Abstract: Gas flow through a turbine is divided, with part of the flow directed to the compressor for the combustion chamber and part directed to the primary power turbine. Division of the gas flow is accomplished by a mixing wheel of novel design. Before passing to the primary power turbine the gas flow passes through a secondary power turbine that drives the compressor for the combustion chamber. Both the secondary power turbine and the compressor rotate independently of the main turbine rotor shaft. The power input to the secondary power turbine is varied in accordance with the pressure differential between the gas pressure at the outlet of the compressor for the combustion chamber and the outlet from the mixing wheel. If the speed of the main turbine shaft slows down more power is put into the secondary power turbine and the combustion chamber compressor is speeded up so as to produce a higher gas pressure than would otherwise be the case.