• SD8020-PT (Fig. 12.157)

The 10% thick SD8020 is a symmetric airfoil specifically designed for use on tail surfaces at low Rn, s. As shown in Fig. 12.157, the lift and drag characteris­tics compare favorably with the other symmetric sections tested, i. e. the J5012, NACA 0009 and NACA 64A010. The lift range between Rn’s of 100k and 300k is comparable to the J5012. At 60k, however, separation at the higher angles of attack limits Cimax, making it more like the NACA 64A010, But it is the lift characteristics shown in Fig. 12.158 that are most interesting.

There is no significant deadband, even at a Rn of 40k. (The offset in lift for Rn of 40k was probably caused by operator error when the tare-weight entry was made.) The nearly linear Cj vs a characteristics and acceptably low drag should lead to smooth handling qualities.

Also see: J5012, NACA 0009, NACA 64A010 Digitizer plot: Fig. 10.60 Polar plot: Fig. 12.157 Lift plot: Fig. 12.158

Thickness: 10.10% Camber: 0.00%