The Barn Find Build [Archive] - Page 2

Eric Page

02-12-2021, 11:44 PM

Thanks, Phil. I couldn't quite take the day off, but I did go after some low hanging fruit.

I installed four more nut plates, then put in the forward floor board, rudder pedals and brake master cylinder brackets.

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I also got the large pulleys installed in the rudder torque tube arms, but didn't get a photo. That was another opportunity to say complimentary things about the first builder, as the stainless cable retaining straps were just beautifully made [/irony]. Fortunately, I was able to flatten them out and re-bend them to a usable shape.

Speaking of which, I have a question. Is there a reason Kitfox used clevis bolts for those pulleys instead of just using drilled AN4 bolts? There's plenty of clearance for hex heads between the arms, so I don't understand the choice. It would be dead easy to get the required 30-40 in-lb torque if the bolt had a hex head, but it's a Royal B**** to do while holding the bolt with a flat blade screwdriver. It's probably not critical since the return springs serve as cotter pins, but it ain't easy.

Eric Page

02-13-2021, 11:31 PM

109JB

02-14-2021, 09:24 AM

No progress at all today. Power went out at 4:25am in the midst of a once-a-decade snowstorm and didn't come back on until 6:25pm. My good friend and neighbor let me plug a 100' extension cord into his generator so I could keep my fridge and freezer running, but I couldn't keep the garage warm and had no lights. The garage should be warm again by morning, so I'll get back at it!

Best thing I ever did was install an automatic standby generator. The one I have runs everything in the house and barn with the exception of maybe my huge air compressor and welder. Main thing for me is the sump pumps. Without power the basement would flood in about 4 hours.

Eric Page

02-14-2021, 11:36 PM

Good progress made today. I started with the four small pulleys behind the seats. I don't understand the choice of pulleys needing AN5 bolts, but whatever...

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Next I wanted to start routing the rudder cables, but quickly realized that I needed to finish some other things. First of those was installing the adjustment handle detent brackets. To do that I had to get the mounting holes for the center console drilled. I didn't get any pictures of that, but I will say that having a 12" long 3/16" drill bit was a life saver. I don't know how I would have done it without that.

With that done, I carefully positioned and clamped the detent brackets, then removed the console, drilled to #40 and clecoed the brackets in place.

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With the brackets clecoed, I reinstalled the console and tested function of the handles. They were dropping into all of the detents except the most forward on both sides, so I did a little filing on those slots until the lock pins dropped in smoothly and didn't bind against thumb button pressure. With the fit dialed in, I removed the console again, up-drilled to #30, deburred, did a little Alodine touch-up on the filed and drilled areas, countersunk the console top, bonded and pulled the rivets.

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I was disappointed to see that the forward mounting tabs for the center console weren't aligned, so one screw is a bit higher than the other and the console has a slight twist in it (probably why the forward detent was binding). I wish I had noticed that earlier, so I could have put a spacer behind the right side for drilling and installed it with a washer to take up the extra space. My consolation is that it'll be hidden by the instrument panel.

I'm not thrilled with the button head screws called out in the manual, so I'm planning to replace at least the aft two with countersunk flat heads instead.

Next I read through the cable installation procedure and began pulling together all of the parts I was going to need. I found that the cable links had been coated with the same thick, flaky primer that was used elsewhere. It's hard to see in this photo, but it was loose in places and rust had started underneath the primer in several places.

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To remedy this, I went after them with a Scotch-Brite stripping disc and some sanding, which left me with shiny steel parts.

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I cleaned them with acetone, set up a couple pieces of scrap angle as a makeshift stand, then shot the links with etching primer.

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While the primer flashed off, I did what has to be the most infuriating job so far: installing the rudder pedal return springs. These things fought me all the way. I think it took 45 min to install four springs, and I exhausted my vocabulary of epithets. What a pain!

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Finally, I gave the cable links a shot of black paint on one side. I'm keeping the garage warm overnight so it'll cure properly, then I'll shoot the other side first thing tomorrow.

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I'm finding it somewhat frustrating that even though I went through the inventory sheets and re-ordered all of the hardware, I'm coming up short on some things. I must have missed an entire page, as I don't have any of the bolts to install the brake cylinders, or to attach the cable bushings to the rudder pedal adjustment levers. So, another week wait for a Spruce delivery before I can move forward on the controls. Good thing there's plenty of other stuff to do...

Eric Page

02-16-2021, 12:06 AM

Today I continued working on the wingtip attachment strips. I dug out every small clamp I own, trimmed the strips to final length and clamped them in place. I didn't want to risk punching through with a drill and damaging the opposite cap strip, so I just made a divot in the aluminum at each existing hole location. Each strip is numbered for its position and labeled "A" for aft and "F" for forward.

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Next I removed the strips and finished drilling each hole through at the drill press.

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With the holes drilled and deburred, I could cleco them in place on the #10 rib. First the right wing, then the left. I felt a bit like an RV builder with all those clecoes in use at once.

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Can anyone think of a reason not to bond and rivet the wingtip mounting strips at this point in the build?

Sticking with the wings, I dug out the Dynon box and started running the pitot and AOA tubing. Not much to be done at this point except get the tubing from the pitot tube location to the outboard end of the wing. I used a wrap of silicone tape at each zip-tie location to protect the structure and the tubing. I'll run it down the aft spar once the wing is off the rotisserie (probably after covering).

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Finally, I installed the mounting bracket for the parking brake valve. Please pay no attention to the extra hole in my center console (I neglected to consider that the valve body has to clear the rivets -- a fact that the instructions don't mention -- and one of them was too close by about 1/16"!). I later filled the hole with Super-Fil and the console will be fabric covered, so I may have been harder on myself that was warranted.

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Jcard

02-16-2021, 06:12 AM

If my interpretation of the instructions is correct, the wingtip attach strips and #10 rib capstrips get drilled/countetsunk but not installed until after fabric. Finish tapes then cover the rivets on the wing.
The fabric must give the rivet more to bite on.
If I misunderstood the directions it would be great to install the strip and be done.

109JB

02-16-2021, 08:48 AM

It is not to give the rivets more bite, it is to make fabric easier. The fabric wraps the capstrip and the attach strip sandwiches the fabric in-between. Doing it this way you just have to wrap fabric around the end of the cap strip. If you attach the strip first, then the fabric has to go over the cap strip, joggle down to the aluminum attach strip, then around the end of the attach strip. Much easier to just wrap the cap strip. Getting fabric to lay in an inside corner can be a pain.

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Eric Page

02-16-2021, 02:32 PM

Sorry, guys. Y'all must think I've got a two-digit IQ. We just covered all of this in my other thread a few days ago, and yet I asked the same question here, again. I'll pull the clecoes and wait till after covering. Thanks.

Eric Page

02-16-2021, 10:42 PM

Another slightly frustrating and unproductive day. I got the roll servo mounted, but wasted a good hour and a foot of aluminum angle fabricating a bracket that didn't work on the airplane like it did in my head.

In the second photo below, you'll see two plastic cable ties around the servo motor. They're temporary, until I get a long enough steel hose clamp. The fuselage tube under the motor is wrapped with silicone tape, then there's a thin wood shim (which will come out for varnish tomorrow) to level the motor. The hose clamp will hold it all together and stiffen the mounting since the 3/4" angle isn't quite rigid enough on its own.

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After installing it in the plane and safety-wiring it in place (because why do it on the bench?), I installed a new shear screw in this servo, which Dynon was kind enough to send for free.

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I pulled the clecoes from the wing tip mounting strips and stored them for later.

A package arrived today from Spruce that had the 1" Adel clamp for the pitch servo to grab ahold of the elevator push-pull tube. I didn't mount it yet since the tube length isn't set, but I loosely attached it to the servo pushrod so it won't disappear.

bbs428

02-18-2021, 05:22 AM

Your the last person who I would think has a two digit IQ... That slot is reserved for me. :D

Love your work Eric. Keep on trucking!

Eric Page

02-20-2021, 12:19 PM

Took a day off on Thu this week. A Spruce package arrived with the missing hardware for the brake masters and rudder cables, so I got to work on those yesterday. First was the brakes, and I'm really glad I ordered another bag of -10 and -10L washers! Getting them in was a bit of a fiddle, and the hose fittings will need to be removed and reinstalled to clock them correctly, but it's progress.

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Remember those eight rudder links that I spent a couple of hours stripping, priming and painting earlier this week? Well, yesterday I found this in the S7 manual:

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That bold note isn't in the S5 manual, but reading ahead to the appendix that describes adjustable rudder pedal installation would have revealed that they're not used. However, the similar links that attach the cables to the rudder's control horns are missing, so I'll modify four of the pedal links for that duty.

Rudder cables were next. I read through both the S5 and S7 manuals, and the S7 instructions made more sense WRT position of swaging the co-pilot's cables to the pilot's. The S5 manual called for 67" but that put the swage right in front of one of the nylon pass-throughs, so I went with the S7 manual's 62" measurement.

I put a thimble on the end of the cable, attached it to the adjustment handle, then fed the whole length of cable around the pilot's pulley, through the plane and cut it off about 8" beyond the tail. Wash, rinse, repeat. A couple of C clamps held them in place while I worked, and I'll bundle them inside the fuselage for later rigging. I repeated that for the co-pilot side, except I cut them off at just beyond 62" aft of the carry-through, then taped them to a fuselage tube for now; I'm sure if I swage them now, they'll have to come out for something later.

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You'll notice that in the second photo above, the far (left) thimble attachment is fatter than the others. The tape slipped off the end of the cable during swaging and the cable immediately untwisted and went in all directions. The loose ends kept piercing the heat shrink during shrinking, so I had to put a wrap of gaffer tape around it to hold it tight, then cover that with larger heat shrink. You'll also notice that the washers are missing from the thimbles on the adjustment handle; I'm still mulling whether to order a box of 100 stainless steel #6 fender washers and drill some of them to a larger ID, or just grind a flat on some AN970s and hit them with primer.

I even remembered to put a Nicopress sleeve and a piece of heat shrink on the pilot's cables as I fed them through!

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I can't say that I'm terribly impressed with the Economy No. 3 Swage-It (https://www.aircraftspruce.com/catalog/topages/no3swageit.php) tool. It works well enough for what it is, and if I had it to do again I probably wouldn't buy the $300 tool (https://www.aircraftspruce.com/catalog/topages/63vxmp.php) for just eight sleeves, but the No. 3 Swage-It isn't easy to align correctly. The instructions tell you to leave a 1/32" gap between crimps, but you can't see into the jaws of the tool well enough to know if you've got that spacing. Sometimes as you tighten it, the sleeve slips sideways so you're tightening on the first (center) crimp instead of the end. Anyway, not all of mine are as pretty as I'd like, but I'm satisfied that they have more than enough margin for safety.

I was confused by one aspect of the cable installation. The instructions say to put the adjustment handles in the middle of their travel, but they don't mention a position for the rudder pedals or pulleys. Once the cables are in, it's pretty easy to pull the pedals upright from the tail by pulling on the cables. Is there a specific pedal position required for swaging the co-pilot and pilot cables together? It seems like having the cables kind of loose when you do that could lead to problems later. Shouldn't the pedals be pulled up to a position that matches the adjustment handles?

bumsteer

02-20-2021, 03:42 PM

Eric

Go to "builders hints and tips" and look at #47. It's a excellent method for swaging the cables. Also, if they still carry them, go to Lowes website and search for swaging tool. Got mine there for $30.

Rick

alexM

02-20-2021, 04:03 PM

Well I don't have adjustable pedals but I can tell you for sure in my instructions told me to clamp the pedals so the vertical tubes were perpendicular to the floor. I found that a chunk of 1x4 inserted just aft of the vertical tubes in the front of the fuselage was the perfect size to block the tubes vertical.

I thought I had a picture but I can't find it right now. Anyway that is when I discovered that the pedals weren't exactly lined up when the torque tubes were. So the step in the manual where it has you set the brake master cylinders to an exact length is only a starting point. I took the time to fine tune them until my pedals and tubes were all in perfect alignment, then clamped them and the 1x4 to the forward fuselage tubes.

I also cut and swaged my cables for the rudder per the helpful hints section (page 46-ish), and once those were nailed I swaged and cut the right side cables. Make sure your rudder hinge gap is where you want it, and the rudder is clamped in the centered position before cutting the aft ends!

I had zero issues with the swaging tool (bought mine from Kitfox but it looks like yours), and have actually used it since to crimp up some heavy duty battery cables (different vehicle). Just eyeball it best you can and alternate tightening the two bolts about 1/4 turn at a time. My instructions said to bottom the tool out, so I did. I swaged the center of the ferrule first and then one on either side. Easy.

I also used the superglue trick on the cable, soaking about an inch of it pretty good before cutting. I think I only created one "meat hook" but it's hidden under the heat shrink now.

Eric Page

02-20-2021, 07:26 PM

Go to "builders hints and tips" and look at #47. It's a excellent method for swaging the cables. Also, if they still carry them, go to Lowes website and search for swaging tool. Got mine there for $30.
Thanks for that. I've read that whole thread, but remembering everything good that you've read on here is nigh impossible, and coming back here before every step is a recipe for an endless build! Definitely worth reading again.

Shucks, if I had known that cheap hardware store crimper would do the job, I never would have ordered the Swage-It tool. I assumed those things were for another kind of sleeve and wouldn't be suitable for aviation parts. Home Depot carries the identical tool.

...I can tell you for sure in my instructions told me to clamp the pedals so the vertical tubes were perpendicular to the floor.
Yeah, this whole process is a bit if a muddle. The appendix in my S5 manual (PDF) for adjustable pedals just says to put the handles in the middle of their travel. The pedals aren't mentioned until the "after covering" paragraph about swaging the rudder connections, where the pilot's adjust handle and pedal go full forward with the brake deflected. The next paragraph (which is done before the paragraph that precedes it!), about swaging the co-pilot's cables, says to "set both adjust levers in the same notch [and] put all four pedals in the same [unspecified] position." I'll just follow the advice in Hints & Tips, and use your 1x4 trick. Apparently it works!

I thought I had a picture but I can't find it right now. Anyway that is when I discovered that the pedals weren't exactly lined up when the torque tubes were. So the step in the manual where it has you set the brake master cylinders to an exact length is only a starting point. I took the time to fine tune them until my pedals and tubes were all in perfect alignment, then clamped them and the 1x4 to the forward fuselage tubes.
When you say, "pedals and tubes ... in perfect alignment," I'm not quite picturing what you mean. The tabs that the cables attach to (or in my case, the pulleys) are fixed with respect to the pedal uprights. Do you mean that the pedals were all in the same plane, and at the same angle (as set by the length of the master cylinders)?

I'm more or less forced to stop at this point anyway, as I don't have the firewall I'm going to be using yet, so I can't set the 1/4" spacing between the pedals and foot-wells. I'll probably have to wait until after covering.

Just eyeball it best you can and alternate tightening the two bolts about 1/4 turn at a time. My instructions said to bottom the tool out, so I did. I swaged the center of the ferrule first and then one on either side. Easy.
Yep, that's exactly what I've been doing. I guess I got the cool and you got the talent!

I also used the superglue trick on the cable, soaking about an inch of it pretty good before cutting. I think I only created one "meat hook" but it's hidden under the heat shrink now.
First time I've heard of that. If it's in the Hints and Tips thread, I must have been falling asleep when I got to that part. I'm definitely stealing that idea for the rest of the job.

Just computer work today, dreaming about the instrument panel. Didn't touch any tools.

Eric Page

02-23-2021, 12:35 PM

Finally got back to the project yesterday afternoon. I started by making a ground plane for the transponder antenna, this time doing the math correctly. The part is cut from a piece of galvanized step flashing from the aviation section at Home Depot. I center-punched the middle, then used a compass to mark out the circle. It was cut out with a manual nibbler, which was slow-going but produced a nice accurate edge that only needed a touch on the sander to smooth it out.

Just for belt-and-suspenders reasons, I shot it with etching primer, minus the area where the lock washer makes connection on the back side. Finished weight: 1.8 oz.

I only bought one piece of flashing and there wasn't enough left for the ADS-B antenna, but I'll be in town tomorrow so I'll stop for another piece.

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I made up my mind to try modifying some AN970 washers to replace the odd-ball washers supplied by SkyStar as thimble retainers on the rudder cables. It seemed to work fine, so I also primed and painted them black to match the adjustment handles. The bolts here are corroded garbage from the first build.

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Finally, I shortened four of the rudder pedal links to serve as rudder links, then re-primed and painted them as well. I'll need to re-ream the holes after four layers of primer and paint!

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Eric Page

02-23-2021, 01:22 PM

I spent a couple of hours this morning working on repairing a hinge slot tear in my flaperon skins. I wrote up that process in the "Repairing flaperons" thread (https://teamkitfox.com/Forums/threads/4445-Repairing-flaperons?p=97999&viewfull=1#post97999).

Eric Page

02-24-2021, 10:49 AM

Spent most of the day in the garage yesterday. I installed a total of three leading edge patches on my flaperons (two on one, one on the other) and one at the aft end of a slot. I'm really happy with how it turned out. The flaperons would be prettier without patches on them, but this worked much better than I expected.

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Once the patches were done, I got busy sanding out the numerous scratches with 320-grit. It appeared that the first builder had sliced the plastic protective film in a chord-wise direction, about every four inches across nearly the whole span of the flaperons, leaving straight scratches. They were also just generally beat up after 25 years of handling and storage.

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After about an hour of gentle sanding, they look and feel a lot better. I'm never going to have polished flaperons, but with judicious use of SuperFil to cover a few small dents that remain, they should look good after painting.

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One down and one to go...

jiott

02-24-2021, 01:03 PM

Eric, just FYI, I don't know what type of 320 grit sandpaper you used, but be aware that the builder's tips say not to use a silica based sandpaper on aluminum due to possible corrosion issues. Scotch brite is recommended. If you did use a silica sandpaper there may be a deep cleaning process to remove all the silica debris before paint.

jrevens

02-24-2021, 06:11 PM

Jim's right... you want aluminum oxide, if anything. Silicon carbide is bad. Also, FWIW, I'd be cautious of too much sanding. I believe those 0.016" skins are 2024-T3 alclad - a very thin layer of pure aluminum on the surface of the 2024 alloy. I would hazard a guess that you have already removed much of that protective layer. A good protective primer is going to be very important. I'm sure you probably know that already, but figure it doesn't hurt to mention it.

Eric Page

02-24-2021, 06:59 PM

Thanks, guys. I'm using 3M aluminum oxide paper. I'll give them a couple of good wipe-downs with acetone and get a mist of primer on them once I'm finished, so they're protected until paint.

