Wings with flat bottom airfoils are certainly easier to build with a high degree of accuracy. However many assume that a flat bottom airfoil wing is incapable of anything beyond beginning aerobatic maneuvers, and this is simply NOT true. The design of the airframe, incidence angles and tail design have WAY more to do with aerobatic capability. Many trainers are designed for a high degree of positive stability, indeed many trainers from the early days of RC were set up more like free flight aircraft than RC trainers. It’s no surprise their aerobatic capabilities are limited.

Remember that when the wing sits flat on the fuselage with the BOTTOM surface flat with tail, the wing actually has about 2 degrees of POSITIVE incidence which will cause a pitching up with speed or power increases, and will certainly affect inverted flight. Remember that the angle of incidence for the wing is measured from the CENTER of the leading edge to the center of the trailing edge and has nothing at all to do with the bottom surface of the wing.

An airplane with a REAL Clark Y airfoil, set at a TRUE 0-0 incidence with the tail, and a few degrees of down thrust, will likely surprise you with it’s aerobatic capabilities, inverted flight, and reaction to power and speed changes.