Flattening the potato chip?

[wwwarbird]

 I've got a model, the Super Combat Streak, that I finished about a year ago that I haven't even put fuel in yet. This is because for some reason the fixed flaps decided to curl up like a potato chip a few weeks after the model was completed. Looking at it from the rear, there is a gradual but significant "S" wave in each flap all the way from root to tip. The only potentially good thing (not really) is that the wave is symmetrical from wing to wing. This issue is extremely frustrating because everything was dead straight and perfectly aligned throughout the entire building and finishing process. The wing itself still looks great, it's just the fixed flaps that are the issue.

 Anyway, short of cutting them off and having to refinish everything, I've been considering an attempt at steaming them. I have no real experience with steaming and am not super confident in trying it. What I worry about is compounding the problem and warping the wing itself which is still nice and straight.

 Any suggestions?

[Steve Helmick]

While the boss is away, take a terry hand towel, fold it lengthwise, dip in a large "flying pan" (sic) with boiling water, then apply the towel to one flap. Fold it in half lengthwise again, with the flap between two layers of hot/wet terry cloth. Lay it on the edge of a handy kitchen counter, then apply the steam iron to the top layer for awhile. Repeat the process for the other flap. There may be some finish degradation, or not.  Steve

[Tim Wescott]

Fold it in half lengthwise again, with the flap between two layers of hot/wet terry cloth.

Actually, when you finish this step you can just remove the splinters, then replace the fixed (and folded) flaps with ones made out of C-grain balsa.

 

[Geoff Goodworth]

The pics suggest that one warp may cancel out the other on both flaps. Why not fly it and find out.

[Mike Haverly]

I have witnessed Howard pour boiling water on an airplane, (mine) then twist to the shape he wanted.  I've tried it myself on my then new Shrike flaps, worked fine.  Use a hot pad to grip the desired area and straighten.   It shouldn't hurt the finish but will remove any wax.

[Larry Cunningham]

First, I'd actually fly it and see how bad it is. (You might accidentally discover a Stunt secret weapon or something..)

Second, I'd not waste time with hot water attempts to straighten those flaps. That might have worked (though not with certainty) before the wood was all finished, but I'll bet dollars to donuts it won't now. However, if you must, try it anyway.. {When it succeeds, you can point out that Cunningham has a prune in his whiskers - once again.}  

Third, either initially or after failed boiling water tricks, get your Dremel out and cut the potato chips off. Make, finish and install new flaps, this time from light C-grain balsa.

Go forth and enjoy your Streak!

Best wishes,

L.

PS - edited when I remembered that Flite Streaks don't have moveable flaps.. duhh..

"The English are not very spiritual people, so they invented cricket to give them some idea of eternity." -George Bernard Shaw

[dennis lipsett]

Mine are still perfectly straight. But then again I didn't subject them to water, dope and thinner, the 3 worst enemies of balsa wood. Seriously, enter the dark side and use film.
 


dennis

[Gene O'Keefe]

I actually like my Flite Streaks with movable flaps....I set them up only to move about 15 degrees...seems to make
corners more square for me... JMHO

[Clint Ormosen]

Another vote for flying the plane first. Since it's not a precision stunner, I doubt that those little warps will make much difference. Don't panic until there's a reason to panic.

[wwwarbird]

The pics suggest that one warp may cancel out the other on both flaps. Why not fly it and find out.

 I've considered that too, they just might cancel each other out. The thing is that I would rather just have it be "right", plus I can't stand looking at it the way it is.

 I should also mention that I definitely don't blame the problem on Walter. The crappy thing about it is that I did substitute some harder balsa for the flaps instead of what originally came in the kit. They really should have been fine, but obviously that plan backfired.

[Mark Scarborough]

The hot water and towel, with steam idea will work even on finished surfaces ,, give it a shot,, what do you have to loose,,

[Clint Ormosen]

 give it a shot,, what do you have to loose,,

.....could make it worse, I guess.

[Mark Scarborough]

Clint, true enough indeed,, but I guess if he is going to hack them off anyway,, its worth a shot to remedy it before commiting to hacking them off

[Clint Ormosen]

Yup, I guess that's true too. Either way it appears Wayne won't be happy with them unless they're perfect. I see his point. I suppose I wouldn't either.

[Mark Scarborough]

yeah  I feare there are quite a few of US who are that way ,, I guess its part of what makes us fit this hobby eh?

[wwwarbird]

 Well, when I get a chance I think I'll try the hot towel and iron thing if I can find a suitable counter spot to hang it over. If it doesn't work it will probably end up under the knife at some point.

 I could probably just fly the thing as it is and be fine, but someone might see it.

[John Rist]

I have found that my best flying airplanes have ugly drag - usualy the results of crash repair.  I say go for it as-is. 

[Michael Massey]

Hot towels work great.  I get towels very wet, roll them up, put them in a large plastic bowl and put them in the microwave.  I do 3 - 2 minute shots.  Be very careful taking the plastic bowl out of the microwave.  I accidentally pulled out the glass plate in the microwave (before I used the plastic bowl to contain the wet towels) and it dropped to the granite counter top.  Nuf said.  Cost 50 bucks for that glass replacement.

But, the towels get very hot.  Use gloves when you unroll them and apply them to the plane.  Like others here, I have found that real hot towels do the job and do not damage the finish.

[john e. holliday]

As stated earlier,  try a flight on the plane first before going to all that trouble.   I have had planes with warps that flew great and som that were straight as could be done that needed tabs to fly wings level.  You ever seen combat planes with dihedral.   

[wwwarbird]

 Well I just went through the wet towel/microwave routine, repeat, repeat, repeat, repeat...

 I used a wash rag since it was a handy size to manipulate. It's really a bugger trying to handle the rag when it's as hot as it needs to be, much like playing "Hot Potato", kind of ironic in this case.
 
 I didn't have a counter surface that would work without some sort of obstruction, so I just had to freehand it. I ended up getting the flaps much better, far from perfect, but definitely better than they were. I'd at least be satisfied enough to take it to the field at this point. I did end up with a very slight buckle in the covering along part of the "hinge" line on each wing, but luckily only on the bottom. I'm gonna let it sit for a couple of days now and see if things stay put. If so, I might try to fine tune it a bit more, or not.

 Thanks for the tips!

[jim ivey]

easy fix iron them straight on an ironing board  no steam , dry, but dont burn it!  it needs to be hot!! come on you can do it.  jim

[Gerald Arana]

What I do is use the "Mono-coat" heat gun. Simply wave the gun back and forth on high while holding the part (with glove if you must) until its "hot" and then let it cool in that position. When cool you can release it.
Simple, clean and repeatable.
Caution; You can bubble the paint real easy...............that's why you move the gun!

Jerry