PapuaPilot

02-25-2021, 10:03 AM

From what I see in the pictures you haven't gone through the Alclad layer. It is usually very obvious if you have sanded though the layer, the alloyed aluminum in the center is not as shiny.

The AMT General Handbook says the outer layers are normally 5.5% of the total thickness per side. This means for 0.016" aluminum the outer layer would only be about .001" thick. That doesn't leave much for sanding.

Eric Page

02-25-2021, 10:28 AM

If that's the case, I'd have a hard time believing that I didn't get through the Alclad in a few places. Some of the scratches were sharp enough that I definitely wanted to eliminate them, and deep enough to exceed 0.001".

PapuaPilot

02-25-2021, 10:34 AM

I would recommend using the red Scotch Brite to finish up.

Eric Page

02-25-2021, 11:43 AM

Do you mean maroon ("very fine")? The charts I've found list maroon pads as 320-grit aluminum oxide, same as the paper I've been using. What's the advantage of using a Scotch-Brite pad of the same grit?

PapuaPilot

02-25-2021, 02:48 PM

Yes, maroon. I like how it works because it doesn't lose any of the grit. It does a great job over an around rivet heads and getting in corners. It doesn't sand down rivet heads like sandpaper does.

bumsteer

02-25-2021, 03:54 PM

I would totally agree with Phil.

Rick

Eric Page

02-25-2021, 10:56 PM

Ah, OK, got it. Just easier to work around various items on the surface with a pad than with paper.

Started out today by finishing sanding out the flaperon scratches. Once I was happy with that, I wiped them down really well with acetone, then mixed up a few grams of SuperFil and smeared it into all of the dents. Many of them were very small and probably could have been left alone, but I had the cup in my hand, so I went nuts. Those will get another light sanding to take down the SuperFil in a couple of days.

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Maybe then I'll see what I'm going to do about shaping the outboard ends. I bought the plastic tips from Kitfox, but I'm not much impressed with how they fit; I think another round of pink foam, Hysol and SuperFil might be faster and easier than fighting with those.

Next I fabricated the second antenna ground plane, for the ADS-B receiver. I used a cut-off wheel on the angle grinder this time, and it went a LOT faster than the hand nibbler. That got it within about 1/8", and about 10 minutes at the disc sander and Scotch-Brite wheel had it dialed in exactly. I got one side shot with primer and I'll get the other side tomorrow.

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A package arrived from Kitfox a few days ago, containing the fabric reinforcing plates that I'll need for covering, and a new chunk of Delrin for the horizontal stab bearing blocks. I cut that in half, sanded it to fit the holders on the leading edge and installed the stab to set their position.

I dug out the horizontal stab brace rods for the first time since bringing the plane home, cleaned and lubricated the rod end bearings, used ACF-50 and Scotch-Brite on the male threads at the top ends of the rods to remove a little rust, installed the missing jam nuts and set about aligning the stab. That's where I've run into a problem.

I've measured the horizontal stab's position three different ways:

Using a tape measure from the middle of the vertical stab tip to the middle of the horizontal stab tips
Using a string from the outer bushing carriers across the top of the vertical stab
Using a digital level to compare the horizontal stab with the wing rear spar carry-through

In the first two cases the measurements agree exactly and with the digital level it's within 0.2°, which is probably within the accuracy/repeatability of the instrument.

My problem is this: the rod end bearing on the left side has about 1/4" of thread showing between the bearing body and the end of the tube, but on the right side, I've got the rod end threaded on as far as it will go but the assembly is still too long by about 3/32".

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The only solution I can think of is to grind some length off the body of the rod end to allow more room to wind it further onto the rod. Is that permissible, or can anyone offer another idea? At this point I'm kinda stuck!

jrevens

02-25-2021, 11:31 PM

[QUOTE=
My problem is this: the rod end bearing on the left side has about 1/4" of thread showing between the bearing body and the end of the tube, but on the right side, I've got the rod end threaded on as far as it will go but the assembly is still too long by about 3/32".

The only solution I can think of is to grind some length off the body of the rod end to allow more room to wind it further onto the rod. Is that permissible, or can anyone offer another idea? At this point I'm kinda stuck![/QUOTE]

Just curious... have you compared the exact length of the two struts?

109JB

02-25-2021, 11:40 PM

Have you sighted the trailing edge of the stabilizer to see if it is straight?

napierm

02-26-2021, 03:11 AM

I used Hysol mixed with micro balloons. Added micro until it was a light fluffy paste. Very light and tough.

Maybe then I'll see what I'm going to do about shaping the outboard ends. I bought the plastic tips from Kitfox, but I'm not much impressed with how they fit; I think another round of pink foam, Hysol and SuperFil might be faster and easier than fighting with those.

Jerrytex

02-26-2021, 07:29 AM

On the stabilizer lift struts....I ran into the same issue when rigging my horizontal stabilizer. What I found was the welded "cross member" on the frame was welded in slightly off center. I have seen this on a few earlier kitfox 5 frames now that I know about it. On the bare frame, it's hard to see, but after covering, it's more noticeable. I did exactly what you said..... I ground down a little (3/16") from the end of the rod end. The amount is negligible, and after discussing it with a 30+ year aircraft mechanic, he agreed.

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Eric Page

02-26-2021, 11:39 AM

Just curious... have you compared the exact length of the two struts?
Yes, and (unfortunately?) they're within 1/32" of each other.

Eric Page

02-26-2021, 11:46 AM

What I found was the welded "cross member" on the frame was welded in slightly off center. I have seen this on a few earlier kitfox 5 frames now that I know about it. On the bare frame, it's hard to see, but after covering, it's more noticeable.
Yup, you nailed it; mine is off-center by 1/4"!

I did exactly what you said..... I ground down a little (3/16") from the end of the rod end. The amount is negligible, and after discussing it with a 30+ year aircraft mechanic, he agreed.
Thanks. I'll do that too. I figured it would be fine since there will still be at least an inch of thread engagement.

Eric Page

02-26-2021, 11:49 AM

Have you sighted the trailing edge of the stabilizer to see if it is straight?
I had not, but just did. It's straight as an arrow.

Eric Page

02-26-2021, 11:27 PM

I started today by getting the stab trim actuator installed. The bottom end went fine, but I thought at first that the top was going to be a problem. It came from SkyStar with a rod end bearing that has a 1/4" through-hole and uses and bushing to adapt it to an AN3 bolt. The bushing was missing from the hardware I received with the project, but shortly after posting a question about that bushing, I remembered that I had an extra rod end from the three I replaced at the rudder (the other two aren't usable). I replaced the rod end on the actuator with that one, which has a 3/16" through-hole, eliminating the need for a bushing.

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Next I flipped the flaperons over and inspected the other side. One was totally clean of dents and the other had just a few, so I wiped that one with acetone, mixed up 3g of SuperFil and covered those dents.

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I had sprayed primer on the second side of yesterday's antenna ground plane last night, so I scraped away a small ring on the back side for electrical contact and installed the antenna. So, both of those are done.

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Remember how I had to remove the bottom few inches of the fiberglass fairing on the rudder for welding the tail post reinforcement, then reattached the fairing piece and reinforced the cut with thin strips of wood? Yeah... that wasn't a good idea. They're blocking the tips of the rudder stops on both sides so the rudder only has about 10 degrees of movement.

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I think a light touch with the angle grinder should square off those tips and give them clearance, but it sure would have been nice to see that coming and use shorter sticks of wood. And yes, I agree, I need to clean up that SuperFil on the inside of the rudder. I didn't realize that much squeezed through!

Anyway, while the rudder was on-and-off, I got the new rod end bearings set at the right length to set the rudder position. I'll need to reshape the aft end of the vertical stab tip just a bit, as I left it square until I could see how much needed to be removed.

As suggested in a post above, I removed the rod end from the right side horizontal stab brace and shortened it on the disc sander. I also had to shorten the male threads on the end of the brace tube, but I've got a very nice fit now, and there's still lots of thread engagement in the rod end.

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With that sorted out, I got back to the slider blocks. I squeezed them tight against the square tube in the tail, then carefully removed the stab to my work table. I closed them up by what looked like a few thousandths, then drilled through with a #34 and actually hit the hole on the other side of the rectangular tube all four times! With the hardware installed I test fit it and found it too tight, as intended. This allowed me to sand a bit at a time until it slid smoothly into place with zero fore/aft play at the tips of the stab -- a much nicer fit than I had before.

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While I had the horizontal stab on the bench, I began fabricating the cover plates for the brace attachment points. The first builder already installed the brackets they screw into, and they're functional if not pretty, so I didn't try to remove them. I first marked out the cut lines and hole positions, then used the nibbler to cut them out.

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Once drilled, all the holes lined up and it looks like it'll work just great. It'll need a little gentle shaping to sit flush against the aft tube but I'll plan to do that, and make the slot and hole for the brace tube, when I get closer to final assembly.

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I repeated that on the other side with the same result. It's amazing how nicely parts turn out if you think through the process, use the right tools and take your time.

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taff

02-27-2021, 10:08 AM

alexM

02-27-2021, 08:33 PM

I think Tanya Harding lives down in your area. I'm going to have to hire her to slow you down so I can catch up.

Eric Page

02-28-2021, 01:01 AM

I think Tanya Harding lives down in your area. I'm going to have to hire her to slow you down so I can catch up.
Ha! You're nowhere near as far behind as you think. I still have plenty of first-builder-repairs to accomplish along the way. If I'd break down and order some electronics, I could really get moving on the fuselage, but there's still so much other stuff staring me in the face. One item I'm dreading is putting the wings on to check rigging; if that was done as poorly as the rest, you'll shoot right into the lead.

Today's efforts began with a lot more sanding. The SuperFil on the flaperons was cured, so I set about removing almost all of it. It worked like magic, and I now have one flaperon that's nice and smooth, and one that needed three spots (the deepest dents) slathered with a second application. I put that on as thinly and evenly as possible, to reduce the sanding effort required tomorrow afternoon.

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The large hose clamp arrived from Spruce, so I got that installed around the autopilot roll servo. It took another wrap of silicone tape to protect the fuselage tube, but it's now very solid. Is it common practice to apply torque seal to the drive screw on a hose clamp?

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Next up was some more work on the rudder. I filed down that excess SuperFil you saw yesterday, then attacked the fuselage rudder stops with my angle grinder so they would clear the wood reinforcements inside the fiberglass fairing. I ended up removing just a bit more than is shown here, but you get the idea. Once I'm sure they fit, I'll prime and paint them.

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I needed to reshape the trailing end of the vertical stab tip to make room for the rudder, so a few minutes with the wood rasp took care of that. I'll get some Hysol on it tomorrow. I meant to do that today, but I got a bit red-faced over something else and never got it done...

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Today's frustration centered around two things:

First, the build manual has you set the rudder's spacing from the vertical stab by measuring between their respective vertical tubes at the top and bottom, and adjusting the rod end bearings accordingly. That's great if you're doing it in the order shown in the manual, but just you try doing it when the fiberglass fairings and "pleasingly shaped" tip are already installed. The only way I could come up with to approximately measure the gaps was to mark a small strip of wood at the appropriate lengths, then slide it into the gap and sight across the front of the rudder's vertical tube. When I got it set to my marks, it still looked like it would rub at the bottom once the fabric is on, so I wound that bearing out one more turn. I find it frustrating that I can't do it "right" and be totally accurate, but I know it's not critical.

More frustrating was the second issue. With the rudder attached at the top and bottom bearings, the bottom of the rudder was offset to the right by roughly 1/8" and the center bearing was out of alignment by at least that much. The only way I could fully install the rudder was to pull the middle of the rudder's forward tube to the left while inserting the center bolt (which would be impossible once it's covered). The torsion that created in the tube caused the rudder to spring to full left deflection when you let go of it. It only took an ounce or two of force to re-center it, which might not be noticeable in flight, but I ain't havin' it!

I could think of only two ways to resolve this: either cut off the threaded bosses on the tail post, load the fuselage back on the flat-bed trailer and take it to the welder to have them reattached in the proper alignment; or, put a lever on the bearings and gently bend them a bit. I chose the latter. My biggest adjustable wrench was pressed into service as a makeshift pry bar, and in short order I had the bottom bearing axis centered and the middle bearing aligned with the rudder's mounting tabs. Reassuringly, the rudder is now happy to hang in perfect alignment with the stab.

The next problem will probably be rudder overtravel. I need to pick up an angle finder to be sure (I'll be at Home Depot tomorrow morning), but it appears that my rudder can rotate more than the specified 25 degrees, despite the fact that no material has yet been removed from the stopping surface of the rudder stop bracket. I'll measure it tomorrow, but get your suggestions ready!

Eric Page

02-28-2021, 01:10 AM

I was looking at this photo, may I suggest a method to avoid getting paint flowing at edge and making the disc stick to the table.
It's easier to pick object off table and It help prevent the object from blowing away when you use normal spray equipment.
That part didn't actually stick to the table, believe it or not. I've been putting nuts and bolts from my garbage pile underneath parts to lift them up for painting, but I could see how a light object might not stay put when sprayed. I like your technique, as it not only lifts the part but holds it in place. Thanks!

efwd

02-28-2021, 06:13 AM

alexM

02-28-2021, 08:50 AM

I had the same issue regarding setting the rudder hinge length, since my rudder fairing had been installed by the previous builder. No way to measure the metal to metal distance and who knows if the fairing was installed right after that?

I fiddled with the gap for quite a while, leaving out the center bearing until I got the gap at the top and bottom set. You need to account for the fabric that will be doubled up on both sides but you don't want a giant gap either.

Thankfully I did not have the issue you did with the sideways shift of one of those bearing mounts.

I am also facing the issue with rudder over travel. Mine swings far enough to hit the elevator. The good news is there are some creative solutions here on the forum which involve adding some set screws, which provide adjustment.

jrevens

02-28-2021, 10:25 AM

You might consider using a piece of rubber hose to protect the airframe from that large hose clamp rather than the silicone tape. I employed the silicone tape under a number of wire ties on the engine mount and on this 100hr engine inspection I notice a couple wire ties that cut through the silicone. Much more heat and vibration in my installation but something to consider since it is a metal edge of the clamp that will do some real damage if the silicone tape fails.

Good point Eddie. Silicone tape is very soft, and it “cold flows”. My experience is that it’s not particularly good under clamps. Clear urethane tape - the kind that is used for protection of leading edges of wings and propellers, car bras, etc., is very tough and great for that purpose.

Eric Page

02-28-2021, 11:29 AM

You might consider using a piece of rubber hose to protect the airframe from that large hose clamp rather than the silicone tape.

Good point Eddie. Silicone tape is very soft, and it “cold flows”. My experience is that it’s not particularly good under clamps. Clear urethane tape - the kind that is used for protection of leading edges of wings and propellers, car bras, etc., is very tough and great for that purpose.

EXCELLENT points, gents. I'll make that change next time I'm in the garage. I have some rubber hose that came with the project (part of a 912UL firewall forward kit, I think). I'll chop off a short length of that and split it open.

I had the same issue regarding setting the rudder hinge length, since my rudder fairing had been installed by the previous builder. No way to measure the metal to metal distance and who knows if the fairing was installed right after that?
Exactly. I suspect that the fairing on my rudder is too far forward, hence the inadequate room for fabric even with the tube spacing set. I'm not that bothered, given that there's still 80% of the rod ends' threads engaged.

I am also facing the issue with rudder over travel. Mine swings far enough to hit the elevator. The good news is there are some creative solutions here on the forum which involve adding some set screws, which provide adjustment.
I'll do some searching for that; thanks.

Eric Page

02-28-2021, 11:37 AM

I found the info you mentioned, Alex, as well as this very sage advice from Jim Ott:

I strongly recommend you don't set you final rudder stops until you have covered and painted the tail (applies only to airfoiled tail). The reason is the covering and painting add quite a bit of thickness to the rudder leading edge as well as the fairing on the vertical tail. You will then find you need to back out the rudder mounting rod eyes to allow clearance. As soon as you do that, it changes the rudder stops, which then requires you to ADD material to the rudder stops which is far more difficult to do than removing material. Just cool your jets and wait until covering and painting are done, then tackle this easy task of final rudder stops. Don't ask me how I know all this.

I think I'll be happy with getting the alignment fixed and sit tight on the rest for now. Thanks, Jim!

Eric Page

03-01-2021, 12:02 PM

Not much time on the build yesterday.

I took the big hose clamp off the roll servo and cut the silicone tape off of the fuselage tube. I'm very glad I did, as the clamp had already cut through it despite the plane sitting stationary on sawhorses. I found a few lengths of 5/16" MIL-H-6000 hose in the engine components box (1/94 manufacture date -- won't be using that on the engine!). I cut about 3" of it, slit it open, and put it around the fuselage tube. It not only does a much better job protecting the tube, it also replaces the wood shim I had in that space. Thanks again, Eddie and John.

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I assembled the hardware for the trim actuator scissor links. All great except I'm missing two #10 nylon washers. I was very careful to keep hardware organized as I removed it (usually put it back through the holes it came out of), so I can only conclude that the first builder didn't install them. The four nylon washers in this assembly are the first hardware that I've reused; everything else on the plane has been new.

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Eric Page

03-02-2021, 11:38 PM

Began today sanding on one of the flaperons again. This is the one that had the three deepest dents, which I filled with SuperFil last time. I block sanded them until they were flush and flat, but two had very slight divots in the SuperFil that needed just a tad more applied to get them smooth. So, more sanding next time!

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I put a layer of Hysol on the aft end of the vertical stab tip, sealing up the exposed foam. That'll also need sanding. I wonder if RV builders do this much sanding...

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Next I got to work on the outboard tips of the flaperons. I cut two pieces of pink foam to the right size, traced the outline of each flaperon onto them, then worked them with a utility knife and some -- you guessed it: sanding! -- until they were the right shape to slip into the ends of the flaperons.

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Then I mixed up some Hysol, smeared it around the inner half-inch of the foam plugs and bonded them in.

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I'm guessing there'll be more sanding tomorrow.

Eric Page

03-03-2021, 11:03 PM

Today I started by sanding out the three spots of SuperFil that I added to one flaperon yesterday. One of them still needed a bit more to bring it level with the surrounding aluminum, so I mixed up a bit more and did that.

While I had the flaperons in front of me, I did some more work on the tips. I started with the trusty wood rasp, first the rough side, then the fine, giving them a "pleasing" shape.

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Then I mixed up a batch of Hysol and added some micro balloons to slather on the foam. I didn't get a photo of it, but I did mask the end of the aluminum before applying the Hysol, then peeled it off before it set up.

