Lafayette

Guys, if any of you have flown airplanes with significant wrinkling in the covering, please post pictures. I wanna see just how bad the covering can go for an rc airplane. If any of you have web site addresses with flying rc airplanes which have wrinkles covering, or if you possess any pictures, I would very much appreciate it if you would share it with me to cheer me up a bit. I ahve a considerable amount of wrinkling orund 2 servos under my 74 cm wing (and there are two of those). I am not sure if the wrinkling will affect the lift that the wings will produce (im not talking about drag here i can overcome that with a stronger engine), will it affect the amount of lift created?


Yishht. Thank you.

Jburry

No pictures to show, but several members of our club fly very wrinkly planes. Since our aircraft produce lift by flowing air over carefully shaped surfaces, deviations from that shape will affect the lift they produce. Their lift/drag ratio will be affected to some degree. That said, the wrinkly planes seem to fly pretty well. I'm sure that flight times are somewhat reduced, and most importantly, their stall characteristics are probably negatively affected. Wrinkles on top of the wing will have a much greater effect than those on the bottom.

You have some wrinkling around servos on each wing panel. Why not just fix it? If you can't simply iron it out, cut out a roughly circular patch around each servo bay, enough to remove the bulk of the wrinkles. Then cut a new patch piece, overlapping about 1/4" all around, no sharp corners (cut'em rounded to prevent peeling). Tack it down with the iron on low heat, then turn it up to shrinking temps and tighten it up. Should be about 1/2-1 hour's work.

Even if you leave it alone, for sport flying you probably won't notice..... Depending on just how bad it is and how much wing is affected..... and how much differently one is affected than the other..... If you flew pattern (doubt you do or you'd not have asked), you likely would notice some effects.

J

bkdavy

My Feedback: (1)

Just hit it with a heat gun and shrink the covering again. If you don't have a heat gun, try a hair dryer on high. Or just buy a covering gun. They're not expensive. And a few wrinkles aren't going to cause enough problems that the plane won't fly.

Brad

da Rock

The answers you got in your thread in the Aerodynamics forum pretty much answered it, but one detail wasn't mentioned.

Stalls happen when the airflow over the top of the wing detaches from the surface and go turbulent. If the wrinkles are large enough and happen to be in critical locations, they'll trigger detachment when it would not have released otherwise. And no way to predict without the probability or severity of that increased tendency to stall.

Why the strong resistance to fixing the covering job? Honest, nobody can tell you whether or not that wrinkled job is "good enough" to leave as it is.

Lafayette

Alrity, thank you guys. I find it useful to check the werinkling on my wing my puting the covering against strong sunlight and see the light relfectiong from faults in the wing. Does teh sunlight exagurate the wrinkling? Because there seems to be much mroe wrinkling against sunlight than when i just plain look at it or pass my finger gently over the wrinkles, as the air will in real flight?

Yishht.

scratchonly

Fly it.

jetmech05

sunlight does not cause wrinkles....sunlight (low prolonged exposure to heat) causes the wood to release water vapor or sap...this causes the wrinkles...just heat gun them out...
do you wanna know how bad it can get...well the covering can detach itself from the aircraft in flight....

Lafayette

I dont weanna know about covering in flight, although what you described wud have been quite funny to others.... not the pilot tho . I wanna know how bad the covering job can go for a flying aircraft.

Please post pics, Yishht897.