Warped Wing on Great Planes Extra 330L
 

I am building the left wing panel of this kit (GP Extra 330L) and it has come out slightly warped.
It was twisted at the tip (I was able to fix this by wetting it down and holding it past its normal place for a while).

There are 14 ribs on each wing panel - starting at about rib 8 going to the tip it is warped - the tip is about 1/16" (maybe a little bit more) down compared to the root. I am not sure how to fix this as the wing is built with a full length shear web.

I have built several kits, but this is my first 1/3 scale kit. I have not had any problem building the plane as of yet, the tail feathers are complete and the right wing panel is complete, none had any warping in them.
I was very carefull to make sure that I matched the spars, and that everything lined up correctly to the plans before gluing.
I also used the leading and trailing edge jigs provided for this purpose while lining this all up.

No sheeting has been installed on the wing as of yet.

Here are my questions for you:
1. What kind of an effect will this have on the flying characteristics of this plane?
2. What can be done to correct this?
3. Does this need to be corrected?
4. Should I contact Great Planes and have them send me all new wood for this wing panel and start over again?

The plane will be used for IMAC competitions and basic 3D flight.

Thanks for any help & suggestions on this.

- Kevod

RE: Warped Wing on Great Planes Extra 330L
 

Kev, Don't worry about it. Make sure the wing is held down FLAT before installing the sheeting. The sheeting will take 99% of that warp out.

RE: Warped Wing on Great Planes Extra 330L
 

Just to be a little bit more precise, that is the LAST sheeting you will glue that will lock everithing in place. I am building the exact same plane right now and I also had a slighly warped wing and everything is OK now after the bottom sheeting was glued about 30 minutes ago:D.

If the wing is still warped after the sheeting is in place, I think it is better to have the wingtip with some washout than some washin, it will help prevent tip stalling.

I hope this helps.

RE: Warped Wing on Great Planes Extra 330L
 

Minn & 3D:

Thanks for the replies - I will go ahead with the construction of the wing panel and will be very carefull to make sure that I get the wing flat on the building surface during the install of the sheeting.

-- Kevod

RE: Warped Wing on Great Planes Extra 330L
 

MinnFlyer and Kevod are absolutely correct. When a wing is sheeted on one side or not sheeted at all, you can twist the heck out of it. Once you get all the sheeting in place a warp is pretty much there forever unless the wing is still flexible.

If that's the case, you can try holding it over steam or even twist the wing while shrinking the covering.

Anyway, to answer your other question, if the wing isn't absolutely straight, the aircraft's trim will be speed sensitive. In other words, if you get it trimmed at mid-throttle, it will roll one way when more throttle is applied and the other way when less throttle is applied.

I doubt a plane that isn't absolutely straight would really stand much of a chance against top competitors unless the person flying it was even better because you not only have to perform the maneuvers better than everyone else, but you have to do it with a plane that doesn't fly straight.

While I'm on my soap box, I'd also like to add that it's worth taking all the time necessary to build straight in the first place. To me that means putting everything together without glue and getting it aligned as if it's the real deal.

That step alone, called dry-fitting, will accomplish a couple things. First it will expose any problems that may exist. Second, it gives you practice putting it together and allows you to try different things until you find the best order to assemble things.

Lastly it gives you the opportunity to ensure whatever jigging method you are using actually works.

If it takes a full day to dry fit a fuselage or even a week, it's worth it because once it's done, you have to fly it that way forever. Even if it adds a month to the build, what is that in comparison to having a plane for 5 years that never performs to its potential?