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I can't say that I'm a fan of the Hysol+micro combination. It got really thick and stringy; much harder to smear to a smooth finish than straight Hysol. I'm hopeful that it'll be easier to sand than straight Hysol, because if it's not, I've got big job ahead of me. In either case, I'm sure they'll need a couple applications of SuperFil to get to a finished state.

You probably noticed that the trailing edges of these foam tips are very thin. I strongly suspect that they'll break off if I look at them the wrong way, so I'm contemplating just breaking them off on purpose and rebuilding them out of SuperFil, perhaps with some chopped glass fiber mixed in for strength.

Next I got started on repairing the seat pan. I put it in the plane and took some photos of the areas where the fit is poor, or where the cuts made by the first builder were unacceptably rough. I won't post the full horror, but here's a sampling of the butchery.

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I have absolutely no idea what's going on with all of the drilled holes in oddly shaped groups.

My first step was to get the thing looking a little better, so I sanded the gelcoat lightly to remove staining and scratches. In the first photo, the right half is done, and in the second, the whole thing. If you haven't done it, I can't recommend this job. Gelcoat sands to a very fine powder that floats away and coats everything. Quite a mess.

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Next I started on the repairs. Using coarse (100 grit?) paper, I sanded the back side of the pan around each of the spots where it was drilled to rough it up for patching. Then I vacuumed up the dust, wiped it well with acetone and applied a piece of packing tape over each group of holes.

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Then I opened a can of this stuff...

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...and just about gagged. Talk about foul! The lid went right back on while I put on my respirator. With PPE in place, I measured out 10 grams and added 5 drops of MEKP activator (or is it catalyzer?). The putty (really more of a gel consistency) comes out of the can a pale blue color, but changes to a light green when you mix in the MEKP. Like with Hysol, it's a handy way to know that you've mixed it thoroughly.

Working from the back side, I troweled a small amount into each group of holes, including a thin skim of it on the surrounding area so it will hopefully get a good grip on the seat.

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Once the holes were all filled I had some of the putty left, so I decided to do a little experiment on one edge. I don't really know what I'm doing here, so go easy on me if you're a fiberglass pro (Alex...).

I used a piece of packing tape to form a small dam against the edge of the seat pan where there was a particularly rough cut, then applied putty against the edge of the pan and the tape. I built it up to what looked like enough, then set the whole mess aside to cure. I suspect this won't have enough strength to avoid snapping off, but I went into it thinking it was an experiment. If it does snap off I'm right back where I started, with only a few minutes wasted.

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I think when I use this stuff again, I'm going to mix in quite a bit more chopped glass fiber to thicken it up. It was a very loose gel, and hard to sculpt to the shape I wanted. It doesn't slump, but it's very soft.

Jerrytex

03-04-2021, 07:56 AM

Looks good. Yeah the original builder probably did everyone a favor by passing on that plane to someone who actually cares about workmanship.

On my untouched seat pan, the upper corners seemed weak. They flexed quite a bit and were cracked. I reinforced both corners with layers of fiberglass and reshaped. Not sure if it was just the quality of the fiberglass parts back then or what. However, I will say that even the new fiberglass parts leave a lot to be desired. Although, the beauty of fiberglass is... it's easy to fix but still a PITA.

taff

03-04-2021, 09:14 AM

I saw the molded seat units your working on.
Boy is that downright butchery:eek:

It looks like you have the right product to fix the muckups.
It's good to see that your not leaving the buggered up units the way they were.

efwd

03-04-2021, 09:30 AM

regarding the foam on the flapperon, I tapered mine back where the relief just met the trailing edge of the aluminum. I don't have any free hanging material by the time it reaches the trailing edge. Use a 5X7 index card like a squeegee. Wrap it around the tip and drag it across the foam and hysol. Straight Hysol goes to a glossy smooth finish when used alone. I barely needed to sand on the hysol at all. I then filled in the low spots with smurf poop and sanded smooth for paint.

Eric Page

03-04-2021, 07:05 PM

Looks good. Yeah the original builder probably did everyone a favor by passing on that plane to someone who actually cares about workmanship.
I do care about it, I'm just not sure that I always achieve it! I'm pretty sure this airplane would have become a statistic if it had been completed. That is, assuming it had gotten an Airworthiness Cert. Having met the builder a couple of times, I'm not sure that would have stopped him from flying it.

On my untouched seat pan, the upper corners seemed weak. They flexed quite a bit and were cracked. I reinforced both corners with layers of fiberglass and reshaped.
Yes, the corner near the pilot's left shoulder on my seat pan is cracked where it lays on a diagonal tube, so I think I'll have to do the same thing. I got some fiberglass and resin from Spruce, just in case.

regarding the foam on the flapperon, I tapered mine back where the relief just met the trailing edge of the aluminum. I don't have any free hanging material by the time it reaches the trailing edge. Use a 5X7 index card like a squeegee. Wrap it around the tip and drag it across the foam and hysol. Straight Hysol goes to a glossy smooth finish when used alone. I barely needed to sand on the hysol at all. I then filled in the low spots with smurf poop and sanded smooth for paint.
That sounds like a good idea. I wasn't able to work on the plane today, but I'll check the tips tomorrow and see how sturdy those trailing edges are. I don't expect them to work as I did them, so I'll probably just cut the foam off flush, glue on a new piece and do as you suggested. Thanks for the idea!

alexM

03-04-2021, 07:20 PM

That crime scene of holes is because the series 5 manual has you make slots and use zip ties to hold the seat pan to the tube structure. We all know your PO had terrible aim with a drill, but wow. He was either mostly blind or highly intoxicated.

Filling with resin/milled fiber was the correct thing to do. And absolutely nothing wrong with using packing tape or pretty much any damn thing you can think of to hold the stuff to a shape. It's pretty damn strong stuff. I never tried it but you could probably tap a threaded hole in it.

Oh speaking of intoxicated, that smell you experienced is the styrene in the resin. Do NOT be tempted to use that stuff on the foam you used on your flaperon tips. That stuff is styrene too and any contact from that resin/milled fiber will eat holes instantly.

Eric Page

03-06-2021, 07:26 PM

Well, it would seem that fiberglass work isn't as easy as it looks on TV.

After 18 hours my garage still stunk to high heaven and the putty I put in the seat pan holes had only firmed up a little bit (ambient temp ~65dF). I moved the seat directly in front of the heater with a fan blowing across it, and after 36 hours most of the patches have cured but a few are still tacky. Most don't feel very solid and I wouldn't dare attempt to re-drill through them (except to remove the failed patches).

As I suspected, the edge repair didn't grab ahold of the existing glass/resin and snapped off with very little pressure. I don't think this putty is going to work as an edge repair.

The repair putty cured to a translucent appearance, and it doesn't seem to contain very much glass fiber. I'm thinking that I should mix in quite a bit more for the next attempt.

Oh, and don't ever put packing tape on the gelcoat side of your seat pan. The tape comes off fine but leaves all of its adhesive behind. Removing it takes a lot of acetone and a lot of elbow grease.

Anyway, I'm at a loss on how to proceed...

taff

03-06-2021, 09:26 PM

Go to Pep Boys or somewhere.

Buy a rotary sanding mandrel and 24 grit disc (I think they are 2" across.)
You will need this in your drill to prep the back side of the seat. Do a good job, to make sure the repair holds good.

Buy a fiberglass mat and resin kit.

Get some of those real cheap 2" brushes and some paper mixing cups from Walmart or somewhere.

Get some light soft aluminum and bend form it to the white side of the seat. This will be your support for applying the fiberglass.
Tape in down with duct tape.
Before taping down the aluminum cut a piece of kitchen wax paper. this is going to prevent the polyester resin from sticking to the aluminum.

Get a little glue to hold the wax paper to the aluminum.
(if you have a spray can of upholstery glue that would be good but anything will work. It ain't going to hold good because you trying to stick wax paper, but something to stop the paper from falling out.)

109JB

03-06-2021, 11:40 PM

Not sure but I think the seat pan is epoxy resin, which means you can't use polyester based resin on it. Even if it is polyester you can use epoxy on it, so I would default to epoxy.

taff

03-07-2021, 07:02 AM

Agree, use epoxy if the part is made with epoxy or polyester resin.
Polyester resin if part is made with polyester resin

The seats have a white gel coat, this is normally a polyester resin, so I am thinking they are all polyester. And from memory of when I built my Fox.
If your familier, you can detect polyester while your grinding the back side, from the smell. (wear a mask while sanding and sniff after the dust settles)

Or hand sand a area of white gel coat with P180 grit, just a small area enough to get white powder on the sandpaper and smell = this is polyester.
Compare the back side sanding to that smell. If it's the same = polyester.

I was thinking...Instead of getting thin aluminum. Get a large soft drink bottle (Coke) something with non profiled sides.
And cut it down the length to fit the shape of the lip of the seat. Maybe that would work?

This is a good epoxy (from ACS) it has a quick drying hardener also.

rv9ralph

03-07-2021, 09:00 AM

Also, when doing a patch like that on fiberglass, you need to scarf (think wood joint) the edge to give the repair some "grip". I just did some repairs on my seat pan, I scarfed the edge at least 1". If you use something to support the edge to build it out, put packing tape on it and the resin won't stick to the tape. The easiest way to apply the glass, is to lay out some plastic sheet on a flat work surface, wet out the glass on this using the minimal amount of epoxy needed to wet the glass, use a rotary cutter to cut the wetted glass into 1" wide strips, apply the wetted strips to the repair overlapping the edges and build up the edge area to the appropriate thickness. Do this from the front and again from the back, When the glass is partially cured to the "leather" stage cut with scissors to the desired edge.

Ralph

Eric Page

03-07-2021, 11:43 AM

Thanks very much, guys. Lots to go on there.

I must have been expecting magic from that edge repair; it didn't have a hope of sticking with no overlap (scarf).

I'll be away much of today, but I'll do the sand-and-sniff test this evening to see if I can confirm the seat is made from polyester resin. If so, I'll re-try the hole repairs first, mixing in more milled glass fiber to get a much thicker slurry. Maybe it would be useful to sand a rough divot into the gelcoat side with coarse paper, so the putty has something to grab onto on both sides. I think I'll also add a couple more drops of MEKP to see if it'll cure faster than three days.

If that works, then I'll take a stab at the edges. I have a couple yards of glass mat and a quart kit of Poly Epoxy (https://www.aircraftspruce.com/catalog/cmpages/polyepoxy.php?clickkey=58233).

Eric Page

03-09-2021, 12:00 AM

I guess I got a little burned out. I was away from the project for a few days, except for spending some time working on instrument panel layout. I don't have anything to show for it yet, but a few ideas are forming up in my tiny brain. Today I got back out to the garage.

Speaking of the instrument panel, that's today's first-builder-horror-show. He must have intended to use a traditional radio stack down the middle, as he had glued and riveted two pieces of aluminum angle to the back, presumably to support radio trays. I wish I had taken a photo of the panel before I started working on it, but I forgot. The back side was awash in what looked like Gorilla Glue, and he had used flush rivets from the front, except...

...wait for it...

...without countersinking the aluminum! The result was that the rivet heads were sticking up proud of the surface at odd angles.

You'll also notice in the photo that there are four columns of rivet holes instead of two. I guess the first two columns were in the wrong place. By a full quarter of an inch. Because good layout is so much work.

Anyway, I drilled out the rivets, knocked the Gorilla Glue loose, used a sharp wood chisel to remove most of the caked-on glue, then sanded the back side with 120-grit to remove the rest of the residue. On the front I found that none of the rivet holes had been deburred, and the panel was stained and had glue spots on it as well, so I block-sanded with 320-grit, in line with the grain.

I think it looks a LOT better, but I'm still unsure whether I'll be able to use it. I'm planning to put something over the aluminum anyway, so the extra holes won't show, but it will depend whether they interfere with any of the cutouts I need to make for the screen and other items. Fingers crossed that I haven't wasted an hour of work.

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Next I got back to work on the flaperon tips. About half an hour with my trusty wood rasp (this airplane is the most use that tool has ever gotten!) took down all the high spots and sharp edges on the Hysol (it was no easier to work with microballoons than without). I followed that with some 120-grit sanding, which gave me roughly the shapes I wanted. Unbelievably, the trailing edges are quite strong and seem to be stuck to the aluminum, so I'm going to press on with them for now and keep my fingers crossed.

The two tips aren't identically shaped, but since they'll be ~25 feet away from each other, I'm not going to worry about it!

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I mixed up 1.5 oz of SuperFil and liberally coated the tips to fill in all the low spots. I was also careful to coat a bit of the aluminum as well, so I can sand it back to a perfectly smooth transition from aluminum to tip.

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Eric Page

03-09-2021, 05:52 PM

This morning I stopped by the powder coater's shop to pick up my door frames. They don't look quite perfect (some of my grinding on the weld puddles shows through the coating), but they look like a million bucks compared to how they looked after I stripped the Lexan and fiberglass off of them.

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Next I went back to the flaperons and got the SuperFil on both tips sanded down. They came out really nice, apart from a few small spots where tiny chunks of SuperFil came off. That seems to happen pretty often when I use the stuff, almost as if it has tiny inclusions in it that flake away from the surface. Very strange...

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Since there were those little flaws in the otherwise smooth surfaces, I mixed up a little more SuperFil and gave them some minor touch-ups. I should have them ready for primer/paint tomorrow (that's still quite a way off...).

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The seat pan came back to the table next. In the two days since I last looked at it, the putty in the holes had hardened up completely. The putty didn't completely fill the holes, however, so I set about filling them from the top side. First I used 120-grit to roughen up the gelcoat around each group of holes, followed by an acetone wipe.

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Then I mixed up half an ounce of repair putty. This time I used 10 drops of MEKP instead of 7, which seemed to have the desired effect (it was beginning to stiffen by the time I finished). I also stirred in about a teaspoon of additional milled glass fiber, which gave it a significantly more sturdy feel. Finally, using a popsicle stick with the end cut flat, I filled the holes and sanding depressions with putty, then set it over by the heater/fan to cure.

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I didn't want to spend a lot more time in the garage today since I had to wear a respirator once the putty can was opened, so I just did a bit of rasp work on the trailing end of the vertical stab tip to shape the Hysol I applied last week, then I mixed up a little more SuperFil and gave the tip a light coating.

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I remain optimistic that some day I'll be done with all of the sanding on this project, but every time I think I see the light at the end of that tunnel it turns out to be a freight train coming the other direction, loaded with parts that need sanded!

taff

03-09-2021, 06:19 PM

Eric Page

03-11-2021, 12:13 AM

Only a partial day in the garage today. I sanded down the second SuperFil application on the flaperon tips, then moved those back to the wing cradle for storage. Apart from a good cleaning, they're ready for primer and paint.

Moving back to the seat pan, the stronger mix of MEKP in the polyester repair putty did the trick. This time the patches cured overnight and were rock hard when I set about sanding them this afternoon. They feel really solid now, so I think I'm calling the hole repairs done.

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Now I need to screw up the courage to start grinding at the edges of the pan to make those repairs...

I put the seat pan back into the fuselage to see where I needed to extend edges, and by how much. While I was standing there looking at it, I started idly fiddling with the copilot's stick and discovered a problem.

The pushrod from the control column back to the mixer assembly, which passes under the pilot's bum, was fouling between the bottom of the seat pan and a fuselage tube.

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I tried rotating the pushrod both ways (bend to the right and to the left), but it made no difference. With the stick full right (pushrod fully aft), there was about 1/4" total space between seat pan, pushrod and fuselage tube. As the stick was moved left and the pushrod came forward, that space diminished to nothing and the pushrod made contact with the seat pan before reaching the left stop.

To make matters worse, I have the roll limit screws in the copilot's side of the control column screwed in all the way to their most limiting position, so once I back them out to set control rigging, the seat interference would get worse. And, all of this was without my posterior weighing down the seat.

Then, while typing this up just now, I realized that I must have installed the pushrod back-to-front. I ran out to the garage, turned it around so the bend was toward to rear, and voila! It fits perfectly.

In my defense, that page in my PDF copy of the Series 5 assembly manual was very clumsily scanned, with another page obscuring half of the diagram...

alexM

03-11-2021, 05:11 PM

That aileron push-pull tube doesn't have much room to spare. I played with the stack of washers on the bell crank it attaches to in order to maximize clearance.

Eric Page

03-13-2021, 10:42 AM

I tried that and gained just a little more space too. Thanks.

Eric Page

03-13-2021, 01:42 PM

Remember a couple days ago, when I said my flaperons were ready for primer and paint? Just kidding!

Yesterday I installed the inner end ribs in both flaperons. One of them slid right in with no adjustment required, but the other took nearly an hour of grinding and filing to make it fit right. That flaperon had its innermost foam rib installed a little too close to the end, so the ScotchWeld fillet interfered with the steel end rib flanges. I tried removing some of the adhesive but it quickly became clear that I was going to damage the foam, so instead I ground about 1/16" off of the rib flanges. With that done, it slipped right in.

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Next I laid out, drilled and clecoed the holes for ten rivets per rib.

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Once that was done I went to my big bag of rivets and discovered that I have exactly zero of the correct rivet for this task.

So, I moved on to laying out and drilling 19 holes at 8" spacing along the trailing edge of each flaperon...

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...whereupon I discovered that I don't have any of those rivets either! That of course triggered another Spruce order, and I sprung for my ELT too, so I can get that mounting figured out. All of that should be here next Friday.

Eric Page

03-16-2021, 03:31 PM

I won’t have much progress to report for the next week or so, as I’ve been called back to work and have to spend some time studying for my requal sim. I’ve been on leave for almost a year, so there’s a bit of rust removal needed.

I had a nice visit today from Jim Ott, who flew his beautiful yellow and white Kitfox up from Portland in cool, clear weather. We chatted for a bit about his plane, then rode over to my place. Jim gave my project a good inspection and offered some helpful pointers about engines and where to mount avionics for best weight distribution.

Thanks for coming up, Jim! Cant wait to have mine done so I can join you for some Kitfox adventures.

alexM

03-16-2021, 06:51 PM

And the engine choice is?

:confused:

Good news on getting called back. Now I might catch up.

Have fun in the sim. I'm sure it will be just like falling off a horse: Painful.

Eric Page

03-16-2021, 07:17 PM

Rotax 912iS. It doesn't excite me, but the truth is I'm building the airplane because I want to fly and enjoy it, not because I want to fool with an unproven engine. For every other engine I seriously considered, if I looked hard enough, I found something that put me off of it. By all indications, a Rotax just works.

jiott

03-16-2021, 08:42 PM

Nice talking to you today Eric. You really have had a rough go fixing all the previous builder's issues. After thinking on my flight home about your Kreemed fuel tanks with less than reliable looking fittings, if it was my project I would replace those tanks. Its so much easier to do now than when problems occur after covering. Just my opinion.

