-
1 Attachment(s)
Project 5 build thread
Well originally I wasn't going to create a build thread, mostly because there are already many great ones and I didn't feel like I would have anything new to contribute. However, I recently read about how important it is to have some kind of build log with photos showing all my work - including all the mistakes I make along the way. The other thing I learned is that not everything required for the matrix brain transplant is found in the "hints and tips" section.
Instead I'm finding that many of you experienced builders follow along on current build projects and offer great advice and encouragement. I'm plenty encouraged so far, but will take all the advice I can get. So here goes!
I'll introduce myself in the next post but I wanted to start with the important part, and that is the project I just obtained.
Attachment 24532
I saw this project online sometime in late February. It's an old Skystar Kitfox 5 that was never finished or flown. It appealed to me because it came with a bunch of upgrades, and included the 912 ULS FWF kit for a model 7 and a bunch of white Oratex. Upgrades include one piece windshield/skylight, aero struts for wings and tail (along with the originals), fiberglass leading edges, upgraded tail wheel spring and the AWB tailwheel that looks suspiciously identical to the Scott 3200 on my Citabria.
It has also had some defects and some mistakes made. The most glaring defect was the less than flawless powder coating on the fuselage structure, which was apparently common in the Skystar days. And the most glaring mistake made was by the previous owner when he drilled the strut attach fitting and ended up with insufficient edge margins on the internal spar extrusion. The good news is that the kit came with new spars, new internal extrusions and new wing strut attach fittings.
The seller disclosed all the above and it appeared that from 2000 miles away I was still getting a good deal. That only left the issue of transporting the project to my hangar in Tacoma, Washington. I started with the basic cost of flying me and my youngest son to Ohio and renting a 26' Uhaul. From their I sought quotes for a semi truck, DIY shipping container, etc. The Uhaul would have cost about $2600 by itself, not including gas, airfare, hotels and incidentals.
While I was in the process of getting quotes the Corona Craziness took hold, and before long it became obvious that air travel to Ohio was probably not in the cards. Fortunately one opportunity presented itself. At the airport where the project was stored there was a truck driver (a pilot and guy who restored a C150 under the supervision of an IA), who drives west twice per month and is always looking for things to "back haul". Win, win. His quote was about equal to what I was getting from the DIY container places. This left the burden of loading on the previous owner and the truck driver. Thankfully they were willing to do so, and now that the project is here I can say both of them were stand up guys who kept in contact, sent pictures of the load and the plane arrived without a scratch. The trucker sent me a satellite tracking link and he arrived within 15 minutes of his predicted ETA.
The picture above was taken the day the truck showed up. I wheeled my Citabria out of the hangar and tied it down outside so that we weren't wasting the truck driver's time and I had the space to look things over.
More about the unpacking, the builder/pilot and what I've done so far coming up.
-
Re: Project 5 build thread
Alex,
Congrats on your find and successful delivery.
I will say, for the record, if you have the S7 FFW for a Rotax, that is great. Some of my friends with the S5 and old "dynafocal" engine mount system used at the time of the S5 leaves a bit to be desired - those had to have the intake manifolds reversed port to starboard which places the carbs so far away from the engine centerline that vibration and consequent fuel leakage as well as the carb popping off the socket were not unheard of.
Best to you and keep us old timers:rolleyes: on the list informed of your progress.;)
-
Re: Project 5 build thread
Alex, Congrats on the success of getting your fox. Just rigtht down the road on south Hill. Should get mine soon too. So please keep us updated on your build.
-
1 Attachment(s)
Re: Project 5 build thread
Thank you for the warm welcome. I've had the plane now for a bit over two weeks. I spend time every day with the manuals (I have one for the 5 and one for the 7). Some days I focus on my very first steps and other times I flip to the end to see how the story goes.
I've watched some builder videos (Bryan Bowen's work has really been helpful). I've made about four trips the hangar to put my hands on parts and compare them to what I know about the aircraft so far. The plane is starting to make sense to me and I can visualize most of the steps.
To level set before I go on, the first builder (there have been two) had done quite a bit of work as evidenced by the parts in my possession and the second one did some work, but then became disappointed in the quality of the powder coating and decided to "back the truck up" to have the fuselage stripped and redone. I know this because he disclosed it during our discussions and also because he left a build thread here. It looks like he stopped posting at the time he discovered the errors in drilling up the wing attach fittings and also before he started removing everything from the fuselage.
Initially I was going to continue stripping the fuselage but have changed my mind (several times actually). I am electing to NOT strip the fuselage to have the powder coating redone. I base my decision on the following:
The previous owner inspected the entire fuselage for loose powder coating and corrosion, then addressed it all using white epoxy primer. Hey, at least it will be easy to see where to paint over it.
Secondly, I have spent quite a bit of time examining the fuselage and have found no evidence of other defects in the powder coating.
Third, I would either have to remove all the control surface bushings that have been installed with loctite or spend a whole lot of time masking them off.
Fourth, I'm assured that powder coating has come a long ways in the past 20 years, but I notice that the manual for the KF7 still points out the need to look in all the places that powder coating may be thin or not present.
Lastly, it sure seems like if I did have fresh powder coating I would still be spending a lot of time reaming through it, sanding at least part way through it, roughing it up, touching it up - and then gluing covering over the whole mess not to be seen again for at least a couple of decades. So as long as the visible sections look nice (and the red does look sexy), and corrosion has been addressed, what is the point?
I spent about four hours in my hangar yesterday. I hesitate to call it doing inventory because I didn't document anything. Below I'm going to itemize the good and bad, in the form of what has been done correctly and then what has either been done incorrectly or removed by the previous owner.
The good:
The original owner did good work on the horizontal stabilizer, elevator and rudder. They are all intact and undamaged. The rudder appears ready for cover but the other two pieces will need their foam/balsa end caps added and filled.
The original owner had most of the flight controls installed at one point
The bad:
The previous owner has removed all the previously installed wood ribs, bulkhead etc, access panel closeouts, etc from the aft fuselage and vertical fin. Most of those pieces were damaged in the process.
The previous owner also removed the aluminum tube side stringers and the rudder cable guide tubes
The previous owner removed the aluminum door trim pieces.
The ugly:
The wings? They're going to need their own post. Fortunately I have that plan worked out already.
Step one took place took place after only two days, and that was to make it so I could fit my Citabria back in the hangar, along with my son's MR2 and one motorcycle. I hung one wing on the wall and dismantled the rotisserie, then got the Citabria in. Currently, if you want to fly the Citabria you have to wheel one wing outside and put it back once the Citabria is pulled out. It's not ridiculous, but hardly ideal.
Attachment 24534
-
Re: Project 5 build thread
Last week I made my first order from John at Kitfox. I ordered all new vertical fin ribs, bulkhead, aluminum extrusion for the stab closeout panels, rudder cable guide tubing and foam blocks for the tips of the control surfaces. I also ordered new ribs for the wings.
