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109JB got another wrecked Kitfox

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Posted

I've known about a farmer owned Kitfox near me but didn't know the man who owned it. Well, a few weeks ago we had a bad storm roll through our area and the shed he kept his Kitfox in partially collapsed onto the airplane. A friend of mine who was with a group that helped him lift the barn roof up told me about it. Last week I went to talk the man and found out the airplane had not flown for several years. He had stopped flying it when his wife got sick. He didn't have interest in fixing it himself so after discussing we made a deal and I brought it home. The airplane was on a trailer with the wings folded when the shed collapsed

I picked up the airplane 2 days ago. As you can see from the pictures, the airplane took a pretty big hit but it could have been worse. here is my assessment of the airplane and damage.

  1. Aft fuselage bent much like typical trailering damage
  2. Tail spring destroyed
  3. Rudder destroyed
  4. Fin bent
  5. Windshield broken
  6. A few slightly bent tubes in the skylight area
  7. Flaperons have some damage
  8. Left forward strut tube bent
  9. left fiberglass wingtip has hole from trailer jack.
  10. Left tip rib cracked
  11. Both flaperons damaged (maybe repairable)
  12. Various holes in fabric to repair
  13. Upper forward cowl  damaged (repairable)
  14. One prop blade chipped
  15. Go through engine and systems

That list probably sounds worse than it is. The airplane isn't really in all that bad shape. The farmer was a darn good craftsman and it was a very nice build. A month ago this was surely a beautiful airplane. It is a Kitfox 3 fuselage with Kitfox 4 wings and mixer assembly, so it is essentially a Kifox 4 1050 in my book. It has a 582 gray head so I will be doing a pressure test of the seals before running it. This airplane should be a pretty quick fix, so my other Kitfox project will be on hold until this one is flying.

 

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Posted

I've had the airplane for 2 days and here is what i have accomplished.

  1. Replaced tail spring with one I had
  2. started straightening of the aft fuselage
  3. removed windshield
  4. removed rudder
  5. removed fin fabric and straightened fin

The fuselage straightening is being done like my first Kitfox that incurred a bent fuselage from trailering damage. I removed the top fabric and corner tapes from the bay that was bent. I then used my crude tool for straightening the tubes to slowly pull them as straight as possible. The diagonals straightened just fine, but the longerons are kinked a bit, so will need to be replaced in that bay. These pictures were before some of the tubes had been finish straightened, but even so the fuselage looks a lot better than it did before.

I'm now waiting for my tubing order which includes tubing to enlarge the fin and rudder to later kitfox 4 size. Hope to have fabric on the aft fuselage by next weeken.

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Posted

work is progressing one this one.  Got the wing rib fixed and patched the holes in the stab and wing fabric. Just needs UV block and top coats on those.  Still waiting for the tubing to repair the aft fuselage. There are a few pictures of the airplane outside with the wings in position just before a buddy helped me remove them to work more on the fuselage.

 

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Posted


Easy fix I think you did  good.

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Posted

Good job with this guy!   Always cool to see a good "rescue plane" story with someone willing to bring one back to airworthiness.

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Posted

Yeah. It is going to be a pretty easy fix. Lots of little things though. To get the airframe all fixed up will be about $500 in materials. Somewhat bad news but not unexpected is the engine probably needs new seals. I did a crankcase pressure test and it leaks down way too fast. On my sleds they normally hold 5 psi for minutes but this one leaks down to 4 psi in 10 seconds. Soapy water shows it isn't the test setup, spark plugs, etc. Most likely seals. I'll pull the C-gearbox next to soap the front seal. I'll probably do a top end rebuild kit for about another $500 but at least another weekend of work to pull the engine to get to the rear seal..

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Posted

Got more done this week. Tubing finally arrived and I got the longerons fixed and side covering on.