Sure was a nice day; after leaving Toledo, flew to Astoria, down the coast to Nehalem Bay, then home.

efwd

03-16-2021, 09:00 PM

alexM

03-17-2021, 11:35 AM

Yep. Not judging, just curious. I knew there were other engines under consideration.

Eric, you'll remember I have a 912 FWF that is surplus to my needs. I've only pirated a few items out of it.

Eric Page

03-17-2021, 04:29 PM

Thanks, Alex. I’ll try to remember,her that. I’m pretty sure my engine mount will work (it was for a 912UL). I’ve got an exhaust system and two radiators as well, but don’t know if any of that is usable. We shall see...

Eric Page

03-30-2021, 10:32 PM

Well, I lost the plot for a few days, then spent a few more getting through re-qualification training at work, then the second Pfizer shot knocked me on my backside for a day and a half (worst headache of my life!). Finally got back to the plane a bit in the last couple of days.

I first mixed up a little Hysol, smeared a thin bead on the freshly cleaned flaperon end ribs and riveted them in place.

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I intended to add the 19 solid rivets along the trailing edges next, but the rivet squeezer I went to borrow from a neighbor turned out to be this enormous thing, with no dies. Apparently it was sourced from the old Boeing Surplus store back in the 80s and hasn't been used in anger since then. I didn't have the heart to say no, so I brought it home for a picture.

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I've got a manual squeezer coming from the Yardstore, along with a small assortment of dies, so I'll get back to the flaperons next week.

Today I got the header tank mounting tabs drilled and the tank situated where I want it, but not without some trouble. It took me longer than I'd like to admit to figure out how to get the hole locations marked and drilled (hold the tank in position with one hand, squeeze an Adel clamp into position with two hands, then use my fourth hand to wield the Sharpie).

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I'd like to have a frank exchange of ideas with whoever welded the tabs onto that tank. The upper left tab was placed right behind the bung for the left wing tank feed, so there's no room for the bolt. I fiddled with it for too long trying to find a position where the hole would be in a corner of the tab and might clear the bung, but had no luck. I'll have to chamfer the back edge of the bung before I do the final installation. If the tab had been attached 1-1/4" to the left, I could have turned the Adel around and put it on the other side of the fuselage tube.

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As you'll see in those photos, I also reinstalled the brass fittings for the fuel feeds, breather line and quick drain. That was a bit of a production too, as I put the sealant too near the ends of the threads and would have had squeeze-out inside the tank (I discovered this when I assembled the breather barb into its reducer bushing). So, I had to clean everything again and start over.

Once those were sorted I also installed the 90-degree NPT-to-AN fitting in the bung on the front of the tank, shortly after which it occurred to me that it's probably the wrong size (a rare 5AN, for some reason) for the 912iS installation. Removing it revealed that it had galled the first few threads, so I threw it away and ordered a 1/4 NPT tap so I can clean up the bung. Thank goodness they're a tapered thread.

Last I figured I'd make a start on re-fitting the doors. That turned into another problem: with the right door in place, clamped so that the top and front are flush with the fuselage frame, the bottom lines up pretty close, but the pointed end at the back edge is 1/2" out of alignment with the fuselage. I didn't notice it when I removed the doors because they were covered with plexi- and fiberglass.

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Has anyone else had this problem with door fitment? I would welcome any suggestions on fixing it, especially if they don't include welding since I just got the door frames back from the powder coater!

alexM

03-31-2021, 06:22 AM

Nice. I was wondering who I was going to borrow a rivet squeezer from.

Jerrytex

03-31-2021, 08:24 AM

You just tweak the frame. The manual mentions doing this. They call it "gently reshaping". On mine, I tweaked/bent and got it "averaged" out the best I could.

alexM

03-31-2021, 09:02 AM

Agreed. Earlier I was on my phone and couldn't really see the picture very well. You just need to show that door some love. Clamp it securely by the good part and get physical. 4130 is pretty amazing stuff.

In any machine shop I have worked in the new guy/gal/other starts out deburring parts and graduates to "line up", which is making parts straight again when they come back from welding, heat treat, etc.

Eric Page

03-31-2021, 10:27 AM

Nice. I was wondering who I was going to borrow a rivet squeezer from.
Ha! You read my mind. I was hoping it would be more useful than just my 38 rivets.

You just tweak the frame. The manual mentions doing this. They call it "gently reshaping". On mine, I tweaked/bent and got it "averaged" out the best I could.

Huh, I missed that. My reading comprehension skills aren't what they once were, apparently.

You just need to show that door some love. Clamp it securely by the good part and get physical. 4130 is pretty amazing stuff.
OK, guys, I'll give it a try. I was nervous because the frames are actually aluminum, not 4130. I was afraid (and still am, frankly!) that aluminum square tube will be more likely to fail suddenly than steel. Proceeding with care...

Eric Page

03-31-2021, 10:41 PM

Nice. I was wondering who I was going to borrow a rivet squeezer from.
Oh, and don't buy rivets. Minimum order is 1/8 of a pound, which is a hell of a lot of 3/32 x 1/8 rivets; I have plenty.

Eric Page

03-31-2021, 10:58 PM

Well, I tried tweaking my door frames this afternoon and much to my surprise, it worked! It took what the youngsters would call "getting medieval," but I was able to get a nice fit on both sides without breaking anything. Thanks again for the suggestions.

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Since I've been jumping around in the manual so much, I thought it would be a good idea to go back through the fuselage and wing chapters page by page to be sure I hadn't missed anything important. It turned out I had: the large cotter pins that serve as cable keepers under the four small pulleys just behind the seats. They were a bit of a chore to install, but getting them in made the review worthwhile.

I also found some things in the wing chapter that have me a bit worried about the rigging done by the first builder. I have no actual evidence that anything was done wrong, but it's keeping me up at night. I have a string of days off in mid-April, so I'm going to make a point of putting the plane back on some wheels, rolling it to a neighbor's hangar, re-fitting the wings and checking the measurements.

I've been getting frustrated lately with not being able to find things when I need them, so I spent the rest of the afternoon emptying all of the boxes I got from the first builder, deciding what was salvageable, what I would be selling or giving away, and what was trash. I whittled eight boxes down to two and regained access to an exterior door that had been blocked since the plane came home last July.

I have a couple more days of training for work coming up, but I should be back on the project on Saturday.

Eric Page

04-14-2021, 10:11 PM

...And, two weeks later, here we are with very little done on the plane. I finally found some time this afternoon to get back to the flaperons. There was a little bit of Super-Fil to sand out, then I installed and squeezed all of the trailing edge rivets. It was definitely worth it to buy a rivet squeezer for this job, and I'm very happy with the appearance of the solid rivets vs pop rivets.

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Back to work tomorrow for four days, then a nice stretch of time off. Hope to make some good progress again...

Eric Page

04-27-2021, 09:07 PM

Two more weeks and not much to show for it. I'm beginning to feel like I'm letting down the team here!

I did take the plane across the street to a neighbor's hangar a few days ago so that I could install the wings and check their rigging. That turned out to be a bit of a mixed bag.

I started by installing the gear, wheeling the fuselage over, then removing the gear and setting the plane up on jack stands. I had to shim the right side a bit, but fairly quickly got it level left-to-right.

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I found a scissor lift cart and tried using that to hold up the tail, but it very slowly leaked down, so within about 15 minutes the tail would be down about half a degree. I then commandeered a card table and some scrap wood and used them to level the fuselage fore-and-aft.

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Then a couple of neighbors helped me get the wings and struts installed. It turned out the first builder had primed the ends of the spar tubes after drilling the holes, so they needed reaming again before the bolts and pins would go through. My first fear was that the holes wouldn't be aligned vertically, but it took only a few gentle taps with a tack hammer to get the fasteners in. With that done, I set up the string line across the leading edge.

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This immediately revealed a problem: the wings are noticeably swept back. If you'll forgive my use of fuzzy jute twine, here are the left side measurements...

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...and here are the right side measurements:

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Please check my math: I used 5/16" (0.3125) for the left inboard measurement and 3/8" (0.375) for the right. Subtracting those from the 1" outboard measurement gives the height of the triangles (0.6875 and 0.625, respectively). Plugging those numbers into an online triangle solver (https://www.calculator.net/triangle-calculator.html) (gimme a break; geometry class was a long time ago!) along with the 120" dimension along the spar and a 90 degree corner gives 0.328 degree sweep on the left and 0.298 degree sweep on the right.

Questions:

1. Are my wings scrap?

2. If not, then making this work will require moving some weight (e.g. avionics LRUs) aft, correct?

3. Looking at this excerpt from the Final Assembly chapter of the build manual...

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...can I extrapolate that my aft CG limit would be farther aft than the zero-sweep limit? For example: 16" (zero sweep limit) - 14.75" (1 degree forward sweep limit) = 1.25" of aft limit change per degree of sweep. 1.25" x 0.3 degree sweep = 0.375". 16" + 0.375" = 16.375" adjusted aft limit.

With my blood pressure well and truly spiked, I moved on to measuring dihedral and washout. Dihedral was within spec and equal on both sides, but washout was a mess. Fortunately, a bit of adjustment on the aft strut bearings put that right.

With dihedral and washout set, I locked down the strut bearing jam nuts and started test fitting the jury struts. I discovered that I'm missing one of the four "rings" that hold the jury struts to the wing strut tubes, so I could only check one side at a time.

The first builder had wrapped the wing strut tubes with masking tape at the ring locations and left it in place for 20 years, so it had turned into superglued paper. Removing that from one wing strut took over an hour, so I packed it in for today and came home to seek advice from the Kitfox hive mind.

CoClimber

04-28-2021, 05:38 AM

I'm going to take a stab at this. The total CG range is 6.5 inches. Your mean sweep is ~.35" which is ~5% of your range. An aft CG is dangerous so if you use the factory numbers, you automatically build in an additional safety margin. Aerodynamically, that sweep back shouldn't be detectable in flight. The slightest side slip would be far greater than that angle.

Basically, I think you are good to go.

efwd

04-28-2021, 07:22 AM

Hi Eric. When setting up for the sweep, the blocks of wood or whatever are adhered to the spar itself. The leading edge plastic is not installed. I would recommend that you factor into the math that added material. In spite of the fact that Jigs are utilized to establish the correct placement of the leading edge, there is a fair amount of opportunity to get that placement a little off. Be certain you are measuring those spots from the locations that the manual suggests.

jiott

04-28-2021, 10:19 AM

Agree with Eddie, make sure the plastic leading edge sticks out beyond the spar the same amount inboard and outboard; if not adjust your measurements.

Assuming your approx. 1/3 degree sweep-back is correct, I think you are fine. It will help compensate for a heavy tail. Most of the SS7's tend to be somewhat tail heavy. On mine, with full load of fuel, baggage and passenger, I always reach rear CG limit before GVW. I have never reached fwd cg limit.

alexM

04-28-2021, 10:29 AM

With that 0.3 degree aft sweep I think you're going to want to go with turbine power (kidding).

I will counter that an Aft CG condition is NOT dangerous, it is in fact desirable. It's being beyond Aft CG which is dangerous. At the aft limit you can expect slower stall, slower landing with more elevator authority (already an issue with the Kitfox), lighter control feel. My old Cardinal RG with its stabilator loved a good load in the back. At the aft limit it cruised 10 knots faster than at the forward limit.

I wouldn't spin a plane at the aft limit as a habit, but I have no fear of being loaded towards the rear.

And damn cool seeing your plane with the wings on. Looks familiar.

Oh, and I have round tube jury strut brackets which are surplus to my needs. I recently found that I own both round tube and aero jury struts.

Eric Page

04-28-2021, 09:12 PM

...if you use the factory numbers, you automatically build in an additional safety margin. Aerodynamically, that sweep back shouldn't be detectable in flight. The slightest side slip would be far greater than that angle. Basically, I think you are good to go.
I like safety margin, and 3/8" additional range isn't useful anyway, so I'll do that. I had a feeling that 0.3 deg wouldn't much affect the flight characteristics of such a benign airplane.

Hi Eric. When setting up for the sweep, the blocks of wood or whatever are adhered to the spar itself. The leading edge plastic is not installed. I would recommend that you factor into the math that added material. In spite of the fact that Jigs are utilized to establish the correct placement of the leading edge, there is a fair amount of opportunity to get that placement a little off. Be certain you are measuring those spots from the locations that the manual suggests.
I noticed that, but the PVC leading edge is already Hysol'ed in place so I was stuck with it. I did verify that it's the same thickness from the spar tube at the root and at the 120" point, so it didn't make any difference to the measurements.

I've actually got three build manuals (Series 5 in PDF form, early Series 7 in printed form and current Series 7 downloaded from Kitfox) and I read all three to be sure I was doing the steps the right way. There's actually one item that's confused between manuals. In the section on checking dihedral, both the Series 5 and early Series 7 manuals say to use the front spar in the text, but the rear spar in the diagram. The current Series 7 manual says to use the front spar in both places, so that's what I did.

Agree with Eddie, make sure the plastic leading edge sticks out beyond the spar the same amount inboard and outboard; if not adjust your measurements.

Assuming your approx. 1/3 degree sweep-back is correct, I think you are fine. It will help compensate for a heavy tail. Most of the SS7's tend to be somewhat tail heavy. On mine, with full load of fuel, baggage and passenger, I always reach rear CG limit before GVW. I have never reached fwd cg limit.
Mine's a 5, but I'm using a 7 elevator, two servos behind the seat and a comm antenna in the vertical stab, so it'll be a little heavier aft than it otherwise would be. I'm inclined to press ahead with avionics forward, and if I have forward CG limit problems I can always move a couple of boxes aft later. I also have a larger spare tailwheel assembly that I can swap in for additional far-aft weight.

With that 0.3 degree aft sweep I think you're going to want to go with turbine power (kidding).
I wanted that anyway! Hard to believe no one has put a small t-prop on a Kitfox yet. Solar Turbines should sponsor one of the YouTube guys. I'd watch that video.

I will counter that an Aft CG condition is NOT dangerous, it is in fact desirable. It's being beyond Aft CG which is dangerous. At the aft limit you can expect slower stall, slower landing with more elevator authority (already an issue with the Kitfox), lighter control feel.
All true! I'll just introduce my plane at airshows as "The Swept-Wing Kitfox." It'll never win a Lindy, so a little fighter-like notoriety will have to do.

Oh, and I have round tube jury strut brackets which are surplus to my needs. I recently found that I own both round tube and aero jury struts.
Excellent; SOLD! Speaking of which, have you had a minute to sort through that box of goodies in your hangar?

alexM

04-29-2021, 07:33 AM

I've actually got three build manuals (Series 5 in PDF form, early Series 7 in printed form and current Series 7 downloaded from Kitfox) and I read all three to be sure I was doing the steps the right way. There's actually one item that's confused between manuals. In the section on checking dihedral, both the Series 5 and early Series 7 manuals say to use the front spar in the text, but the rear spar in the diagram. The current Series 7 manual says to use the front spar in both places, so that's what I did.

[and]

Excellent; SOLD! Speaking of which, have you had a minute to sort through that box of goodies in your hangar?

No but I've tripped over it enough times that I need to get that done. I'll try to get that done tonight.

I got myself confused with the series 5 and 7 manuals on this step too, which is probably why John discourages people from referencing both manuals. The text of my series 5 manual matches the drawing, and has you use the aft spar for setting dihedral and then moving the forward lift strut attach fitting to check/set washout. My confusion was because I read the words but projected my imagination into what they meant. Once I got real careful I saw what was going on.

Series 7 has you set dihedral using front spar, setting washout with the lift strut fitting on the aft spar - which makes WAY more sense to this model airplane guy. After I worked it out I came to the conclusion that it would result in the exact same setup from two different directions. Upon further reflection I realized that's not true. The series 7 will end up with 0.2 degrees more dihedral.

Reason? With both configurations you get your 1 degree dihedral. So far, so good. Then with the series 5 you remove 0.5" dihedral on the other spar, while on the 7 you add 0.5" dihedral to the other spar.

You say potato, I say potato. Hey that doesn't work when you type it out.

And believe me, I've considered a Solar T-62 in something. I would like to design a scaled down OV-10 Bronco and use a pair of them.

Eric Page

04-29-2021, 08:40 AM

No but I've tripped over it enough times that I need to get that done. I'll try to get that done tonight.
Why do you think I put the box right in front of your fuselage?! ;) Just kidding -- thank you.

Series 7 has you set dihedral using front spar, setting washout with the lift strut fitting on the aft spar - which makes WAY more sense to this model airplane guy. After I worked it out I came to the conclusion that it would result in the exact same setup from two different directions. Upon further reflection I realized that's not true. The series 7 will end up with 0.2 degrees more dihedral.

Reason? With both configurations you get your 1 degree dihedral. So far, so good. Then with the series 5 you remove 0.5" dihedral on the other spar, while on the 7 you add 0.5" dihedral to the other spar.
I'm afraid I didn't think it through that far, but that makes sense. I used the procedure in the current Series 7 manual, figuring that since the other two contradicted themselves and that one didn't, it must have been corrected.

And believe me, I've considered a Solar T-62 in something. I would like to design a scaled down OV-10 Bronco and use a pair of them.
Oh boy, that would be a really cool airplane! You're going to need tip tanks, drop tanks and a belly tank to run two T-62s.

I disassembled the plane last evening (again, with the help of two neighbors) and brought it back to my garage. Now I'm off to work for four days...

Jerrytex

04-29-2021, 06:21 PM

We are all building model 5's and I too am using a combination of the the KF 5 manual and the new manual.

I ran into something that the new manual addressed, but the old manual didn't, and it bit me. There is no mention (or at least that I saw, but then again, I can read something 5 times and get 6 different meanings) of folding the wings in the KF 5 manual after rigging and checking the clearance between the #1 rib and the rear cary through spar. The new manual has this in it and specifies that the #1 rib might need trimming (before covering) so that the wings will fold back all the way. Well....I missed this and sure enough, the left wing hits about 2" shy of folding all the way back, and my wings are covered. I haven't figured out what I want to do on this screw up yet. But just a heads up for y'all.......since you're about to be at this stage.

Eric Page

04-30-2021, 10:29 PM

Oh dear. Looks like I might have to reinstall the wings again to check this.

I'm pretty sure the ribs have been trimmed already, but I'll post a photo when I get back home and y'all can tell me that you think.

Eric Page

05-06-2021, 08:47 AM

OK Alex, I'll see your avionics package...

