottom of one handle so it didn't foul on the fuselage tube. That got a shot of primer/paint before being installed.

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Final task today was getting the grease removed from the mid-fuselage push-pull tube bearing. There was just enough room around the tube to slip a piece of paper towel in there, so I was able to get virtually all of the grease out without too much hassle.

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alexM
02-02-2021, 10:02 PM
Remember way back when you looked at the pile of parts and read the manual and thought it was way too vague? It's funny that as you proceed through your build the statement "slap some s*** on there and sand it to a pleasing shape" makes complete sense.

When I started with my horizontal and elevator they were mounted to the fuselage. I got as far as bonding on the balsa, rough shaping it and gooping it up with SuperFil before I realized it would be much easier if I hung it with the leading edge straight up at eye level so I could sand the it symmetrically. Once I had the basic shape, you know, pleasing I took the stab/elevator apart so I could smooth out he joint between them.

Eric Page
02-02-2021, 10:29 PM
Very true! I'm doing just the opposite; some time pretty soon I'm going to have to connect them together to be sure the shape on the elevator matches the one on the stab.

Eric Page
02-04-2021, 12:16 AM
Today I got the top of the vertical stab dialed in the way I want it...

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...then got to work shaping the first coating of filler on the elevator. I had to take off most of the SuperFil and a good part of the foam to get the profile somewhat close to the horizontal stab. They're not a perfect match, and they probably never will be, but once they're covered and color-matched I think they'll look just fine. This was the first time I had mated the two since installing the elevator's ribs, and I was pleased to see that the largest rib misalignment is only ~1/8".

Right side:
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Left side:
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That two hours of sanding was followed by mixing 40 grams of expired-but-free Hysol and slathering it all over the elevator tips. I guess that means more sanding tomorrow. Oh, joy.

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I finished up today by finishing the SuperFil on the door and window frame angles. I'm finally happy that I have smooth surfaces over the rivet locations, so they'll only show through a little bit, instead of enough to wear a hole in the fabric.

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In other news today, I got a document from a local citizens' group that's opposing a major commercial expansion of the sleepy, rural county airport to which my home is immediately adjacent. This image shows the state DOT's rendering of the project; the red dot is approximately where my house is located. So, I've got that going for me...

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alexM
02-04-2021, 10:25 AM
LMAO! There must be at least 5 or 6 single engine aircraft operations per day at KTDO so of course it is ripe for a multi runway expansion and a terminal. Oh and a county with a population of at least a couple thousand. I mean, aviation is BOOMING right now so they need to get ahead of this. Maybe they can name it DB Cooper International since it's just north of where he jumped.

At my airport the port commissioner emailed us a survey with their vision of the future. It includes tearing down the rows of fully occupied T hangars and replacing them with 60' box hangars. The plan shows there isn't enough room to taxi a 59' plane between the hangars but that's just a detail. Oh and almost zero parking for cars.

They're pandering to the jet crowd because there are 5-6 business jet operations per week, so of course the hundred or so rent paying/fuel buying piston singles can GTFO. On the upside, they claim one phase is to develop the far side of the airport to put in 40' T hangars, a campground, a grass runway and fuel farm for planes on that side.

That will never happen. It is many millions of dollars they don't have and can't justify spending, and any previous attempts to develop that side of the runway meet with a lot of push back.

Included in their plan is the delusional expectation of self driving quad rotor air taxi service are right around the corner.

Eric Page
02-04-2021, 11:30 AM
I've got news for you, my friend. TDO is only one of six airports on the state's short list, along with Arlington, Bremerton, Shelton, Paine and, yep, Tacoma Narrows!

Eric Page
02-05-2021, 11:16 AM
Yesterday I got started on the rudder tip first thing, so the Hysol gluing on the foam block was able to cure by evening.

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When I got back to it later, I attacked it with the wood rasp, then 120-grit. Once it matched the shape of the vertical stab tip and was a tad smaller (to allow for build-up), I gave it a coat of Hysol and set it aside.

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In the meantime, I rasped and sanded the elevator tips to take down Hysol high spots, then gave them a skim of SuperFil to smooth out the divots. I'll sand those today and should have them finished.

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Since Oratex shrinks less than other fabrics, I'm dreading the sharp curve at the forward root of the vertical stab. So, I've been mulling my options for installing a razor back of some kind. I grabbed a 10' length of 1/2" Sch40 PVC conduit from the Kitfox aisle at Home Depot and hacked at it to see what I could mock up. I started with a long piece that went from the vertical stab all the way to the back of the turtledeck, but the forward half of it was basically laying flat on the spine of the fuselage, which looked silly. Then I shortened it and cut a notch in the end, placing it between the second rib in the vertical stab and the lateral tube at the aft end of the antenna plate.