Also had a crack at repairing the busted upper cowl. To fix this I simply used a cutting wheel on a dremel to open the cracks and allow the pieces to be pulled back into position. From there I used bits of tongue depressors and hot melt glue on the outside to hold the cowl in proper position. Then a right angle air grinder with roll-loc disks to grind down to bare clean glass and layed up glass on the inside. Used mostly 2 layers, but sometimes more depending on the area. Amazingly a trial fit shows it worked.

 

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Posted (edited)

Well, I met my goal of having fabric on the fuselage by this past weekend. The fabric was attached using Ekobond and I'm using the latex paint method on the patches. I decided to do this after checking a spot of old fabric by cleaning it with acetone. There is obvious darkening of the paint over the years so even though I know the polyfiber color, new paint would not match well. Anyway, I've now got the weave filled and starting on color. Before anyone says anything the color on it in the picture below is too dark.  This was a computer color match but doesn't match. Since I'm using latex I went to the paint store and rather than refund my money, I got them to sell me another quart at 1/2 price that was tinted too light.  I've been experimenting with different ratios of dark and light paint and am pretty close to a perfect match using 2/3 light and 1/3 dark color. I'll get the exact ratio I need after a few more tries. In the meantime the dark paint is on as a base since yellow is such a pain to cover.

I also moved on to enlarging the vertical tail to match the size of later model 4s. I didn't know the fin leading edge tube was 0.049 wall thickness, so I had to order a new piece. Rudder was enlarged and instead of rounded corners I went with squared off corners.

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Edited by 109jb
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Posted


moving right along

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Posted

Tail modifications done and fabric going on them.

 

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Posted


Compare that system with poly for me? What do you like better.

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Posted

Hi TJay,

I'm doing the repair on this airplane and all the cover on my other Kitfox using the process described in this link:

http://wienerdogaero.com/Latex.php

So I start with applying the fabric and tapes using Stewart's Systems Ekobond.  Actualy I'm using 3M Fastbond 30NF contact cement which I'll talk about later.

I have also covered my Sonerai using the complete polyfiber process.

As far as attaching the fabric, Ekobond is super easy and I much prefer it to polytak. It is not nearly as messy, doesn't smell, doesn't cause me headaches like Polytak, etc. Before "locking" it down, the fabric can be positioned temporarily while held loosely by the glue, repositioned as much as you want, and then locked down with an iron on low heat (225F). When I did my Sonerai I remember using dozens of clothes pins to position and hold the fabric for applying the Polytak. So far covering the parts of this airplane and also my other Kitfox I have not used a single clothes pin, clamp, or anything except what the Ekobond/Fastbond provides.

On to applying the tapes. If you have used polyfiber then you know the tapes go on with polybrush. I was never thrilled with how polybrush worked for applying the tapes. It always seemed difficult to get them to lay flat, and especially doing the control surface leading edge tapes it was a pain. With Stewart's, the tapes are also applied with the Ekobond/Fastbond. Again, I absolutely love the way this system works for tapes. No clamps, very easy to do.

From this point is where the latex "system" I'm using deviates from the Stewart's System. You can read about that system here: http://wienerdogaero.com/Latex.php . I am very happy with how the latex finish is coming out on my other Kitfo, and I'm sure this one will go well too. As far as latex goes, my Sonerai got stained by bird crap on the polytone, which i could not get out. Rather than paint it with polytone or Aerothane to cover the stains, i painted it with Behr brand gloss latex enamel paint, and that was about 2016 and it looks as good today as the day I sprayed it aside from a few scuffs and scrapes which are not the fault of the paint.

As far as the rest of the Stewarts system, I haven't used it so can't say but a friend is and so far he likes it and has gone through finish coats on his tail surfaces.

I also can't say if the Ekobond/Fastbond is compatible with later coats of anything not waterborne. So I would not mix it with say polyfiber products.

In a nutshell, after using the Ekobond/Fastbond, I would not go back to the polytak. This is for ease and the lack of noxious headache producing fumes. If I wanted to do a complete STC'd system I'd go with Stewart's over polyfiber. I haven't used any other systems like superflite, oratex, Randolph, etc.