The only physical work I've done on the plane was to bring the aluminum door surround pieces home to test out removing Hysol with a heat gun. It was low risk and turned out to be quite easy. A few seconds of moving the heat gun around on it and the stuff nearly jumps off. On one of my trips to the hangar I brought the pieces back to the plane to see how they fit. That was a good exercise in RTFM because I had imagined them bonding to the outboard AND top surfaces of the square tubing, when in fact they only bond to the outer surface and stand proud of the tubing. I totally get why now, and was able to get all the pieces to fit in place. They aren't perfect but they are pretty good. I will probably just clean them up, fix one rivet location that was close to an edge and then turn to my new friend Superfill
I was so encouraged at how easy it was to get the Hysol removed cleanly that I turned my attention to the wing not hanging on the wall. There I discovered a completely different set of characteristics. Basically that the structural adhesive used (my KF5 manual indicates it is a 3M product) does not reach glass transition phase as cheerfully as Hysol does. I could see where the previous owner had worked away at the adhesive around the forward spar and it appeared he wasn't getting it hot enough to cause the adhesive to turn to rubbery stage. After an hour of experimenting on a rib that I was willing to sacrifice I was only partially successful, and that only after seeing the wood start to discolor from the heat. The adhesive was still mostly rock hard.
Possibly I could develop the technique through continued experimentation. I know people buy older wrecked Kitfoxes and make them airworthy all the time, so maybe there is a trick I don't know. Bottom line, I know what my time is worth and if it took 100 hours to remove 16 ribs (all time spent going backwards and not forward) I should consider finding out how much new ribs cost. $1200 is the answer, to which my response was "shut up and take my money".
The added bonus John brought to my attention is that by going to the new style ribs (no "hinge rib" or "plain" rib) I can use the new style flaperon attach brackets. After he said that I looked in both my manuals. Wow, yeah. I'll go with the new style for sure.
Since my project came with new spars, new inserts and new strut attach brackets (the old ones are actually fine), the only thing I will be salvaging is the drag/anti-drag tubes and fittings. Now those I can get off even if it means extra heat on those ribs where they pass through. Building my own wings from scratch will be satisfying on several levels, and of course also contribute to my needed 51%.
Oh, and because I'm babbling randomly: One of the reasons the previous owner elected to strip the fuselage was because he wanted to upgrade to the KF7 style turtle deck. I'm still not completely clear on what those differences are but I believe it would require tabs welded somewhere. I've seen versions of 1 piece turtle decks for KF5 on this forum and I think I'll be fine with that (my Citabria has no baggage door of any kind and I'm still alive).
-
2 Attachment(s)
Re: Project 5 build thread
I thought I would throw in a couple of pictures of the other planes I fly while I'm on a computer that has them, and add a quick bio for the curious.
First up is my 1965 7ECA Citabria, s/n 290 which I have had for about three years. It was upgraded to a 150hp O-320 decades ago so it is comparable to a 7GCAA. It has been a great aircraft for me and if I were able to perform my own maintenance, inspections and upgrades I would not be building a Kitfox. I was actually at the threshold of buying a kit three years ago when I realized I could buy a flyable aircraft and just put gas in it for less than the cost of a kit without engine/prop/avionics. No regrets, I've put a bunch of 100LL through this plane and it has treated me very well.
Attachment 24562
Next up is the T-6, or more properly an SN5. Oddly I took this picture over a year before I ever met the owner or knew I would be flying it. At the time I was flying my uncle's BT-13 and this plane caught my eye because the paint scheme was similar to a T-6 my uncle restored when I was a kid. The green stripes indicate it was an instrument trainer. The cool thing about this particular warbird is that the paint scheme is not only authentic, it is in the livery that this exact airplane had when it last served the US Navy in 1956. After putting somewhere north of 120 hours on the BT-13 we sold it to a guy in Texas and I flew it down there with him.
This SNJ popped up on the used market here in our state so we went and looked at it. I have only put about 20 hours on this aircraft. It had some radio issues that kept me from attending some of the airshows I wanted to get to, and we were also trying to flip it (for a T-28) but the buyer backed out in the end. I have since upgraded the radios to a GNC255 and a Stratus ESGi transponder. I liked the transponder setup well enough that I installed the exact same unit in my Citabria.
Attachment 24563
Me, I'm in my 50s. I've been flying for about 24 years. I became a CFI in the early 2000s and made a go of it for a while. I thought I wanted to live out of a 21" carry-on for days at a time but ended up going back to a desk job and have now worked for a very large airplane company for the past 13 years. My career has been mostly CNC programming, aerospace tool design and more recently flight deck design. My current job places me as a link between the design engineers and the pilots. Prior to coming to my current employer I worked for various suppliers. I worked hands on with factory workers on sheet metal, machined extrusion and composite parts. I have also been building and flying model airplanes since I was a 2nd grader.
That's me in a nutshell I guess.
-
Re: Project 5 build thread
I've continued to read through the manuals and compare between the series 5 and 7. I've noticed that on the aluminum side stringers they don't have you use the cross pieces anymore. They have also gone away from the single wooden stringer up the middle of the belly and replaced it with an aluminum tube. I actually like both of those changes.
As for the door trim pieces, I am trying to figure out if the trim along the lower edge of the door has changed, or if the detail drawing view in my particular manual is in error. My pieces adhere to the outboard vertical face of the square fuselage tubing -end of message. However,the cross section view in the series 7 manual shows it covering the outboard face, the top face and the inboard face of that same square tube. Like an upside down U.
Soliciting input from the gallery as I look ahead:
1) Does everyone use the supplied seat belts, and does everyone route them the same way (with the slots in the seat pan) as shown on the drawing? So far what I'm finding in my search is "yes" and "yes". I'm just used to strapping in with a set of Hooker harnesses and I'm surprised they aren't more common, especially with the improvised runway crowd. Getting those slots in the right place seems a bit of a guess.
2) For removing powder coating and paint from the various fuselage mounting tabs, what is the preferred method? I need to address all the floor mounting tabs where some plywood shims were de-bonded by the previous owner. I would like to clean them up and hit them with epoxy primer. I don't want to hit it with a wire wheel or sand paper if that is forbidden. I got the message regarding sandpaper on aluminum parts from the front section of the manual, and just want to know if I'm missing the same kind of instructions for the steel tubing.
Scotchbrite wheel on an air motor maybe?
3) Wing tips. My plane came with the Hoerner style (still untouched). I like the look and I like that they add a bit of wingspan. What I don't like is the weight. By they time they are faired and finished it will be like a couple of boat anchors out there. I'm thinking about the newer removable type, but only if they are significantly lighter.
Dang, I had more questions but I blinked a few times. I'm sure they'll come to me when I hit "submit reply".
-
Re: Project 5 build thread
Alex,
To address the bottom door channel - the 5, 6, and early 7 (meaning pre John Mcbean 7's) had the piece bonded to the outside of the steel tube at the bottom of the door opening only. The current ones slide over the steel frame member which is a superior solution.