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I think that looks a lot better. Much to my surprise, with that much compression on the conduit it's really robust. I think with a couple of vertical supports from the steel structure below, the conduit could be a permanent solution.

Thoughts? Other than welding in 4130 tube, what have others used to form this feature?

jiott
02-05-2021, 12:08 PM
For the razorback I've seen an aluminum tube with wood plywood supports.

efwd
02-05-2021, 01:38 PM
Oratex is going to require some heat to activate the glue that you will use on that PVC. I don't believe that it will be suitable. Be careful heating up your tips while applying the fabric. Hysol gets soft and Foam is no match for the iron or high heat applied with the heat gun. Unfortunately, pressure is what is required, along with heat to get the glue to work as designed. Don't apply too much pressure or everything will collapse underneath.

jrevens
02-05-2021, 05:40 PM
I agree with Eddie. My kit came with a curved piece of 1/2" aluminum tube and the plywood supports like Jim said. This was before the factory began to weld the curved razorback tube as a standard part of the fuselage. I did mine a little differently and my "razorback" curved tube is shorter than the normal one... that's because I located my antenna mounting plate further back. The longer it is, the easier it is to make the fabric conform to the curve, so it was harder to do mine than most of them.

Eric Page
02-05-2021, 07:13 PM
Oratex is going to require some heat to activate the glue that you will use on that PVC. I don't believe that it will be suitable.
Hadn't thought of that. I think you're right; the heat would make the PVC soften and deform. Not a good idea.


Be careful heating up your tips while applying the fabric. Hysol gets soft and Foam is no match for the iron or high heat applied with the heat gun. Unfortunately, pressure is what is required, along with heat to get the glue to work as designed. Don't apply too much pressure or everything will collapse underneath.
Very good advice. Thank you.

Eric Page
02-05-2021, 07:57 PM
I started out this morning working on the door frames again. I picked them up from the welder a couple of weeks ago but never got back to them again. I just had the welder plug up the holes along the center bar, and where the latch mechanism was mounted on the lower bar. I left the rest of the holes alone, as they'll be covered by the double-sided tape that mounts the bubble door plastic. Anyway, I ground down the welds so they're flat and smooth (sorry, forgot to take an after photo).

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With that done, I took them to a local sandblasting and powder coating shop to be stripped and re-coated. Would you believe $50 for both? Gotta love a little mom-and-pop business in a shed behind the owner's house. In the end, my investment in refurbishing the old frames will be $175 and about four hours' work. That beats the heck out of buying new.

Next I sanded the SuperFil on the elevator tips. They came out perfect, so I'm calling them done. Horizontal stab and elevator are ready to cover.

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I grabbed the wood rasp next and took down the high spots in the Hysol on the rudder tip, then put on a layer of SuperFil.

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Final item of progress today was a little work on the floor boards. As you can see in this photo, they got some reddish splotches on them somewhere along their journey, and I was only partially successful removing them with sanding. So, I decided to stain the plywood to cover them. I picked a Red Chestnut stain, which looked about as close as I was going to get to the existing splotches. Apart from one strange blob that appeared in the forward floor board, I think they look pretty good. Here's before...

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...and here's after two coats.

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With two hours between coats, I should be able to get two on the other side before bedtime tonight. Then I can make them smooth with 320-grit and get on with applying varnish.

The remainder of the afternoon was spent screwing with wingtips, but I've posted some questions about that mess here (https://teamkitfox.com/Forums/threads/11348-Wingtip-Confusion).

Eric Page
02-06-2021, 08:10 PM
Nice progress today, but not many photos. I started out with the rudder while I waited for the heater to take the chill off in the garage. It needed two operations today. First was sanding down the SuperFil on the tip...

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…followed by bonding in reinforcements at the base of the fiberglass fairing. I don't know why, but on both sides the first builder cut almost all the way through the fairing edge, just above where it's relieved (much too far) for the control horn. I had actually broken the thin section of fiberglass that remained on the left side, so I cut and sanded two thin strips of wood (from a large tongue depressor) and stuck them in place with Hysol. They'll get varnished tomorrow.

