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.

An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft has an airframe including first and second wings with a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. A flight control system is configured to direct the thrust vector. In the VTOL orientation, the first wing is forward of the fuselage, the second wing is aft of the fuselage and the coaxial rotor system is configured to provide thrust in line with a yaw axis of the aircraft. In the biplane orientation, the first wing is below the fuselage, the second wing is above the fuselage and the coaxial rotor system is configured to provide thrust in line with a roll axis of the aircraft.

An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. Tail assemblies are coupled to wingtips of the first and second wings each having an elevon that collectively form a distributed array of elevons. A flight control system is configured to direct the thrust vector of the coaxial rotor system and to control movements of the elevons such that the elevons collectively provide pitch authority and differentially provide roll authority for the aircraft in the biplane orientation. In addition, when the flight control system detects an elevon fault, the flight control system is configured to perform corrective action responsive thereto at a distributed elevon level or at a coordinated distributed elevon and propulsion assembly level.

An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. Tail assemblies are coupled to wingtips of the first and second wings each having an elevon that collectively form a distributed array of elevons. A flight control system is configured to direct the thrust vector of the coaxial rotor system and to control movements of the elevons such that the elevons collectively provide pitch authority and differentially provide roll authority for the aircraft in the biplane orientation. In addition, when the flight control system detects an elevon fault, the flight control system is configured to perform corrective action responsive thereto at a distributed elevon level or at a coordinated distributed elevon and propulsion assembly level.

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.

A compound rotorcraft comprises a fuselage, a rotor coupled to the fuselage and a wing mounted to the fuselage. The rotorcraft further comprising a first outboard propeller, a first inboard propeller, a second outboard propeller, and a second inboard propeller. The first outboard propeller having a propeller body and propeller blades, the body mounted to a first wing-half at a first incidence angle. The first inboard propeller having a propeller body and propeller blades, the body mounted to the first wing-half between the first outboard propeller and the fuselage at a second incidence angle. The second outboard propeller having a propeller body and propeller blades, the body mounted to a second wing-half at a third incidence angle. The second inboard propeller comprising a propeller body and propeller blades, the body mounted to a second wing-half between the second outboard propeller in the fuselage at a fourth incidence angle.

A rotor assembly includes a first rotor hub and a second rotor hub. The second rotor hub is coupled to the first rotor hub via a shaft fairing. The first rotor hub has a flat first surface coupled to the shaft fairing and a curved second surface opposite the flat first surface. The second rotor hub has a flat first surface on the lower side and a curved second surface opposite the flat first surface.