An airframe or a part thereof 3, for example a skin assembly or a profile such as a structural profile, comprises: a wall W having an aperture A therethrough, wherein the wall W provides a frame F surrounding, at least in part, the aperture A; a panel P conforming with the aperture A; and wherein the airframe or the part 3 thereof is configurable in: a first configuration, wherein the panel P and the frame F are mutually spaced apart; and a second configuration, wherein the panel P is received in the frame F and wherein the frame F resists movement of the panel P in two or three mutually orthogonal directions.

A multi-segment oblique flying wing aircraft which has three distinct segments including two outer wing segments and a central wing segment. The central segment may be thicker in the vertical direction and adapted to hold pilots and passengers. The outer wing segments may be substantially thinner and may taper as they progress outboard from the wing center. The multi-segment oblique flying wing aircraft be adapted for rotating into a high speed flight configuration, or may be adapted for take-off and cruise at a constant angle. In an extreme flight case, the central wing segment may rotate to a local sweep of ninety degrees.

The present invention includes a distributed propulsion system for a craft that comprises a frame, a plurality of hydraulic or electric motors disposed within or attached to the frame in a distributed configuration; a propeller operably connected to each of the hydraulic or electric motors, a source of hydraulic or electric power disposed within or attached to the frame and coupled to each of the disposed within or attached to the frame, wherein the source of hydraulic or electric power provides sufficient energy density for the craft to attain and maintain operations of the craft, a controller coupled to each of the hydraulic or electric motors, and one or more processors communicably coupled to each controller that control an operation and speed of the plurality of hydraulic or electric motors.

An aircraft capable of vertical takeoff and landing, stationary flight and forward flight, includes a closed wing that provides lift whenever the aircraft is in forward flight, a fuselage at least partially disposed within a perimeter of the closed wing, and one or more spokes coupling the closed wing to the fuselage. One or more motors are disposed within or attached to the spokes. Three or more propellers are proximate to a leading edge of the one or more spokes, distributed along the one or more spokes, and operably connected to the one or more motors to provide lift whenever the aircraft is in vertical takeoff and landing and stationary flight and provide thrust whenever the aircraft is in forward flight.

An aircraft capable of vertical takeoff and landing, stationary flight and forward flight, includes a closed wing that provides lift whenever the aircraft is in forward flight, a fuselage at least partially disposed within a perimeter of the closed wing, and one or more spokes coupling the closed wing to the fuselage. One or more motors are disposed within or attached to the spokes. Three or more propellers are proximate to a leading edge of the one or more spokes, distributed along the one or more spokes, and operably connected to the one or more motors to provide lift whenever the aircraft is in vertical takeoff and landing and stationary flight and provide thrust whenever the aircraft is in forward flight.

Provided is a flight efficiency improving system for a compound helicopter with a rotor and fixed wings. In forward flight of the compound helicopter, the flight efficiency improving system does not perform a cyclic pitch control of the rotor so as to allow a difference in lift generated by the rotor between an advancing side and a retreating side of the rotor, or the flight efficiency improving system performs the cyclic pitch control to an extent that does not completely eliminate the difference. The fixed wings are provided respectively on left and right sides of a body and are asymmetric to each other so that influence of an aerodynamic interference between the rotor and the fixed wings is reduced.

A rotary wing aircraft that extends along an associated roll axis between a nose region and an aft region and that comprises a fuselage with a front section and a rear section, the rotary wing aircraft comprising: a main rotor that is rotatably mounted at the front section, a shrouded duct that is arranged in the aft region, and a propeller that is rotatably mounted to the shrouded duct, wherein the rear section extends between the front section and the shrouded duct and comprises an asymmetrical cross-sectional profile in direction of the associated roll axis.

A rotary wing aircraft that extends along an associated roll axis between a nose region and an aft region and that comprises a fuselage with a front section and a rear section, the rotary wing aircraft comprising: a main rotor that is rotatably mounted at the front section, and a stabilizer arrangement that is arranged at the rear section in the aft region, wherein the rear section extends between the front section and the stabilizer arrangement and comprises an asymmetrical cross-sectional profile in direction of the associated roll axis.

A rotary wing aircraft that extends along an associated roll axis between a nose region and an aft region and that comprises a fuselage with a front section and a rear section, wherein the rear section extends between the front section and the aft region, the rotary wing aircraft comprising: a propeller that is rotatably mounted at the rear section in the aft region, a main rotor that is rotatably mounted at the front section, and a source of asymmetry that is connected to the front section such that the front section comprises at least in sections an asymmetrical cross-sectional profile in direction of the associated roll axis, wherein the source of asymmetry is configured to generate sideward thrust for main rotor anti-torque from main rotor downwash.

A multi-segment oblique flying wing aircraft which has three distinct segments including two outer wing segments and a central wing segment. The central segment may be thicker in the vertical direction and adapted to hold pilots and passengers. The outer wing segments may be substantially thinner and may taper as they progress outboard from the wing center. The multi-segment oblique flying wing aircraft be adapted for rotating into a high speed flight configuration, or may be adapted for take-off and cruise at a constant angle. In an extreme flight case, the central wing segment may rotate to a local sweep of ninety degrees.