Repairs & Mods: custom cowl, new gear,etc

87 posts in this topic

Posted (edited)

Edit: The original title of this thread was " not an airplane anymore". I'm building a custom cowl for it and Yammafox suggested i change the thread name to make it easier to find.  End edit.

 

I'm a total freaking moron. The plane has been sitting on the trailer in my garage for the last month and i finally decided to do something with it.  As i was getting it off the trailer the tail wheel jumped the track and the aft fuselage smacked down on the trailer frame:(.  Fortunately i think it only got 1 longeron not any of the verticals but still it separated the fabric on the seam.   I guess I'm going to be recovering the fuselage now aren't I?

Still getting over the shock of that. Probably want to puke soon. So as the title says it's not an airplane it's a project. 

Even before my stupidity forced the issue that's the direction i was heading. After reading a bunch of comments about how squirrely the stock gear made the plane i had decided to buy a set of gear from Stace Shrader of Rocky Mountain Wings.  He makes and sells wider gear legs even for a KF1 and does it for $900 a set.  I'm going to have to have brackets welded to the fuselage for those gear legs anyway so i guess fabric repair was in the cards anyway. 

One other thing I'm going to do is make a new  cowling for it.   I have a bunch of aircraft grade fiberglass for another plane I'm building and plenty of aeropoxy resin. Since the plane is going to be down for a long time anyway and money is on short supply i might as well do what i can.  Its probably going to look a lot like the -7 cowling just based on the fact that i don't want to modify the motor mount cowling attach points but i guess we'll see as time goes on.   

 

Ok so here's the list of must haves before it can fly again:

1. New gear legs

2 fuselage repaired

3 new prop

 These are things I'd like but not required:

1. Gap seals on tail feathers

2. Vg's

3. Weight reduction if possible

4 new cowling

I also have the feeling that i was so eager to have a plane that i got duped. There is some rust showing through a lot of the tubes on the fuselage that i didn't look at when i bought the plane. I have a feeling I'm going to get very intimately aquainted with this plane before it flies.  So stay tuned and i gladly welcome your input on how to handle the fuselage repair.  I'm not a welder or metal worker btw so this is going to be a steep learning curve.  Fortunately there's some good welders in my EAA chapter.   

20181002_201419.jpg

20181002_201426.jpg

Edited by Willja67
More accurate thread title

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Posted

If the tube isn't kinked, maybe it can be straightened.  If not,  it shouldn't be real hard to replace a section of the tubing.  Course you get to learn how to cover an airplane  or at least some patching either way.  While you are at it, I would widen the fuselage at the doors as well.  See how TJay did his Kitfox 1.  Another thing, if the landing gear you mentioned fits later Kitfoxes up to the 4, it should fit the Kitfox 1 as well.  JImChuk

PS  bummer about the bend in the plane.  

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Posted

If the tube isn't kinked, maybe it can be straightened.  If not,  it shouldn't be real hard to replace a section of the tubing.  Course you get to learn how to cover an airplane  or at least some patching either way.  While you are at it, I would widen the fuselage at the doors as well.  See how TJay did his Kitfox 1.  Another thing, if the landing gear you mentioned fits later Kitfoxes up to the 4, it should fit the Kitfox 1 as well.  JImChuk

PS  bummer about the bend in the plane.  

it's not kinked, so that's a huge relief. So how does one go about straightening atube like that?

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Posted

This video may give you some ideas.  JImChuk

 

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Posted

Ouch! Stuff happens all the time. At least, you will get to go over the entire airframe prior to flying it. I usually want to redo any airframe I get just because it most likely was covered years ago. Surface rust is pretty common on older rag and tube aircraft, especially if it wasn't epoxy primed extremely well.  I've heard the tales of how squirrelly the older Avid's and Kitfoxes were for years. And people have been flying them for years. It does require a little training from a good tailwheel instructor, but not a terror to land as some would have you believe. The wider gear is nice but can be pricey.  I think the Grove gear runs almost 2K. Me, I'd prefer to spend that 2K on training. But, you will learn what your feet are for. Good Luck with the new bird and enjoy the rebuild. Don't think of it as a chore, consider it as making a good solid aircraft that you don't have to worry about in the air.