Just a hint on that - the new one is better; however, the old version works fine if a person is careful to glue the fabric over the seam and into the corner and iron it in. I know of one S5 where the builder did not run the fabric over the bond seam and the angle separated a short time after the plane was finished. Those with the old version, including ours, stay secure with the fabric overlap.
Don't know about the belts, however, I got mine from John and they are the hookers 4 points. No problem with slots in the seat pan - a person can sit in the pan and pull the lap belt out to where it will go and pretty see where the slot should go. There really isn't any way to use the seat pan without slots.
Good to hear of your progress!
-
Re: Project 5 build thread
Great read Alex. I'll be following along. All the best! :D
-
1 Attachment(s)
Re: Project 5 build thread
Got my first shipment from Kitfox a couple of days ago. It arrived in perfect condition and the parts all look great.
Attachment 24582
I had no idea the McBeans were Italian (dang I hope at least one person gets that one).
I sold my non-aero shaped wing struts to a member of this forum, and they left here this morning in a Prius owned by the builder of a Highlander - headed for Homedale, ID. Funny because he didn't know me or the buyer of the struts, just a guy helping out because of our common interest in amateur built airplanes.
Today I'm in the process of building a set of precision 46" long saw horses so that I can begin fabrication of the wings. I just found some ideas on the internet and then bought the straightest lumber I could find. Then I further selected them to create a pair of pin-straight I beams.
The rest of the lumber will be used for the legs, and when they are done I'll square them up and Bondo them to my brand new garage floor (cringing a little bit on that but sacrifices have to be made).
-
Re: Project 5 build thread
I am now more envious of the build threads of you guys with immaculate three car garages with epoxy floors. I wonder how many of the rest of you fell into the same trap I have, requiring some nest building before really getting any airplane parts cut. It's a rabbit trail that goes deep into the earth.
We moved in March to a house we bought over a year ago. The 'new' house is a Victorian built in 1905. The house was a dump but it had good bones and once my favorite woman is done with it, it will be quite an upgrade (it's actually shocking how much we've done so far). The garage though, not so much. Before the move I had an approximately two car garage before with a pretty good loft, and now I have a long single car garage. I won't win any contests for building in the smallest space, especially because I already have a hangar, but it's not ideal.
115 years old and no one ever poured a slab in the garage. Where the house has good bones the garage does not. At some point in the last century someone extended the garage from roughly 11.5 x 21' to about 11.5 x 30'. I'm happy for the extra 9' but it's obvious that whoever did the extension had no structural background of any kind. Where the studs used to go up to the rafters, they cut them off. At first glance it appeared like they installed a header. In reality they nailed a 2x6 to the side of the cut off studs and provided no support at the ends. It was literally hanging from the studs instead of holding them up.
The stud spacing for the entire structure ranges from 24-29". Several of the ceiling joists (the horizontal piece) was sagging from people using them as loft storage. Upon exposing the studs on the long back wall I found many that were a Rube Goldberg variation of scabbed together 2x4s at random angles.
We had a slab poured about twenty days before we moved in. With the house being a priority I have been tripping on everything I own just getting various projects done. This past weekend it was time to make space to bring the fuselage home or build wings. I started by staring at those messy studs and then came to the conclusion that I would need to shore up the structure before I put in any work benches, extra outlets, or hang anything on the walls.
At the end of one long sweaty day I had removed the imposter "header", trimmed the hanging studs a bit higher, installed a plate a cross the bottom of the them, created a more substantial header from two 2x6s and made two stub walls to support it. I doubled up the ceiling joists with full length "sisters", jacking up the old sagging pieces before joining them together. I'm a big fan of screws and haven't spent much time swinging a hammer in the past few decades, and certainly not since getting bifocals.
I have replaced the dreary incandescent bulbs with some of those LED lights with "wings". Holy smokes I could probably offer the place up for surgical procedures if they didn't mind some dirt. I've got several pieces of peg board to put up and some budget for benches, cabinets and storage solutions.
My saw horses for wing construction are done. One of them came out pin straight, sits rock solid on the garage floor and shows perfectly level. The other is also pin straight but wobbled a little bit. At one end it measures exactly the same height (32-3/16")and the other is a tiny bit low. That will actually work out well for purposes of leveling them and making them "fast" to the floor with bondo.
-
7 Attachment(s)
Re: Project 5 build thread
I haven't posted in a bit but I have been moving forward, mostly with the logistics and preparation. A few shots here and it has improved since then. After making structural improvements on the garage I sheeted most of the walls with OSB and primed everything. I added LED lighting and three strategically located outlets. I set up a charging station for various electric tools. I bought a big roll around tool chest to use as a bench and to store the majority of my automotive tools. It won't actually be moved except to retrieve FOD. In a stroke of OCD insanity I used my label maker to identify every drawer.
Attachment 24819
Attachment 24817
I loathe peg board but put some up anyway. We had some gray paint left over from another project which my girlfriend encouraged me to use up, so that's what is going on there. You can see my charging station to the right under one of the new outlets. That is an antique dynamite crate I bought when I was a single dude. New tools include the 4' digital level and a good 4' straight edge. The yellow plastic level is junk more suitable for playing whiffle ball than establishing either straight or level. I've got a real nice 6' level in my hangar that I'll be replacing it with. Not visible are the Milwaukee die grinder, angle grinder and pop rivet gun.
I also went through the list of builder tools and realized I wasn't going to get very far before obtaining some of them. After doing some online shopping I came to the conclusion that the Kitfox prices on Hysol, Clecos, drill bits, reamers, swage tools, etc. are quite competitive with the rest of the world, so that became my second order. I also bought a ton of clamps.
Attachment 24818
I then bought a smaller roll around tool cart to have next to me while working on the plane. Then I pulled out the bins of hardware that came with the project. Pro tip: Don't drive around for three weeks in your sporty SUV with those in the back even if they're shrink wrapped. My first new skill was learning to identify pop rivets and AN hardware. In doing so I learned quite a bit, including identifying and cross referencing everything.
Attachment 24816
The manual starts with flight controls so that's what I did too. Part of my hardware identification skills came when I disassembled everything and measured every fastener, checked torque and measured any dimensions that were left to the builder to fabricate. It was going along swimmingly until I came to the white parts on the bench, which you'll all recognize as the rudder pedal/brake pedal attach brackets. They look fine but had several dimensional issues.
Another email to Kitfox resulted in an order for prefabricated parts, which are now in hand. While those were on the way I flew to the east coast to ferry a Cardinal RG back to Seattle for a friend/previous student of mine. He and his wife had been on vacation in St Maarten and were "stranded" when the pandemic struck. They were finally able to get a repatriation flight to the US, and in the meantime Mike had bought this plane sight unseen. The trip started with gear retraction issues (fixed on the ground and test flown satisfactorily), then radio issues (solve in the air) and some typical Cessna gauge issues. Then throw in some of the craziest weather along our route of flight, we finally arrived in KBFI after 24.1 hours of flight time. The last pic shown below is SW of Casper, WY where we had a ground speed of 28 knots. It was a rough ride. We had two times we landed to wait for thunderstorms to blow over us and fought some marginal VFR across Idaho.