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...and raise you an upholstery set:

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The avionics will be a single 10" Dynon Skyview HDX, primary ADAHRS, remote magnetometer, GPS receiver, engine monitoring system, Mode S transponder, dual-band ADS-B receiver, comm radio with control head, pitch and roll servos with autopilot control head, intercom, heading/altitude/baro knob head and EFIS adapters for WiFi and camera input

The upholstery is about as close to my Oratex colors (silver and red) as I could come up with. I'm really happy with how they turned out; whoever does the upholstery work for Kitfox does a beautiful job.

Eric Page

05-06-2021, 09:03 AM

Here are the photos of my butt ribs that I promised a week ago. They appear to have been trimmed, but I don't know if that's true, or if this is how they come from the factory. So, have these been trimmed for wing-folding clearance? As usual with my build, please ignore the first builder rough edges...

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alexM

05-06-2021, 10:08 AM

Show off! Those seat cushions look great. For planning purposes, what was the lead time on those?.

Not sure about the rib clearance thing. Did you attempt to swing the wings when you had them on? Seems like that would be the only way to know for sure.

Eric Page

05-06-2021, 11:10 AM

For planning purposes, what was the lead time on those?
I ordered at the end of Sep or early Oct. Delivered early May. In other words, call them today.

Not sure about the rib clearance thing. Did you attempt to swing the wings when you had them on? Seems like that would be the only way to know for sure.
No, that would have been the sensible thing to do. So I didn't.

Jerrytex

05-07-2021, 09:50 AM

The trimming that I mentioned is actually on the #1 Rib on the wing. When you swing the wings back, the top capstrip might need to be trimmed since it might contact the carry through spar before the wing is all the way folded back. At least that is how it is on mine and had I caught it before covering, it would have been a lot easier to address.

Eric Page

05-07-2021, 11:16 PM

Aaah, OK. I'll take another look when I get home tomorrow. I sure don't recall any trimming of the #1 rib, but we'll see...

Eric Page

05-10-2021, 11:41 PM

There's no sign of any modification to my #1 ribs, so I guess I get to reinstall the wings and check folding clearance. Oh, joy!

Today I test fit the baggage sack and was pleased to see that it fit perfectly. I'm a bit confused by the sticky-backed Velcro that's attached to it in a few places, but I presume its purpose becomes obvious once the rest of the fuselage is complete.

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Next I installed the ELT. I was going to make a mounting plate and attach it to the area behind the passenger seat like so many others have done, but instead decided to use the frame just below and behind that location. Eight tubes come together there, so it should be a very strong (read: crash-proof) location. It also had the benefit of not needing a bracket made; I was able to attach the mounting tray by simply using Adel clamps. The only bracket I needed was for the antenna, and I was able to hack that from a scrap of angle in just a few minutes.

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Since the antenna mounting bracket is electrically isolated by the Adel clamps and powder coat, I added a ground strap from the bracket to the welded tab that will support the baggage compartment floor. I'll remove powder coat from that tab and install the ring terminal with a star washer at final assembly. I'll be able to reach the ELT for service by removing the right side of the baggage sack and leaning over the back of the seat.

Yes, the ELT is upside down in those photos. It'll come out for covering.

jiott

05-11-2021, 10:35 AM

Eric,
The velcro with sticky tape on the back is to anchor those strips to the frame tubing in various places. However, due to the roundness of the tubes it does not work very well. After time in the sun, etc. it start moving around and loosening. I used nylon zip ties to hold it in place wherever possible.

Eric Page

05-11-2021, 11:47 AM

Thanks, Jim. It wasn't clear to me whether the sticky-back Velcro was supposed to go on the tubes or the inside of the turtledeck. Either way, I don't like the idea of failing adhesive and sticky residue once it gets hot. I'll plan to remove the sticky part, poke some holes in the edge with a hot nail and use black zip ties.

Jerrytex

05-11-2021, 06:47 PM

I riveted the velcro down in a few places to hold it down. Easy to drill out alum rivets if ever needed. Surprisingly it worked good. Just another idea.

Jcard

05-11-2021, 07:31 PM

Like the zip and rivet fixes for the baggage velcro.

alexM

05-12-2021, 08:08 AM

I riveted the velcro down in a few places to hold it down.

You riveted to the frame tubes?

Jerrytex

05-12-2021, 09:35 AM

No to aluminum.

On my KF 4, I added aluminum angle around the perimeter of the baggage area and perimeter of turtle deck, thinking it would give the velcro a nice flat surface to stick to. It didn't. The sun loosens it quickly. So I put rivets through the velcro into the aluminum angle to hold the velcro in place.

On my new build, I am doing something similar. I am not using the supplied turtle deck so I am cutting up the light weight angle that came with it, and bonding it to the lower triangle window frames and back around under the perimeter of the turtle where there is velcro needed. Then rivet the velcro to the aluminum angle. Hope that makes sense.

alexM

05-13-2021, 09:07 AM

Makes more sense than drilling frame tubes! My employer doesn't trust sticky velcro so they bond it in place. Lasts 20+ years and 100k hours in use all over the globe. I always thought it was epoxy but I just looked it up. It's some form of Bostik urethane (I think) which can only be purchased by the gallon, so that's out.

taff

05-13-2021, 10:49 AM

Was this the Bostic material? comes in various sizes.

https://www.ampro-online.com/items/BOSA38921

rv9ralph

05-13-2021, 01:45 PM

Try DAP Wildwood Contact Cement available at most home improvement stores and Wally World. This type of adhesive is used on laminate counter tops and upholstery.

Paint on both surfaces let it dry then put the parts together... get right on the first try, you may not get a second chance.

Buy Velcro without adhesive. The velcro adhesive is notorious for letting loose when it gets hot or getting gooey after long exposure to heat (sitting in the sun).

Ralph

alexM

05-13-2021, 02:37 PM

Try DAP Wildwood Contact Cement.....

Good call. Most people don't use contact cement correctly. It seems odd to let both sides dry completely and then stick things together, but you're correct - if they touch at all you better hope that is where you want the pieces to stay. The down side is that contact cement burns like rocket fuel, so for manufacturing of certified aircraft it's a no go.

The Bostik I looked up was 7132R, but that stuff that Taff linked to seems like it would work well.

Eric Page

05-16-2021, 09:50 AM

I did a little work on fabricating new door hinges a few days ago. I ordered new hinge stock from Kitfox, so I was starting with about 6-1/2" of material. As seems to be typical of the SkyStar drawings, there's no way to make the parts as depicted unless you have double the amount of material supplied, as the drawing makes no allowance for saw kerf. So, the hinges end up slightly narrower than the specified 1-1/2".

I was planning to borrow a friend's band saw, but with the kerf issue in mind I decided to try my luck by hand with a fresh hacksaw blade. I marked out the cuts to separate the reinforcing plates from the hinges, then made those cuts. I had to cut from both ends due to the spine of the hacksaw, then finish the center 1/2" of the cut with a bare blade, but it worked out pretty well; much straighter than I expected.

28038

Next I marked out the cuts to split up the material into four separate hinges...

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...and made those cuts.

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Then I had to go to work for a few days, so that's where it sits. Next step will be to clean up the material to the marks on the sanding disc, then figure out how to cut the steel hinge pin without ruining it...

With any luck, the next few days will produce some more progress.

Eric Page

05-18-2021, 11:10 AM

Yesterday I got the new door hinges and reinforcing plates sanded to size, deburred and cleaned up on the Scotch-Brite wheel. I was about to put them through Alodine treatment when it occurred to me that I should wait until the mounting holes and countersinks are done. Also just realized that I still need to round the corners on the reinforcing plates.

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If anyone knows a good way to cut the steel hinge pin, and how to stake the pins once they're installed in the hinges, I'd be pleased to hear it.

Next up was fabricating and installing wood mounting rails for the remote magnetometer. I went to my collection of leftover building materials and found a suitable piece of maple baseboard. I cut it to length on the miter saw (to fit between ribs 3 and 4 in the right wing), then ripped it on the table saw to make two 1/2" wide strips. Those were marked and pilot drilled on the bench, then the magnetometer was attached. Finally, the whole assembly was glued onto the top edge of the bottom cap strips with Hysol.

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Finally, I did a more or less pointless mock-up of the instrument panel (really just an excuse to get some Dynon bits out of their boxes and play with the knobs and buttons!). That 10" screen is a tight fit in a Kitfox.

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This is my current thinking WRT panel layout. Dynon goodies front-and-center, dimmer knob, lane lights and switches to left and below the EFIS, ELT control above the Dynon modules, Van's glove box on the right, and a dual USB charger at bottom right with circuit breakers to the left of that. I'm also considering a mount arm for an iPad (recommendations welcome).

I haven't decided on the exact switches I want to use, so consider the toggles as placeholders. I'm also not in love with circuit breakers, so that may change to a fuse box behind the panel.

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The panel layout was done using the free designer at https://hangarzulu.com/.

alexM

05-18-2021, 11:20 AM

No ECB?

I'm waiting to see what you use for connections behind the panel. Junction boxes of some kind or just crimp wires and be done?

When I swapped out the radio and transponder in the T-6 I found all the wire connections meticulously routed into a junction box. Wow did I love finding that because it made the upgrade so easy. I'm not finding any such contraption available at Aircraft Spruce so I have to assume no one does it that way anymore.

Eric Page

05-18-2021, 12:18 PM

No ECB?
Nah. Heavier and much costlier than old-skool CBs or fuses. I see little utility in resetting circuit protection in flight, which is one reason (cost is the other, obviously) that I'm leaning toward fuses.

I'm waiting to see what you use for connections behind the panel. Junction boxes of some kind or just crimp wires and be done?
I'm building most of the harnesses from scratch. The EFIS included its main harness, and one or two of the LRUs appear to have something in the box, but I've got lots of D-Sub parts on hand for the rest. I'm that odd, 1-in-1,000,000 guy who looks forward to doing the wiring.

When I swapped out the radio and transponder in the T-6 I found all the wire connections meticulously routed into a junction box. Wow did I love finding that because it made the upgrade so easy. I'm not finding any such contraption available at Aircraft Spruce so I have to assume no one does it that way anymore.
I believe Advanced Flight Systems installations use a box like that. Spruce sells this thing (https://www.aircraftspruce.com/catalog/avpages/approach1.php), and there's MGL's iBox, of course. The Dynon system uses an optional network hub (https://www.aircraftspruce.com/catalog/avpages/skyviewnethub.php); I'll need one of those.

PapuaPilot

05-18-2021, 02:33 PM

If anyone knows a good way to cut the steel hinge pin, and how to stake the pins once they're installed in the hinges, I'd be pleased to hear it.

Use a Dremel tool with a cutoff disc to cut the hinge pins.

Food for thought. I decided to not stake the pins, which makes them a permanent installation. They will also be a pain if you ever need to replace them.
On my plane I made 4 L shaped pins that can be pulled out in a few seconds. That way I can remove a door in about a minute after popping the gas strut clip loose. Just put the bent end to the front, they won't come out.

efwd

05-18-2021, 02:41 PM

Hi Eric
Dremmel cutoff wheel cuts the pin easily. I used a spring loaded center punch to put indentations around the ends of the hinge pins once they were inserted. I regret that. One of these days I will disassemble these and make a removable pin. Something like the ones that are used to hold the main spar bolt in, smaller ones of course. I would love to remove my doors on those days I just stay in the pattern.

Well, I see Phil agrees.

Eric Page

05-18-2021, 03:15 PM

Excellent, thanks gents -- that's a great idea. I have plenty of Dremel wheels to explode, and Spruce sells extra hinge pin material.

jrevens

05-18-2021, 10:37 PM

I made pins that looked similar to this, like a safety pin, but then I found these nicer ones from McFarlane. They're a Cessna part that are the perfect size. Kind of pricey, but they fit perfectly.

Eric Page

05-18-2021, 11:42 PM

...I found these nicer ones from McFarlane. [...] Kind of pricey, but they fit perfectly.
Boy, I'll say. They're awful nice, but $95 for a set of hinge pins is a bit much for this cheapskate!

jrevens

05-19-2021, 08:59 AM

Wow… they must have gone up in price. I don’t think I would’ve paid that much either!

Birdseyeview

05-20-2021, 12:09 AM

Eric, I used these hinge pins and bought them at my local hardware store(either Lowes or Home Depot) for a couple of bucks. They are steel and fit perfectly.

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PapuaPilot

05-20-2021, 12:29 PM

I like those. Highly recommended.

Eric Page

05-20-2021, 07:28 PM

Sweet. "A couple of bucks" is much more my speed. Thanks, Larry.

efwd

05-22-2021, 08:55 AM

Thanks Larry. This will be an easy adjustment now. But then again, I may have got my pins trapped better than I think they are.

Eric Page

06-04-2021, 08:09 PM

Wow, it's amazing how quickly time can get away from you and momentum gets lost. It seems like May was a really unproductive month...

Today I pulled the old cables out of the wings and installed new for the wingtip lights, which I ran through the aft spars. Those are 4-conductor cables to run Whelen Orion 600s, which I chose for two reasons: they're a direct replacement for the old incandescent Whelen lights that came with my plane so their footprint will fit the fiberglass light mount that I have, and they feature lenses that are field-replaceable ($17 ea.) if they get scratched or cracked. Anyway, the four wires are for ground, position, anti-collision and synchronization.

I also installed cables for landing and taxi lights, which I terminated at the strut attach fittings. I figure on hanging some off-road lights there since my Hoerner wingtips have no provision for leading edge lights. Those cables are two-conductor, and I'll roll my own controller to accomplish wig-wag.

Finally today, I pulled the pitot and AOA tubing through the aft spars and coiled it up at the #1 rib. It looks like I'm going to need to buy some more tubing, as I don't think what's left will make it all the way to the ADAHRS box.

In other recent progress, I brought home a bunch of Rotax 912 installation parts from AlexM's hangar, which he sold to me at a generous discount since they're of no use for his Verner radial (thanks again, Alex!). Debra was kind enough to send me the inventory sheet for Kitfox's 912iS installation kit, so I compared Alex's parts against that, then put in an order to Kitfox for the remainder of the parts to complete that kit.

I also ordered the engine from Kitfox. They haven't told me yet what the lead time is on it, but I'm at least several months away from needing it. The engine I ordered is a 912iS Type 3, which Debra informs me is correct for a hydraulic constant speed propeller governor. Yes, ladies and gentlemen, I'm installing a blue knob!

I just couldn't resist doing something a little outside the ordinary. The propeller will be a 71" 3-blade DUC Hélices FLASHBLACK (from France), controlled by a Jihostroj P110-030/A governor (from the Czech Republic). The hub, blades and spinner are mostly carbon and weigh a combined 15.2 lbs, and the governor weighs 2.3 lbs. Add 5 lbs for the control cable and hardware, and the installed weight should be under 23 lbs. I ordered the prop and governor this week as well.

alexM

06-05-2021, 09:27 AM

I know what you mean about productivity. I went from about 3 weeks ahead of my imaginary schedule to feeling like I'm a month behind in just a blink.

You're a turbine guy. Are you even going to know what to do with a blue knob?
;)

Hydraulic? Am I to understand this version of the 912iS allows for a conventionally governed CS prop? I didn't know that was even an option.

Eric Page

06-05-2021, 09:50 AM

You're a turbine guy. Are you even going to know what to do with a blue knob?

Hydraulic? Am I to understand this version of the 912iS allows for a conventionally governed CS prop? I didn't know that was even an option.
Hopefully I'll remember enough not to break anything on the first flight!

Neither did I. Apparently the Type 1 is for fixed/adjustable pitch props and the Type 3 has a pad for a standard oil-pressure-driven governor. No idea if there's a Type 2.

Eric Page

07-12-2021, 04:06 PM

Figured I might overcome the shame and self-loathing of making so little progress if I posted a small update. This covers more than a month, so you can understand the first sentence!

I ran the cables in my wings for the wingtip nav/position/strobe lights and landing/taxi lights. All of them pass through the rear spar, both to keep them neat and to facilitate wing folding with minimal strain on the cables. Sorry, no photo.

I ran the two-core cable for the elevator trim motor and the comm antenna coax from the tail up to the front. This gave me an excuse to learn and get plenty of practice using lacing tape. There were some moments of frustration to be sure, but it looks nice and is quite satisfying.

28390 28391

I also built a forest-of-tabs ground block from a piece of brass plate (sourced cheaply on eBay), some brass hardware from Home Depot and four 6-way 0.250" Quick Connect tabs from Digi-Key. My gas cook-top worked quite nicely as a heat source to melt the solder paste used to attach the QC tabs. It'll be held against the firewall with a 1/4-20 brass bolt, and the engine-side ground strap lug will be pinched between two brass flat washers, secured with an internal tooth stainless lock washer and two brass nuts.

28392 28393

Next, I built a 7-ft extension harness for the magnetometer. This will extend the magnetometer's pigtail from inside the wing to just below the seatback, where another harness will take it behind the panel. The wires inside match the Dynon color scheme and twist callouts, and the outer jacket is 1/4" flame retardant expandable sleeve (Techflex Clean Cut FR (https://www.techflex.com/advanced-engineering/flexo-clean-cut-fr-fray-resistant?product_selected=CCF0.25TB)), held at each end with adhesive-lined heat shrink tube.

28394

If anyone has any interest, I'd be happy to post a tutorial on building harness cables, showing the necessary tools, parts and techniques. I know electrical wiring is a bugaboo for many builders...

Finally, I designed and built a wig-wag controller for my landing and taxi lights. Since my 1995 Hoerner wingtips have no provision for landing lights, I'm planning to use off-road pod lights, mounted at each wing strut attach bracket. The controller and panel switch-ology will allow a choice of taxi light only, taxi+landing, or one of two different programmable wig-wag flash patterns.

28395

That's it for the last six weeks or so, I'm afraid. Sadly, it's not going to get better for awhile, as I have a big training event coming up at work and I need to get a lot of studying done. It'll probably be into October before I can dedicate much time to the Kitfox again.

avidflyer

07-12-2021, 09:05 PM

Just remember, the longer it takes to get back to working on it, the easier it is to put it off till "later". That's how kits get to be 25 years old and still aren't finished. Do the best you can though of course. JImChuk

alexM

07-12-2021, 09:26 PM

You're such a nerd. So you're skipping the part where everyone has to call you Captain Eric from now on?

I'm raising my hand as someone who would really like to see a tutorial on making wire harnesses. I'm rapidly coming up on that point and could use any help possible. I recently obtained some heat shrink tube which runs through my label maker. I felt like the smartest guy in the room (well, until someone else walked in).

As you know I have Hoerner tips also. I'm with you on not attempting to chop them to add provisions for landing lights, and I'm also with you on adapting off road lights for the task.

For a while now I have intended to use the same exact LED off road lights I have on my motorcycle. They are from Cyclops in Kent, WA. The name likely comes from an early product they produced which was a headlamp used my dirt bike racers for the extended Baja races.