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Posted (edited)

Allen is 100% right! See this as an opportunity. Some ears ago I made a bad landing and the landing gear safety wire broke the seat struss (don't get me going on that... ). So after some consideration I decided to take the opportunity to tear down the entire plane and do a full rebuild rather than just repairing the seat struss. Just the minimum repair would have required quite a lot of tearing down and recovering etc. so why not... It was a second hand (well, a number of hands over 22 yeras) model C serial # 479 that I had bought some years before and I knew it was not in mint condition - but I got some surprises when I started to pull of the fabric... Just one example, I think this one is from the tail plane...image.thumb.jpeg.cc3c7208c216d570a5e3fd9

Btw, seen the damage on your plane from the tail wheel jumping the track, I guess you where unloading with the wings still folded. With the wings folded the weight is way back with a lot of weight on the tail wheel (or on the rear of the fuselage if the tailwheel jumps the track - happend to a friend of ours very recently...). With the wings folded it is badly ballanced and difficult to maneuver, strongly recomend to load and unoad the trailer with the wings in their normal position.

Good luck with your project and know that we are always here to share our experiences and provide any help we can.

Fred

 

Edited by FredStork
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Posted (edited)

I actually am kinda looking forward to getting to know the nuts and bolts of this plane and doing more to make it mine, however I'm already building a plane and this was supposed to be an interim flyer not a project. Now i have 2 projects with not enough money to get either flying very soon.

 

As for wanting a better landing gear about 6 years ago on my first tail dragger solo I dumped a legend cub on its nose. It was my first landing and i wheel landed it and that was fine but i prematurely pulled the stick back to set the tail on the ground and it started going side to side on me so i added a little brake to the mix and it went over real nice and slow onto its nose. I forgot i didn't have 160 lbs of instructor holding the tail down like the previous times I'd done that. Everyone has told me that i should have goosed the throttle, didn't know that then though. In any case once bitten twice shy. And i haven't flown a tail dragger since. I'm thinking of moving the gear forward a little also since i have to weld new brackets on anyway. I want to stack the deck in my favor as much as possible. 

One thing that i need to do on this project is slim the plane down. It only has a 382lb useful load and I'm worried that with all the repairs I'm going to have to do it'll lose some of that. 

I've already decided that the aluminum wing tank will go if its easy ie don't have to recover the whole wing. I imagine i'll have to add some ribs? I can still see some of the original sloshing compound in it that is peeling off and I've read on here that those aluminum tanks were prone to leaking.  

 

Anyway for now the cowling will be what i work on since i have the materials on hand. Btw what diameter spinner do kitfoxes with fixed pitch props usually use?

Edited by Willja67

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Posted

Don't be tempted to move the undercarrage forward,you will creat more problems than you will solve.

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Question for the brains in the group. Comparing a steerable tail wheel vs. a breakaway tail wheel, does on have an advantage over the other as far as keeping from doing doughnuts on the ground? For close quarters the breakaway is nice but the steerable (non-breakaway) can be turned quick with forward stick and a shot of power.

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By "breakaway" you mean "free spinning" or "steerable but will release at a certain angle"?

I have the classic Maule tail wheel fork (I have replaced the Fred Flintsone wheel with a pneumatic wheel) and is one of few who likes it..., it is steerable and great for taxiing and ground handing. It has never released without me wanting it to do and is easy to release when pulling the plane into the hangar. I have the impression that steerable will help to keep you on track and help avoiding ground loops but never tried a free spinning tail wheel. I see no downside with the steerable as long as it can release when needed. 

tail_from_front.thumb.jpg.332cd4922838b0

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Posted

Free spinning wheels belong on toolboxes not airplanes.

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Posted

Don't be tempted to move the undercarrage forward,you will creat more problems than you will solve.

