The 21st Century Film is allot like the Ultracoat film as well. I dont know if it was a wierd isolated incident or what, but a week a go two brand new planes that were covered but two different club members had Ultracoat come off during flight in the same day. The first plane I think that it would have pulled off no matter what covering you used, the builder only covered to about a 1/8 inch past the mid point of the leading edge. We heard some flutter and he slowed the plane and started to bank for the approach and a whole section of the covering came off the wing. I tell you what, with out a top and bottem of the airfoil planes dont fly real well. Got wet getting that one out with the piolit. The second was covered well past the center of the leading edge of the tail section and it also started to come up in flight. The tail of this plane was sheeted so it wasn't as critical. Heard the flutter and landed with out incident. Thats two in one day. Ive used Utracoat without incident, but I always go at least a half inch past the center of the leading edges. I know that most people have stated that they really like Ultracoat, but this make me a little leary. I think it would be fine as long as you dont leave any joints exposed to the wind.