An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a forward flight orientation. The aircraft has a blended wing body and includes an engine, a trinary lift fan system, a forced air bypass system and an exhaust system. The engine has a turboshaft mode and a turbofan mode. The lift fan system includes a plurality of ducted fans in a tandem lateral and forward orientation. In the VTOL orientation of the aircraft, the engine is in the turboshaft mode coupled to the lift fan system such that the engine provides rotational energy to the ducted fans generating the thrust-borne lift. In the forward flight orientation of the aircraft, the engine is in the turbofan mode coupled to the forced air bypass system such that bypass air combines with engine exhaust in the exhaust system to provide forward thrust generating the wing-borne lift.

An active flow control system for generating roll control moments for an aircraft during forward flight. The system includes right and left roll effectors disposed on a trailing edge of the wing. A pressurized air system includes a pressurized air source and a plurality of injectors operably associated with the right and left roll effectors that influence the path of airflow across the wing. Based upon which of the injectors is injecting pressurized air, the right and left roll effectors generate no roll control moment, generate a roll right control moment or generate a roll left control moment.

A ducted fan assembly for generating thrust during edgewise forward flight. The ducted fan assembly includes a duct having an inlet with a leading portion and a diffuser with a trailing portion during the edgewise forward flight. A fan disposed within the duct is configured to rotate relative to the duct about a fan axis to generate an airflow through the duct from the inlet to the diffuser. An active flow control system includes a plurality of injectors including a first injector configured to inject pressurized air substantially tangential with the leading portion of the inlet and a second injector configured to inject pressurized air substantially tangential with the trailing portion of the diffuser such that when the injectors are injecting pressurized air, flow separation of the airflow at the leading portion of the inlet and the trailing portion of the diffuser is reduced.

A ducted fan assembly includes a duct having an inlet, an inner surface, an expanding diffuser and an outlet. A fan disposed within the duct between the inlet and the expanding diffuser is configured to rotate about a fan axis to generate airflow. An active flow control system includes a plurality of injection zones circumferentially distributed about the inner surface. The expanding diffuser has a diffuser angle configured to create flow separation when the airflow is uninfluenced by the active flow control system such that the airflow has a thrust vector with a first direction that is substantially parallel to the fan axis. Injection of pressurized air from one of the injection zones asymmetrically reduces the flow separation between the airflow and the expanding diffuser downstream of that injection zone such that the thrust vector of the airflow has a second direction that is not parallel to the first direction.

A hybrid power system for a vertical takeoff and landing (“VTOL”) aircraft including a first power source operable to provide a power output for at least a forward flight mode; and a second power source configured to provide a high specific power output for an altitude adjustment flight mode, the second power source including an auxiliary gas generator coupled to a turbine and a drive system. In other aspects, there is provided a VTOL aircraft and methods for providing power to a VTOL aircraft.

An aircraft comprising a wing; a tractor propulsion means (TPM); a pusher propulsion means (PPM); a cruising propulsion means (CPM); and wherein the TPM is capable of providing a thrust, the direction of thrust reversibly movable from a forward propelling direction, to an upward propelling direction; and wherein the PPM is capable of providing a thrust, the direction of thrust reversibly movable from a forward propelling direction, to an upward propelling direction; and wherein the CPM is capable of providing a thrust, the direction of thrust being in a forward propelling direction; and wherein the TPM and PPM are connected to the wing, and wherein the TPM is located in fore of the wing and the PPM is located in aft of the wing.

A system and method enabled to increase efficiency during a VTOL aircraft's transition. A VTOL aircraft enabled to operate multiple lift fans arranged into separately controllable groups, wherein the VTOL aircraft initially has vertical flight but transitions to horizontal flight. A first group of lift fans may be kept at full throttle, a second group of lift fans may be throttled to balance thrust and/or weight, and a third group of lift fans may be shut off.

A thrust assembly motor is described, which can be used in a distributed electric propulsion system. The thrust assembly motor may include a revolved-wedge shaped ring on a leading edge of a motor stator, with a row of axial stator blades extending therefrom. The revolved-wedge shaped ring provides a mounting surface for the axial stator blade row while also controlling the ratio of airflow mass entering the outer gap versus the inner gap. The axial stator blade row, mounted to the revolved-wedge shaped ring, is configured to convert tangential kinetic energy (i.e., associated with a velocity component of the airflow) in the cooling airflow aft of the cooling fan rotors into static pressure rise after interaction with the axial stator blade row, during flight of the hybrid-propulsion aircraft.

A system and method enabled to increase efficiency during a VTOL aircraft's transition. A VTOL aircraft enabled to operate multiple lift fans arranged into separately controllable groups, wherein the VTOL aircraft initially has vertical flight but transitions to horizontal flight. A first group of lift fans may be kept at full throttle, a second group of lift fans may be throttled to balance thrust and/or weight, and a third group of lift fans may be shut off.

A convertible rotor aircraft (CRA) able to convert between airplane and helicopter flight modes during flight, comprising: at least one tillable proprotor assembly (TPA) comprising a proprotor that is tiltable to change the axis of rotation of the proprotor between a substantially horizontal airplane mode and a substantially vertical helicopter mode; and a main rotor system for providing lift during helicopter mode comprising at least one rotor, which produces airflow that flows through at least a portion the proprotor blades of the at least one TPA.