I'm guessing at least one of those problems is structural since the seat truss wouldn't be supporting the gear loads anymore. What else would it affect?

 

As you can see the first step in creating a new cowling has been taken. That's a 9" diameter piece of plywood. I'm not going to wrap the engine and do the pour foam method like I've seen a lot of guys do.  My plans right now are to add foam bulkheads with little dabs of hot glue and then wrap it with sheets of dollar tree foam board until i get the shape i want, then lay up the fiberglass over that. 

 

 

20181004_224506.jpg

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Posted (edited)

Don't be tempted to move the undercarrage forward,you will creat more problems than you will solve.

I'm guessing at least one of those problems is structural since the seat truss wouldn't be supporting the gear loads anymore. What else would it affect?

You would put more weight on the tail. The tubes near the tailspring are known to break trough stress. More weight on the tail wheel will also put more stress on the tailspring and when it breaks it flings up and damage the rudder. This is also one of the moments when the rear tubes get a lot of stress, i.e. when landing with a broken tailspring so added weight is not what you want...
I guess ground handling would change as well but not sure in what direction...
I don't think it is a good idea, nor do I think it is particularly needed... and it will take a lot of work to get the brakes strong enough to tip the plane...

One friend of mine converted a nose wheel Avid to tail wheel just by moving the landing gear to the front position... He tipped it by braking on the first test run as he didn't know the landing gear geometry is different... completely differet gear.. But other than that I have not heard about tipping - but I'm sure someone else has. But I don't think it is a frequent problem.

Edited by FredStork

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Posted

One thing that i need to do on this project is slim the plane down. It only has a 382lb useful load and I'm worried that with all the repairs I'm going to have to do it'll lose some of that. 

I've already decided that the aluminum wing tank will go if its easy ie don't have to recover the whole wing. I imagine i'll have to add some ribs? I can still see some of the original sloshing compound in it that is peeling off and I've read on here that those aluminum tanks were prone to leaking.  

I'm missing something here, normally we try to slim the planes down so we can carry more fuel, loosing weight by removing tanks is a somewhat surprising initiative. But you are right, if there is sloshing compound in the tank it might already be leaking. The wing tanks are a part of the stucture and without it you need to add a diagonal drag tube unless it is still there (I have seen some aluminium wingtanks built around the drag tube.

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One thing that i need to do on this project is slim the plane down. It only has a 382lb useful load and I'm worried that with all the repairs I'm going to have to do it'll lose some of that. 

I've already decided that the aluminum wing tank will go if its easy ie don't have to recover the whole wing. I imagine i'll have to add some ribs? I can still see some of the original sloshing compound in it that is peeling off and I've read on here that those aluminum tanks were prone to leaking.  

I'm missing something here, normally we try to slim the planes down so we can carry more fuel, loosing weight by removing tanks is a somewhat surprising initiative. But you are right, if there is sloshing compound in the tank it might already be leaking. The wing tanks are a part of the stucture and without it you need to add a diagonal drag tube unless it is still there (I have seen some aluminium wingtanks built around the drag tube.

The tank hasn't been used in some time and is not currently plumbed, and in addition to the sloshing compound the integrity of the tank itself is suspect therefore if it could come out in the name of weight reduction so much the better but since it's part of the structure unless i recover the wings that's not likely.

 

More progress on the cowling (very little):

20181005_223315.jpg

20181005_223326.jpg

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Posted

Got a little more done:

20181006_183442.jpg

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Looks good.  But a warning, if you are used to landing a round nose Kitfox now, this cowling may cause you problems.  You will have to get used to being able to see over the nose in a three point landing. :-)  Kind of joking there, but  I'm really not a fan of the Kitfox cowl and the way it stuck up 6" higher than it needed to.  I'm bouncing ideas around in my head on what I'm going to do for a cowling my self.  I'm inclined to make a mold and make a nose bowl and then use aluminum for the rest of the cowl.  Kind of like a Chief or Champ did, although, the original nose bowls on them were aluminum as well.  I'm going to need 4 of them eventually if I ever get all my projects done.  I did figure out that the Avid Jabiru cowl will cover a 912 in a Kitfox very nicely, and is only 1 1/2" above the prop flange at the front.  Maybe that's the way I'll end up going.  It doesn't match the back at the doors or windshield however.  JImChuk

