Hello Phil and evikfkr....

The really good airfoil is the SG6042. The 6043 has about the same profile but is thicker. When we did the wind tunnel tests, the 6043 didn't provide as much lift as the 6042. I think it has something to do with the greater profile drag of the 6043. HOWEVER, I would bet that for a very light, small autogyro with a slow rotating rotor, a thicker airfoil would work better. It's all a question of the L/D at the operating air velocity of the aircraft.

Bill