repaired wing question

[nhask]

Repaired a 52" x 9" 16% wing and it ended up with the left tip warped upward. From about 9" in from the tip to at the leading edge. The trailing edge looks straight. Now the left tip took the most damage in the wreck, but the breaks were all closer to the tip than where this warp starts. So either I missed it when I originally assembled the wing halves or something else is bent under the sheeting The first pic shows the left tip under reconstruction. Next one shows the leading edge from center looking left, at the warp.

This wing was made out of hardwood, spars, leading & trailing edges all Spruce. The ribs and sheeting are basswood. I think the all hardwood construction and some missing glue is the reason it shattered in the wreck. A wind gust hit the right wing tip while 2' off the ground on final approach 12mph. It rolled left & cartwheeled. It is from a Sonic .25 high wing mounted to a SuperStar ep fuselage.

My question is since the trailing edge is straight will this wing fly level? Or is it toast?

[JetPlaneFlyer]

Sighting along the leading edge like that can much exaggerate any slight misalignment. I'm guessing the bend is probably 3mm or less, if that's all it is then you will easily be able to trim it with aileron.

In the ideal world of course it would be dead straight. It would be worth trying to steam it. With so much hardwood and bass you probably wont get much movement with steam (but worth trying non the less)

Steve

[nhask]

Originally Posted by JetPlaneFlyer

Sighting along the leading edge like that can much exaggerate any slight misalignment. I'm guessing the bend is probably 3mm or less, if that's all it is then you will easily be able to trim it with aileron.

In the ideal world of course it would be dead straight. It would be worth trying to steam it. With so much hardwood and bass you probably wont get much movement with steam (but worth trying non the less)

Steve

Thanks Steve, I've never steamed a wing before what's the procedure?

Ned

[JetPlaneFlyer]

Boil up a kettle or pan of water and with gloved hands hold the wing in the steam, concentrating the steam where you want the wing to bend. Now twist the wing in the direction you want it to go keeping it in the steam. Hold it there for a few minutes (longer the better) keeping it twisted. Take it out and hold the twist in until it cold. You should then put the wing on a flat surface with some sort of weights and shims that hold the wing in the position you want it to 'set' in. Leave it overnight to dry out.

With balsa wings you can pull all sorts of twists out this way.

Steve

[nhask]

Originally Posted by JetPlaneFlyer

Boil up a kettle or pan of water and with gloved hands hold the wing in the steam, concentrating the steam where you want the wing to bend. Now twist the wing in the direction you want it to go keeping it in the steam. Hold it there for a few minutes (longer the better) keeping it twisted. Take it out and hold the twist in until it cold. You should then put the wing on a flat surface with some sort of weights and shims that hold the wing in the position you want it to 'set' in. Leave it overnight to dry out.

With balsa wings you can pull all sorts of twists out this way.

Steve

Thanks for the help Steve.
I don't think I could do much with this hardwood wing with the sheeting in place, but its good info to have for future problems. I think I will just balance and cover this one as is. The left wing tip is .75g heavier than the right. Or at least that is what the piece of scrap I set on it weighed to balance it.

Ned

[nhask]

Finished it & flew today, it rolled left on take off. Almost wrecked again. Got it trimmed out with lots of right aileron trim. Yes I checked and double checked travel, zeroed sub-trim. I started out with no trim and ailerons centered, before I left the house. Ended up with right aileron up 2mm, left down 2mm, to get her flying without a roll. That's 9 clicks of trim.

I did fly it till storm clouds rolled in. 3 flights, 3 landings.

The only thing I'm happy with is the blue bottom, with white top colors are easy to see.
I guess I will have to learn how to build wings next time business is slow.

Ned