Warp.- HELP!!!

LAST EDITED ON Jul-21-04 AT 10:53 AM (CDT)
 
HELP!!!!!!!!!!!
I took pins out of my wing last night and was checking it out. My youngest son said it looked like dinosaur bones. I was admiring my handy work when I looked down the TE and saw a warp in the center of the TE wood on the center rib. The center 3 ribs are not as tall as the other ribs, but I think this is because of the decking that will go on top.
My TE looks kind of looks like the drawing below. The warp is not as bad as the drawing shows, about 1/8 in. Just wanted to show the warp.
I have seen post on warps in wings and I know it is not a good thing.
My first guess would be to cut out the section of warp and splice in new wood.

What do you guys think?

Thanks
Paul

First what plane? Full fuse, Profile? Second Are these ribs going to be sheeted over? Third can the ribs be cut and lowered?

LOTS of planes have been built with this problem. Nothing new.

You need to draw a center line from wing tip to wing tip on the TE just to see how much you're off.

It is a Skyray 35 Profile. The ribs will be sheeted over. The rib where the warp is located is lower then the other ribs.
I will try and take a picture and post later.

Thanks
Paul

Hi

While you will want to remove the warp if you can, it may not be
much of a problem flying. If the TE is drooped in the centre of the wing only so the warp is symetrical on each wing, there will be
little overall roll effect. Are the wing tips aligned with each
other? That's the more important thing.

A symetrical warp like you describe will not be a disaster
but may cause some aberant behaviour in advanced manouvers
as it's effect might be very slightly asymetrical.

If it is simply bent wood, soaking and clamping until dry will
fix it but it may be a building error so we need those pics.

Thanks guys,
Here are the pics. Everyone jump in!!! Please.

Paul

I agree with Ken. A wide-angle picture from directly behind the wing would help, though.

Rootbeard,

I know you are going to be covering this in Monocote so there are a couple of things you can do....

First, wet it and clamp it as suggested above......weight the TE down with some flat weights. or a straight edge with weights on it to keep it straight when it dries...

OR

YOu can pull a small warp like that out with the "Cote when you shrink it.....it is nothing nmajor that you have there...I have had worse and they all seem to come good with either of the above methods

Paul,

Put the high side up and balance between two block or even phone books. Then dampen both sides with a wet rag or sponge, push against the warp with a block of wood or gloved hand and turn your hot air blower on it alternating between top and bottom. Repeat until warp is gone. Let it stablize over night and check again. The hot air gun saves time.

>Then dampen both sides with a wet rag or
>sponge, push against the warp with a block of wood or
>gloved hand and turn your hot air blower on it alternating
>between top and bottom.

Assuming you can find a way to jig the thing so that it's straight and the smaller center ribs are supported in line (fake sheeting in place if you are relying on the rib edge to align it), then I'd go soak the whole wing in hot water until the balsa is fully relaxed.

Put the wing in the jig, weigh it down to insure it stays there.

Put it in a warm dry place, maybe near a heater vent if you have one.

Forget about it for a week. Come back when it's completely dry and then see what you have.

Cy.

LAST EDITED ON Jul-21-04 AT 09:41 PM (CDT)
 
Here's the fix. Steam it out. I have removed worse warps with steam. Good luck.

I suspect this warp was caused by having that rib "upside down", relative to the others. My Banshee kit ribs definitely had an up and a down. Not a problem, as long as all are the same way. It is also possible that your building board has this same warp in it.....like my card table. The wing can't be any straighter than the board or bench it's built on.

I would slice that rib (vertical, no angle intended) loose, about 1" ahead of the TE sheeting. Then straighten the TE itself, perhaps steam, water, shimming, weights, etc. Then splice the rib back together, in a relaxed state. Recontour the mismatch, add wood, add doublers. If the TE is stubborn, you might need to cut out a section of the bottom (to leave the top looking better), remove it, and splice in a new piece of TE sheeting. Use scarf joints, and put some cross grain doublers inside, or fiberglass outside. It's not that hard. Lay the new piece over the old, and cut both at once. A little sanding, and it's ready to glue. Take your time, and it'll be fine. Steve

Thanks Everyone!!!!
The Steam seemed to work last night. I got the wife's iron hit the steam button and pressed it on the wing. It took most of it out. I let is sit for a few hours and checked it late last night. I think one more time today will get it close enough for goverment work.

Paul