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Once the garage warmed up a bit, I spent the rest of the day trapped behind a respirator, working on varnish. I'm going to pause here for a small rant:


It takes a very special kind of idiot to package poisonous, volatile and highly flammable chemicals in metal cans with spouts from which it is physically impossible to pour the contents without spilling them all over your work surface. Can someone please explain to me why we use this ruinously expensive, horrible s*** instead of buying $30/gal spar varnish at Home Depot?

Anyway... the markings on my mixing cups led me to prepare way too much varnish. I ended up with 16 oz, and tossed 10 oz of that at the end of the day. Once I had the varnish catalyzed and reduced, I put the first coat on one side of the floor boards, the bottom rib in the aft fuselage, the unpainted wood pieces that I used to mount the comm antenna, the new false ribs, all of the rib cap strips in both wings and the ribs in the new elevator.

I didn't take any photos of the varnishing since it doesn't look any different than the parts would otherwise. Lesson learned: use the ounce markings on the mixing cup and ignore the ratio markings to avoid a big waste of $180/gal material.

avidflyer
02-06-2021, 08:39 PM
Shame to spill all over the place, and mix up to much, but on the plus side, the less product left in those cans, the easier it is to pour out of them with out spilling. Sorry, couldn't resist. I've spilled my share as well, and usually now I try to pour half into another empty container, so I only spill some the first time. Keep at it though, one of these days you will have an airplane! JImChuk

jiott
02-06-2021, 09:08 PM
I dipped mine out of the can with some large measuring spoons; solves the spill problem and makes getting the ratio right easy. Spoons clean up fine with a paper towel and denatured alcohol.

Eric Page
02-06-2021, 11:31 PM
All good ideas. Too bad I didn't know an alternative method was needed until I poured it the first time and made a mess! Only two more mixes required, at most, and I've got plenty of varnish left. I just felt like complaining. Thanks, guys.

Eric Page
02-07-2021, 07:39 PM
Just a partial day in the garage today, due to a family obligation.

While today's smaller batch of varnish was catalyzing, I did a little more work on the builder damage at the base of the rudder's fiberglass fairing. There was still a bit of unnecessary slot visible, so I mixed up a tiny bit of SuperFil and put a blob on the inside and outside of each slot, which I'll sand back to flush once it cures.

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The remainder of today's effort got the second coat of varnish on all of the parts I did yesterday. The organic vapor canister in my respirator gave up the ghost about five minutes before I was done, so I was pretty happy it lasted until I could finish without having to de-glove. Fresh canisters installed for tomorrow, when I'll start on the second side of the floor boards and get the third coat on everything else.

Oh, and I noticed today that the wood stringer on the belly of the plane had never been varnished, so it got a first coat as well.

Eric Page
02-08-2021, 06:30 PM
No photos today. I spent the morning doing some reading and electrical planning, and the afternoon applying another coat of varnish. Once that was done, I started spit-balling the mounting locations for A/P servos and the transponder and ADS-B antennas.

I think I've narrowed the pitch servo location down to mid-fuselage, just below the antenna mounting plate. There are tubes in convenient locations nearby, and that mounting plate can serve as an upper anchor point as well, since I probably won't use it for an antenna.

[Side-note: if you're considering putting an autopilot into a Series 5 (and probably a Series 6), the Kitfox servo mounting kit will not work. Both of the mounting plates provided in that kit are specifically designed to mount on tubes and plates that are missing from the Series 5 fuselage. The roll kit could possibly be adapted to work, but the pitch kit is a no-go.]

I'm considering putting the transponder and ADS-B antennas inside the wings (on fabricated ground planes, obviously). There's a nice open bay just outboard of each fuel tank, between ribs 3 and 4. This would put them well away from other antennas and from the A/P servos. Has anyone put these antennas in the wings? Can anyone think of a reason not to put them there?

PapuaPilot
02-08-2021, 07:24 PM
Here is my AP installation in a model 5 that I did last year. I made my own brackets with angle aluminum and mounted each bracket with four adel clamps. The roll servo is under the baggage sack and he pitch servo bracket starts just aft of the baggage area.

FYI I came up with my own pushrod and mounting hardware instead of buying the Garmin kits. It was almost $100 for two Garmin kits. There is a list of the contents of these kits in the G3X installation manual. What I realized was the kit was just basic aircraft hardware (bolts, washers, nuts), 2 rod ends and a length of 1/2" solid aluminum rod. I got 2x of everything except the pushrod stock for $30 at ACS. I was able to find 2 feet of 1/2" aluminum stock for the pushrods where I work (free). Even if you buy the Garmin kit the pushrods are custom made by the builder to fit their aircraft; you cut the rods to the correct length, drill and tap them to fit the rod ends.

