AIRCRAFT POWER PLANT WITH SUPERCRITICAL CO2 HEAT ENGINE

Aircraft power plants including combustion engines (18), and associated methods for recuperating waste heat from such aircraft power plants are described. A method includes transferring the heat rejected by the internal combustion engine (18) to supercritical CO (sCO) used as a working fluid in a heat engine (20, 120, 220). The heat engine (20, 120, 220) converts at least some of the heat transferred to the sCO to mechanical energy to perform useful work onboard the aircraft.