of the combustor 58 it will also be observed at the plenum in addition including the radially outer housing wall 30 includes a generally radially extending wall 62 along with a radially inwardly located annular wall 64 so as to substantially entirely surround the combustor 58 in space relation thereto consequently the combustor may be cooled by gas flowing in the plenum about the same an igniter 66 may extend through the wall 62 and into the interior of the combustor 58 to ignite an air fuel mixture therein to provide an air fuel mixture for combustion within the combustor 58 advantages taken of a discovery and material such as vaporized fuel will take a discrete path through the compressor 18 the diffuser 28 and the plenum in spite of varying speeds of the rotor 10 that is to say the ratio of the axial velocity of gases entering the machine to the rotor tip speed as represented by for example the speed of the ends 22 of the compressor 18 is substantially constant for all operational speeds above approximately 20 of rated speed thus the invention contemplates the provision of possibly as few as a single fuel jet or nozzle 70 which may be configured similarly to the high speed jet in an automotive carburetor the jet or nozzle 70 is located at about the periphery of the rotary compressor 18 as can be seen in fig1 and slightly upstream of the inlet ends of 24 of the blades 20 thereof as a consequence fuel provided to the jet 70 by the pump 40 will enter the inlet to the compressor 18 at an area of less than atmospheric pressure that is the so called compressor.