HYDRA III Hybrid Rocket Engine - Flight Version Test Results

Abstract

The flight version of the HYDRA III hybrid rocket engine was built by the ExperimentalRaumfahrt-InteressenGemeinschaft e.V. (ERIG) in cooperation with the Institute of Aerospace Systems of TU Braunschweig. The HYDRA III engine was improved to a thrust of about 1300 N for the supersonic rocket named FAUST of the Studentische Experimental-Raketen program (STERN), which is initiated by the German Aerospace center (DLR). The launch of the FAUST rocket is planned to be at the end of this year at the Esrange Space Center in Kiruna (North Sweden). The aim of the STERN program is to motivate and educate students for aerospace sciences by developing a rocket. The ERIG advanced therefore the hybrid rocket engine HYDRA III, which bases on a liquid oxidizer and a solid fuel grain as propellants. Therefore, liquid nitrous oxide is used as oxidizer and hydroxyl-terminated polybutadiene (HTPB) with metal powder as solid fuel grain. For the flight version of this engine a carbon fiber reinforced plastic (CFRP) oxidizer vessel and the CFRP flight pressure vessel with helium were used. Also a new lightweight flight version valve segment was used to control the high amount of oxidizer mass flow into the combustion chamber. The latest test results of this flight engine from the horizontal test bench as well as the set-up of the vertical test bench are presented.