G1K

Here are two pictures of my problem. It id the smaller (does not contain center section) wing for a sig 1/4 cub.





How do I fix the problem? Can I pin it to a flat surface and mist it with water? I was planning on using a fabric type covering if that makes any difference..


TIA,
Ryan

rcmodelr

No guarantees, but if you can't get the warp out by loosening and regluing some glue joints or misting the wood, I have pulled similar warps out of wings while covering the plane.

Cover the wing as usual.
After the covering is shrunk down evenly, you may need a helper.
Have your helper (or do it yourself), twist the wing to slightly past straight. This will cause wrinkles to form in the covering. Use a heat gun, and re-shrink the covering to shrink the wrinkles out, and if you worked the wing far enough, the re-shrunk covering will probably hold the wing straight.

I've never built a large plane like yours, but I have worked warps out of wings on smaller planes using this method.

TerrellFlyer

I would try to straighten the wing with water or windex first,then use a covering that can be shrunk to take the rest of the bend out,recheck the wing occasionally,the sun can loosen some covering's,made need to restretch occasionally.

OUTCAST

I've had some good success with the following, SATURATE the wing with a 80/20 mix of water and alcohol {I use the bath tub and hold it under for about 5 min}, rubber band the wing to a sheet of plywood bent in the opposite direction just a LITTLE past straight. Use finishing nails to hold the rubber bands and balsa blocks on the spar and sheeting to prevent damage to the now soft wood. After 24 hours saturate it again without removing the rubber bands and let it dry completely. It seems the alcohol helps the wood soak up the water and also speeds the evaporation. The mix does not seem to have any effect on most glues except white carpenter types. This was taught to me by my uncle, he used to make, believe it or not, coo-coo clocks. :^)

Tenthumbs

It looks like the wing is warped span wise, right? And it's only on one wing panel?

I'm one who likes perfection or at least close to it when it comes to building my projects and if it were mine, I'd just build another wing panel. It doesn't take too long to cut things out and it looks like a very simple wing to build too.

You can probably use most of the same pieces, except anything warped of course
About the soaking and twisting it back into shape, it works but I've only seen it done when the twist is chord wise. Same thing on the fix with the covering.
I've used amonia sprayed directly to the wood, twisted and held in place with weights and shimed with anything I could come up with

Keefer

My Feedback: (2)

I've used ammonia as well, spraying both sides, but more heavily soaking the side that needs to expand. Then hold like OUTCAST says. I've used ziplock bags full of sand to weight it down on a flat table. It may take a couple of iterations.

OUTCAST

Keefer, I've never used ammonia but a lot of people do and I understand it works just as well, but smells REAL bad when wet. :^)

Keefer

My Feedback: (2)

Sure, ammonia stinks, but you can just watch a piece of 1/16" sheeting almost roll up when you spray just one side. Makes sheeting leading edges a snap.

Sporty

Ryan; I would try using steam. Just hold oppisite pressure on the wing,and hold over a teakettle for a few minutes ,let it cool a few minutes, then check it out. Repeat if nessesary. Sporty

rcman-RCU

My Feedback: (31)

I have tried to straighten wings using the water, warp and dry method. The problem I have had is the wing wants to go back into the warped shape over time. Some time it takes a month or two. If you use this method, wet all the sheeting: leading and trailing edge, top and bottom. Then bend the wing past straight so it is warped a little in the opposite direction. Let it dry overnight. It will spring back over time and hopefully end up about straight.

P.S. - I have heard that adding ammonia to the water is of no benefit. It also stinks and discolors the balsa.

coxsairforce

My Feedback: (2)

hi gk1
I am having the same trouble with a 4* 60 did you get your warp out? mine looks just like your photo.

ebeygin

i'm having the same problem!

I haven't touched it yet.. trying to leave to last, since I'm really worried. My wing tips come up 1/16 or 1/8 (don't remember) inch on each side.

From the hundreds of suggestions that I got, I decided to just use a spray bottle.. spray the middle portion with water.. mainly the spars.. put a piece of wood about 1/8 high under the wing in the middle.. and then put weights on the tips.. making the wing tips bend slighty opposite of the bow. Clamping it down on a straight surface will not bring out the bow fully...since it will spring back slightly.....

Eugene

P.S. This is what happens when you get your first kit.. run to get the closest board near you.. and start building

OUTCAST

For some reason that I have no explanation for it's important to wet the wing twice without removing it from its jig. This somehow sets the wood and it will stay there for years.

longboard

My Feedback: (2)

I have a similar problem with a Great Planes PT-40 MK-II.Igot a kit before they updated the construction manual and I used the wing jig that sets the wash-out in the wing panels(both)backwards so now I have wash-in!How do I fix this?This wing is built rigid, I don't think any of the above solutions would work.Any suggestions?Right now I'm thinking about just buying a new wing kit and rebuilding.

teufelhund

My Feedback: (2)

Longboard, that's the only option I could think of also. Ben