mooseflier

I just pulled a wing half off the building board and it's warped. No idea why... I check the spars and leading/trailing edges for warps before I pin them down. The problem is the trailing edge... it's basically warped up as it moves away from the fuse. Was hoping somoene had some advice, other than trying to straighten it with the covering. I took a quick video of it to show the problem: http://www.youtube.com/watch?v=eqImaDF7wNg (it's loud, turn your sound down. my wife had the music cranked up.)

I've built at least a dozen planes... never seen a wing warp so bad. This is a flat bottom trainer (Telemaster 40 - gas). If anyone has any advice, please let me know. Maybe Icould soak the trailing edge and some of the ribs... leave some books on it for a week or something.

Thanks

Quikturn

My Feedback: (12)

It looks like your trailing edge stock may have a bow to it. Whenever I see this, I orient the bow forward/aft instead of up/down. A light bow can be straightened once the trailing edge sheeting is glued in place.

What you can do is take off the trailing edge sheeting on the warped wing, straighten the wing and reglue the trailing edge in place. I prefer to have the center of the bow up on the top side (if that makes any sense).

I've straightened a twisted wing by reheating the covering but not a warped wing.

Best of luck,

Joe

airbusdrvr

You can most likely correct this problem very simply. Half fill about a dozen sandwich bags with sand(dirt will do). Measure the warped distance(work surface to the lifted wing tip end TE) and make a shim from a hardwood strip or plywood this thickness. Using a misting spray bottle, dampen as much of the wing as you can(skin, spars, ribs, etc). This is not a soaking, but just enough to lightly dampen the wood. Now on your building board or other flat surface like a kitchen counter top, place the shim under the outboard leading edge. The sand bags are now placed so as to keep all four corners of the wing against the flat surface as the wing dries. When the wing is dry, check the amount of warp remaining. You may have to repeat this procedure a couple of times. I usually have to make my shim about twice the thickness of the warp. It seems the amount of twist removed is usually about half the shim thickness. When I mentioned above to use a shim the thickness of the warp, this is for the first try. You will see the wing should start to straighten and on subsequent misting/shim/drying tries you can adjust the shim height as needed.

ARUP

Cut thru the shear webs and separate the sheeting from the ribs on bottom side where sheeting is near the trailing edge. Pin it all down then re-glue the sheeting (reach with scrap stick as glue applicator or get a syringe w long tip- use Titebond or similar) and install new shear webs. It may still have a little twist due to the sheeting at the leading edge. Good luck. P.S. it's a Hershey Bar wing and would be easy enough to just build another panel(?)

mooseflier

Thanks for the suggestions! I'll probably give the counter-warping idea a try first and see how it goes. Worse case I can just rebuild it, but I'm hoping Idon't have to.

Thanks again for all the suggestions!

JNorton

My Feedback: (2)

Grab a straight edge and check to make sure your buildinig board is not warped, front to back and side to side. I use a 4' aluminum ruler. Sometimes it's the obvious that we overlook.
John

mooseflier

I did check the board. That was the first thing I verified since I use sheet-rock... as well as the table it's on. Both were straight. Checked them with a 6' level and a string (in case the level was warped). Anyhow, thanks for the advice nonetheless JNorton.