PURPOSE: To recuce the size and weight of a power unit by driving an air compressor using exhaust gas from a jet engine and by supplying compressed air generated in the air compressor to the air motor on a driving shaft.

CONSTITUTION: When a jet engine 1 is put into operation and the exhaust gas from the engine 1 is ejected from a conduit 2 into an air compressor 3, a vane 7 on a shaft 6 is rotated, and rotation of the shaft 6 rotates a vane 8, thereby generating compressed air. Next, this compressed air is supplied to air motors 15 and 16 installed to the right and left car shaft 12 via a hose pipe 5 and pipes 10 and 11, rotating a vane 17 and by turns the car shafts 12 and wheels 13. Thus, the car runs.