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Looks good.  But a warning, if you are used to landing a round nose Kitfox now, this cowling may cause you problems.  You will have to get used to being able to see over the nose in a three point landing. :-)  Kind of joking there, but  I'm really not a fan of the Kitfox cowl

Well as I've never even flown one i guess there'll be nothing to get used to. 

Got a little more done tonight. I think it looks like I might be on the right track:

 

20181011_222927.jpg

20181011_222911.jpg

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Just had a huge load taken off my mind about this plane. Every Saturday guys from my EAA chapter meet for lunch and there's a older gentleman that has a reputation as a magician welder and as someone who's seen, done, flown, and worked on just about every kind of plane you can imagine. He said he'd weld the brackets for the new gear on my plane and said he has a tool designed for straightening bent tubing "that makes it a snap". I've been stressing a little about getting that bent fuselage tube fixed and getting the brackets welded on and he made it all sound so simple.  I'm a carpenter by trade and any metal work beyond really simple stuff is intimidating to me. 

 

The gear will probably be here in the next month. That gives me a deadline on getting the cowl done and making some modifications to the trailer, both to make loading and unloading easier and prevent or significantly minimize the risk of damaging the plane a second time. I know what's been said about unloading the plane with the wings folded but the pic below shows the main culprit. That's where the tail wheel jumped the track.  Haven't decided exactly what I'm going to do yet but definitely something. Probably put a plywood deck on there so even if the tailwheel jumps out it has a place to land.

20181013_172256.jpg

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Going slowly but still going

20181016_224556.jpg

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Posted

What is the thin white foam you are using? It looks like it is bending and conforming well to make nice curves without a ton of sanding and making a mess. Looking good. 

 

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What is the thin white foam you are using? It looks like it is bending and conforming well to make nice curves without a ton of sanding and making a mess. Looking good. 

 

Thanks. It's Dollar Tree foam board otherwise known as Rediboard. Its 20 x 30 x 1/4" thick with paper facings on both sides. The RC guys like it for making their models.  To get the paper off just soak it with water left it dry THOROUGHLY, then the paper usually comes off in one piece.  I've been using packing tape along the edges that i want to be a little stiffer. Overall it is pretty easy stuff to work with. 

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The tubing repair video JimChuck posted is very much worth the time to view it. It does talk about a new wonder material called 'asbestos', however! Just use 1/4" plywood underneath instead. To stop heat from travelling too far along the tubes, I like a product called Hot Dam! made by IBS. It is a heat dissipating spray, product #74187 that works very well.

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The tubing repair video JimChuck posted is very much worth the time to view it. It does talk about a new wonder material called 'asbestos', however! Just use 1/4" plywood underneath instead. To stop heat from travelling too far along the tubes, I like a product called Hot Dam! made by IBS. It is a heat dissipating spray, product #74187 that works very well.

I did watch the video and was impressed at how good/ informative it was.  Fortunately I've got a very skilled gentleman lined up to help, ie do most of it. I would need to practice quite a bit before i risked makingit worse. 

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The tubing repair video JimChuck posted is very much worth the time to view it. It does talk about a new wonder material called 'asbestos', however! Just use 1/4" plywood underneath instead. To stop heat from travelling too far along the tubes, I like a product called Hot Dam! made by IBS. It is a heat dissipating spray, product #74187 that works very well.

I did watch the video and was impressed at how good/ informative it was.  Fortunately I've got a very skilled gentleman lined up to help, ie do most of it. I would need to practice quite a bit before i risked makingit worse. 

Golden opportunity. You get a quality repair and get to see how he does it. I put a high value on learning new (old) skills and passing them on to anyone willing to learn them.

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