The lights on my bike are the Long Range Optimus LED (https://www.cyclopsadventuresports.com/-Long-Range-Optimus-LED-Auxiliary-light-Round_p_10.html) lights. I run one spot and one "wide beam" light, a combination which they recommend. They are solidly built and work fantastic. I've dropped my motorcycle on them several times. I'm even lazier than you apparently because I'm going to mount mine on the tubing of my main gear. My plan is to use some Cyclops bar mounts (https://www.cyclopsadventuresports.com/Round-Tube-Mounts--78-through-1-14-Inches_p_55.htmlhttps://www.cyclopsadventuresports.com/Round-Tube-Mounts--78-through-1-14-Inches_p_55.html) for the job.

Eric Page

07-13-2021, 10:50 AM

Just remember, the longer it takes to get back to working on it, the easier it is to put it off till "later". That's how kits get to be 25 years old and still aren't finished.
Indeed. I’m still determined to finish this thing. I hate wasting large sums of money!

So you're skipping the part where everyone has to call you Captain Eric from now on?
Once I pass upgrade we can talk about appropriate forms of address. ;)

I'm raising my hand as someone who would really like to see a tutorial on making wire harnesses. I'm rapidly coming up on that point and could use any help possible. I recently obtained some heat shrink tube which runs through my label maker.
OK, I’ll see about getting that done. It may take a little while…

I got some of that labeler heat shrink too, and found that even the 1/2” tube (the largest my labeler will take) isn’t big enough to go over a Dynon harness with four twisted pairs. It’ll work great for individual wires or smaller harnesses, but I’ll have to stick with labeling the D-Sub connectors for the Dynon harnesses.

The lights on my bike are the Long Range Optimus LED (https://www.cyclopsadventuresports.com/-Long-Range-Optimus-LED-Auxiliary-light-Round_p_10.html) lights. I run one spot and one "wide beam" light, a combination which they recommend. […] My plan is to use some Cyclops bar mounts (https://www.cyclopsadventuresports.com/Round-Tube-Mounts--78-through-1-14-Inches_p_55.htmlhttps://www.cyclopsadventuresports.com/Round-Tube-Mounts--78-through-1-14-Inches_p_55.html) for the job.
Those look very nice. Their Aurora 2” 19-watt light looks like a good option too, with a bit less drag, but it’s only available with a 15° beam. Being a cheap pilot, I was considering the Rigid Industries D-Series Pro 3” LED lights (one spot and one flood).

Thanks for the tip on those tube mounts. They’d work nicely on the wing struts too.

PapuaPilot

07-14-2021, 03:32 PM

I Being a cheap pilot, I was considering the Rigid Industries D-Series Pro 3” LED lights (one spot and one flood).

That is exactly what I did back in 2015 on my plane. I looked at the specs on some of the name brand aircraft LED lights and found that the Rigid D Series lights met or exceeded those specs. I put a pair of Rigid spot lights in my plane and wish I had gotten one spot and one wide angle. They work great for being seen and landing at night.

Eric Page

07-16-2021, 01:35 PM

Thanks, Phil. I appreciate the field report. It's hard to know how a non-aviation part will work without direct experience.

Eric Page

08-21-2021, 01:21 PM

My propeller has arrived. I ordered a 3-blade hydraulic constant speed FLASHBLACK-M unit from DUC Hélices (http://www.duc-propellers-usa.com/) of France, and a governor from Jihostroj (https://www.jihostroj.com/en/governor-models.html) of the Czech Republic. I'm probably taking a bit of a risk with a prop system that doesn't have a lot of installations on Kitfoxes (particularly the hydraulic constant speed units), but both are well-established companies with considerable history, so I'm not too worried. That said, fingers crossed...

All of the parts look very nice; fit and finish are excellent. Here are some photos (with weights).

Hub (72.700 oz):

28625 28626

Blades (53.625 oz, 53.635 oz, 53.680 oz):

28627 28628

28629 28630

Hardware (30.660 oz):

28631

Spinner and backing plate (25.915 oz):

28632

Governor (36.735 oz) (stock photo; I'm not removing mine from its protective shrink-wrap until I need it):

28633

So, the total weight of everything comes to 20 lbs 6.95 oz. With some allowance for a prop spacer, cockpit knob, control cable and a bit of hardware to route and secure it, I'd say the installed weight shouldn't much exceed 22 lbs. I'll be sure to weigh everything else as well, so I can report an accurate all-in weight.

Now I just have to hope that it works as well on the airplane as it looks on the bench!

Delta Whisky

08-22-2021, 05:01 PM

Eric - those pieces and parts sure do look nice. Anxious to hear how they do in the air.

Eric Page

09-24-2021, 05:59 PM

Airplane parts and pieces are beginning to take over my house. I really need to get back to work and start attaching some of them to the airplane.

I received a pallet of stuff from Kitfox last week and finally got around to breaking it down this afternoon. It included a new firewall and almost all of the remaining parts for a complete 912iS firewall-forward kit, as well as a few other miscellaneous items.

Among the "other miscellaneous items" was this:

28825

This is a "Type 3" engine. The covered plate right behind the gearbox, with the hard oil line going to it, is the propeller governor mounting pad.

The sharp-eyed viewer will note that I somehow lucked into #152 of a 200-unit run of 100-year anniversary edition engines. Since there's no such thing as a free lunch, I'm guessing that it's absolutely identical to every other engine, apart from that decal.

The prices of these things are eye-watering, but I figured out a way to rationalize the purchase: According to this website (https://smartasset.com/financial-advisor/how-much-does-it-cost-to-buy-a-horse#:~:text=Since%20the%20type%20of%20horse,to%2 0the%20University%20of%20Maine.), the average horse costs about $3,000. So, to purchase 100hp in actual horses would cost $300,000 -- 12 times more than the 912iS. See? It's a bargain!

Plus, the engine will sit quietly in the corner of my garage, demanding nothing of me until I need it. One hundred horses, not so much...

28828

DesertFox4

09-24-2021, 08:41 PM

It is a beauty Eric. They do look great bolted to the fuselage. Soon, you’ll see. Keep after it.😀

alexM

09-24-2021, 10:26 PM

Very cool Captain Eric!

efwd

09-25-2021, 07:06 AM

Your valve covers are Red as well. My 912iS is green. :D

Eric Page

09-25-2021, 02:48 PM

That HAS to be worth at least 5hp.

Per valve cover!

Eric Page

09-30-2021, 09:58 PM

Would you believe, I finally got back to working on the plane for a few hours today? I spent about an hour at the computer fleshing out my instrument panel design (using the free panel designer at Hangar Flying (https://hangarflying.com/)), then headed to the garage.

I set the copilot door in the fuselage opening, shimmed it with tongue depressors to center it in the opening and clamped it in place.

28878

Then I grabbed two hinges, positioned them below the butt rib bracket, marked the hinges through the existing holes (drilled by the first builder), center punched the hole locations and drilled them out. With that done, I fixtured them in place with temporary bolts, pinned the hinges and clamped the lower half of each hinge against the door frame.

The rear hinge ended up slightly out of alignment with the butt rib bracket, but it'll hold the door on so I'm going with it. I read somewhere that perfection is the enemy of completion.

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Next up will be to countersink the holes in the hinges for flush head bolts, then back-drill through the existing holes in the door frames and through the lower half of each hinge. Then I can back-drill in the opposite direction through the little rectangular backing plates. Aligning the existing rivet holes on the inside of the door frames will require that I jury-rig some sort of strap duplicator. I have an idea for that...

It's really nice to finally be making some progress again!

Eric Page

10-01-2021, 06:55 PM

I'm having a bit of analysis paralysis and could use some advice.

I'm looking at mounting the LP Aero Plastics bubble windows on the door frames. The guidance from Kitfox, in both the S5 and S7 manuals, shows the hinges mounted to the outside face of the butyrate (S5, left image) or polycarbonate (S7, right image) window material:

28884 28885

The instructions from LP Aero Plastics, which are text only, say this:

[...] When alignment is satisfactory, using a china marker grease pencil, mark the door hinge location for notching of the window for hinge clearance. Notch the window with a small drum sander mounted in a rotary (Dremel) tool.

That sounds like a terrifying procedure, so I'm wondering how others with the LP Aero bubble doors accomplished the hinge mounting. If you notched the window, how much clearance did you leave around the hinge plate? Did you later fill that gap with something like silicone?

EDIT: The instructions for installing the bubble door that are provided by Kitfox don't say anything about the hinge mounting, but one of the images appears to show the hinge plate on the outside of the window plastic.

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jiott

10-01-2021, 10:10 PM

Eric, I mounted my hinges on the outside of the bubble door material (which is Acrylic by the way, not polycarbonate) without any notching.
Remember to space out the bubble door frame from the fuselage with some rubber like you will use to seal the door.

Eric Page

10-02-2021, 09:21 PM

Thanks, John. I'll get back to this soon and see how it goes.

I spent most of today going through the Rotax installation manual, trying to get my head around its electrical system and how it integrates with the airframe electrical...

Eric Page

11-13-2021, 05:17 PM

I'm finally getting back to making progress on this monster that's taken over my garage. I've put aside mounting the doors for now; I need some more time standing there looking at them and thinking before I gather enough courage to start trimming the bubbles.

I started today making a template for a part to extend the rudder control horns. Details are in another thread (https://teamkitfox.com/Forums/threads/11893-Modify-rudder-control-horn?p=102254&viewfull=1#post102254), so I won't repeat it all here.

After shattering the rudder cap during that project, my next order of business was to remove the broken portion, cut the foam back to a square, unbroken section, then prepare and bond on a replacement section of foam. That should be ready to shape and coat tomorrow.

29215 29216

The rest of the day was spent installing items that will be difficult to reach once the fuselage is covered. Obviously, some of this started a few days ago...

First was a slightly unorthodox mounting for the GPS antenna. It's located in a bay aft of the turtle deck, mounted on a couple sticks of 3/8" square wood dowel. The wood is varnished, then bonded to the fuselage tubes with Hysol. This turned out surprisingly rigid; it should be plenty sturdy enough, given that the antenna weighs next to nothing. The top surface of the antenna will sit ~3/16" below the fabric. The four-wire loom is routed up to the firewall with a couple of feet to spare.

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Next was a quickie. I mounted a SkyView network hub just behind the pitch servo. It will gather the cables for the two autopilot servos and the ADAHRS to a single cable going forward. All this required was a couple of nylon cable ties.

29218

Next up was the ADS-B receiver. That went on a small piece of varnished plywood bonded to the fuselage, right behind the copilot.

29219

The last item mounted today was the tray for the transponder. That went right behind the control mixer, on the left side of the fuselage. Definitely the most complex project today. That sucker isn't going anywhere.

29220

I want to get the ADAHRS mounted as well, but that requires getting the fuselage leveled fore/aft and left/right. I stacked up most of the loose garbage I could find in the garage, lifted the tail onto it, and it all added up to perfectly level. Left/right just required a tiny shim on one side. I've got some more 3/8" square dowel sections coated with varnish; they'll cure overnight and I'll get them installed as near to square and level as I can tomorrow.

29221 29222

Eric Page

12-08-2021, 11:08 AM

I'm not doing a very good job keeping this thread updated, but here's what I've accomplished since the last post.

Once the Hysol cured on the new foam on my rudder cap, I shaped it to about 1/16" under the undamaged part, then coated it with Hysol and set it aside to cure.

29426 29427

Once that hardened, I used a rasp to shape it, then gave it a coat of smurf poo.

29428 29429

With the poo solidified, another go with the rasp and sandpaper put the cap back in good shape.

29430 29431

I didn't get photos, but I also mounted the ADAHRS right behind the baggage sack (using a similar method to the GPS antenna, above), made a short SkyView network cable to connect it to the 5-port hub, then made a long network cable to connect the hub to the avionics in the instrument panel.

I also finished the remaining plumbing/wiring in the wings (pitot/AOA, wingtip lights, landing/taxi lights, magnetometer cable), so now the only remaining tasks to be done before the wings can be covered are locating the flaperon brackets and priming the spar tubes. I think the priming operation is going to make a mess since the wings are already assembled, but the primer won't hurt anything and it'll all be hidden from view. Fortunately I can heat my garage, so I don't have to wait for the spring thaw.

WRT the door bubbles, I think I'm going to have to notch the window around the hinge plates. The first builder already drilled the butt rib brackets for the hinges, so their distance from the door frames is set in steel. If I sandwich the window between the vertical hinge plate (on the door) and the door frame, it will push the horizontal hinge plate about half a diameter out of alignment with the existing holes in the butt rib bracket. I think the only way around this would have been to get the holes welded up and re-drill them, but that train already left the station.

alexM

12-08-2021, 11:37 AM

That's some smooth looking poo Eric. I forget, were you going to use a conduit of some kind for the wires and tubing?

jiott

12-08-2021, 02:34 PM

One thing I learned on shaping the end blocks for rudder, elevator and horizontal stab was that the basic shape was important, but no need to spend a lot of time smoothing and polishing the surface finish. It gets covered with so many layers of fabric and trim tape that scratches and pock marks will not show thru.

Eric Page

12-08-2021, 04:36 PM

I forget, were you going to use a conduit of some kind for the wires and tubing?
I ran most of them through the aft spar tube (no conduit; they're just laying in there). A couple of them I didn't want to take all the way to the wingtip and back, so I used a few dots of bathroom caulk to tack them in the space between the aft spar, the fuel tank and the false ribs. They'll enter the fuselage right behind the spar attach fitting.

One thing I learned on shaping the end blocks for rudder, elevator and horizontal stab was that the basic shape was important, but no need to spend a lot of time smoothing and polishing the surface finish. It gets covered with so many layers of fabric and trim tape that scratches and pock marks will not show thru.
For sure! I realized that after spending a lot of time applying multiple coats and sanding like I was prepping for paint the first time around. As you can see from the last photo, I didn't bother so much this time.

bbs428

01-20-2022, 07:03 PM

I can relate to the shattered rudder endcap!

My "ready for paint" rudder fell over and landed on the only thing in the paint booth that could damage it, so I'm recovering...sigh.
On the upside I now can do the rudder control horn mod that you described earlier.

Some nice work going on with the doors and the Skyview cable hub & network.

Eric Page

02-18-2022, 11:16 AM

With the flaperon bracket problem finally solved (https://teamkitfox.com/Forums/threads/12012-Problem-with-Flaperon-Brackets?p=103585&viewfull=1#post103585) I started working on locating them on the wings, and immediately ran into two more problems. The hinge for the #1 rib is part of the control horn assembly that's attached to the inboard end of the flaperon.

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It appears to me that the shim slides over the end of the flaperon horn's tube, then inside the two flanged nylon bearings and the retaining ring, with the hinge captured between the flanges of the nylon bearings.

First problem: I have a significant mismatch between the outside diameter of the shims and the inside diameter of the bearings. There's about 1/8" of slop between the parts. What am I missing here? Am I misinterpreting the drawing, or is this a known problem?

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Second problem: Location of the #1 hinge arm. With the other four hinges lined up perfectly, the #1 hinge arm measures exactly 35-1/2" from the #3 arm (as shown in the drawing), but the arm is about 3/32" too far inboard to align with the center of the #1 cap strip.

The bearing flange isn't thick enough to be sanded to align the arm. The only solution I can come up with is to reduce the length of the tubular section of the hinge so that its arm sits slightly farther outboard. Is that what others have done?

Delta Whisky

02-18-2022, 05:12 PM

Eric - If I'm understanding what you wrote correctly, the shim doesn't go in the bearing but locates the bearing/arm assembly. HTH, Darrel

Eric Page

02-18-2022, 07:29 PM

OK, never mind. Boy, do I feel like a chump!

Darrel's response made me think this through again and mock up the assembly (embarrassingly, not for the first time). I see now that the nylon bearings fit over the spar stub that protrudes through the rivet boss on the end rib. The bearings do not ride directly on the shim. The shim fits perfectly between the control horn tube and the flaperon spar. So, all I need to do is remove some powder coat and trim the bearings to length, and everything will fit together perfectly.

Thanks, Darrel.

EDIT: Thanks also to Eddie for a message that has mysteriously disappeared, suggesting a dog-leg bend in the #1 hinge arm to correct the alignment problem.

efwd

02-21-2022, 06:20 AM

No problem Eric. I deleated after looking at the manual diagram and realized I had misunderstood the bushing part of your question. I forgot to leave the other part.

Eric Page

04-10-2023, 05:10 PM

I received a nice PM the other day from @Navycposd enquiring about the lack of activity in my build. Thank you, whoever you are.

I'm a bit surprised to see that I haven't posted anything here in more than a year. Yikes! It's remarkable how easily life gets in the way and project work habits are lost. The good news is that I haven't been completely idle on the project. I haven't done any physical assembly of the airplane but I have been applying my electronics hobby to the effort -- something that I can do in hotel rooms on layovers. I've designed and built several modules that will go into the electrical system:

Pitch Trim Buffer. This module uses two half-bridge drivers to buffer the output from the Dynon SV-AP-PANEL (limited to 2A maximum) to a high-current drive for the elevator trim linear actuator motor. Size: 1.72" x 1.72", 0.77 oz.

32104

Rudder Trim Controller. This is two circuits on one board. The first is an 8.4V supply to power an RC rock crawler steering servo (torque of 40 kg-cm or 556 oz-in) and the second is a pulse width modulation generator that controls servo position in response to a potentiometer input. The servo will drive a small tab on the rudder to allow in-flight adjustable trim. Size: 1.14" x 2.15", 0.78 oz.

32105

LED Strip Dimmer. This is a very simple adjustable linear constant current driver to control an LED strip that will be mounted under the glare shield for night-time flood illumination of the instrument panel. Size: 1.72" x 1.72", 0.64 oz.

32106

Landing & Taxi Light Wig-Wag Controller. This one uses a microcontroller and some transistors to switch power to the landing and taxi lights. Two panel-mounted switches will send signals to this module to turn on taxi alone, taxi and landing, and make them steady on or flashing. There are two programmed flash patterns, selectable by a 3-pin jumper. Size: 1.72" x 1.72", 0.78 oz. This photo -- and the next -- show the boards attached to base plates that will allow neat mounting in the plane. All others will be mounted the same way.

32107

Brown-Out Booster. This is a DC-DC boost converter designed to carry the load of the Dynon EFIS and all components powered through its SkyView network, keeping them alive during engine cranking. When the charging system is active, this module stops switching and simply passes bus power through its inductor and flyback diode. Ignore markings on the board; it was designed for a slightly different purpose and the electrical system design has overtaken the board's silkscreen. Size: 2.56" x 3.90", 3.26 oz.

