Have a set of plans which looked to have a familiar airfoil drawn to the ribs. After subtracting the 3/32 skin, the ribs look to be an N.A.C.A. 2319. Most places the lines on the plan match within less than 0.010", which I figure to be good enough, EXCEPT for one area.

Using some of the 8" to 15" long ribs for example, everything forward of about the 60% lines matches real close, top and bottom. In between the 60% and the 80% lines it gets more rounded and thicker and varies on the upper surface to about 0.030" maximum. Then from 80% to 100% it goes back about to normal again.

Considering this to be a model, anyone think this variance will affect the flying qualities of a scale model?


Wm.