Now comparing Ekobond to 3M Fastbond 30NF. First, I read online that some had determined that the Ekobond was essentially the same as 3M Fastbond 30NF. So, I bought s quart of the 3M stuff and also got a bit of Ekobond from my friend using that system and did up a couple test frames including some tapes on those frames. They look the same, feel the same, act the same, apply the same, etc. I peeled the fabric off of both frames and unscientifically could not tell a difference in how well each product held the fabric. Based on this, I decided to use the 3M Fastbond. When the quart I bought was gone, I bought a gallon of it. That is what I'm using on my airplanes.

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Posted

I used ecobond on some repairs on my Polyfiber covered plane.  I really liked working with the product as you say very easy.  That said I can see the there is a compatibility problem with Poly finish coats.  The paint is beginning to release from the Ecobond.  Also gasoline turns the stuff into a jelly goo.

My friend uses it on the Back Country Super Cubs with great results but he is painting with Superflight.

i can see where it would work fine with any water based system like latex.  Also the stuff is not tolerant  to freezing so if you live in northern climates order before winter sets in and keep I warm.

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Posted

Aft fuselage damage done. Paint looks like a perfect match in the shop. Tomorrow I'll roll it outside and see how good it is. Next will be re-installing the root ribs on the cabin and making a windshield. At that point if the wings were on it could be considered airworthy but I have a few more things to finish, Mainly finishing fiberglassing the left wingtip damage, the front upper cowl and painting those. I also have to replace the seals in the engine, but it is getting there.

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Posted

Wish I could get 1/10th of a project done in the time it takes you to do it!

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Posted

Thanks Yamma-Fox.  I'm very motivated on this project and am in "don't think too hard., Just do" mode.

Got more done today. Got the patches on the horizontal stab painted last night, so today I installed the tail surfaces for the last time, Installed the tailwheel and redid the springs because I didn't like how the previous owner did them. I also installed the cabin root ribs, made a windshield and installed it (Fits perfect), and started the fabric on the closeout between the fuselage and root ribs. Once I paint those the doors will go back on and it will be essentially fixed except for the engine stuff. Later tonight I'm going to pop the cylinder head off to make sure it is still standard bore and will order the top end kit for the 582.

 

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Posted

Finally rolled the fuselage outside in the sunlight to see how the paint match came out.  It came out a little dark on the fin and rudder, but the fuselage is perfect. The fin and rudder were the first to get sprayed and I saw it was just a tiny bit dark and adjusted the mix. Even the fin and rudder aren't noticeable unless you are looking for a mismatch, so plenty good enough.  Have been working on little projects. Mounting the com and ELT antennas. Didn't like where they were previously. Repairing a little damage to the trailing edge of the landing gear fairings. Replacing rotted hoses on pitot static system, Replaced the corroded ELT batteries with new and cleaned the battery contacts. Painted the cabin to wing closeout fabric, and cleaned the shop. I have my engine parts on order, so the engine comes out tonight for new seals and a decarbon of the pistons. I've already pulled the head and the cylinder bores look great but the pistons do have a pretty thick coat of carbon on them. Not sure what he was using for 2-stroke oil, but I've been using either full or semi-synthetic oil in my snowmobiles with great success. Both seem to burn cleaner leaving less carbon buildup. Will probably drain the oil tank and replace what is in there now. Good news is the coolant when I drained it was orange, so he was running Dexcool which means the cross shaft seal is probably good. Once the engine is done, hopefully this weekend, the wings can go back on and it will be ready to fly. It may fly before I paint the cowl as that is just one piece that might even be easier once the plane is moved to the airport and I have a bit more room in the shop.

