hi
i am building a uproar and the trailing edge is warped how can i get the warp out, thanks rye

You can buy new pieces at LHS, or you can try to straight it out by wetting the balsa piece with windex and clamp it on the building board. Repeat process as necessary.

Depending on how bad the warp is then it's very easy to straighten it out with your covering and a heat gun. I do it a lot on ARFs for people. They often have warps in the surfaces.