Attachment 24820
Attachment 24821
Attachment 24822
-
Re: Project 5 build thread
Awe hell. You would probably have a heart attack if you came to my garage. I started out organized but my true nature come to light within days.
-
Re: Project 5 build thread
Looking mighty fine! Organization will save you untold hours of frustration.
I'm in Eddie's camp as no matter how "organized I try to be, my kaos nature kicks in and my workspace turns to doggie doo. I always replace my tools prior to quitting time so tools can be found, however my trick is to pick up a vital part/hardware and then put it down in the most unlikely place. Then I spend hours looking for said part/hardware! When I'm having a bad day I clean the shop and go thru all the boxes and cubby holes. I usually find what I'm looking for BEFORE I order new hardware... most of the time! :rolleyes:
-
Re: Project 5 build thread
Great thread. I just sold my KF 4 and I am in high gear now on my model 5 build, which means the aircraft spruce boxes are going to start piling up.
I'll be following your thread closely.
I am sure you probably have already researched this but in case not, it would be wise to do the rudder pedal assembly reinforement now since everything is still disassembled.
-
Re: Project 5 build thread
Nothing I hate more than looking for tools!
-
3 Attachment(s)
Re: Project 5 build thread
Thanks for the replies. This garage is the most organized I've ever had. I can relate to the shops in disarray because it is in my DNA. My dad's mode was that if it would keep for 6 months and you might have a use for it, it stayed. His last shop looked like Russian soldiers ransacked a hoarder's garage. I used to only sort of joke that every time I got a decent tool box it was stolen shortly after that. About four years ago I had to rebuild the engine in a Porsche, and damn was I organized for that project! It went so much smoother being able to see a missing wrench from across the room. At the end of each work session I took the time to put everything away, and it more than made up for time spent searching for a missing tool/part.
Good call on the rudder pedal reinforcement. It is part of my current work.
Yesterday was the first time I felt like I accomplished direct hands on work on my Kitfox. With the new rudder pedal brackets in hand I got to practice surface conversion. My project came with Bonderite C-IC 33 Alumiprep acid deoxidizer and M-CR 1201 Alodine. I printed out the data/instruction sheets, mixed my chemicals and did an initial cleaning of the parts with acetone. I got dirt on my rag so that was a good idea. I used the temperatures and times suggested and was quite surprised at the fizzing away as the parts were etched. I rinsed thoroughly to see the very shiny parts, and then it was straight to the Alodine. I'm used to Alodine treated parts being a little splotchy but these came out beautifully as if they were gold anodized. Rinsed again and dried.
Attachment 24852
The other thing I did was head to my local Wesco auto body supply store to get a can of custom enamel to match the red powder coating of my steel parts. While I was there I inquired about a product I had never heard of before: two part epoxy in a spray can. My uncle was doing some work on the SNJ recently and started talking about it. I thought he was losing it but it's a real thing. Maybe I'm just late to the party but I got a can of epoxy primer yesterday. You use part of the cap to break something inside and it mixes the catalyst. Then you have 8-12 hours to use it up.
Attachment 24853
I've got the two part Epoxy from Kitfox but as of yet I haven't mixed or sprayed any. I'm guessing there is a learning curve and I don't want to make my freshly alodined parts ugly. I have some prep work to do on the fuselage still so I'll wait until I can justify cracking open that can. I pick up the can of red this afternoon. It's single part so not as life limited as the epoxy.
Attachment 24854
Regarding the rudder pedal reinforcement: Last night I used the pattern depicted on the Service Bulletin to make a 1:1 paper doll and test it on my rudder pedal torque tubes. I didn't love the way it fit or looked, so I used the pattern as a basis for a new one. I'll be mocking that up before I cut any stainless steel. The one I made is slightly asymmetrical in order to work with the rivet pattern already established on the torque tube. I'll post pics when I get there.
-
Re: Project 5 build thread
Great job on the alodine parts! :D
-
Re: Project 5 build thread
Alex., do you have the name of that two part epoxy primer in a spray can? I wasn't aware of it either and would be nice for small jobs that I have. thanks Bruce N199CL
-
Re: Project 5 build thread
I'm curious as to why you are cutting the gussets out of SS? (I'm not familiar with the SB - if that is what it calls for.)
-
Re: Project 5 build thread
That's actually a damn good question. SB38 can be found on the kitfox web page. Apparently I have been hallucinating because I just read through the entire thing and the material type isn't mentioned anywhere.
Possibly I've read what others did, or possibly it's because I happen to have some 0.016" stainless.
Astute readers will observe that the SB lists the Vixen but it is tribal knowledge that all model 5s and on need reinforcement.
The SB states that the kit with parts will be provided free of charge but it is a Skystar document and I don't feel like it's the McBean's responsibility to fill that order.
I made two paper doll iterations before arriving at what I think will be the ideal flat pattern.
Interested to hear what material others have used
-
2 Attachment(s)
Re: Project 5 build thread
Quote:
Originally Posted by
airlina
Alex., do you have the name of that two part epoxy primer in a spray can? I wasn't aware of it either and would be nice for small jobs that I have. thanks Bruce N199CL
Bruce
That's the stuff right there. Check with your local auto body store.
Attachment 24859
Attachment 24856
I left one of my non Puka pedals with the paint shop so he could match my custom rattle can. One of these two pedals was used for a test and the other came out of my tub of parts I'll never use. I would say I'm pretty happy with the results
-
Re: Project 5 build thread
The reason I asked about the material choice was because I once had a really bad experience with SS welded to mild steel. I don't know how a SS to steel weld would behave in the long term on the pedal assembly but I would hazard a guess that the pedal is made with 4130 and would recommend that you stick with that. Additionally, some SSs are too malleable to be strengtheners on 4130 and I'd be concerned with .016 not being up to the job in any event. Just one opinion and it is worth exactly what you paid. Maybe there is a metallurgist on the forum and will weigh in.
-
1 Attachment(s)
Re: Project 5 build thread
Ah. It's not welded. It's riveted and bonded with structural adhesive.
I'll see if I can find a good visual aid.
Edit:. This is from the service bulletin
Attachment 24860
-
Re: Project 5 build thread
thanks for the photo of the primer cans Alex. And also there was a recent thread on the rudder pedal issue and i posted some pics of how I handled it on my Series 5 without welding with SS , rivets and scotchweld (3m version of hysol) . Bruce N199CL
-
4 Attachment(s)
Re: Project 5 build thread
One step forward and a few steps back
I’m sure I’m the first person to experience setbacks while building an aircraft. After doing the alodine treatment of my rudder pedal brackets I had one of those forehead slapper moments when I realized that the previous builder had installed the flight controls into the fuselage at one point – which means that they match drilled the (dimensionally incorrect) brackets to the steel channels in the fuselage. That in turn means that my new brackets are unusable unless I have the holes in the steel channels welded up and I re-drill them. More on that later.
