Integrated auxiliary power system

A method of starting a vehicle and cooling heated components thereof, said method comprising:

• providing at least one gas turbine engine in said vehicle, said engine having in serial flow arrangement a compressor section having at least one engine compressor for compressing ambient air to produce compressed air, a combustion section, and an engine turbine section having at least one turbine for driving the compressor section via an engine shaft;
• providing an auxiliary unit having a starter compressor and a starter turbine, said starter turbine connected to said starter compressor by a starter shaft to drive said starter compressor;
• linking rotationally the starter shaft and engine shaft via a mechanical linkage;
• accelerating the rotational velocity of the engine shaft by driving the engine shaft with the starter shaft until the engine shaft reaches a predetermined velocity:
• pumping fuel to said combustion section, and combusting said fuel and compressed air therein, thereby producing engine combustion products;
• driving said engine turbine by expanding the engine combustion products therethrough, thereby driving the connected compressor;
• disconnecting the mechanical linkage between the engine shaft and the starter shaft;
• driving the starter compressor by expanding a portion of the compressed air through the starter turbine until the portion cools to a temperature cooler than said components;
• and
• flowing the expanded portion into contact with the components.