I noticed just before covering the ailerons and elevator of my LT-40 that they are warped. Is this to be expected? Should an attempt to straighten the pieces be made? How do I go about straightening the pieces?

You should try to straighten them. if they can't be straightend I would think about building a couple new ones. Two ways to try and make em straight. One get them damp with amonia and place them under a heavy book to dry. Two After you cover them have someone twist them past straight the oposite way and heat out the wrinkles in the Monocoat. The elevators is what to be most concerned about. If you call SIG they will send you new ailerons I'll bet.later daveo

Now that I set them side by side they look pretty bad...here's a pic. The wing spars were warped some too. I hope the whole plane doesn't turn out to be no good.

spray the warped parts with some woater and amonia. Appx 10% household amoinia (which is ALREADY diluted) an enough to start having the liquid run off the wood.

Clamp the wood in proper alignment. It will dry the way you clamp it.

Its a good catch to find the warped wood before assembling the wings... it pays off to notice things like that.

After you straghten the wood the wing will be just fine.

I assembled an LT40 ARF and found the surfaces warped as they came out of the box. I used a heat gun and blocked the surfaces a little past straight in the opposite direction. I was never really satisfied with them. If I had it to do again I would build then new from scratch with straight material.
I ama builder from a long time back and this was only the second ARF I've ever tried. I don't know about the kit built version but my ARF was very tail heavy. After compensating for that problem it flew fairly well with a .46 engine.

If you bought the kit from a LHS, take the warped pieces back and ask the dealer to contact SIG for replacements. I had no problem getting new ones on a kit a couple of years ago. If you mail-ordered it, you could try to contact the company and see what they are willing to do. SIG is usually pretty good about this kind of stuff. Good luck, Dzl

I can relate, my dynaflight A rons were a mess, Warping is a BIG problem with balsa. A LOT of glue can cause warping , even if the part is clamped down. Strip A RONS ARE THE WORST, BECAUSE they are too
long and warp easy.balsa usa uses hard balsa A rons on their stick trainers, 1/2 inch thick at the hinge area.
THIS is the best !!!!! they are 12 inches long and will never warp. I would replace them with hard balsa , or
try backing them with 1/32 ply, then clamping, dont over glue.


have a goody


dan

I called SIG as suggested and they had a new set to me in 3 days. They even came covered so I didn't have to do it again. While cutting the CA hinges to remove the elevator I relearned just how sharp a brand new #11 Xacto blade is...cut my thumb to the bone, had to go to the emergency room etc. Anyway I got the new parts installed even with a lamed hand, thanks for the responses and a wounded thumb up to SIG for getting replacement parts out quickly.