I took advantage of father’s day to spend my day working on my Kitfox. Knowing that all of the following steps are a dry run, and that I’ll be removing all of this at least one more time before final torque values are applied, I installed the control column assembly (the contraption with the sticks) into the fuselage, installed the bell crank for aileron control, and then installed the push-pull tube which goes between that bell crank and the flaperon mixer.
I installed the flap handle and the push-pull tube which goes to the flaperon mixer for flap control. I set the center console in place and verified that the flap detents work with the flap handle (works perfect).
Attachment 24933
I installed the small intermediate elevator bell crank (I think it has a different name but I can’t remember it right now. It’s sort of a pendulum thing) near the back of the seats, installed the elevator push-pull tube from the control column to that intermediate bell crank, and hooked up the forward end of the long elevator push-pull tube used in the model 5. I found that I was missing the sleeve bushing that goes in the tail cone and sent an inquiry to Debra at Kitfox to see if those are even available. They are, and I now have one on the way.
I loosely installed the rudder pedal assemblies and sure enough the previous builder’s match drill efforts resulted in the rudder pedals aligning very well. I was hoping they would be wrong so I could justify welding/re-drilling. Still more on that later.
Of course I had to take advantage of the moment and actually sit in the aircraft. Thank the maker for bubble doors. Occupant comfort will be “sufficient” and not much more, but I’m okay with that. I learned to fly in a C152 and find the room pretty comparable. I would have said the Kitfox was easier to get in and out of until I installed the sticks.
While sitting in the airplane I boxed the controls a few times and felt friction in the ailerons. Part of it was caused by me sitting in a seat which was flexing quite a bit, a result of not having any hardware retaining it. Contributing was very limited space under the seat from the aileron push-pull tube.
While sorting parts recently I put my hands on the various push-pull tubes to identify them all. Two of them have a slight bend in them. The KF 5 manual doesn’t say anything about the bends, but the KF 7 manual does. Using the dimensions in the KF 7 manual I was able to identify one for aileron control and the other (longer) one for flap control. The manual says the short end of the bend on both tubes goes aft, so I labeled the parts and installed them that way.
I wondered if maybe the KF 5 used straight tubes originally but mine are powder coated red the same as the rest of the fuselage, and once installed I don’t see how straight tubes could possibly have worked. So I think it was just a shortcoming in the KF 5 manual that it doesn’t tell you how to deal with the bent tubes.
The loosely assembled aileron bell crank came with a stack of washers so I knew there was going to be adjustments needed. I quickly discovered that this bell crank needed to be biased as high as possible between the fuselage mounting tabs in order to keep the aileron push-pull tube from contacting the fuselage tubes as it moves. I got it to clear but just barely. Eventually I found the sweet spot for orientation of the bend in the aileron push-pull tube so that it would not contact either the fuselage tubing or the bottom of the seat (even with the seat flexing because of my gravitational impact).
Attachment 24934
My other side project was to incorporate the Service Bulletin to address the cracking issues in the rudder pedal torque tubes. I used the SB (found in the technical section of the Kitfox web site) to create a mylar template. I thought I would be able to send my CAD file to a couple of places that could make the parts for me but I was no-quoted both times. I guess working with thin stainless wasn’t their favorite thing to do. So I ordered some 0.020” stainless shim stock from McMaster-Carr. I used the cut off wheel on my die grinder to make one part before I realized it was pretty crude for the process, not to mention having consumed an entire 2” cut off wheel for one part.
So I obtained some aviation tin snips (both left and right) and practiced some more. I used my cut off wheel to slice the remaining shim stock into 2” strips, giving me 6 parts where I needed 4. I’ve been in the business long enough to know I would probably need those extras.
I guess Dykem layout die is not as popular as it once was. We can thank CNC machinery for that. I couldn’t find any locally, so I improvised by dusting the stainless with some self-etching primer, then got to work with a carbide scribe and a spring loaded center punch. The tin snips worked very well for cutting the shapes out. I drilled one hole in each end of the parts and used clecos to hold them all together. That allowed me to use the 3M discs on my angle grinder to get the periphery of the parts closer to the same. And finally, I used my drill press to drill the other four holes with the parts stacked together. They’re not perfect but they’re not terrible (and yes, they are intentionally asymmetrical)
Attachment 24935
Welding
Now I’m at a cross road. I have three areas where I could use the services of a skilled welder, and I could theoretically avoid all three – but do I want to? While going down the path of creating the stainless straps for the rudder pedal torque tube Service Bulletin I kept going back to the possibility of finding someone to weld the triangle gussets employed by the factory currently. Where I initially had concerns that the gussets would difficult to dodge the rivets on the outboard pedals, I am now equally concerned about being able to pick up the three holes common to the existing rivet pattern and translating them to my stainless straps. It is going to require some luck and possibly those two extra parts before I declare success.
Upon further review, if I go the welded gusset route I would have to drill out the existing rivets anyway, and the only ones which would be difficult to access for reinstallation would be the two up on top that would be between the gussets. I have verified that I can reach the most inboard one with gussets in place and may be able to reach the outboard one. If not I could just add another rivet where ever I can to meet the design strength.
The second application of welding is the one I referred to for rudder pedal mounting brackets. Again, I could go either way and just get over it but I would always know I let a discrepancy slide. Not a safety issue, just an OCD thing. And I’m not very OCD.
Lastly, I have read recommendations to beef up the tailwheel support at the back of the fuselage. The link I followed yesterday shows it is just a doubling up of the existing plate, which should be cake for any welder.
I’m prepped as far as primer and paint goes, so at this point I can deal with some welding. It will require that I load up the fuselage and take it to the chosen welder, or that they be mobile. I’m going to seek quotes today and decide. If I employ a welder at all, I will be going with my new rudder pedal brackets.
Attachment 24936
The other thing I did was buy a new 1/4" drive torque wrench of much higher quality than the harbor freight crappy one I have used to strip two AN3 bolts with already. This new one is very small and cheerfully applies as little as 10 inch pounds.
-
1 Attachment(s)
Re: Project 5 build thread
Time to invest in a small mig welder and get some OJT. My millermatic is essential piece of gear out here in the country. I'm self taught and not the best welder but .023 wire will allow me to make some nice stitch welds on thin tubing.
My fix was to the rudder pedals Port side only. Was a bit dicey as the tubing is so thin. Glad it's done and over. Prior to welding I was wishing I'd just riveted the darn thing! lol. ;) A screw up here would not be good.
All the best and Keep up the great work!
-
Re: Project 5 build thread
Learning to weld has actually been on my "to do" list for decades. The pieces have never fallen into place for that, but that might have changed yesterday afternoon. I looked on my local craigslist for welding services offered and found an ad that said all the right things (TIG, 4130 and that he's an A&P). So I called him up and we had a nice conversation. Not only is he a qualified welder he flies a King Air and he teaches the A&P curriculum at a local community college.
