Patent ID: 8887488
Filing Date: 2014-11-18
Classification: F01D

Abstract:
1. A power plant for a UAV comprising: a first gas turbine engine having a first compressor and a first combustor and a first turbine where the first turbine is connected to the first compressor by a first common rotor shaft; a second gas turbine engine having a second compressor and a second turbine connected to the second compressor by a second common rotor shaft; the second gas turbine engine having a second combustor that is not directed to discharge a hot gas stream into the second turbine; a first flow valve connected to the first turbine and directed to selectively channel a first turbine hot exhaust into an inlet of the second turbine or into a second flow valve in flow series with the first valve; the second compressor is connected to the second combustor such that compressed air from the second compressor flows into the second combustor; the second combustor is connected to the second flow valve such that a hot gas stream produced in the second combustor flows into the second flow valve; a hot gas conduit connected between the first flow valve and the second flow valve; a power turbine connected to the second flow valve such that a hot gas flow from the second flow valve will flow into the power turbine; an output shaft driven by the power turbine to propel the UAV; in a power mode, both the first gas turbine engine and the second gas turbine engine are operated in which the first turbine hot exhaust flows from the first flow valve and into the second turbine, and a second hot gas from the second combustor flows into the second flow valve and into the power turbine; and, in a loiter mode, the second gas turbine engine is not operated while the first gas turbine engine produces the first hot gas flow that flows through the first flow valve and the second flow valve and into the power turbine.