A propulsion unit with a propeller includes a nacelle; a propeller rotatably mounted in the nacelle by means of a hub. The propeller has blades mounted in a blade cuff that is pivotable about a pitch axis relative to the hub. Each blade is pivotable relative to the cuff about a folding axis. A folding device includes an actuator for folding the blades. The folding device includes a control member rotationally affixed to the blade cuff and driven by the actuator. A connecting rod is pivotably mounted, on the one hand, on a root of the associated blade and, on the other hand, on the movable control member.

A flight vehicle includes a front rotor on a front part of an airframe, a rear rotor on a rear part of the airframe, a front deflection mechanism that changes an angle of the front rotor with respect to the airframe within a first range, a rear deflection mechanism that changes an angle of the rear rotor with respect to the airframe within a second range, and a main module, which is in the airframe, for containing objects to be transported. The first range is set to a range in which a plane containing the rotation surface of the front rotor does not pass across the main module. The second range is set to a range in which a plane containing the rotation surface of the rear rotor does not pass across the main module.

A flight vehicle includes a front rotor on a front part of an airframe, a rear rotor on a rear part of the airframe, a front deflection mechanism that changes an angle of the front rotor with respect to the airframe within a first range, a rear deflection mechanism that changes an angle of the rear rotor with respect to the airframe within a second range, and a main module, which is in the airframe, for containing objects to be transported. The first range is set to a range in which a plane containing the rotation surface of the front rotor does not pass across the main module. The second range is set to a range in which a plane containing the rotation surface of the rear rotor does not pass across the main module.

Embodiments include an aircraft comprising a fuselage; a wing connected to the fuselage; and first and second propulsion systems connected to the wing on opposite sides of the fuselage, wherein at least a portion of each of the first and second propulsion systems and at least a portion of the wing are tiltable between a first position in which the aircraft is in a hover mode and a second position in which the aircraft is in a cruise mode, wherein each of the propulsion systems includes pylon and a rotor assembly comprising a plurality of rotor blades.

An electric motor nacelle for a vertical take-off and landing (VTOL) aircraft includes a fairing wherein an electric motor is housed equipped with at least one propeller extending outwards from a top face of the fairing, and a cooling device designed to cool the electric motor when the aircraft is in take-off, cruise and landing phases and including a reversible coolant fluid supply and exhaust manifold, designed, alternately: in the cruise phase, to receive a stream of cold fluid generated by the movement of the aircraft and to convey this stream of fluid, through the motor, towards an outlet situated opposite the propeller, and in take-off or landing phase, to receive a stream of hot fluid transmitted by the propeller and having passed through the motor.

A tiltrotor aircraft having a propulsion configuration that divorces the engine core power from the thrust fan, using a combined gearbox with a plurality of clutches to couple and decouple one or more rotor systems and one or more thrust fans. The aircraft can be operable for vertical takeoff and landing (VTOL) in a helicopter mode, forward flight in a proprotor mode, and high-speed forward flight in an airplane (jet) mode. The propulsion configuration provides shaft horsepower (SHP) to rotors for VTOL flight, while also providing SHP to the thrust fan for high speed flight. Allowing the rotor and the thrust fan to be clutched on and off, sequentially, enables transition from rotor-borne VTOL flight to wing-borne thrust fan flight, and back.

A drivetrain for an aircraft includes an engine, a driveshaft to receive rotational energy from the engine and a gearbox including a multistage planetary gear system to receive rotational energy from the driveshaft. The multistage planetary gear system includes an integral multistage ring gear system having flanged and cantilevered ends. The integral multistage ring gear system forms a first stage ring gear at the cantilevered end and a second stage ring gear interposed between the flanged end and the first stage ring gear. The multistage planetary gear system includes a first stage sun gear, first stage planet gears and a first stage carrier. The first stage planet gears mate with the first stage ring gear. The multistage planetary gear system includes a second stage sun gear, second stage planet gears and a second stage carrier. The second stage planet gears mate with the second stage ring gear.

A drivetrain for an aircraft includes an engine, a driveshaft to receive rotational energy from the engine and a gearbox including a multistage planetary gear system to receive rotational energy from the driveshaft. The multistage planetary gear system includes an integral multistage ring gear system having flanged and cantilevered ends. The integral multistage ring gear system forms a first stage ring gear at the cantilevered end and a second stage ring gear interposed between the flanged end and the first stage ring gear. The multistage planetary gear system includes a first stage sun gear, first stage planet gears and a first stage carrier. The first stage planet gears mate with the first stage ring gear. The multistage planetary gear system includes a second stage sun gear, second stage planet gears and a second stage carrier. The second stage planet gears mate with the second stage ring gear.

Techniques to control flight of an aircraft are disclosed. In various embodiments, a set of inputs associated with a requested set of forces and moments to be applied to the aircraft is received. An optimal mix of actuators and associated actuator parameters to achieve to an extent practical the requested forces and moments is determined.

Techniques to control flight of an aircraft are disclosed. In various embodiments, a set of inputs associated with a requested set of forces and moments to be applied to the aircraft is received. An optimal mix of actuators and associated actuator parameters to achieve to an extent practical the requested forces and moments is determined.