We discussed the three potential applications for welding on my Kitfox and he asked me questions about wall thickness and the type of filler material. I got a brief education on preheating and stress relief - both of which should be of minimal concern with the thicknesses involved here. I've got some measuring to do for wall thicknesses, and I need to figure out how thick the triangle gussets need to be and also the reinforcement for the tail wheel. He mentioned ER70S-2 instead of 4130 filler (confirmed now that I've read up a bit), but it also looks like ER80S-D2 could be used.
He told me he has no problem teaching me and letting me practice on some scrap material and then supervising while I do the actual welding. I'm to obtain the 4130 and filler since he doesn't have any on hand (says almost all the welding demand he has now is for stainless and aluminum). Then we'll coordinate me trailering my fuselage to his shop. I'm thinking that when the welding cools off I'll bring it to my garage to do the primer and paint fixes and complete the installation of flight controls so the fuselage is ready to cover.
For the rudder pedal reinforcement I will be doing both sides since I will be flying from the right seat quite often (possibly most of the time).
-
1 Attachment(s)
Re: Project 5 build thread
I'm anticipating my elevator push-pull tube bearing from Kitfox any day now, along with my latest aircraft spruce order. That order will contain my usual fistful of hardware and the 4130 sheet metal, welding rod etc.
I took the opportunity to deconstruct the rudder pedal torque tubes by drilling out the rivets. Back in my 20's I drilled out hundreds of aluminum rivets when I had a job at a place that sold sea kayaks. Except that these are steel, not aluminum so it was much slower going.
I started out using some Harbor Freight (supposedly) HSS TiN coated still bits I already owned. I swear I've eaten pasta that is tougher. So I ditched that plan and used one of the bits I ordered through Kitfox recently. Much better. I spent part of my life as a CNC programmer and took pride in learning the proper feeds and speeds for various materials (and wow is it a wide range). With a decent drill bit and proper lube I was able to drill out every single rivet and still have a sharp bit when I was done.
Attachment 24987
-
Re: Project 5 build thread
I keep catching blurbs from someone building a CH701 with the line "something every day". Well I can't claim to be doing something on my Kitfox every day but I finally got a major task complete and that was taking my fuselage and rudder pedals to the welder. From where I'm at now I need to do some light grinding, sanding, primer and lastly my color matched red. Then I can make some progress installing flight controls, floor boards, seat etc - all of which I've read ahead on many times.
Before I get long winded (which I know is about to happen because I've already typed it) I'll say that the three thing welded were the triangle gussets on the rudder pedal torque tubes, filling the outer holes for the rudder pedal torque tube brackets, and reinforcing the platform for the tail wheel leaf spring.
When my Aircraft Spruce order showed up I got to work fabricating triangle gussets. I wanted to make them 1.75x1.75 so I started by cutting 2" squares out of the 2x36" strip of 0.032" 4130 stock with my tin snips. I took my time and made some very accurate 2" squares. I scribed lines for the finished long edge of the triangle and rough cut the triangles, then came back and cut to the line. Maybe someone out there can follow an exact line on the first pass but I can only get "pretty close" and I don't like the results as much.
In the end I was pretty happy with my very uniform 1.75" triangles, so I deburred them with a 2" scotchbrite wheel, cleaned them with acetone and set them aside without touching them.
I also made a reinforcement piece for the leaf spring mount at the rudder post. The example I saw doubled up the thickness of the flange and then bent almost 90 degrees to form a sort of triangle gusset attaching it to the rudder post. I don't have a press brake and as much as I'd like to have one, the ones I can afford are good to about half the sheet thickness I needed. In the end I made a gusset flange out of 0.125 4130 and it's welded to the existing flange quite solidly. For that piece I accurately laid out some thin scribe lines, then laid some masking tape exactly on that line. Next I took a sharpie pen and made a big fat line along the tape edge. Pulling the tape off I then had a nice thick, very clean edge to follow with my 3" cutoff wheel. I got lucky and my first one was right on the dimensions after deburring.
I'll edit later to insert some pics, but I coordinated with the guy that would do the welding and went to rent a trailer or possibly a truck at U-haul. The only thing they had that could possibly do the job was a 26' truck.
I took one of my sons to the airport and loaded up the fuselage. He pulled the tail up the ramp and I duck waddled the front of the fuselage until I could get the mains into the truck, then I secured it from moving. I'm guessing there won't be too many trips with this plane that will be this easy.
I get up the next morning and see that the outer dually is flat (the bead was loose). Blah, blah and U-haul roadside assist came through and we're on the way. The welder was a super nice guy who was stoked to be working on a plane. A lot of his business is race cars.
He put me and my son to work using 2 and 3 in scotchbrite wheels to remove the powder coating where the welding would be done. The first thing he did was fill the holes where the rudder pedal brackets mount to the fuselage channels. Easy job.
Then he moved on to the tail reinforcement. Once he had it welded to the tail post and front edges we rolled the fuselage up on it's side so he could complete a nice bead on the outer corner. He also discovered a weld in the most acute inside corner at the very back that wasn't welded well so he fixed it (I'll note here that I have a Skystar fuselage, not a current build Kitfox)
I was able to practice a few inches of TIG welding with the equipment. I learned pretty quickly that my bifocal glasses were all wrong for the welding helmet because the auto dimming window was perfectly positioned for the distant portion of my glasses. If there's a next time I'll dig up my single vision glasses I hardly wear but would be perfect for this.
I probably should have destroyed the evidence of my welding prowess but I didn't start the place on fire or get to smell myself burning so I'm marking it down as a win. Needless to say I let him do the gussets. It was apparent that we should have sanded the powder coating off further from the weld than I did. Again, 2" scotchbrite wheel removes everything back to clean metal and feathered into the good powder coating.
Today I picked up some 2" sanding discs so I can blend the filled holes to make them invisible after paint. I did not have him fill the holes for the center bracket or brake master cylinder bases since they were all correctly located.
Then we trucked the fuselage back to the hangar. Since I had the truck, I picked up the crate with the new spars and extrusions and took it to my garage.
-
5 Attachment(s)
Re: Project 5 build thread
I've learned that a feature of this forum is that you can't come back later and edit a post to add pics.
Since all my pics are taken with my phone and typing significant content isn't phone friendly I will post some pics now and then do another post with a real keyboard
Attachment 25221
Attachment 25222
Attachment 25223
Attachment 25224
Attachment 25225
-
3 Attachment(s)
Re: Project 5 build thread
Okay the explanation of the above. First picture is the gussets I made from 0.032" 4130 that I ordered from Aircraft Spruce. I didn't do very careful math and ended up making 16 when I needed 8, so I'm giving the other set to Eric (reference his barn find thread here in the builders section).
