Design of an Engine Quickstart System for Rotorcraft Application

Authors

M. Kerler - Institute for Flight Propulsion, Technische Universität München
C. Schäffer - Institute for Flight Propulsion, Technische Universität München
W. Erhard - Institute for Flight Propulsion, Technische Universität München

Abstract

Current helicopters of the light and medium class have two engines installed due to safety reasons. However, this installed power is rarely needed during a flight mission and the engines are operating mainly in part load leading to poor specific fuel consumption. An intended shutdown of one engine during flight increases the load of the remaining engine and the overall fuel consumption gets better. In case of a failure of the remaining running engine, the shut-off engine has to be quick-start capable due to flight safety reasons. Therefore, a quick-start system for the Allison 250-C20B engine was developed at the Institute for Flight Propulsion. This system drives during engine start-up the radial compressor of the engine using pressurized air. Since shop air is actually used for the quick-start system, a new system is designed for independent air supply and for integration into a helicopter airframe. It comprises of pipes, hoses, valves and pressure tanks. This new pressurized air supply is simulated in ESPSS. For identification of the usability of ESPSS a validation is done. For this validation the shop air supply system is modeled in ESPSS and a quick-start is simulated. Simulation results of this model are compared to experimental data of the test bed.