Rocketman612:

For what it's worth there was an article in RC Scale International about this a couple years ago on this subject written by a Top Gun competitor (I will not use his name without his permission). He said the grain of the 1/64th plywood should run the same as the chord of the wing. It is much stronger this way. If it is run parallel to the wing there is a greater chance of breaking it off even if it is glassed. I have built all of my warbirds this way and have never had a problem with the trailing edges.