That is interesting info. I am scratch building a 60 big stick from plans and I have decided to build it with flaps to. Seeing that it is a scratch build it will be easy to change the design as I go. It will be about a 65 inch span and I plan to make the flaps about 10 inches by 2 inches and the ailerons the rest of the span [strip type as the original ,about 17.5 inches by two.What do you think of this plan,darock? These are thick wide wings and I bet it would still fly at 5 mph[with the flaps down]. What do you think ?