We Claim,
1. Gas Turbine Starter (GTS) is an application specific engine developed to supply compressed air bleed to start main engine of 20-25kN thrust class of trainer aircraft.
The engine consists of a single stage centrifugal compressor with a radially bladed impeller and a vane-less diffuser followed by radial and axial vane diffuser sections, such that the air is compressed to desired pressures. The air bleed drawn out from the diffuser is uniquely designed to adjust the output flow during main engine start. Any variation in air mass flow causing exhaust gas temperature variation is counteracted by the fuel metering unit by regulating the fuel flow to the combustor and thereby regulating the speed which in turn ensures required air mass flow into the engine.
The fuel metering unit is of modular arrangement housed inside a single casing for easy maintenance. The engine has a dedicated gearbox with drives for fuel pump, oil pump and starter motor. The gearbox is a machined unit as against the cast units of contemporary engines, fetching savings in development time and cost.
2. The Gas Turbine Starter as claimed in Claim 1, is capable of supplying high pressure compressed air mass flow of around 0.4 kg/sat 165 ± 10°C at ISA-SLS condition to an ATS (Air Turbine Starter) which in turn starts the main engine of aircraft, characterized in that the engine is coupled to ATS mounted on main engine gear box.
3. The Gas Turbine Starter as claimed in Claim 1 employs a carbon seal with a special design to balance the cavity pressure. This design has resulted in reduction of oil consumption by around 50% compared to the other contemporary engines.