All of my antennas are in the fuselage. I have COM, ELT, ADSB and transponder antennas. It was challenging to get the recommended spacing. I haven't had any problems other than a one time ELT (ACK-04) false activation caused by the Garmin GTX-23 transponder (according to the ACK rep) and that has been fixed.

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Frontier Fox
02-08-2021, 09:30 PM
This is my installation of the pitch and roll servos on my model 7. I have Dynon servos mounted on brackets of my own design.2720527206272072720827209

Frontier Fox
02-08-2021, 09:32 PM
I see that my photos are sideways also🧐

efwd
02-09-2021, 09:41 AM
I know nothing about putting antennas in the wings or on the vertical stabilizer but, Kitfox has placed antenna mounts on the airframe. I used the the mount underneath the pilot seat (aft of the seat actually) for my ADSB in & out. That happens to be about 12" from one of my AP servos and only about 18" from the other. My ELT is mounted to the mounting plate on the passenger side. No ground planes on my antennas, just the airframe, and my Xponder works great and servos work as well. My Com radio antenna is mounted up top, behind the turtle deck. I can talk with the tower at least 30 miles out no problem. I haven't tried it out at any greater distance since I can't recall ever needing to reach out to ATC from further away. There have been lots of posts regarding this subject. I only provide my $.02 worth to possibly point out that things might just work out just fine without engineering yet another installation design. I get it, some folks don't like the antenna sticking up from the top of the airframe etc. etc.. I bet if I measured, I would find that there isn't 36" between any one of these items and it is all working fine. Keep posting, I always enjoy following your thread.

Eric Page
02-09-2021, 12:25 PM
Here is my AP installation in a model 5 that I did last year. I made my own brackets with angle aluminum and mounted each bracket with four adel clamps. The roll servo is under the baggage sack and he pitch servo bracket starts just aft of the baggage area.
Thank you, Phil. Your photo is enormously helpful. One question: does the wood belly stringer hold the fabric down enough that it doesn't contact the Adel clamps?


FYI I came up with my own pushrod and mounting hardware instead of buying the Garmin kits. [SNIP] I got 2x of everything except the pushrod stock for $30 at ACS.
Yes, that's my plan too. I got some servos from another builder that came with rod end bearings and a couple of short rods; I just need a long rod and some mounts.


This is my installation of the pitch and roll servos on my model 7. I have Dynon servos mounted on brackets of my own design.
Beautifully done, Joe. That looks like it came from the factory with those brackets built in!


Kitfox has placed antenna mounts on the airframe. I used the the mount underneath the pilot seat (aft of the seat actually) for my ADSB in & out. [SNIP] My ELT is mounted to the mounting plate on the passenger side.
My plane doesn't have that plate on the left side; just a small one on the right that wouldn't be big enough for the ELT. I'm looking at a spot on the left side of the fuselage about halfway back to the tail for the ELT. It looks like the strongest spot, as seven tube ends meet there.


My Com radio antenna is mounted up top, behind the turtle deck.
My plane has that spot, but I wasn't thrilled about having an antenna sticking up from there. I installed this antenna (https://www.aircraftspruce.com/catalog/avpages/antennasystems.php) inside the vertical stab. My goal is to hide all antennas inside the fabric envelope.

However, I'm not sure about the ELT antenna. I don't like the idea of having it external where it could easily be damaged if the plane flips over, but I don't see a good place to put it inside the frame. I need to break down and buy it so I can mock up the antenna, but I've been holding off because ACK's warranty reads, "...warrantied [...] for a period of three years from their manufacture date."


Keep posting, I always enjoy following your thread.
Thanks, Eddie. Will do!

alexM
02-09-2021, 04:27 PM
However, I'm not sure about the ELT antenna. I don't like the idea of having it external where it could easily be damaged if the plane flips over, but I don't see a good place to put it inside the frame. I need to break down and buy it so I can mock up the antenna, but I've been holding off because ACK's warranty reads, "...warrantied [...] for a period of three years from their manufacture date."

That reminds me of the book Adrift by Steven Callahan, floating in his life raft for 76 days. One day he was looking at the manufacturing tag and saw that it was warranted for 40 days, and wondered just how he might be compensated if it didn't last longer.

PapuaPilot
02-09-2021, 08:12 PM
Thank you, Phil. Your photo is enormously helpful. One question: does the wood belly stringer hold the fabric down enough that it doesn't contact the Adel clamps?

