Designing and Evaluating an Aerospike Rocket Engine for Increased Thrust

Abstract

This project sets out to create a cost-effective rocket engine that will produce more thrust for its weight and size than comparable engines. In this experiment an aerospike is designed and constructed along with the standard cone-shaped nozzle. The exhaust in this aerospike exits from a ring surrounding a conical spike. In a classic nozzle, the gas expands and pushes against the walls on either side. However, in the aerospike design, the gases push against the spike and use the atmospheric pressure as an artificial wall. In theory, this should make the engine efficient across a range of pressures seen at increasing altitude. This experiment compares the thrust generated by an aerospike against the classic nozzle, modifying parameters of the design to generate the most force. Thrust is measured using a strain gage and graphed over time. The prototype version made from pipe and cement, was then machined out of metal. This research is applicable to all rocketry as well as jet airliners. I have seen that the aerospike engine produces an impulse of 12.0 lb· sec and a max thrust of 3.6 lbs compared to the cone engine with an impulse of 7.2 lb· sec and a max thrust 2.4 lbs. From this we see that the aerospike is significantly more efficient than the cone nozzle.

Summary:

  • Built bell nozzle rocket engine out of PVC pipe and cement
  • Designed and built aerospike rocket engine out of PVC pipe and cement
  • Using a strain gauge I compared the engines, measuring ISP, impulse, and max thrust
  • Aerospike significantly outperformed the bell nozzle engine
  • Machined aerospike out of Aluminum