Kitfox IV `project fifty`

Hi all,
I like to introduce my project ´Kitfox fifty´

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Searching and considering long time, I finally decided to step into the KF world and let my dream come true with a Mod. IV-1200. I´m very excited, because it could turn into a nightmare also…
The plane is airworthy, but aged and needs some love…others may say I only bought a bunch of work!

Some background about me:
So far I´m doing only hanggliding and WSC aircraft (check ´Revo´ or ´Larry Mednick´, if you need an idea about that…). This little bird is the only reason for me to step into 3-axis world. So settle back and enjoy. This could get funny (hopefully also for me!)

Regarding my strange spelling pls. bear with me! As I live on the opposite side of the big water, more precisely Europe/Germany, I`m still learning…:D

Inside this thread, I`d like to present and certainly discuss my restoration (I will sure have way too many questions) while trying to avoid issues discussed already a lot of times.
As I`m a big fan of the `support your dealer/factory´ idea, unfortunately Kitfox/Homedale is more than 8.500km away. Both transportation costs and time will be limiting factors. So please note, that if I will ask for DIY solutions this doesn´t indicate that I`m afraid of spending money to the factory!

Thanks (sorry for long introduction)!
Marc

P.S. Why Kitfox fifty you may ask? Well, I´m at the age of 47 right now. Target is to get airborne (plane+pilot) aged 50.

Hi Marc, this is Marc ;-)

Also from Germany.

Where in Germany are you located. There is quite a big Kitfox Community in Germany(6 of them in EDKB), so a lot of people that can help you out and answer questions.

Congratulations on your project! I have a Model 4Speedster and a Model 5 Speedster myself.


Cheers,
Marc

Hi Marc,

thanks!
I`m located south nearby Stuttgart.

Congratulations Marc. I too started my build at 47. Just turned 50 March 1st, so Flying starts for me again Sunday (wind allowing) after 25 years of being earthbound.

…pick up of the plane at the airfield. To have a safer transportation, I decided to take the wings off completely. About 800mls. to go…
From a distance the bird doesn`t look too bad…although the color scheme isn`t my favorite.
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main tasks
- re cover + new paint, due to peeling automotive coat
- thoroughly structure check
- safe some weight – keep it light
- poss. engine swap 582 to 912
- turn her into a beauty...

documentation since `95 :rolleyes:
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...

Congrats on your "new to you" plane. I'll be following along. Welcome!

It will be interesting journey!! :)

Ok, update...
meanwhile

sorry!

OK, update...
meanwhile I removed wing covering completely. Collect each single piece in a waste bag to check the weight. Unbelievable amount of car paint not sticking to the poly-fiber...All trash!
I found some unglued false ribs, a leaking tank which contaminated ribs with 2stroke mix and came off parts of alloy end. I think this is also the reason for the wrinkles, I described in my previous thread. As flaperon brackets were removed by previous owner and put back in place on covered wing, riveting was incomplete and also only into wood capstrip. Alloy strips were no more in place...
By the way I built a wing rig. Due to my bicycle profession I decided to use 2 workstands, some tube crap wrapped with handlebar tape. Bolt together with wodden angles. Nice adjustable and quick solution...
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I really enjoy reading your reports. It sounds like you already have a really good idea of what a quality build should look like. Keep the reports coming.

Keep thinking the way you are and you'll end up with a restoration you can have confidence in. Nothing worse than having niggling doubts when couple of thousand feet in the air !!.

so today I wanted to learn more regarding the "batwing design" of my horizontal. Very uneven look although I like the slightly speedster styled tails.
Look at the trim tab area :confused:

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Insight shows a mess of thin, unattached ribs, hold in place only by PVC electric tape. Some housebuilding insulation foam was added for "strength"
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OK. steelframe is good, w/o corrosion. I think, I like to have a slightly shaped tail again (hope that`s not naughty!). At the moment vertical is flat while horizontal was with profile. Where to find a suitable pattern/shape? My manual shows only an outline of a horizontal rib with 1.25 height? What about the elevator? Further 6pcs. are mentioned, but if you check 1st pic. there are many more. So how to proceed?

Next there is a trim servo labeled with 8V or alike. It`s still working, but I have only 2 wires and there is no end stop (elctronic/mechanic). Should I keep this item or is there a more modern one nowadays standard?

I don't even know what to say..... I can't believe there are builds like this out there. Good thing you decided to take it apart. This will be a good one to watch you work through!

Whoever owned and flew this before had a death wish. That “workmanship” you’ve uncovered is appalling. Go well with the restoration.

When I ordered my first Model IV, I wanted the trim tab option so ordered the "Speedster" elevator with the trim tab cut-out and ribs. I found it curious that the ribs sent were similar to what you show in the pictures. I was not too pleased with the rib design that provided separate airfoils on the horizontal stabilizer and elevator - sort of like an hour glass shape on its side. I opted to do something a bit different by providing a coordinated airfoil shape from leading edge to trailing edge - typical on most airplanes. The airfoil shape was not "engineered" but laid out by placing the stabilizer elevator assembly on a flat surface, putting blocks under leading and trailing edges to level and then placing a piece of wood inboard to outboard that provided the lift where I wanted it. Thin aluminum, strips placed fore and aft and secured with clamps to the leading edge and trailing edge tubing gave an airfoil like shape that could be copied to ribs. For weight saving, I chose 1/4" urethane foam for the ribs that were then covered each side with a single layer of light weight fiberglass cloth and resin. After cutting and sanding to the desired shape, the edges between the glass surfaces was then covered with epoxy resin thickened with micro-balloons and finish sanded. Due to the tight hinge line - welded tube hinge - designing the gap closure resulted in some challenges. The attached diagram explains what was done to solve that problem. The full chord ribs also gave the needed spacing for a smooth transition to the trim tab on the elevator.

On build number 2 in the hope of saving a little weight, I made some patterns from which I made some fiberglass shapes that could then be bonded to the ribs on either side of the hinge line to provide the gap seal. The last photo shows the geometry of the needed shapes. Both ideas take a bit of time, but in practice, I never felt a need for gap seal tape to gain maximum elevator authority.

On the vertical stabilizer - rudder gap, the rod end bearing hinges gave sufficient spacing that the gap closure was more typical and didn't require the complex shapes needed on the elevator hinge area.

First, thanks for your comments!
I‘d like to clarify that it isn‘t my concern to blame former owners or builder of my plane. Especially the original builder did a great job in 1995 and realized nice details which are still here today - 25 years later! Me so far, I did only tear down things to see and certainly learn to get a reasonable rebuilt done- someday! Not in position to point at somebody...

Thanks Lowell for the insight into the world of tail-airfoiling! I will check and see what I could adapt/realize. Overall I‘m in need to save some weight, means the plane is too heavy at the moment...

going on with the horizontal, I ask myself if the elevator horn is initially straight or some kind angled sideways? (pls. see pic)
Would be kind if someone could confim, I was already close to straighten out both elevator surfaces as I found the important information in the builders manual that there is some deliberately misalignement...

So what about the horn?
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Thanks!

I´m still here…in case some have imagined the newbie quit already!

More disassembly is going on. Each section has its surprises :confused:
Hoping that I could complete and partly renew existing stuff, (e.g. like wiring) it turned out that cleaning up the mess is better…
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After finally finishing disassembly of my bird it feels good to fabricate sth new again at last.
First a couple of new false ribs.

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Regarding the horizontal I decided to go with the easier non-speedster option. Not sure if I got it right. By manual there are 6 ribs required all with equal thickness of 1.25 scaled to proper length. I made according cardboard samples which look quite ´flat´...
Worry I misread something…:confused: