Static Performance of a Cruciform Nozzle With Multiaxis Thrust-Vectoring and Reverse-Thrust Capabilities

A multiaxis thrust-vectoring nozzle designed to have equal flow-turning capability in pitch and yaw was conceived and experimentally tested for internal, static performance. The cruciform-shaped convergent-divergent nozzle turned the flow for thrust vectoring by deflecting the divergent surfaces of the nozzle, called flaps. Methods for eliminating physical interference between pitch and yaw flaps at the larger multiaxis deflection angles were studied. These methods included restricting the pitch flaps from the path of the yaw flaps and shifting the flow path at the throat off the nozzle centerline to permit larger pitch-flap deflections without interfering with the operation of the yaw flaps. Two flap widths were tested at both dry and afterburning power settings. Vertical- and reverse-thrust configurations at dry power were also tested. Comparison with two-dimensional convergent-divergent nozzles showed lower but still competitive thrust performance and thrust-vectoring capability.