An experimental investigation of control surface effectiveness and real-gas simulation for biconics

Aerodynamic coefficients, pressure distributions, and oil-flow patterns measured on spherically blunted, 13 degrees/7 degrees on-axis and bent biconics at Mach 6 and 10 in air are compared. Angle of attack, referenced to the axis of the aft cone, was varied from zero to 40 degrees. The effect of deflection of base-mounted flaps on aerodynamic characteristics was examined at Mach 10. Real-gas effects on aerodynamic coefficients, pressure distributions and shock detachment distance were simulated by testing the biconic models in Mach 6 air and Mach 6 CF4 flows. (Density ratio equal to 5.3 for air and 12 for CF4.) The on-axis biconic is stable but cannot be trimmed at angles of attack above zero with the assumed center of gravity and flap configuration. Flaps on the bent biconic produced a stable and trim configuration for angles of attack from zero to 23 degrees. A significant effect of density ratio on aerodynamic coefficients, pressure distribution, and shock detachment distance was observed.