how do i straighten bent balsa aileron

[crispin church]

got a built up balsa aileron thats bent

tried reshinking and iron and clamp it between 2 boards

am i chasing a loosing battle ?

[Engine Doctor]

If its a built up aileron it will probably be easier to make a new straight one than straighten it. Once the skins are glued on both sides an aileron or wing for that matter becomes very stiff. You could try removing one skin and glueing the new skin in place with the aileron straight but its going to require a bit of surgery .just twiting it etc is unlikely to correct the twist.

[ken anderson.]

hello crispin.......what i've done in the past with built up stuff is set the heat gun on...laid on a worktop....held the bent/warped bit in the hot air and twisted to where i want it......removed it from the heat -still held and when its cooled off it should be un-bent(straight).....

ken anderson ne..1 hot air dept....

[Erfolg]

Crispin.

Kens solution will probably work, at least in the short term.

Replacement, my type of solution, again will work, again if it is a permanent solution, time only will tell, how permanent is permanent.

I have had a wing, where distortion had occurred. In my case, the distortion was so severe only a rebuild was practical, to correct the issue. Which I have done, the work taking some time.

At present, I am trying to get my "A" certificate. I am using a 30 year old model, the wing has warped, to some degree. In this instance, I am living with the problem, at least for the present. The model does not fly perfectly, requiring corrections. Yet a re build is a lot easier to talk about than do. So i am living with a less than perfect model, as it is acceptable.

I do not think there is one solution. Each case needs careful consideration, as to the work involved, how severe the present problem is and the benefit that you will gain from a partial rebuild.

Edited By Erfolg on 03/04/2013 21:06:16

[Devcon1]

I think you have three options.

1. Do the same as you have already but clamp it up slightly over bent the other way.

2: Seperate some of the glue joints and re-glue whilst clamped. (also slit along the grain)

3: Build a new one.

[Pat (rActive) Harbord]

Crispin, is the aileron twisted or bent? A twist could be relatively easy to cure, a bend along its length would be considerably harder.

You will need to remove the aileron from the wing and then remove the covering For a twist in a solid surface. You can then mist with water and twist the other way slightly more than straight and hold over a heater/radiator until it is straight when you relax your grip. This can be repeated ad infinitum until perfect. You should then weigh the aileron down on a flat surface and leave for at least 24 hours.

a built up structure can often be straightened with use of the covering by applying heat whilst holding in opposite twist, allow to cool before relaxing the twist. Don't over heat the covering as it will lose its tension. You should see wrinkles appear as you hold in the opposite twist, you just need enough heat to smooth these out. I find an extra pair of hands and a covering iron good, but others prefer a heat gun.

[Pat (rActive) Harbord]

Ah I see Ken already answered - so what he says should work.

[Pat (rActive) Harbord]

If its bent, I would look at stripping the covering off and rebuilding it starting with the leading edge. If you can release the glue joints you you may find its the trailing edge that's bent, so re glue the leading edge and remove the trailing edge and replace with new (straight) wood.

[ben goodfellow 1]

i was told ammonia works well for bending balsa ,not sure how true it is

[Pat (rActive) Harbord]

All my old books suggest the same. Can you still get ammonia? I guess it works as a wetting agent helping the water to sink into the wood.

[Erfolg]

I do not know about the rest of you guys, I find that these types of jobs have a habit of growing a lot bigger than initially envisaged.

Even the simplest solution. That of trying to straighten in position. The first issue is getting the item straight. Or straighter than it was. Then finishing the damaged/removed covering is an issue.

The second solution of getting the aileron of. That is often far more involved than ever imagined. Then a new part is to be made. The hinging issue addressed, which can involve some work. The new bit covered, remounted. That is hinged, connected to servo etc.

All seem easy, in reality,take time, effort, some skill, if the finished result is not only to be better, but be right.

My experience has tended to indicate that quick fixes, seldom last, or work. Indicating, that if the model is to be fixed properly, count on some time and effort.

[001]

Instead of Ammonia spray the structure with window cleaning spray such as Mr. Muscle, let it soak in and the wood will relax, but it will also probably loosen the joints if they are made of PVA or white glue!

[crispin church]

Many thanks for all replys

it bent and a twist in it and does affect flying a lot

i am now at the stage that cover is coming off one side so will have more detailed look at it and put your comments in to good use

[crispin church]

well done it

took cover off one side found cross pieces not glued

reglue them and rubbed thin CA over then whole piece and clampped it down

hour later recovered now straight see over time if it stays

many thanks

[Myron Beaumont]

I suspect that the original shrinking was not the same all over which caused the problem bearing in mind that the woodwork was isolated from the environment by the covering .Hope you have rectified it by re glueing

[Erfolg]

Congratulations on successfully rectifying the issue.

So expeditiously completed too!

[crispin church]

soaked all joints in CA

checked it today and still straight

[crispin church]

flew today wing still nice and straight

cog a bit out need some weight on front but very flyable now many thanks to all