Solid Rocket Booster (SRB)-Based Starter System

In this Phase I program, Ultramet proposes to demonstrate the feasibility of using a modified solid rocket booster (SRB) to provide the hot gas cranking and ignition source for starting a small turbojet sustainer engine, in addition to boost propulsion. This SRB-based starting system would replace the pyrotechnic starter cartridge currently used as a gas generator and ignition source for the sustainer engine, thereby reducing both the cost and weight of the total system without sacrificing performance. The primary difficulties involved are fivefold: reducing the 5000 R, 1500-psia SRB flame to conditions that will not damage the turbine rotor; maintaining sufficient gas velocity, pressure, and mass flow to the impingement nozzles to successfully start the engine, taking into consideration pressure losses due to gas cooling and frictional effects; demonstrating materials of construction capable of surviving th erosive, high temperature propellant gas; modifying the SRB to account for pressure and heat losses due to gas diversion; and possibly filtering carbon, alumina, and other condensible matter from the hot gas stream before its introduction into the turbine section. This program will demonstrate a workable design capable of surmounting these obstacles through theoretical calculations and hardware demonstration of a SRB-based starter system.