Test Campaign of a 10000 N Hybrid Rocket Engine

Abstract

A 10000 N hybrid rocket engine called HyRES (Hybrid Rocket Engine Stuttgart) is developed, built and tested by the student team Hybrid Engine development (HyEnD) at the University of Stuttgart within the DLR STERN program. It serves as the main propulsion system for the HEROS sounding rocket, which shall be launched from Esrange in Sweden. The rocket shall reach an altitude of at least 20 km, and this determines the engine thrust and burn time. HyRES is aimed to have a total impulse of over 100 kNs with a nominal burn time of 10-15 sec. The targeted combustion efficiency is more than 90 % in order to provide high performance for maximum flight altitude. HyRES is using a liquefying paraffin-based solid fuel and Nitrous oxide (N2O) as oxidizer. The usage of liquefying fuels enables a simple single port fuel designs and a higher fuel utilization compared to low regression rate fuels like Hydroxyl-terminated Polybutadien (HTPB). The application of a self-pressurizing oxidizer permits a simple propulsion system with good performance, without external pressurization. The development and the test campaign of HyRES is described in detail. The main goals of the test campaigns are to achieve a high combustion efficiency of the hybrid rocket engine and provide stable operation with low combustion chamber pressure fluctuations.