NACA Research Memorandums

The aerodynamic characteristics of two flat-bottomed bodies having a semicircular and a semielliptical cross section have been determined at a Mach number of 3.12 for a range of angles of attack from -10 degrees to 10 degrees and for Reynolds numbers of 8 x 10 (superscript)6 and 14 x 10 (superscript)6 (based on model length). A comparison of the flat-bottomed body characteristics with those previously determined for an equivalent cone-cylinder body of revolution shows that significant increases in lift and lift-drag ratio are obtained with a flat bottom. Additional improvement in lift and lift-drag ratio was achieved at positive angles of attack by expanding the plan form in the spanwise direction