Abstract: A dual mode turbofan engine includes a jet engine portion having a compressor, a turbine disposed aft of the compressor, and a shaft coupled to the compressor and the turbine. The jet engine portion is configured to produce an exhaust. The system further includes an auxiliary turbine having a plurality of auxiliary turbine blades. The auxiliary turbine is disposed aft of the turbine and decoupled from the shaft. The system also includes a diverter disposed between the turbine and the auxiliary turbine. The diverter is configured to selectively direct the exhaust to an inner flow path bypassing the plurality of auxiliary turbine blades or to an outer flow path engaging the plurality of turbine blades. A plurality of propeller blades is hingedly connected to the auxiliary turbine.

Abstract: A variable bypass turbofan engine includes a bypass fan having a plurality of bypass fan blades mated to a first low pressure shaft segment. A second low pressure shaft segment includes a low pressure compressor and a low pressure turbine mated thereto. The engine also includes a clutch coupled between the first low pressure shaft segment and the second low pressure shaft segment and is configured to selectively couple and decouple the first low pressure shaft segment from the second low pressure shaft segment. A brake is configured to selectively halt or oppose rotation of the first low pressure shaft segment or the bypass fan.

Abstract: A system to improve jet engine powered aircraft performance and efficiency includes a jet engine having a pressurized air port configured to convey a pressurized airflow from a compressor or a bypass fan disposed in the jet engine. A primary airfoil has a trailing edge, a top surface, and a boundary region. The system further includes a secondary airfoil disposed at a distance from the top surface of the primary airfoil. The secondary airfoil has a bottom surface and a trailing edge. An exhaust region is formed by the trailing edge of the primary airfoil and the trailing edge of the secondary airfoil. A primary airfoil ejector port and a secondary airfoil ejector port are pneumatically coupled to the pressurized air port. The primary airfoil ejector port is disposed proximate the boundary region and the secondary airfoil ejector port is disposed on the bottom surface.