CadFlyer

My Feedback: (16)

I have a 90" Great Planes J3 Cub. I recently discovered that the outer 2/3 of the left wing has a 1/4" front side upward twist. This plane is a flying plane, but poorly flying that is. Can anyone tell me if there is a technique to "un-twist" this wing????? I am fearing that I will ultimately re build the wing in the future but for now I am just looking to try and pull some of it out. I am also thinking that I can pull a little out by adjusting the struts on that side. All comments are greatly appreciated.
Thanks
Cadflyer

William Robison

My Feedback: (3)

Cad:

The strut adjustment will help as a temporary fix, but it's best to remove the warp.

Set the wing panel on a flat bench with shims to bend it an equal and opposite amount to the warp, weighting the other corners, and use your heat gun to re stretch the covering. Then turn it over and do the same to the under side.

Might take two or three attempts, but this will work whether it's film or fabric covering. And try to have the top and bottom pulled an equal amount. If you get too much on the top or the bottom the wing can end up with a bow.

Bill.

CadFlyer

My Feedback: (16)

ok, great. I will try that. It is covered with Monokote film (unfortunetly) But it sounds like you idea just might fix it. It is only out a 1/4 of an inch so I feel like it won't take much. I will try to fix it today and let you know back how it turns out.
Thanks
Cadflyer

CadFlyer

My Feedback: (16)

Thanks for the tip. I just tried what you suggested. It worked perfect. I got all the twist out of it and it is straight as it can be. Thanks alot.
Cadflyer

William Robison

My Feedback: (3)

Cad:

I'm pleased.

Bill.