How to fix a sheet balsa wing warp? - RC Groups
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Jun 20, 2004, 02:46 AM
Team30 Micro EDF
NitroCharged's Avatar

How to fix a sheet balsa wing warp?

Hey guys,
I have a balsa sheet wing ( Micro Pitts ) and need to fix a slight warp in the wing end which happened during construction.
I did a search on the board and found various recommendations on how to acheive this.
"Spray the wing using window cleaner and set. Apply ammonia ( which I dont have ) and lastly, apply hot water and set."
I dont want to steam as I dont have the best steaming application to get it right. Can anyone offer their comments/methods to steer me in the right direction, please? ( the wing is attached to the fuselage already - its the rear of the wing tip that is lifting up slightly)

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Jun 20, 2004, 03:05 AM
Food For The Maggots
speeddemon281's Avatar
Your best bet is Ammonia,its what i use.

Are you able to take the wing off?If you are,then take a paper towel,get it wet,then rub down the wing with the ammonia,then lay it and have a electric fan blowing under the book onto the wing,Leave it like this for 2 hours.
then it will be straight as a board.(A non Warped board)
Jun 20, 2004, 03:09 AM
Team30 Micro EDF
NitroCharged's Avatar
For all responses - please note "I don't have ammonia"...
Thank you.

Jun 20, 2004, 04:00 AM
Kiwi's Can Fly's Son
TimayTheToolman's Avatar
Try holding it how you want it over a hot light bulb, and it will soften the wood then take it away and keep holding it until it cools then it should stay.

Jun 20, 2004, 07:03 AM
Sticky Shepherd
Graham Stabler's Avatar
There was a time when I didn't have any ammonia either.

Just use water if you can't face the cost of buying some.
Jun 20, 2004, 07:32 AM
Team30 Micro EDF
NitroCharged's Avatar
So your recommendation is to use Ammonia too, Graham?
Jun 20, 2004, 08:59 AM
Gravity is a harsh mistress.
Tim Wolff's Avatar
Your window cleaner (ie Windex) should contain some ammonia. You will need to guess at how much opposite deflection to use and imobilize the panel until it dries throurghly-like overnight.
All you need to do steam is a small pot of boiling water. It may take several applications.
The warp sounds like washout which can be a good thing in moderation and if the other wing is warped in the same fashion. I'd prob. just try to reduce the warp a bit and add some to the other side too.
Jun 20, 2004, 10:09 AM
Registered User
gbarc's Avatar
Try this...i use an ammonia/rubbing alcohol mix. I can't remember where i got the info from but it works great. Almost instant softening of the wood. Then just pin down the part on a warp free board.(But you already knew that).

Jun 20, 2004, 11:53 AM
Sticky Shepherd
Graham Stabler's Avatar
Ammonia does seem to help but you can just soak the wood in water. So you don't HAVE to use it, but if would not be difficult to get some.

Jun 20, 2004, 11:58 AM
Gravity is a harsh mistress.
Tim Wolff's Avatar
I think the key is be able to guess how much to reflex the part when wet AND to leave it imobilized until it dries throughly.

I recently straighted a Diddlebug wing that was warped by the covering. Just shimming in some areas and weights in others straightened it out when I left it set 24 hrs. No moisture used (though that was my next option).
Jun 20, 2004, 09:41 PM
Team30 Micro EDF
NitroCharged's Avatar
Thanks guys. I'll let you know how it goes
Jun 21, 2004, 02:56 AM
Registered User
Martin SJ's Avatar
I had the same problem with a Lil Skeeter, especially after flying it in the early mornings and landing on grass covered with dew. I completely fixed the problem by attaching a pair of criss-crossed threads on the underside of each wing. The threads go from the leading edge at the root to the trailing edge at the single rib, and from the trailing edge at the root to the leading edge at the rib. The two threads on one wing should just touch where they cross - attach them there either with a spot of glue or with a small loop of thread. I got the tension on the two threads the same by tying a single crossed-over loop attached at the leading edge and trailing edge at the root then suspending a weight from the loop (probably needs a diagram), but however you achieve it you do need some tension on the threads. I believe the structure of the Pitts wing is the same so it should work for you too.