PERFORMANCE EVALUATION OF AN AEROJET-GENERAL CORPORATION EXPANDABLE NOZZLE EXTENSION AND A NON-RIGID CONICAL NOZZLE EXTENSION AT SIMULATED ALTITUDES

Presented is the design of the expandable nozzle extension and the non-rigid conical nozzle exten sion. These unusual nozzle extensions were evaluated at simulated pressure altitudes up to 108,000 ft. The stainless steel expandable nozzle extensions, which attached to a 71 area ratio fixed nozzle, were cylindrical prior to testing. The extensions expanded to a conical configuration and maintained this configuration during the rocket engine firing. Area ratios from 321 to 371 were achieved during the rocket engine steady-state operation, and the thrust coefficients obtained were 96 percent of the theoretical values. The conical non-rigid rubber nozzle extensions evaluated at pressure altitude conditions were flexible, having both constant and tapered wall thicknesses and nominal area ratios of 401. The non-rigid nozzle exten sion with the thickest constant wall 716 in. was stable during the rocket engine firing how ever, other non-rigid nozzle extensions were un stable and oscillated. Author