Ok, now I am a believer!   

I asked Sparky last weekend to watch my Twister as I flew it through a pattern or two and see what he thought about trimming it out better - now that I have a more stable engine run (thanks Allen B. and Bill M.).  He watched it fly and then looked it over after I landed.  He said I had a warp in the wing and that was making it fly strangely in the wind.  He offered to help me take the warp out - he said he used STEAM.   

I said: "But Sparky, It is already covered with Solarfilm, how can STEAM do anything through plastic covering?"  He said trust me and bring the plane over to his house some evening this week.

Well I visited the inner sanctum this evening and together Sparky and I STEAMED that wing over a boiling tea kettle on his kitchen range and he took the warp right out!  I wouldn't have believed it had I not only seen it but participated in the STEAMING.

Not taking that as the definitive proof, I told Sparky I had my recently built and basecoated Ringmaster in the car as well.  He looked at it critically and declared that it too had a warp - similar to the Twister warp.  Built both on the same building bench, hmmmm... guess I gotta get a better bench!   

Anyway the Ringmaster is covered with polyspan and dope.  We did the STEAMING thing again over the now refilled kettle on Sparky's kitchen range and after a while we had taken the warp out of the Ringmaster wing as well.   

Now I am a believer!  I would not have thought that this would work after finishing, particularly with the Solarfilm covered wing on the Twister!

Seeing and doing is certainly convincing.  Now Sparky and I are going to FCM this weekend to see how well the de-warped Twister does in competition.

STEAM rules when you have a warp that you gotta get out!   

Steam works (to an extent) in removing warps. 

I beg to differ It works in all cases! It just takes longer in some. Bigger warp more steam. I can bend a 2X4 with steam.

It opens the grain of the wood. Relieving the power thats built into it.

Same as above. STEAM makes no difference what the covering is.

Whew!  From the title. I thought this was going to be a thread about Ty's  Navy days!   

Steam may not penetrate MonoKote or other glossy, heat sealed plastics, but the wood will be subject to the heating and 'loosen up' some. Dope seems to be a little more permeable to steam or hot water - or it just may expand more when subjected to those.

Whether mylar or paper, the heating itself causes tautening when the surfaces cool. MonoKote particularly needs to be shrunk many times to reach a stable, taut surface that won't pucker up on a hot day. This reflects some RC glider experience from days when $Kote was the covering of choice... Heat gun one side of the warp, twist it past zero-warp, wipe with a damp, cool cloth. Flip to the other side, heat gun as needed, and hold straight before wiping with that damp, cool cloth.

Chilling it prevents gradual cooling and a slow re-appearance of the warp.

Steaming it is probably safer. The temperatures are high enough to shrink dope or film, but not hot enough to burn through (as can be done with a heat gun or iron). You're working with visible vapor or liquid and you KNOW it is hot - a heat gun or iron can burn you as easily as the model's covering.

Hi,  Would this work to straighten a bent profile fuselage, that is  1/2" thick?  Anyone have any experience with this?     Thanks,  Mike  Boucher

Yes.

It takes patience, but using steam to bend all types (and sizes) of wood is a truly "ancient" method.

What is the proceedure for getting warps out with steam?  Do you steam the side of the wing that you want to move it towards?  My inboard wing on my Super Chipmunk is high at the trailing edge wing tip by about 3/16".  Would I steam the bottom of the wing?  Or do I steam it and twist it by hand and hold it until it is cool?  The plane is covered with Monokote.

I steam both sides evenly. Try not to get the covering too hot. I think with all this Voo doo involved I will do a short video next time I have to steam. Its not that hard to do and it works in all cases with all types of covering in all conditions all the time every time. The thing is the bigger the warp and the Thicker the wood (profile fuse) the longer it takes.

And yes I can see the warp in anyones wing as its flying. Among-st other goofy stuff thats going on in a airplane in flight.

I think it was James Mills who I watched his airplane fly and picked out a trim problem from mid air. I also pick these slight things out on NATS top fliers planes but they would never listen to me Im just a mechanic.

When I use heat or steam for warp removal, I warp the surface equally in the opposite direction and let it sit a day or 2, that tells me how much of the warp is structurally induced and how much is covering induced and how much covering tension is takes to overcome the structure permanently. When is stablizes, I then warp it to neutral, I've never had one rewarp. As a matter of fact, my FF wings normally are flown with various combinations of washin and washout in the panels. Allot of guys build it into the structures. I build them flat then warp it in using the same method, my models stay in trim for years.

Thanks for the input guys.  I know the wing was straight when I built it and I'm not sure when the warp appeared.  Never the less it's there now.  Retracing my finishing steps, I could have made a mistake by leaning the plane against the livingroom radiator overnight to speed the drying of the paint on the fuselage.  Because this was during January the radiators got pretty hot.  I have the older type of radiators that are about 2 feet high and finned used with an oil/ hot water burner.  The more I think about it the more I think that it was a bad idea.  Right now I have the plane in the basement with towels and barbell weights twisting the wing the opposite way of the warp.  I left it like this for about a week some time ago and it got the warp out before but it seems to have come back.  As soon as I get some time I'll do the steam method.  I'm busy dealing with issues getting some of my other planes sorted out for the flying season.

I love the knot in a board part above, that's fabulous.  And if anyone needs further proof of the power of steaming, go to your nearest music store and look at the acoustic guitars.  Those curved sides are steam formed in most cases, though we do it by soaking the hardwood in the bathtub over night and then formimg them in some cases.  You can also bend any wood, that's ANY wood, by making a bending apparatus of a pipe with an end welded on it and aiming a small propane torch into the pipe - then you form the wood around the pipe by wetting it repeatedly and putting pressure on it against the pipe.
That probably wouldn't be a good ida with balsa, however - can you say fire department?