 

 

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Posted (edited)

Only one picture this time.  I had to go out of town for a few days but did get the cylinders and pistons off.  The bottom rings on both pistons were stuck at one location around the groove, and there was a lot of carbon buildup on top and in the ring grooves. No damage done but it would not have been long. The 

I made a piston pin puller and some delrin plugs to keep the cageless bearings in place when  removing the piston pin. Worked great. The delrin plugs will really aid in putting the pistons back on too. Below is a picture of the whole pin pulling setup. On one end is the black delrin plug.  It is just slightly smaller than the pin at 0.705" diameter, 0.9" long. The length is long enogh to retain the loose bearings and the little thrust washers on either side of the bearings and yet still allow the piston to be removed/replaced. On the right in the picture is a piece of 7/8" 4130 tube with a washer with a 1/4" hole welded to the end. In my case I had a slug from using a hole saw. It also has a little notch cut so that it can clear the little shoulder below the piston pin bore on the piston.  You then need four 1/4" nuts and a piece of 1/4" all thread. Pull the circlips, then the all tread through the piston pin, the delrin slug and a nut on the other side, and crank it just far enough that the delrin slugh is inside the thrust washers, bearings and other thrust washer. The double nuts are for a wrech to prevent the all thread from spinning. You could just bend a L on the end of the all thread. Once the delrin is centered in the rod bearing, loosen and remove the other puller components and pull the piston off. The delrin slug remains insid the bearing in the connecting rod and the bearings are still in their exact same position.

Pulled the C-gearbox too. Very clean inside and no problems noted except for a bit of rust on the back end of the prop shaft. Polished that with 1500 grit paper then crocus cloth. FYI for anyone interested, a $15 Harbor Freight "steering wheel puller" worked fine for removing the PTO side flywheel. I call this kind of puller a harmonic balancer puller, but whatever name you call it it works just fine. Came with a perfect size end for pushing on the crank end without buggering the threads. Had to get 3 longer 10mm bolts for it though.

 

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Edited by 109jb

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Posted

So I found something  unusual.  I got the pistons cleaned up and back in the engine and since I have the gearbox and flywheel off I performed the leak test again. Still leaking so sprayed soapy water on the PTO end seal and it leaked. So what you say, right? Well it wasn't leaking around the crankshaft or around the crankcase. It was leaking in several locations in the face of the seal With the seal out I could see that it was leaking at locations where there is only rubber on the face. The steel face behind the rubber has several holes around it (6 or 8 I think) and it was leaking from most of those spots right through th face of the seal. 

So I pulled the rotary valve cover and will be removing the magneto components and splitting the bottom of the case, keeping the cylinders and heads on. I'll replace the outer o-rings and the mag side seal while I'm in there, so it should all be good once done.

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Posted

Nice work, What was your technique spraying the latex? I have an Avid Model C SN:573 that had left elevator and top longeron damage. Luckily no kinks and I was able to massage  the tubes back to original. 
 

I used Stewart Systems and it was amazing.  My earlier days working with fabric was Poly Stits.  With Stewart I could work in a closed hangar to keep the temperature above 60.  

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Posted

Hi Doug,

I started with the technique at http://wienerdogaero.com/Latex.php but I have since modified it. He does all of the primer coats as brushed on coats, but I only brush the first coat.  All coats of both the primer and the topcoat are thinned with plain old water. I thin just by guess or by gosh, but it is about 3 or 4 parts paint to 1 part water. Basically as thick as possible but sprayable through my gun. So, here are the steps I used:

1. Brush on a thinned coat of primer (PPG Gripper) with a foam brush. I really slop this on to make sure to get good penetration of the fabric and then "tip" it with the brush to even it out. It dries fast enough that I go back over the tapes an additional time before calling the first coat complete.

2. Once dry, I lightly wet sand the entire fabric area, but spend a little more time on the tape edges. Be careful not to sand over hard structure. It is easy to sand through.  Once sanded, I use a pray bottle of water and lots of paper towels to clean the fabric.

