scope:

Abstract:

The Dryden Aerospike Rocket Test Director's Discretionary Fund (DDF) project conducted flight research of an aerospike rocket nozzle design using high power amateur rockets. The standard nozzles in these rockets were replaced by the aerospike nozzles and the rockets are then flown with aerospike nozzles only. Two aerospike rockets were flown successfully to altitudes of over 26,000 ft and speeds of over Mach 1.5. The flight data acquired during the flight tests were stored onboard and retrieved after the rockets were recovered. The rocket chamber pressure was one of the missioncritical onboard measurements. During the first rocket launch, hot rocket exhaust gas was allowed to impinge directly inside the rocket chamber pressure transducer sensing port. Even though the pressure transducer was designed to survive hostile environments and remained operational, the high gas temperature caused it to produce pressure readings that were erroneously high for the firt two seconds of rocket motor firing. During the second launch, silicon vacuum grease was used to pack the pressure port. This shielded the pressure sensing port from the hot gas impingement, and good rocket chamber pressure measurements were obtained.