Patent ID: 8382030
Filing Date: 2013-02-26
Classification: B64C

Abstract:
1. A powerplant for a VTOL aircraft with a lift fan; said powerplant including a lift-fan engine and a cruise engine; most of said cruise engine being part of said lift-fan engine; but during cruise flight, said cruise engine operating while said lift-fan engine does not; said cruise engine including a gas turbine engine, a driveshaft, a front fan, and a main flow valve; said main flow valve located downstream of said front fan; said front fan being much smaller than said lift fan; at all times during any normal flight: for said cruise flight: said lift-fan engine including a boost compressor connected to said driveshaft and downstream of said main flow valve, a compressed air duct, a combustion chamber, a lift-fan turbine, and said cruise engine with one item different; said one item being said flow valve expanded to a second position; for VTOL flight: said main flow valve being substantially a ring of flaps between said front fan's duct and a casing for said boost compressor; a hinge at the rear of each said flap; said hinges fixed at or near the front of said casing; the noses of said flaps pointing generally toward said front fan; for said VTOL flight: for said cruise flight: said gas turbine engine having several stages of turbine; a later said stage having bypass means for responding to said reduction in the load; said turbine having a housing; said bypass means being a movable portion of said housing; said movable portion located ahead of said later stage; for said cruise flight: for said VTOL flight: supercharging means for said gas turbine engine to additionally handle said load increase; said supercharging means including ducting connecting said boost compressor's said delivery air to the intake of said gas turbine engine; valving in said ducting; for said VTOL flight: for said cruise flight: said lower density reducing the power produced by said gas turbine engine, in keeping with the lighter load on said driveshaft caused by said disabling of said boost compressor.