Leading edge repair

I am looking for some ideas. On an airplane like a twister, or Lignening streak with the diamond leading edge, what is a good way to fix the LE after a crash? There is ususally enough meat on the TE. I seem to be able to knock off outboard wings quite easily

They seem to always break just outboard of the sheeting, and there isn't much space to make a good splice. The method's I have used just don't hold up over time. This goes for the spars also. Usually I can use some ply to beef up the spar on 3 sides but the LE is a problem.

thanks

You can use an outside splice by covering wrapping fiberglass cloth around the outside of the leading edge and using epoxy glue to hold and strengthen it. In fact, doing this ahead of time would be a good precaution.

In the "good old days" when the Sterling kits (Ringmaster, Mustang, Yak) were popular, the wood was soft, and the wing would break just from the pressure of violent turns at this point. I resorted to using cotton cloth soaked in Ambroid that I wrapped around the leading edge to about half a bay past the end of the center sheeting. This moved the stress point out a bit, and alleviated the problem of the plane self destructing. And then, if you broke it in a crash, it usually broke outboard of this cast, which allowed a simple plywood splice to be place behind the break and a simple repair.

If you have a weak point where you know the plane is going to break in a crash, beefing it up there can help move the stress points out a bit and strengthen the whole assembly. As Windy once said (well, someone said it at least), "When you have a crash, do an autopsy. Where the plane broke, make that area stronger next time. And where it didn't break, you probably made it too strong and can get away with removing a bit more structure."

You must be flying combat!!!
I do not understand the "diamond" shape LE. Is it a square piece on edge or two pieces of sheet that meet at the LE?

If the rib at the edge of the sheeting is good, Notch into the rib next to the LE material and lay a stub doubler on the inside of the old LE top and bottom sides inside the LE. That will give you something to attach the repaired LE outboard of that rib to attach to. That doubler material can be fairly soft. Block the wing level and slide the remaining outboard panel up to the stubs and glue it in place. If there is missing parts such as a length of LE missing, stub the remaining LE at the outer section , pin the outboard panel down at the spacing that would be if the parts were there and add new material as necessary. I have replaced as much as two rib panels after collisions this way, The main thing is to get the fuselage attached section blocked and pinned down so that you can get the outboard panel aligned accurately. If you need more, either E-Mail me , ask for more here, or give me a call at (316)838-8494.

Bigiron aka Marvin Denny

If I understand right you are breaking right at the edge of the sheeting. If so I would butt glue the leading edge back together, then, I would cut a slot lengthwise in the leading edge the thickness of a popcycle stick or strip of plywood. then epoxy into the slot. Or as I did on a profile fuselage that kept breaking. Gouge out the leading edge and epoxy in a lengthe of hardwood dowel rod. Later, DOC

I think he means square stock turned on edge.

If the break is clean, line it all up and glue it back together. Then carefully carve the leading edge away about 1 1/2" either side of the break back to the upper and lower edges. Carve a piece of fairly hard balsa to fit into the area you've cleared out, and glue it in place. Shape to match the LE and you're ready to patch the covering. This is probably the lightest and least intrusive way to make the repair.

The leading edge is a 1/2 square one set on edge. I seem to break them clean off just past the sheeting. If it was out one bay or so I could scarf in some and it would be strong.

I seem to be having bad luck with engine cutouts while learning the clover and the hourglass (straight on from top of the circle), as well as snagging a weed or 2 on takeoff (ff across the circle). I think I have my engine run issues worked out. But is cost me 2 airplanes and tanks.

I have tired but joining the brake, then carbon fiber tow over with CA that, but it starts to get loose after a while.

>I think he means square stock turned on edge.
>
>If the break is clean, line it all up and glue it back
>together. Then carefully carve the leading edge away about 1
>1/2" either side of the break back to the upper and lower
>edges. Carve a piece of fairly hard balsa to fit into the
>area you've cleared out, and glue it in place. Shape to
>match the LE and you're ready to patch the covering. This is
>probably the lightest and least intrusive way to make the
>repair.
>
>Randy Ryan <><
>AMA 8500
>SAM 36
>BO all my own M's

BINGO! In my opinion, this is the correct way to attack most damage. It can be quite fast, and turn out very nice, if done with care.
Steve

A way that has worked for me, get some fluted dowels from your local
wood working place, 3/16 or 1/4 dia., drill matching holes in each end of
the leading edge break, epoxy, its a very strong repair.

One of the things I do, sometimes at least, is to cut some gussets out of 1/8 sheet with the grain at 45 degrees. glue these to the leading edge and the sheeting (trailing edge as well), and cut them to make a quarter-circle-shaped fillet. Sand down to fit the airfoil profile, and you get a transfer of the stress point out a bit; also it looks neat.