That's correct, the adel clamps don't touch the fabric. I suppose you could also use pipe strap clamps, which would be much easier to match the holes and install.




https://m.media-amazon.com/images/I/51DfvRGxb2L._AC_SS350_.jpg

109JB
02-09-2021, 10:36 PM
I welded in brackets for the servos. I'm using Garmin servos and here is how they are mounted.

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Eric Page
02-09-2021, 10:46 PM
That reminds me of the book Adrift by Steven Callahan, floating in his life raft for 76 days. One day he was looking at the manufacturing tag and saw that it was warranted for 40 days, and wondered just how he might be compensated if it didn't last longer.
Ha! Thanks for that. Always good to have a little perspective.

Eric Page
02-09-2021, 11:12 PM
Today I applied what I thought would be the last of the varnish, but there'll be more (see below).

I made a Home Depot run, looking for some thin aluminum bar. They didn't have any, so I bought an 8-ft piece of 1-1/2" x 1/16" aluminum angle instead.

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I used the miter saw to cut that into pieces of about the right length for the wing tip attachment strips, then passed those through the table saw to remove the corner (this is where I created more varnish work for myself, as the table saw threw aluminum chips all over my floor boards, which stuck in the still-soft varnish!). That left me with 8 pieces that are 1-1/4" wide x 1/16" thick. They'll just need a little trimming to final length, then match drilling to fit the #10 ribs.

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I had about 21" of the angle left, so I used it to fabricate a mounting platform for the pitch servo in the same location that Papua Pilot showed in his photo, above. I ended up cutting about 5" off of it, then cut up that piece to make two braces for the servo. I'm not sure how rigid this installation is going to be (I haven't cinched it down tight yet because of the nylon lock nuts), so I many end up making an upper brace for it later.

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Fortunately, the longer of the two push-pull rods that came with the servos will work for this location, so I don't need to fabricate a new one. I've got a 1" Adel clamp on my Spruce list to grab ahold of the elevator push-pull tube. Once I'm sure that all fits together and works, I'll torque everything down.

PapuaPilot
02-09-2021, 11:28 PM
Copy cat. ;)

Eric Page
02-10-2021, 12:09 AM
Yep, it looked a lot better than where I was going to put it, and it saved me making a new pushrod. Thanks again!

efwd
02-10-2021, 05:33 AM
Most of us install the ELT antenna along the side, within the airframe, right beside the baggage area.
Look at "EFWD build" post #94 to see Jim Otts installation.

109JB
02-10-2021, 06:33 AM
Here is how I mounted my ELT and antenna. Once again, I decided to weld a bracket for the antenna but there is no reason you couldn't bolt one in.27227

Eric Page
02-10-2021, 09:21 PM
Thanks, Eddie & John. That gives me a couple more spots to consider. I presume airplanes have passed airworthiness inspection, and passed operational tests through the satellites with ELTs and their antennae in those locations.


I did a little sanding and varnishing this morning to fix the floor boards after the aluminum chip debacle yesterday. The rest of the day was a loss, apart from some online part hunting this evening. I should get a full day in tomorrow.

109JB
02-10-2021, 09:39 PM
Mine has not had operational tests as it is in the covering stage of the rebuild. I don't have to worry about airworthiness because my airplane already has one since it is a rebuild project. Before I got it there was a AmeriKing AK450 ELT in it and I opted for the Artek ELT 345. I have read reports that they work fine inside the fuselage. I figure it will be better than the iffy AK450. Will be testing when its warmer though.

Eric Page
02-11-2021, 09:21 PM
I started today's efforts by finishing the physical installation of the autopilot pitch servo.

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I'd appreciate it if someone who's done it a few thousand times could critique my safety wiring. To my eye they look pretty close to the drawing in AC 43.13, but I'm biased!

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I also sanded down the SuperFil that I applied a few days ago in the extra slots that the first builder made in the rudder's fiberglass fairing.

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Next I spent a ridiculous amount of time fabricating two small aluminum plates to serve as ground planes for the transponder and ADS-B antennas. I don't know why this was such a trial, but every time I touched something it went wrong. I should have downed tools and gone inside for awhile, but I'm stubborn. They ended up the way I wanted them, but not before I told a few of my tools what I thought of their maternal line.

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Finally, I started working on a way to mount them in the wings. This will involve some small spacer blocks that I fabricated out of a 3/8" square pine dowel.