32108

Overvoltage Protection Module. This is a work in progress; I'm presently awaiting circuit boards for a new revision. It will sit between the 912iS Stator B and Regulator B and will monitor Battery Bus voltage. If bus voltage rises too high for too long, it will open three relays, isolating the 3-phase stator output from the regulator input. When it trips, it will flash a warning light on the panel and send an alarm signal to the EFIS. A panel-mounted push button allows pilot control of the charging system and module reset in case of a nuisance trip. Size: 2.28" x 3.83", 4.61 oz (weight of populated board and enclosure; with connectors and wiring, ~14 oz).

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Dave S

04-10-2023, 06:20 PM

Eric,

Glad to hear you are making progress, albeit maybe invisible to the casual observer.

It has been said many times on this list that to get an airplane project done - make a point of doing something as often as you can. You'll get there!

Have to say that the LED glarestrip with the dimmer has got to be one of the most useful things a person could add to the panel. Really makes it easy to see everything on the panel. I think of all the crappy solutions that a suprising number of old certificated airplanes seem to have had (you know - the ones some of could afford to rent in the past.)

Thanks for sharing you progress on the electronics.

bbs428

04-11-2023, 02:00 AM

Some really cool stuff Eric. You never cease to amaze me with your depth of understanding and practical application of electronics!

alexM

04-11-2023, 08:11 AM

Dang. Not even sure I understand half of what I just read. I'll be lucky if I don't hook a red wire to a black one.

Nicely done. Are you having that silkscreen work done by a supplier, or doing that yourself?

jrevens

04-11-2023, 09:01 AM

Lots of good stuff, Eric! I always enjoy your posts on the AeroElectric Connection forum too.

Eric Page

04-11-2023, 10:32 AM

Some really cool stuff Eric. You never cease to amaze me with your depth of understanding and practical application of electronics!
Thanks. Don't be too impressed; I make plenty of mistakes. That overvoltage board is about to be built for the third time. Fortunately, I enjoy the work and it's not a very expensive hobby (once you have the expensive tools, that is...).

Are you having that silkscreen work done by a supplier, or doing that yourself?
The boards are made by a commercial fabricator. All I do is upload the "Gerber" files (an industry-standard design file for circuit boards).

Lots of good stuff, Eric! I always enjoy your posts on the AeroElectric Connection forum too.
Thanks. I've made some embarrassing boo-boos on the AE-List forum. Fortunately, that's a good bunch of guys so no one points and laughs!

Navycposd

04-13-2023, 06:56 AM

Good Stuff Eric!

I may have to duplicate your LED dimmer circuit project .... Same purpose, how to light up the instruments for night flight....

Glad to see you are still making progress (now I need to get home so I can get started on my project!)

L

Eric Page

10-10-2023, 04:20 PM

Well, fellas, you're not going to believe this, but I actually worked on my Kitfox today. First actual work in the garage since Feb 18th, 2022.

I moved the car out for the winter (I'll regret that in December when I have to report to work at 5am), moved the wing cradle away from my work table and got busy on a job that I've been dreading since I brought the plane home: repairing the seat pan.

The first builder appears to have trimmed it with a hacksaw blade while three days into a bender. Here are just a couple of examples (there are many more like them):

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I went after it with coarse sandpaper and a rotary sanding drum. My idea was to sand back the damaged edges to eliminate the over-cuts, then add back material -- either with polyester repair putty and milled glass, or with glass mat and resin -- until I have enough to reshape the edges properly. Here are a couple of the bad spots after sanding them back:

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That second photo shows my preparation for adding glass mat to the back side to rebuild the area that's scalloped out of the edge. I've never done any fiberglass work before, so I'm relying on an article in a recent issue of Kitplanes about extending an engine cowling; it looked like the technique would work for this too.

For the small areas where the over-cuts were sanded back, I mixed up some repair putty with a lot of milled glass and slathered it on, making sure to get it spread onto the back surface as well. Here's what that looked like:

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In the center seatbelt slot, I didn't want to extend the slot by sanding so I just filled the over-cuts with putty.

33033

I fully expect the putty to take a week to cure since the garage is only 60-ish degrees, then it'll probably just break off the edge when I start to shape it. Apparently that's not a big deal with fiberglass, as it's supposed to be almost infinitely repairable (or so AlexM told me once). We shall see.

For now, the garage smells like a canoe factory so I'm back inside.

Oh, I almost forgot: the glass mat and resin repairs will have to wait. My PolyEpoxy crystalized into a solid mass in the can. Aircraft Spruce says you can heat it up and it'll return to liquid and work fine, but that it can take many hours to melt completely. I've repurposed a small crock pot to handle that job. Hopefully it doesn't poison my next pot roast...

33034

alexM

10-10-2023, 08:57 PM

^First clue that someone is a bachelor---> Heating up fiberglass resin in a crock pot on the kitchen counter.

Also on the list:
De-greasing car parts in the dishwasher
Baking a car headlight in the oven so you can remove the clear lens

Glad you're working on your plane though! Let me know if you need any help with the fiberglass stuff. That (unlike electrical stuff which you've been so helpful with) is my wheel house.

Geek

10-11-2023, 08:17 AM

Good to see you're back at it Eric!!! After drooling over your prop set up, was beginning to worry you were going to get stuck over at the dark side (turbines) and miss the fun side.

Gary

Eric Page

10-11-2023, 09:37 AM

Let me know if you need any help with the fiberglass stuff.
I'll make you a deal, Alex. You come down here and do my fiberglass work, and I'll head up there and do your wiring. Everybody wins. I'll even swab out the respirator and put fresh cans on it for you.

...was beginning to worry you were going to get stuck over at the dark side (turbines) and miss the fun side.
Fat chance. Unless a turbine is on fire it's pretty mundane flying. I flew out to a little fishing town on the coast a few days ago for lunch with my neighbor in his '53 C-180 (it was actually a 4-ship; the other three were an RV-6, an RV-9A and an RV-12). Kinda lit a fire under my lazy butt.

The RV-12 guy is desperate for me to finish my Kitfox so he won't be the slowest any more!

Kitfox Pilot

10-12-2023, 04:50 PM

[QUOTE=Eric Page;109769]I'll make you a deal, Alex. You come down here and do my fiberglass work, and I'll head up there and do your wiring. Everybody wins. I'll even swab out the respirator and put fresh cans on it for you.

Man I wish I had that deal offer when I was wiring! haha

Eric Page

10-12-2023, 05:45 PM

Well, the polyester repair putty didn't work. It never cured beyond the consistency of chewed gum. I suspect that I didn't add enough MEK to the putty, so it never fully cured. I seem to remember having a similar problem the first time I used it, to plug the badly drilled holes in the seat pan. Anyway, I pulled it off, scraped away as much as possible, then rubbed at it with acetone to remove the sticky residue. Sigh...

Instead of trying that again right away, I moved to rebuilding the edges where I had to grind away significant material. To form a backing for the new material, I softened a hotel key card (thanks, Hilton!) with a propane torch, then formed it to the seat pan and taped it in place.

33040

Next I cut out some patches of fiberglass mat in increasing sizes to layer into the repair.

33041

Finally, I mixed up ~12g of epoxy (the crock pot melted it beautifully), barely saturated the fiberglass, wetted the seat pan surface, then laid in the layers of mat. Lather, rinse, repeat.

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I'm pretty sure they're going to need more glass on the top side once the key card is removed (if they can be removed... it has just occurred to me that I don't know if hotel key cards stick to epoxy!). Oh well, fingers crossed.

alexM

10-12-2023, 08:15 PM

Definitely not enough catalyst on the first try. I did the same thing with the stuff I used on my Laker Leading Edges. Once I started weighing it instead of eye balling it, the stuff worked perfectly.

Weird trick I learned from boat builders which applies to woven fabric (not necessarily the mat like you used) is to apply the big patch first, then medium, then small. Seems backwards to all of us but if you do it the "normal" way it's more difficult to work out the bubbles/excess resin where it steps down.

Last thing and then I'll shut up. It has been a while since I've done a lay up but it used to be that mat and epoxy didn't get along well. The reason is that the mystery goo that holds those random fibers together breaks down readily in the presence of styrene (found in poly, iso, vinyl ester - aka stuff that smells like normal fiberglass resin), but not in epoxy. It's quite possible that mat has been developed for epoxy since then and I don't know about it. It will still work and will still give you good structural properties, it just doesn't lay down as nicely while you poke at it with a brush.

The hotel card is likely made of PVC. Great idea to warm it up and make it a one sided mold. I'm actually not sure it it will release. If so that is a great find!

Eric Page

10-13-2023, 02:40 PM

Definitely not enough catalyst on the first try. I did the same thing with the stuff I used on my Laker Leading Edges. Once I started weighing it instead of eye balling it, the stuff worked perfectly.
The stuff I have here is from Total Boat. The directions on the can say to use 14 drops of MEKP for every 100g of putty. I'm trying to mix 10g batches, so accurately measuring the catalyst is a problem. I tried again today; see my next post...

...apply the big patch first, then medium, then small. ...if you do it the "normal" way it's more difficult to work out the bubbles/excess resin where it steps down.
Yeah, I discovered that. I ended up with a significant step at the edge of the seat pan, which presumably resulted from an air pocket between the glass and key card.

[Mat] will still work and will still give you good structural properties, it just doesn't lay down as nicely while you poke at it with a brush.
I was actually surprised how easy that part was. I expected it to completely come apart since the pieces were so small, but it mostly held together and I only had a few fibers coming away on the brush, even when I used tiny scraps to fill in. I used a disposable 1/2"acid brush; it seemed to work fine.

Eric Page

10-13-2023, 02:51 PM

Alex's worry about the hotel key cards releasing from the epoxy was prescient; they didn't. I did get them off, but both left their top layer of clear plastic behind. You can see it in the second photo below, where some of the printing went with it. Fortunately the violence required to get them off didn't break the fiberglass. I take that as a good sign.

33051 33052

I decided to make another attempt at the repair putty, this time mixing a "hot" batch, with about double the specified amount of MEKP catalyst (3 whole drops in 10g!). Again, I added a good amount of ground glass to make a thick slurry. I troweled that on top of the fiberglass, bringing it about flush with the top surface of the seat. I'll plan to trim it all flush with the edge, then sand and fill with Smurf poo.

33053 33054

Since I had plenty of the putty left, I went after the other spots again as well. I'm not sure how healthy it is to get that crap on your skin, but I found the only way I could shape it the way I wanted was with the tip of my finger, so that's what I did. I haven't started trembling and drooling yet, so maybe I got away with it.

33055 33056

I turned on a heater in the garage and headed inside before the fumes cooked my few remaining brains.

jiott

10-14-2023, 11:29 AM

Eric Page

10-14-2023, 07:25 PM

Eric, just curious why you didn't just wrap the patch material over the edge and onto the front finished side? It seems it would make a stronger, easier applied patch. Admittedly it would require a lot more sanding to bring it to finished dimensions, but a good old Dremel tool would make fast work of it.
I thought about it, but to make the new material flush with the original surface would have meant grinding/sanding virtually all of it away, so I didn't think it made any sense. Given the rough treatment I gave it getting the hotel key cards off, I'm pretty confident that the repairs aren't going to crack off, and once they're trimmed down to final size they'll be quite small areas anyway. Fingers crossed.

My second attempt with the repair putty turned out the same as the first, despite putting double the recommended amount of catalyst in it. I'm suspicious that all the milled glass I've been putting in it is somehow impeding the cure. Whatever the cause, I've got another mess to clean up.

I think my next step is going to be a test run with just catalyzed putty with no additives, just to see if it will cure properly. If it does, I'll have a way forward with materials I have on hand, and if it doesn't, I'll be pretty sure that the putty has gone bad. I'll get that mixed up this evening and hopefully find a solid mass in the morning.

What a ridiculous waste of time...

alexM

10-14-2023, 07:48 PM

Weird. The milled fibers would not impede the cure. But good resin is like good food. The good stuff has a shelf life.

Doubling the MEKP should have kicked it off for sure. And you did use MEKP and not MEK, right? Not same same.
It actually should have got hot or even started smoking. The good news is that you can clean that mess up easily with some acetone and a rag.

You were on the right path to lay up against the credit card (next time put a layer of clear packing tape on it).

Eric Page

10-14-2023, 09:10 PM

Weird. The milled fibers would not impede the cure. But good resin is like good food. The good stuff has a shelf life.
Huh. No idea if Total Boat sells the good stuff, but maybe it has gone bad. It's been in my garage for 2+ years.

Doubling the MEKP should have kicked it off for sure. And you did use MEKP and not MEK, right?
That's what I figured, but my experience with this stuff is nil. Yes, I used the little squeeze bottle of stuff that came with the putty. Pretty sure it says MEKP on the front.

The good news is that you can clean that mess up easily with some acetone and a rag.
Yeah, it wasn't too bad. Worst part is getting the uncured putty out of the weave of the mat/epoxy layup.

...next time put a layer of clear packing tape on it
You'd think I'd know that, given that I've watched Mike Patey build two or three airplanes with foam, packing tape, carbon fiber and epoxy.

I made a test coupon by mixing 5g of putty with 3 drops of MEKP (now up to 4x the recommended amount) and smearing it on a sheet of paper. That's sitting on top of the space heater that warms my garage. I'll know tomorrow if I need to order new material.

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Eric Page

10-15-2023, 06:08 PM

The test coupon cured fine, although slowly, so I think the putty is probably getting old. Anyway, I think I'm safe to mix up what would normally be a really hot batch of the stuff and get the seat pan edge repairs finished.

The test coupon did cure, but it's fairly brittle with no structure inside it, so I'm worried about using it to mend the edges where there are over-cuts. I fear it will crack off with any significant pressure.

Alex, is there a better way to fix those areas, short of grinding them back and building out new material with the mat and epoxy, like I did in the other two spots?

Eric Page

10-18-2023, 08:58 AM

My third attempt with the polyester repair putty was another failure. I mixed it with 4x the specified catalyst and it still didn't cure, so I threw the can away, cleaned up the mess again and moved to plan B.

This time I prepared about 5g of Poly Epoxy, then mixed in enough milled glass to make a thick paste. I applied that in the now familiar way, set up the heater and crossed my fingers.

This morning, success! Everything finally cured rock hard, without the slightest hint of stickiness.

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I somehow missed patching one spot, so I added the fiberglass mat yesterday, and this morning I made more Poly Epoxy paste and did what will hopefully be my last patch job on the seat pan.

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Next step will be to remove most of the added material to shape the edges of the patches to the right profile, sand them down flush with the top surface of the seat pan, and probably do a little fill-and-sand with Smurf poo. Then I can mist some paint over the whole ugly mess and pretend that it never happened.

Did I mention that my that my fiberglass wingtips are butchered too?

Jerrytex

10-19-2023, 11:30 AM

I went through the same thing with my seat pan. I added fiberglass to several areas where it was cut too short and one area had a crack. A real PITA....I feel your pain!

I found some paint that worked very well and it matched the gel coat color so I was able to touch up without having to paint the whole pan.

https://www.homedepot.com/p/Rust-Oleum-Specialty-Rust-Oleum-Specialty-12-Ounce-Appliance-Gloss-White-Epoxy-Spray-Paint-7881830/202056394

It's dries shiny and smooth.

Eric Page

10-19-2023, 05:29 PM

Thanks, Jerry. I couldn't find the appliance paint at my local Home Depot, but I got some other Rustoleum gloss white that looks fine too. More on that later...

I made good progress on the seat pan today. All of the fiberglass repairs are trimmed and sanded.

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It's still far from perfect, but I've stabilized all of the places that were likely to create cracks and made it look good enough to satisfy me. I added a coat of white paint to cover the repairs, but that's going to need some sanding and re-spray because I have zero painting skills and caused several runs.

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Eric Page

10-23-2023, 05:44 PM

Got the paint runs on the seat pan sanded down and repainted. Still not perfect, but good enough. I was standing there feeling smug about the accomplishment when I looked to my right and saw these items sitting on the shelf...

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Now I get to cut up my freshly painted seat pan!

alexM

10-23-2023, 08:44 PM

I hate when that happens!

Geek

10-25-2023, 08:16 AM

........Now I get to cut up my freshly painted seat pan!

But the bright side is that you get to do the cutting and not the other guy!!!

Eric Page

10-25-2023, 08:59 AM

That, sir, is a VERY good point!

bbs428

10-26-2023, 10:01 AM

Hey Eric -

Just a heads up on the seat to get it somewhat smoothed up but remember that it will be all covered in fabric and the seat upholstery. So, it doesn't need to be perfect, just has to be good enough for you to live with it.

Also - When cutting out your seat boxes, make sure you leave plenty of "lip" for the lids to rest on - ask me how I know!
I had to add some small blocks to aid in my lid stability when shut. :rolleyes:

Glad to see your back in the build groove - keep your eye on the prize!

Eric Page

10-26-2023, 10:38 AM

Thanks, Brett. It's far from perfect, and I'm OK with that. Like you said, it'll be covered.

I appreciate the reminder about leaving a lip for the cover. I'm pretty sure I would have screwed that up. Still might!

jiott

10-26-2023, 11:14 AM

I hinged my lids in the back; makes them very stable.

Eric Page

10-26-2023, 01:04 PM

I hinged my lids in the back; makes them very stable.
I was wondering about that while working on them this morning. I presume since the hinge will be under 2” of foam cushion, I can just use a couple of small strap hinges from Home Depot and there’s no reason to fuss about making them flush.

I was also planning to drill a finger hole near the front edge of the lid to ease opening. Either that, or a half-moon shaped relief in the seat pan so I can grab the front edge of the lid.

Eric Page

10-26-2023, 01:35 PM

alexM

10-26-2023, 02:34 PM

Started on the under-seat storage bins today.

I found that a couple of edges on each one weren't cut straight at the factory, so I applied some tape as a cutting guide and Dremeled them straight. Followed that with some block sanding at the edges to deburr and smooth. Disappointed at how unsteady my hands have become with age -- not looking forward to trimming door and windshield plastic.

One rear corner on each bin had a step in the lip that will attach under the seat pan...

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...so I heated up that corner with a heat gun, and when it got a bit floppy, pressed it down against the table top to straighten it out.

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That removed most of the unevenness, so a little bit of sanding took care of the remaining high spots. I was careful not to sand too close to the inside edge where it folds down into the bin, since that will be visible after installation.

Finally, I eased the sharp corners, cleaned them up (use water for this step; this plastic is dissolved by acetone!) and set them aside. Next was figuring out where on the seat pan to cut the lid openings, and where to attach the bins. I put the seat pan into the airframe and quickly discovered that I should have done so before painting it. The reliefs in the pan for the center console aren't cut wide enough and the ones at the top for the fuselage upright tubes need some more relief too, so I'll have to do some more work there.