3. From here, I proceed to spraying the rest of the coats.. I use a cheap Harbor Freight HVLP sprayer https://www.harborfreight.com/air-tools-compressors/air-spray-guns/20-oz-hvlp-gravity-feed-air-spray-gun-62300.html .  I thin the primer and spray it on. I put on about 4 or 5 coats letting it dry between coats. If it is warm you can do these coats in a day.  I don't sand anything between each coat except the pinked tape edges to get them looking nice. I only sand the pinked edges that aren't smooth, not all of them. By the last coat I don't have anything tape edges to sand. All sanding I do is wet or dry paper, about 400 grit.  

4. After the last coat of primer I do wet sand lightly, just to get the little bit of orange peel off. If you thin the primer, it goes on with orange peel but most of the orange peel flows out as it dries. I sand the primer where it ends to blend into the existing paint.

5. Now the top coats.  Since you are doing a patch job, you might be able to do like I did. tried the computer color match twice but both sucked.  One was too light and one was too dark. I wound up mixing them to get a perfect match. Took some experimentation, but I would up with 3:1 ratio of the light to dark.  If I had to do it again, I would just go to the paint store with a scrap of the old fabric and pick out 2 colors from the paint card, one a bit darker and one a bit lighter and do the same as I did on this airplane. Anyway, once you get the color right, thin it the same way and spray the same way. Just be careful as the topcoats seem to run easier than the primer. If you do get a run, "tip" it with a foam brush and it will almost disappear when it dries.  In my case, I had to do many coats of topcoat because yellow is horrible to get to cover. That is also why I didn't get the primer tinted and left it white. You will be in the same boat. I just kept putting coats on until the yellow finally did cover and blended into the existing color. I think it took about 4 or 5 coats. In my case I didn't sand between these coats because it flowed out relatively well and my purpose on this airplane is mainly to get it back flying. It has a little orange peel, but is good enough for me. If you look at the link, he color sands and buffs to get a real glossy flat finish. I'm not doing that, but I will buff the blend area a bit. The only time you can seen the blend on mine is when at the right angle and you can see the overspray area. Once buffed in that area I think it will disappear.

Spray gun cleanup is a breeze. I have a laundry sink and hot water in my barn, so I just rinse the cup out real good, Spray a little straight water through it, then disassemble and rinse better. It takes about 5 minutes I'd say to clean the gun. I just run hot water through all the pieces, use a little plastic bristle brush (looks like an industrial toothbrush) on the external components. The hot water gets all of the latex out of the inside of the gun. Super easy compared to something like catalyzed urethane.

That's my method on this one and is also the method I will be using for the wings on my other airplane. Good luck with yours.

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Posted

Got the bottom case of the engine apart today. Everything looks great inside. Very clean and no sign of corrosion on anything. I'll replace the two outer crank seals and get the engine back together once My Loctite 574 arrives. Right now it is sitting there upside down on the cylinder head nuts with a clean towel over it.

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Posted (edited)

Well the Loctite 574 finally arrived and I got the engine put back together to the point where I could perform the pressure test again. All good now. Pressurized to 6 psi and 10 minutes later it was about 5.5 psi. Here is a picture of the setup. One carb socket plug has a pressure gauge in it and the other has a tire schrader valve in it. Plug up the pulse line and hook a hand pump to it and pump up to 6 psi and remove the air pump. Will give the condition of the seals. It shouldn't leak more than about 0.5 psi per minute.

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Edited by 109jb

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Posted

Got the mighty 582 running today.  Here is a short video of the engine running. It started right up and ran very well. No adjustments seem to be needed. I 

I put in a lithium-ion battery and I have to say that little thing really cranks this engine. I had a 14 AH large motorcycle battery in it but wasn't happy with how well it cranked so bit the bullet and bought a lithium -ion which is smmaller, lighter and cranks the engine better. I also have a  small lithium jump start pack and I think I will put some lugs in the cockpit so I can jump it right from the cockpit if necessary.  

On this airplane I think I am going to put on the Hacman mixture control. For those of you that run one, do I need to up my jet size and then use the Hacman to  lean from there, or just use stock jet and lean it from there?

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Posted

WONDERFUL !

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