Current foot-launched 2-stroke commercial PPG offerings can meet the specified threshold (and in some cases, objective) requirements for flight ceiling, payload capacity and range with little to no modification. We will discuss those in the next section. The APES system enhances the effectiveness and lethality of the PPG-equipped unit by reducing weight of the PPG, increasing reliability and redundancy, reducing pilot workload, and seamlessly integrating with UAV's and UGV's. System improvements in the following areas is assessed: Series hybrid-electric powertrain, Coaxial propellers. Localization, autopilot, and formations, Auto landing and other advanced features, Integration with unmanned systems, and Launch Considerations.

A first propeller has a shorter blade length and a lower inertia than a second propeller. An electromagnetic field emitter is coupled to one of the first propeller or the second propeller and an electromagnetic field receptor is coupled to the other one that is not coupled to the electromagnetic field emitter. The electromagnetic field emitter emits an electromagnetic field. In response to the electromagnetic field: the electromagnetic field receptor and its coupled propeller rotate in a first rotational direction; and the electromagnetic field emitter and its coupled propeller rotate in a second and counter-rotational direction. In response to a second electromagnetic field associated with increasing torque: the first propeller increases and subsequently decreases its rotational speed; and the second propeller increases its rotational speed at a slower rate than the increase in the rotational speed of the first propeller.

A first propeller has a shorter blade length and a lower inertia than a second propeller. An electromagnetic field emitter is coupled to one of the first propeller or the second propeller and an electromagnetic field receptor is coupled to the other one that is not coupled to the electromagnetic field emitter. The electromagnetic field emitter emits an electromagnetic field. In response to the electromagnetic field: the electromagnetic field receptor and its coupled propeller rotate in a first rotational direction; and the electromagnetic field emitter and its coupled propeller rotate in a second and counter-rotational direction. In response to a second electromagnetic field associated with increasing torque: the first propeller increases and subsequently decreases its rotational speed; and the second propeller increases its rotational speed at a slower rate than the increase in the rotational speed of the first propeller.

A propulsion assembly for an aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The propulsion assembly includes a housing coupled to the fuselage of the aircraft. A coaxial rotor system includes a first rotor assembly and a second rotor assembly that are rotatable about a common axis of rotation. The first rotor assembly counter-rotates relative to the second rotor assembly. A motor assembly is operably associated with the coaxial rotor system. The motor assembly provides torque and rotational energy to the first rotor assembly and the second rotor assembly. A gimbal assembly couples the coaxial rotor system to the housing such that the coaxial rotor system is tiltable relative to the fuselage to generate a thrust vector.

A propulsion assembly for an aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The propulsion assembly includes a housing coupled to the fuselage of the aircraft. A coaxial rotor system includes a first rotor assembly and a second rotor assembly that are rotatable about a common axis of rotation. The first rotor assembly counter-rotates relative to the second rotor assembly. A motor assembly is operably associated with the coaxial rotor system. The motor assembly provides torque and rotational energy to the first rotor assembly and the second rotor assembly. A gimbal assembly couples the coaxial rotor system to the housing such that the coaxial rotor system is tiltable relative to the fuselage to generate a thrust vector.

A vertical landing and take-off aircraft VTOL transitions from a vertical takeoff state to a cruise state where the vertical takeoff state uses propellers to generate lift and the cruise state uses wings to generate lift. The aircraft has an M-wing configuration with propellers located on the wingtip nacelles, wing booms, and tail boom. The wing boom and/or the tail boom can include boom control effectors. Hinged control surfaces on the wings, tail boom, and tail tilt during takeoff and landing to yaw the vehicle. The boom control effectors, cruise propellers, stacked propellers, and control surfaces can have different positions during different modes of operation in order to control aircraft movement and mitigate noise generated by the aircraft.

A vertical landing and take-off aircraft VTOL transitions from a vertical takeoff state to a cruise state where the vertical takeoff state uses propellers to generate lift and the cruise state uses wings to generate lift. The aircraft has an M-wing configuration with propellers located on the wingtip nacelles, wing booms, and tail boom. The wing boom and/or the tail boom can include boom control effectors. Hinged control surfaces on the wings, tail boom, and tail tilt during takeoff and landing to yaw the vehicle. The boom control effectors, cruise propellers, stacked propellers, and control surfaces can have different positions during different modes of operation in order to control aircraft movement and mitigate noise generated by the aircraft.

An axial flow turbomachine (102) for producing thrust to propel an aircraft is shown. The turbomachine has an inner duct (202) and an outer duct (204), both of which are annular and concentric with one another. An inner fan (206) is located in the inner duct, and is configured to produce a primary pressurised flow (P). An outer fan (207) is located in an outer duct, and is configured to produce a secondary pressurised flow (S). The outer fan has a hollow hub (208) through which the inner duct passes. A swept area of the outer fan is from 2 to 20 times greater than a swept area of the inner fan.

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 first and second engines, a binary lift fan system, first and second forced air bypass systems and first and second exhaust systems. The engines have turboshaft and turbofan modes. The lift fan system includes ducted fans in a tandem longitudinal orientation. In the VTOL orientation of the aircraft, the engines are in the turboshaft mode coupled to the lift fan system such that the engines provide rotational energy to the ducted fans generating the thrust-borne lift. In the forward flight orientation of the aircraft, the engines are in the turbofan mode coupled to the forced air bypass systems such that the bypass air combines with the engine exhaust in the exhaust systems to provide forward thrust generating the wing-borne lift.

A cam-locking system for use with a retractable driveshaft that includes a housing, a cam carrier located at least partially the housing, and a cam rotatably coupled to the cam carrier. Translation of the cam carrier along a central axis allows the cam to rotate into cooperative engagement with a catch recess on an interior surface of the housing, preventing the cam carrier from translating backwards, and thereby maintaining the retractable driveshaft in an engaged position. Further advancement of the cam carrier allows that cam to rotate into and unlocking gap in the interior surface of the housing, which enables the cam carrier to translate backwards along the central axis below the locked position, thereby disengaging the retractable driveshaft.