In the second picture you can see one of rudder pedal sections after the welding was complete. I had intended to completely disassemble the pedals to avoid getting those plastic bushings hot and blew it. Later on when operated the pedals I found increased friction and thought that was the problem. Well it wasn't, and a lot of you already know what happened: The tube at the base of the T isn't straight after you weld on the gussets.
I read through a thread on rudder pedal friction and found where people fixated on grinding out the weld bead that comes through the inside of the tubes. I was hung up on that too at first. I also didn't see how you could possibly sand enough material off the outside of the torque tube and inside of the T, while also sanding the minimum possible from the plastic bushings.
Well you can't. When you slide the T onto the torque tube and get it slipped onto the inner plastic bushing you will note that the other end of the T and the torque tube are not concentric. In my case it was not necessarily "riding hard" against the torque tube but it was touching. Even a zero thickness plastic bushing wouldn't provide smooth operation.
The issue is that you have two plastic bushings which need to be coaxial but are not, so without spherical bearings there would never be a way to get them to run smooth. No wonder so many people have issues getting their rudder pedals to operate smoothly. I considered chucking the whole thing and making my own design, but decided to stay with it if I could.
Using the straightest piece of steel I own (a set of 12" mitutoyo calipers) I verified that the torque tube was pin straight, and then checked the T. One of those forehead slapper moments where it is obvious what happened. The base of the T had curved due to the welding and they would need to be straightened. What you're seeing in the picture is a fixture I made to accomplish the task. I knew it was going to take some force so I used an 8' 2x6 and some plastic blocks (a motorcycle part I designed and happened to have some extras). I placed them so that they would restrain the sections of the T that I wanted to hold still. A 3' section of galvanized pipe with some strategically placed silicone "rescue tape" brought the OD of the pipe to perfectly match the inside of the T and provide leverage. With the T clamped in place I had my youngest son hold the far end of the 2x6 while I worked the galvanized pipe. I started gently and worked my way up until I was able to get the T within about 0.010-0.015" of straight. Of course the second one went much faster. No need to change anything on my alignment fixture for the second pedal because they are identical at this stage.
I test fit them on the torque tube with both plastic bushings in place. Without having even wiped off the sanding debris or using any form of lubricant they operate very well.
The next pictures were from just yesterday. My fuselage is at the airport, tucked in behind my Citabria so I dragged it out in the open and got to work with a 2" sanding wheel on my electric die grinder to knock the welds down where the rudder pedal bracket holes were filled. That went well and I managed to get it done without nicking a tube with the non working side of the sanding wheel. Thankfully the bottom side of the welds wasn't too thick so the clean up from down under was mostly getting rid of the roasted powder coating and getting it ready for primer and paint.
Next I cleaned up the hole for the elevator push pull tube bushing. It still had hysol in it from where the PO removed the bushing (must have destroyed it getting it out too, I imagine). Heat gun and a little love and it was 90% out. Dremel tool with a flapper wheel and it was done. Test fit is perfect. My project arrived with the elevator push-pull tube in the tail cone but zip tied with pool noodles to keep it from banging around. With the new bushing dry fit in place I was able to do a temporary install of the push pull tube and check for friction at the controls. It is operating nicely. I know it's not much but I finally felt like I got something moved forward.
When I get out there later today I will use my die grinder and scotch brite wheels to remove the white epoxy primer applied by the PO where he removed loose powder coating. The steel has been protected by it, now it's time to get to bare metal and make it all red again.
Attachment 25226
This pic was taken while the welding was being done on my tail wheel reinforcement. I forgot to remove the center console piece but we rolled the plane super careful so it didn't really bang around.
Attachment 25227
This pic taken at the end of the day yesterday. Hoping I can keep up some forward momentum.
Side trip.
Back when I first had some money to buy a plane with I wanted to get a kit. Then I realized that it could be 2-3 years without flying. I ended up buying my Citabria and had instant access to a fun airplane. Now that I have this plane to build I'm motivated, but some days I get to the airport and decide "aw, screw it" and get in the plane that flies NOW. I need to strike a balance.
In the meantime, I'm flying the crap out of the Citabria. I do some informal STOL practice and recently took my youngest son mountain flying. Shown here at Tieton which is a state owned runway here in WA
Attachment 25228
-
1 Attachment(s)
Re: Project 5 build thread
Good progress.
The gussets turned out good. I too went through the "bananna" T-Torque tubes. I used a vise and some pipe to get it as close to straight as I could, and then alot of sanding, and fitting to make them smooth. The crazy part is I was missing that part of the rudder pedal assemly and had to fabricate the longer "T" torque tubes. I was careful when I welded it to keep the heat bending to a minumum and it still happened. I think it's just the nature of the beast when welding on tubing.
Attachment 25229
-
Re: Project 5 build thread
I would agree that it would be very difficult to avoid this exact banana when creating this part, especially with asymmetrical gussets. And I know that some experienced welders use strategically placed applications of heat or short welds to make things flat (or intentionally domed). I will say I'm impressed with the strength of 4130 tube. I was worried about it bending too easily or putting a kink in it. It was amazing how much it flexed before the shape changed at all. No wonder it makes such a fantastic material for bicycle and airplane frames.
Today I flew down to TDO to meet Eric and see his barn find Kitfox 5. He's doing a great job of rolling back the areas of relaxed workmanship standards and what he is down to looks quite serviceable. I'm going to have to get some momentum up if I'm going to get mine built anywhere near his deadline.
To that end I'm planning on sanding off the hand applied white primer and then applying my primer, paint and clear coat this weekend. I just researched to see how much time I needed to allow between coats. I know from the primers and paints I spec as part of my job you have to wait a certain time for each coat to dry, but you also have to get the next coat on before it completely cures - otherwise you have to treat it like existing paint and sand it.
There are also paints that have another time line, where if you do let it go past that initial cure time then you have to let it go for a few days or it will soften the layer under it and possibly bubble up. Good times.
Well I'm glad I read up from the manufacturer because I was lead to believe I have mere hours once I mix the two part epoxy. Manufacturer says 4 days. That would of course be shortened dramatically in the (what locals call) hot weather we're having now. Before I use the primer I'll go over everything with wire brush and detail sander to lessen the need to fill scratches from the sander and scotchbrite, then wipe/flash everything with acetone or denatured alcohol.
-
Re: Project 5 build thread
I put some more time on the project last night (I have to keep up with Eric now). I used my detail sander to prep the surfaces for primer. While I had it out and was making dust I removed all traces of powder coating on the metal tubes both inside and outside where the plastic bushings live. I worked carefully and with good lighting to just barely break through the last molecules of powder coating. That kept the surfaces round and didn't remove any steel.
I test fit the parts dry and was shocked how freely my rudder pedals work now. They literally flop around but aren't the slightest bit sloppy.
Today is much cooler than the past week and it's not windy, so I'm going to get some primer applied.
-
Re: Project 5 build thread
Nice! Can you tell me more about that detail sander? It sounds like something I need to invest in.
-
5 Attachment(s)
Re: Project 5 build thread
A detail sander is just one of those high rpm oscillating head devices that has a head the shape of the rotor in a Wankel engine. The angles are acute so you can get all the way into 90 degree corners.
