Multiaxis aircraft control power from thrust vectoring at high angles of attack
4th Applied Aerodynamics Conference
The multiaxis control power characteristics from thrust vectoring for three different fighter configurations have been determined from investigations in the langley 16-Foot Transonic Tunnel and the lewis IOxIO-Foot Supersonic Tunnel. All three configurations employed two-dimensional convergent-divergent nozzles which provided pitch vectoring by differential deflection of the upper and lower nozzle divergent flaps. Three different means of yaw vectoring were tested: (1) a translating nozzle
... all; (2) yaw flaps located in the nozzle sidewalls; and (3) canted nozzles. These investigations were conducted over a Mach number range of 0.15 to 2.47 at angles of attack up to 35 0 • Nozzle pressure ratio was varied up to 28 depending upon Mach number. The effects of pitch vectoring on the longitudinal aerodynamic characteristics followed expected trends. Pitching moment coefficient was found to vary nearly linearly with nozzle deflection angle. Similar effects on the lateral aerodynamic characteristics resulted from yaw vectoring. Both the jet-off and powered increment in either the force or moment coefficient that result from pitch or yaw vectoring remain essentially constant over the entire angle-of-attack range for all Mach numbers tested. There was no effect of pitch vectoring on the lateral aerodynamic forces and moments or of yaw vectoring on the longitudinal aerodynamic forces and moments indicating no cross-coupling of control forces and moments for combined pitch/yaw vectoring. longitudinal and directional control power was a function of nozzle pressure ratio and Mach number. Powered controls were very effective at low Mach numbers and their effectiveness decreased as Mach number increased due to a reduction in thrust margin. longitudinal and directional control power from thrust vectoring was greater than that provided by aerodynamic control effects at low speeds or high angle of attack.