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Those will lower the base of the antenna a bit from the top of the wing, leaving room for a right-angle BNC connector. More on that later.

jrevens
02-11-2021, 10:39 PM
Eric... regarding the safety wire - since you asked, it's close, but not exactly how I would do it. I think you should have started the final twisting of the pigtails right where the wire exits the hole in the head of the bolt.

109JB
02-11-2021, 10:44 PM
Your ground planes look too small to me. The transponder ground plane should be a minimum of 5.5" and if using a minimum size ground plane they should be round. The ADS-B would be about the same. The rule of thumb is the ground plane should have a radius of 1/4 wavelength. The transponder is 1090MHz

Wavelength = (Speed of light)/frequency = 299,792,458 / 1,090,000,000 = 0.275 meters

Radius = 0.275 / 4 = 0.06875 meters =68.75 mm = 2.71 inches ---> so 5.42 inch diameter

PapuaPilot
02-11-2021, 10:54 PM
I will give you my honest opinion. As a maintenance instructor I would have you do it again.

1. Notice in the picture in AC43.13-1B the twisting between the bolts goes all the way from bolt head to bolt head.
2. The finishing or next twist starts where it comes out the opposite side of the bolt head.
3. Lastly the wire needs to be twisted in the opposite direction where it comes out of the head so that the outside wire stays against the head.


https://teamkitfox.com/Forums/blob:https://teamkitfox.com/8b06c45f-8c92-4cc5-b29d-81b7f86eb46d27239

My antenna ground planes are round and about 6" diameter.

I have never seen transponder antennas mounted on the wing. There is a reason they are mounted on the bottom of the fuselage so they have a full 360 degree downward view. The signal may get blocked by the fuselage if they are mounted too far inboard on the wings.
https://teamkitfox.com/Forums/blob:https://teamkitfox.com/5e9d7017-7533-48d2-bca1-cb0b85173074

Eric Page
02-11-2021, 10:58 PM
I think you should have started the final twisting of the pigtails right where the wire exits the hole in the head of the bolt.
Ah, OK, I see what you mean. I'll give it another try tomorrow and see if I can do that. Thank you!


Your ground planes look too small to me.
Well, that's embarrassing. I'm glad you can't hear me right now. Would you believe that I had an exchange about this on another forum yesterday, in which I mistakenly wrote "diameter" when I meant "radius?" I knew all along that the number I came up with was a radius but I not only wrote it wrong, I actually made them wrong, despite being corrected by two people on the other forum!

Would you also believe that the piece of material I used to make them is now too small to get two parts of the correct size?

GRRRR!!!

PapuaPilot
02-11-2021, 11:19 PM
AC43.13-2B in Chapter 3 is the place to look for information on mounting antennas and ground planes. It's a fairly short read, but packed with information. They don't forbid transponder antennas on the wing, but it isn't best practice.

Eric Page
02-11-2021, 11:20 PM
I will give you my honest opinion. As a maintenance instructor I would have you do it again.

1. Notice in the picture in AC43.13-1B the twisting between the bolts goes all the way from bolt head to bolt head.
2. The finishing or next twist starts where it comes out the opposite side of the bolt head.
3. Lastly the wire needs to be twisted in the opposite direction where it comes out of the head so that the outside wire stays against the head.
Thank you. I missed a couple of the fine details in that diagram. I'll give it another try.


My antenna ground planes are round and about 6" diameter.

I have never seen transponder antennas mounted on the wing. There is a reason they are mounted on the bottom of the fuselage so they have a full 360 degree downward view. The signal may get blocked by the fuselage if they are mounted too far inboard on the wings.https://teamkitfox.com/Forums/blob:https://teamkitfox.com/5e9d7017-7533-48d2-bca1-cb0b85173074
Yeah, I screwed up the size. No surprise after the day I had in the garage. I'll start them over.

I plan to put them fairly far outboard.


Now I'm fed up to my eyeballs with today, and I'm going to bed.

PapuaPilot
02-11-2021, 11:45 PM
Here is how I did my transponder and ADSB antennas. One is behind the pilot on an existing mount and I added the ground plane. The other is just aft of the copilot stick and I mounted it using 2 adel clamps to the bracket and ground plane. After I took the picture I added a wire to ground it to the airframe.

They are almost 3' apart and have worked flawlessly for 5 years.

It seems like your plan to put them in the wings is adding unnecessary complexity and weight.

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Eric Page
02-12-2021, 11:51 AM
You know, Phil, this whole thing would be a lot easier if you'd just sell me your plane. Then I wouldn't have to copy everything you did. ;)