Anyway, there appears to be plenty of room underneath the seat for the bins so I'm going to prioritize a good location for the lid then worry about attaching the bin to match the lid opening.

Did everyone use Hysol to attach the bins to the seat pan? I can't seem to find any instructions for this sub-kit in my pile of airplane paperwork.

Eric,
Mine are attached with Hysol and rivets.

It's not that your hands aren't steady, it's that manual labor like pretty much everything on the plane requires practice to get good at it. If you trimmed 50 of them you'd be a rock star at it.
I once watched a woman on the 737 final assembly line spread adhesive. You know that opening window by each pilot, where it has that fuzzy stuff on the forward lip of the window frame? She would use what looked like your basic caulking gun to lay an absolutely perfect layer of adhesive without the need to even touch it afterwards or clean up anything. Zero squeeze out. I would probably have half the stuff in my hair and on my clothes.

And I'm glad you're back on the build too. I need some competition and Geek has obviously pulled way out front.

Geek

10-26-2023, 03:20 PM

........And I'm glad you're back on the build too. I need some competition and Geek has obviously pulled way out front.

I didn't get to go play in Alaska so not my fault Alex!!!!

Geek

Eric Page

10-26-2023, 05:21 PM

Mine are attached with Hysol and rivets.
Aaah! Rivets, of course. I was trying to figure out how I was going to get them to stay tight against the seat while the Hysol cures. They don't sit flat without some persuasion.

I once watched a woman [...] She would [...] lay an absolutely perfect layer of adhesive without the need to even touch it afterwards or clean up anything.
Yeah, watching someone who has mastered their craft is a joyous thing. I'd like to be that good at something. Anything...

And I'm glad you're back on the build too. I need some competition and Geek has obviously pulled way out front.
Me too. I still struggle to get myself out there, but I'm inching up on it being a habit again. For sure, we're not catching Geek. He'll be flying in to drink our beer and give advice before much longer!

Didn't get anything else done today. A friend with a PA-12 Super Cruiser asked me to fly with him so he could log a couple of approaches for currency. How could I refuse? It's not easy being an instrument safety pilot from the back seat of a Cub, but we didn't hit anything. We even landed in his hay field at the end. Fun stuff!

Geek

10-27-2023, 02:24 PM

.........For sure, we're not catching Geek. He'll be flying in to drink our beer and give advice before much longer!

How about I keep unwanted advice to myself and just drink your beer? I think it's a conspiracy and you both have sent letters to the FAA asking them to hold short on my N number so I can't register or schedule the DAR. C'mon guys - isn't 5 months enough time to wait?
Glad your back on it Eric..... Will be fun to join up on you two and hang out. Thought it might happen when Alex was going to start his motor (yeah I still want to be there Alex!!!) but I guess he's going to be spending more time on my side of the hill so by that time I'll be mighty thirsty and besides Alex probably will want to drink my beer.

Geek

alexM

10-27-2023, 03:56 PM

How about I keep unwanted advice to myself and just drink your beer? I think it's a conspiracy and you both have sent letters to the FAA asking them to hold short on my N number so I can't register or schedule the DAR. C'mon guys - isn't 5 months enough time to wait?
Glad your back on it Eric..... Will be fun to join up on you two and hang out. Thought it might happen when Alex was going to start his motor (yeah I still want to be there Alex!!!) but I guess he's going to be spending more time on my side of the hill so by that time I'll be mighty thirsty and besides Alex probably will want to drink my beer.

Geek
One more night shift tonight and then back home for a week. I'll be really close to engine start by the end of that week.

Eric Page

10-27-2023, 05:02 PM

How about I keep unwanted advice to myself and just drink your beer?
Funny thing... I'm suddenly short on beer!

I think it's a conspiracy and you both have sent letters to the FAA asking them to hold short on my N number so I can't register or schedule the DAR.
I can't imagine why it's taking so long to get an N number. I went on the FAA website (https://aircraft.faa.gov/e.gov/NN/reserve.aspx) and reserved three of them (how's that for optimism!?!?) in a few minutes.

Today I trimmed the cutouts in the seat pan again, aiming to get a better fit in the fuselage frame and around the aft end of the center console. That worked out fine and it now fits like it should. To celebrate, I grabbed a control stick, hopped in and made some airplane noises.

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Back to work. I located where I wanted the lids for the under-seat storage bins, traced them with a pencil, then cut them out with a diamond cutting wheel, a cylindrical burr and a sanding drum in the Dremel. With the gross opening done, I refined it with 120-grit sandpaper and a wood block until the lids fit nicely.

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The feeling of accomplishment didn't last long, as I soon found a spot at one corner where the fiberglass had cracked. It looks like my earlier repair had an air pocket in it and that caused a delamination.

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I got pretty aggressive with the Dremel, removing all of the cracked material and a large area of gel coat nearby, then cleaned it up with acetone.

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Finally, I cut out some more fiberglass mat patches, mixed up 4g of Poly Epoxy, wetted the fiberglass and the repair area, laid the patches in place and pressed them into position, being sure to work out any air bubbles.

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The cleanup after a day of fiberglass cutting and sanding was quite a project in itself.

Eric Page

10-27-2023, 05:16 PM

I'll be really close to engine start by the end of that week.
I'd be interested in riding up there to observe if you turn the key by next Fri. I'm back to work 11/4.

Geek

10-28-2023, 08:11 AM

Funny thing... I'm suddenly short on beer!

I can't imagine why it's taking so long to get an N number. I went on the FAA website (https://aircraft.faa.gov/e.gov/NN/reserve.aspx) and reserved three of them (how's that for optimism!?!?) in a few minutes.

Short on beer? Isn't that a sin? As for reserving the N number - yeah I did that. Went on the website, looked up that the number I wanted was available and paid my $10. Few months later I got a letter saying that the number wasn't available and here's your refund. The website says that their list is "updated at the close of business every day" but I think that's a load of hooey. So I went back in (5 months ago) and 'reserved' two numbers and now I sit (not so) patiently by the mailbox. I have all my paperwork filled out except for my number.

Sometimes "aggressive with the Dremel" is what it takes. I am so far removed from being an expert on fiberglass but I did rebuild a C2 Corvette that needed some body help. A friend of mine was an expert on that stuff, would come over to help me and his instructions were always cut it back a little farther than you think you need to so that you are well into the healthy glass and get a good bond. Alex probably has some of the same experience on this. You're doing good here Eric. Cleaning up a mess (especially someone else's) is never fun and the phrase "What the hell were they thinking" just keeps coming to mind. We probably need to be a bit careful however telling Alex we want to be there for his start.....he's gonna charge us admission.

Geek

Eric Page

10-28-2023, 08:33 AM

...I went back in (5 months ago) and 'reserved' two numbers and now I sit (not so) patiently by the mailbox.
Very strange. Have you tried to contact them since sending the paperwork?

Web form: https://registry.faa.gov/aircraftemail/

Email address: 9-AMC-AFS750-Aircraft@faa.gov

Phone numbers: (866) 762-9434 -or- (405) 954-3116

Cleaning up a mess (especially someone else's) is never fun and the phrase "What the hell were they thinking" just keeps coming to mind.
Amen, brother.

bumsteer

10-28-2023, 10:46 AM

Might well be worth giving them a call. I had a reserved number and had the registration back in a week.

Rick

avidflyer

10-28-2023, 11:06 AM

Best bet is to have something else on the computer to do, call them and leave the phone on speaker so you can hear when they start talking to you after being on hold for maybe an hr. I've done that numerous times. JImChuk

Eric Page

10-28-2023, 11:57 AM

Trimmed the new fiberglass repair on the seat pan, then sanded the edge and surface smooth and flush.

33117

Followed that with 3g of Super Fil to hide coarse sanding scratches and a few tiny voids. Put the heater underneath it to assist curing and will finish it tomorrow.

33118

I'm holding off on the rest of the under-seat storage bin installation until I have lid hinges in hand. Stopping at HD tomorrow to see what they have to offer.

Geek

10-28-2023, 01:10 PM

Very strange. Have you tried to contact them since sending the paperwork?

Web form: https://registry.faa.gov/aircraftemail/

Email address: 9-AMC-AFS750-Aircraft@faa.gov

Phone numbers: (866) 762-9434 -or- (405) 954-3116

Might well be worth giving them a call. I had a reserved number and had the registration back in a week.

Rick

Best bet is to have something else on the computer to do, call them and leave the phone on speaker so you can hear when they start talking to you after being on hold for maybe an hr. I've done that numerous times. JImChuk

Thanks all. Since this is the very essence of hijacking Eric's build, I'll end it here. Apologize Eric I did not mean for this to take a life of it's own. I did call and got put on music hold. The music was designed to make you want to hang up or scratch your eyes out. I emailed and a few days later I received an email back saying that they were just working on requests from mid April. I made my request in June.

G

Eric Page

10-28-2023, 02:20 PM

No worries, Gary, it's good info. We've all learned from your experience to send our applications at least eight months in advance!

alexM

10-28-2023, 09:44 PM

RE: N number reservations

I got home tonight and had a stack of packages (miscellaneous stuff for my Kitfox build) and in the pile waiting for me was a thin envelope from the FAA. My first thought was "what did I do this time?" (I've got stories). Of course I tore that one open immediately. I really wish they would have different types of envelopes. Maybe ones with a smiley face or a Mr Yuck sticker on them.

Turns out it was for my N number. I reserved my number in April of the year I bought my kit, and have to renew it to keep it alive. That month has always been April, and that was when I made an online payment this year. The letter was dated 10/23/23 and good until October of next year. So it only took 7 months for someone to do 5 minutes of work. I'm sure the addition of a smiley face sticker probably would have added 2-3 months.

I guess the good news is that I have a 7 month extension, courtesy of .gov inefficiency.

Eric Page

10-30-2023, 08:07 AM

Quick update from yesterday. Busy day with family, but I managed to find an hour to get the latest seat pan repair sanded down. Also sanded the whole thing lightly with 320-grit to prep for a re-paint. Unless this afternoon is warm enough, that'll probably have to wait until spring. I don't think it'll delay first flight...

33128

Eric Page

10-30-2023, 01:32 PM

This morning I determined the overall dimensions for the lip of the under-seat storage bins, marked them and trimmed to size. If you've been following along, you'll be thinking to yourself, "Didn't he waste time trimming those things last week?" Why, yes. Yes I did.

33130

With the bins ready, I measured and marked 1/2" from the edge of the lid opening (1/4" edge margin each way for 1/8" rivets), then applied a painters' tape outline. That will give me a position reference as well as hopefully making a clean edge after I apply Hysol. I know it'll never be seen, but I'm fed up with ugly globs of adhesive on this project.

33131

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Lunch break is over; more to follow this evening...

Geek

10-30-2023, 04:13 PM

Nice work Eric. There is a difference in satisfaction between doing it to get it done or doing it nice and neat. You are surely working in cat 2. You are resurrecting a hurt puppy here and it's interesting to watch since it's different than mine.

Gary

Eric Page

10-30-2023, 05:06 PM

Thanks, Gary. I'm mostly fumbling around in the dark, but I suppose that describes most first-time builders. "Hurt puppy." Yeah, that's pretty accurate.

This afternoon I started out by making a tape line 1/4" from the edge of the lid opening, then marking out 10 more-or-less evenly spaced rivet holes around the perimeter.

33143

That was followed by drilling to #40 and 3/32" clecos.

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Then I removed the tape, up-drilled to #30 and switched to 1/8" clecos.

33145

Finally, I removed the clecos, deburred the back side of the seat pan and storage bins, wiped the seat down with acetone again, and put on what will hopefully be the last coat of white paint.

33146

I have a large supply of 1/8" x 1/4" blind rivets, but I think I'm going to need to buy some 1/8" x 3/8". I want to use backing washers since the bin material is fairly soft, so I'll need a bit more grip length.

Eric Page

11-01-2023, 08:13 PM

Yesterday and today I worked on fabricating an extended control horn for the rudder. I honestly don't remember where on this forum I read about this, but I was convinced enough of its necessity that I had already made a cardboard template for it and put the material in my basket at Aircraft Spruce. After nearly two years, the details are hazy...

In any case, I found a piece of sheet steel in my scrap pile that fit the bill. Using a 4" angle grinder and the Dremel, I roughly shaped the material to match the template. Here it still has the black powder coat on it from its previous life (it was half of a 1U blanking plate for a network rack).

33151

That large center notch wasn't wide enough to clear the weld bead on the existing control horn but after some additional fettling I got it to fit well and clamped it in place.

33152

I touched it through the existing control horn's cable holes to form a center divot at each bolt location, then removed it and finished the drilling on the drill press. I followed that with a 3/16" reamer, deburred, put it back in place and found that the holes miraculously lined up. It will move the cable attach points outward by 7/8" on each side.

33153

With the fabrication done, I sanded it lightly with 320-grit, cleaned it with acetone and gave it a coat of self-etching primer. The first side dried while I cleaned up the apocalyptic mess made by the angle grinder and put away half the tools in the garage, then I primed the other side. It'll get the first coat of black paint as soon as I finish posting this update.

33154

airlina

11-02-2023, 01:52 AM

Eric, rest assured that the time you're spending on this rudder mod will be worth it. There is a reason the factory lengthened the horn on later models. those of us who built the stock Series 5 have found them too short, but an after completion mod would require fabric removal which I don't want to do, so we live with it. Bruce N199CL

bbs428

11-02-2023, 07:52 AM

Looks great Eric!

I did the same thing. Definitely worth the effort!

Eric Page

11-02-2023, 03:50 PM

Thanks, guys. I'm glad to know that I didn't invent that out of thin air!

Today I finished painting the rudder control horn and set it aside with its hardware.

33169

I had a small home repair to do that called for strong adhesive so I got out the Hysol and discovered a good reason not to buy it in 50ml cartridges unless you're on the Rapid-Build Plan. The resin thickens over time and by the time it reaches its expiration date (last month), it won't come out of the tube any more. When I squeezed the gun I got lots of hardener, then when the pressure got high enough, some resin, but it plugged up the mixing nozzle and wouldn't budge; I had to throw 1-1/2 cartridges away. I have so little gluing left to do on the airplane that I'll probably order another cartridge, but I'll wait awhile and keep a list of things that need it.

33170

The last time I ordered it on Amazon it was $15.69/cartridge. It's now $36.14!

One of the mods I'm doing is to add a rudder trim servo. I need a way to mount the trim tab to the rudder, so I made up a mounting block using a chunk of maple left over from some cabinet trim. I cut the ends to the same angle as the ribs, put a cove in one long edge (I used a tube with sandpaper wrapped around it) and put an angle on two corners to keep it below the fabric on the back side.

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It took a little sanding on the ends to get the fit right, but now it slots in perfectly. That's on the Hysol list.

33173

The plan is to drill three through-holes to match the outside diameter of 10-32 rivnuts. The rivnuts will be Hysol'ed into the holes from the back side, then a piano hinge can be attached with countersunk machine screws from the front. I'm thinking that one of the fiberglass panels I cut out of the seat pan can be hacked up to make the actual trim tab, with some body work to smooth out the rough side.

With the fit-up done, I mixed a little varnish and gave the part two coats.

33174

I've been sitting on a hardware order at Aircraft Spruce for quite awhile so I got that submitted. $640 worth of airplane goodies are on the way!

avidflyer

11-02-2023, 04:06 PM

I had issues with the Hysol not lasting very long as well. Originally Kitfox supplied Scotchweld 2216 with their kits. I have some that is over twenty five years old and have used it in non aircraft uses. Worked just as well as new stuff. I gave up on hysol, and use the scotchweld. It does have a funny mixing ratio, 5 parts to 7 by weight, but I always put the cup on a mini scale and weigh out the amounts so just a bit of math and you know how much to add of the second chemical. JImChuk

alexM

11-02-2023, 07:24 PM

Thanks for reminding me that I need to do that rudder horn modification.

And to check the dates on my 50ml tubes

jrevens

11-02-2023, 07:53 PM

Like Jim, I like the Scotch Weld 2216 also. It is an excellent adhesive and has been used in the aerospace industry for many decades. I did use the Hysol for my Kitfox though, and used a few of the 50 ml tubes toward the end. I’ve got some left that is several years past the date, & that I used on another project recently. I really haven’t ever had it get thick enough to clog the nozzle(s) on the tubes. Just a couple of hopefully useful thoughts about that - first, I’ve always stored the stuff in a dry, cool location in my basement shop. It might even be beneficial to keep it in the refrigerator if it isn’t going to be used for awhile? Secondly, I’ve always been real careful to carefully clean off the tip of the nozzles on the tube after use & before reinstalling the cap, while making sure to not get even a tiny bit of mix between the hardener & resin. Also, always orient the cap so that the same “plug” always goes into the same nozzle (resin or hardener) each time. I’m sure most everyone does that, but just in case…

jiott

11-03-2023, 10:36 AM

When my 50 ml tubes get kind of old, I do not use the mixing nozzle. I just push the two streams of resin & hardener directly out of the tubes into a small cup and then mix it up by hand. The mixing nozzle is VERY restrictive; it takes a lot of pressure to push it through even with brand new Hysol.

jrevens

11-03-2023, 12:06 PM

I do the same thing, Jim.

alexM

11-05-2023, 10:09 AM

Secondly, I’ve always been real careful to carefully clean off the tip of the nozzles on the tube after use & before reinstalling the cap, while making sure to not get even a tiny bit of mix between the hardener & resin. Also, always orient the cap so that the same “plug” always goes into the same nozzle (resin or hardener) each time. I’m sure most everyone does that, but just in case…
Even easier is to just leave the tip on it. The stuff that is mixed in the tip will kick off but only part way up. When I need Hysol I just throw away the old tip and install a new one. I learned that trick from the folks at one of my previous employers.

Funny story about the Scotchweld 2216. My project came with wings made using the stuff (and some poorly drilled holes). At the time I thought I could remove the ribs and use them on my new spars (thank the maker I couldn't get them off because it allowed me to use SS7 style ribs and flaperon hangers). I got as far as drilling out the rivets on the drag/anti drag tubes on one wing and hung them up in my hangar as man cave art. The ropes I used were tied around the spars and pulled slightly outward in each direction towards the roof joists.

Two weeks ago while I was holding down a couch in my hangar that 2216 let go. The forward spar was by itself and the ribs and rear spar danced around overhead while I stared in amazement. I guess that 2216 (and probably 9460) are actually just extremely viscous liquid, like glass is. I put rivets back in the holes to restore my "artwork".