The originals were the German company Fein and were priced accordingly. Mine was a random Christmas gift from years ago and is a Harbor Freight $40 knock off. I guess "multi tool" is the other name because you can run various metal cutting blades, and is what I normally use it for. It has helped up much better than I have come to expect from Harbor Freight but wear ear plugs..
It should be noted that it's not a random orbit sander but you can achieve a random-like finish if you make light passes and keep it moving consistently.
I'm also getting quite a bit of use out of my Dremel tool. I recall a Bryan Bowen video where he had one basically catch on fire and had to buy a new one. I'm now using mine for 20 minutes at a time and I'm starting to realize that catching on fire is a distinct possibility. It gets pretty hot when you're using it "for real" instead of the 30-60 seconds of use per year it normally sees.
The tools I'm really glad I bought are the two Milwaukee M12 straight and 90 degree grinders. The 90 lives with a 2" Roloc style mandrel that I swap scotch brite and sander discs on. The straight shaft motor has been used to cut 4130 up to 1/8" and most recently has been running an arbor with skinny but long sanding drums.
If the Dremel tool burns up I'll just chuck those Dremel accessories on the straight shaft Milwaukee.
Today I ended up using it all.
Attachment 25259
It got all organized and then grabbed my can of 2 part epoxy primer. Followed the directions on the can, shaking for two minutes, whacking the thing on the bottom and shaking for two more minutes. I noted that the can said the pot life was only two days, in conflict with the online instructions.
I had already wiped the parts down with acetone and a lint free towel, so I got to spraying. I was quite puzzled when it came out clear. I know sometimes spray paint can start out clear but I put a pretty good layer on and it still had no color.
Huh. Maybe this primer is clear. I kept spraying but then realized bought gray primer so it should probably be gray. Oh look, I mixed up the two part clear coat that goes on after the red. I guess I know what I'll be doing this weekend after all.
An acetone soaked rag removed all traces of the clear. I wasn't sure that was the case yet but discovered a few hours later that acetone will in fact remove even the incredibly durable epoxy primer on a few swipes.
Once the correct spray can was catalysed I sprayed all the parts. The Germans sure know how to make a good rattle can. It lays on nicely. The only flaws were where I didn't feather the powder coating down smoothly enough.
Attachment 25260
You know how it is when you hear that voice in your head that says "don't touch it"? Right. I waited 45 minutes and attempted to feather it in with some 400 paper and light pressure. Made a complete mess of the uncured primer.
Thats when I learned that acetone took it right off, and I was able to pretend it never happened. The second time I sprayed, I skipped the lint free rag. Won't be making that mistake again, but at least this time I didn't try to fix it.
Instead I set the parts aside to cure, gathered my things and headed to the airport.
There i wheeled the fuselage outside, used the detail sander to reduce scratches and feather the powder coating back a ways, acetone rag and lint free - starting to get the hang of this.
Attachment 25261
I used strategically placed rags to protect adjacent structure, flight controls, etc then shook the can again for good luck. I started on the bare steel up front and was happy with the way that turned out.
Attachment 25262
Then I addressed the areas the PO applied two part epoxy. It's good primer so I really didn't need to remove it, I just needed to smooth out out. Detail sander to the rescue. Acetone wipe, lint free, spray
Working my way to the back of the fuselage, I propped up the tail and removed the rear clamp for the tail wheel. Then I proceeded to use every device I brought with me to clean up the welds, the bare metal, feather the powder coating, etc.
I thought I found a crack and was busy digging at it with various small Dremel bits when my hangar neighbor came by. I had just come to the conclusion I was digging at a glob of powder coating when it came out. He welds and inspected it all. It was all good, so I finished the clean up and sprayed out the last of it.
Attachment 25263
Next up, things I should probably already know about spraying red.
-
Re: Project 5 build thread
Quote:
Originally Posted by
alexM
A detail sander is just one of those high rpm oscillating head devices that has a head the shape of the rotor in a Wankel engine. The angles are acute so you can get all the way into 90 degree corners.
Ah, OK. I know the tool you're talking about. I've got one of those oscillating cutters; I'll have to see if anyone makes sanding heads for it. Thanks, and nice work today!
-
4 Attachment(s)
Re: Project 5 build thread
I was tempted to spray the red last night but then remembered a step mentioned in the manual directing builders to fill moisture traps with structural adhesive. The crevices on the insides of the gussets definitely count as such.
I probably should have done the Hysol before primer but this isn't about strength as much as it's about gap filling. So I apply the expression I often use in my day job: "it doesn't hold the wing on". Besides, fresh primer on good metal isn't a terrible place to start.
So I eye balled the ratio and mixed up my first batch of Hysol. After mixing thoroughly I put it in a sandwich bag and nipped the corner off, cake decorator style. That allowed me to lay a bead in those tight areas with making a mess.
I used the end of a pen to make a fillet, then came back with my finger and some denatured alcohol to clean up any excess. I didn't hate how it came out.
I'm curious what scales you folks use to weigh Hysol?
Attachment 25286
I let that cure overnight, then this morning I was up early trying to get some paint on without disturbing domestic tranquility. I flashed all surfaces with lint free alcohol wipe and coreographed how I would apply the red without getting any finger prints in my paint.
I ended up using the same cheater pipe I used to un-banana the inboard rudder pedal tubes. I shot the tight spots by hand and then slid each T onto the pipe. Set on a pair of saw horses I could then get every where else without touching anything.
Attachment 25287
The red went on perfect. Not a run or flaw of any kind. I let that dry for maybe 30 minutes then repeated the process with the clear.
I was worried about having rushed the job and was concerned that it might fish eye or worse. What to do other than put my stuff in the car and head to the airport and keep going before I knew, right?
The red went on absolutely amazing. This is going to sound funny but I'm color blind. Oddly, I may not be able to tell you what color something is, but I can detect the slightest mismatch. In a different lifetime I used to do gelcoat repairs on damaged canoes and kayaks. Matching the color on a surface which has weathered can be difficult but once I knew the color I could make the damage invisible.
I can see red just fine, and was super stoked to see the only way to tell where I had painted was because it was flat instead of gloss.
Attachment 25288
To keep from rushing the job I walked down to the airport restaurant with my son where we had breakfast. I gave the clear coat a good shake and covered the flat red. That work is now tucked into my hangar to gas off, while I returned home.
Inspecting the rudder pedals I am quite happy with them. No fish eye and no house flies mating in the middle of my wet paint.
Attachment 25289
Pretty happy to be at this point. I feel like I can now make forward progress. I'm going to let the red and clear cure the rest of the day, then I'll clean everything well, do another dry fit of the plastic bushings, then lube it up and rivet the assemblies back together.
-
Re: Project 5 build thread
Alex,
FWIW, I mixed it by volume. It was very easy to do small amounts using measuring spoons & popsicle sticks, then mixing in dixie cups.