USMeagle

My Feedback: (1)

Busted up my PT40 today. Not totally my fault, but....well....it is usually the pilots fault

Anyways, on the third flight of the day (and last) got up about 10 feet and engine died right as I was starting to climb out. Don't know why (that's another issue). Regardless, the runway has a small drainage ditch at the far end and as luck would have it, that's where I had to deadstick it down. It wasn't pretty..cartwheeled out and broke the fuse completely in two, right where the tail feathers start. Rudder and horiz. stab are still glued together and undamaged, but the fuse is broken. Wing was undamaged (believe it or not), not even a tear in the monocote.

How to fix this? The last former is where it broke (it is shattered)..I can build a copy of the part that broke off, but do I just butt it up to the fuse and expoxy it, then re-mount tail feathers? Or should I get some epoxy and cloth to put over the joint (to reinforce it)? Or should I strip the balsa sheeting back some, and re-sheet the back half of the plane?

I'll take some pics tomorrow when I find my digital camera, and possibly you all can get a better idea of what I'm talking about.

Honestly, I probably should retire it, it has went well past above and beyond...

gus

Pictures would be good....

On the other hand, I would be inclined to "fiddle" the fuse together so that you can get the two parts to fit back together (inter-weave all the broken fibers) as best as you can.

Strip the monocote back about 1" away from all the breaks. Make the remaining monokote as neat as you can. Be very careful not to cut any more balsa when you trim the monocote. I have always carefully used a single edge razor blade, but a soldering iron is apparently also good to "melt-cut" the covering.

You will be surprised how well you can re-mesh the parts if you are patient enough. "Practice" putting it together a few times, then liberally apply (30 minute) epoxy to the parts and re-mesh them again. Use T-pins and gravity perhaps to hold the parts in place while the eopxy cures. Maybe some "joined" elastic bands around the stab and wing mount dowels as well.

Get a piece of fiberglass tape and bandage the joint using epoxy just like you bandaged the wing-join.

If you can re-mesh the parts well, you will have a stronger plane (The epoxy is stronger than the old balsa/CA)

Good luck.

For reference I have repaired planes in much worse condition.... I got the following to fly again.... really well.

gus

smedsky

This is why the lessons learned in kit building are invaluable. Unfortunatly the learning curve takes a lifetime, and if you learn it all, you have exceded your lifetime.

phread59

Here is what I would do. Cut away some of the bottom sheeting under the joint. Say 3 inches either side of the break. Fit the fuse together. Square up the tail feathers with the tail mocked up with as much put together as you can. When everything is as close to square and as much is put back together as you can use thin ca to glue it together. Make a scab joint of wood and sheet the insides where it cracked acrossgrain to the break. Use epoxy to do so. Resheet the bottom. As suggested some fiberglass and thin ca on the outside. Some lightweight filler sanded smooth. Recover the repair. Rebalance the plane. You are done. Just be sure to go easy on the glue and wood. Use just enough of both. Experience here is invalubale. If possible seek out an accomplished builder and se if he will double check your ideas before committing glue. After a few repairs it will seem almost simple. Good luck with it.

Mark Shuman

MinnFlyer

My Feedback: (4)

Basically, you could stick the two pieces together (make sure they're straight) and drip some thin CA on it and go flying.

Or you could go through great lengths to make it look brand new again.

Or you can do something in between.

I only say this because we are all different - Some people want their planes to always look their best, and some just want them to fly.

So the choice is your as to how much you want to put into it.

BTW, that rear former isn't doing a heluva lot, so I wouldn't go through a lot of work to replace it.

USMeagle

My Feedback: (1)

soon as i get some batteries tomorrow for my digital camera I'll take a pic or two off the damage--that'll help.

I was going to re-construct the broken pieces, tack them with thin CA, then go over it with thinned epoxy..but some of the pieces are so small that will be impossible for all practical purposes...plus I evidently left one or two on the field..so that's out.

I am probably going to strip everything back a little ways and repair like Mark S. suggested...given what I have to work with, that will be easiest and look the best (not that this is a "show" quality trainer, by any stretch!). I can make patches directly from the blueprint, so that's good, and should make the whole job easier. The whole fuse needs recovering anyways, it has been built for a few years, so this will be a good time to do that.

I'll leave that last former (f-6) out, like Mike B. suggested, I really didnt see how it did a heckuva lot anyways. There's pretty much nothing left of it anyways!

I've looked around on here and see some of the crash 'victims' that have flown again, that made me feel better!

leftnut

My Feedback: (1)

a dremel is nice to have....
this is want i do.

put doublers on the inside of the fuselage at the break.
1" beyound before and after the break piont.
drill 1/8 od (dowls/ tooth pick) into the fuselage and doublers.
kind of like riveting the pieces
it won't add much wiegth.
this way the outter jigsaw puzzle pieces are not going to be holding everthing together.
puddy and patch accrodingly. and recover
the plane looks new like it had never suffer a crash .

i seen people just use thin ply boubler on the outside..it aint purdy but it works.

the break pionts are usually at a former.
if you don't what to remove the former.
you can knotch the coners of the formers
This way you and slide a hard piece of wood for each coners
on the inside of the fueslage.
CA or epoxy into place.

I try just using CA or epoxying before. it'll last for a little while
The planes takes a lot of stress.

glue and wood = good bond
glue and glue = not as good of bond

good luck and have fun