A leading edge structure for an aerofoil is disclosed. The leading edge structure includes a skin configured to form an external aerodynamic surface of the aerofoil. The skin includes a plurality of first regions interleaved with a plurality of second regions. Each first region includes a plurality of holes extending through the skin, and each second region includes an electrical heating system configured to increase the temperature of the skin.

Embodiments of the present invention enable a user of a drone to operate it more quietly. Embodiments of the present invention relate to such a system, apparatus, and a method of and for a drone that may be quiet, that can fly far while minimizing the need to recharge, that may have protective shells, that may employ operational redundancy, that may provide stealth capabilities due, for example, to the design of the shell, and that may allow a drone to stay in position at, for example, 329,999 feet for months. In one embodiment of the present invention, electro-magnetism is used to propel a drone while another embodiment uses an expandable outer shell. The embodiments, while also increasing a drone's range, provide enhanced maneuverability due to the unique shape and drive and steering systems of the drone. Embodiments may provide stealth and overall convenience, together potentially resulting in increased safety to creating a class of sub-space vehicles.

A method and system delay the laminar-to-turbulent transition of a supersonic or hypersonic boundary layer flow moving in a flow direction over a surface. For supersonic boundary layer flow, oblique first-mode instability waves present in the boundary layer and propagating at an oblique angle relative to the flow direction cause a laminar-to-turbulent transition in the boundary layer flow. These instability waves have a wavelength associated therewith in a direction perpendicular to the flow direction. Flow disruptors are used to generate modulations within the boundary layer flow wherein a wavelength of the modulations along the direction perpendicular to the flow direction is less than one-half of the wavelength of the instability waves. For hypersonic boundary layer flow, the flow disruptors generate modulations within the boundary layer flow wherein the wavelength of the modulations is less than streak spacing for optimal transient growth or, equivalently, in the range of one to two times the boundary layer thickness.

A method of preventing separation of a fluid flow flowing over a flow surface is described. The method includes generating longitudinal vortices for suppressing or delaying separation of the flow, and enhancing the longitudinal vortices. A flow body system having a flow body and a flow control arrangement is further described.

A propulsion assembly for an aircraft, the assembly including a turbojet having at least one unducted propulsive propeller, and an attachment pylon for attaching the turbojet to a structural element of the aircraft, the pylon being positioned on the turbojet upstream from the propeller and having a streamlined profile defined by two opposite side faces extending transversely between a leading edge and a trailing edge. The pylon includes a plurality of blow nozzles situated in the vicinity of its trailing edge and configured to blow air taken from a pressurized portion of the turbojet, the blow nozzles being positioned over at least a fraction of the trailing edge of the pylon that extends longitudinally facing at least a portion of the propeller. A method of reducing the noise generated by a pylon attaching a turbojet to an aircraft is presented.

A tandem fan for a boundary layer ingestion engine is disclosed. In various embodiments, the tandem fan includes a fan disk configured for rotation about a longitudinal axis; a primary fan blade extending radially from the fan disk, the primary fan blade having a primary fan blade span; and a secondary fan blade extending radially from the fan disk, the secondary fan blade having a secondary fan blade span within about ninety percent to about one-hundred percent of the primary fan blade span.

A circulation control system for an aerial vehicle. The system comprises an air supply unit attached to the aerial vehicle configured to generate a specified amount of mass air flow; an air delivery system, the air supply unit and the air delivery system being connected via at least one tube that turns at least one right angle; a circulation control wing through which air from the air supply unit is delivered through the air delivery system, the circulation control wing comprising at least one plenum configured to blow the air out of a slot in a trailing edge of the wing, and at least one dual radius flap positioned behind the slot.

Method and apparatus for controlling the aerodynamics of an aircraft using an active flow control system is disclosed herein. In one example, the active flow control system includes an airframe and a plurality of fluidic oscillators. The airframe includes an inlet configured for flight speeds ranging from subsonic to hypersonic. The plurality of fluidic oscillators is mounted about a curvature of the airframe. Each fluidic oscillator includes a body and an integral nozzle coupled to the body. The body has an inflow portion and a narrow nozzle inlet formed opposite the inflow portion. The integral nozzle is coupled to the body by the narrow nozzle inlet. The narrow nozzle inlet forms a single fluid flow path from the inflow portion to the narrow nozzle inlet.

A propulsion system for an aircraft includes an electric power source and an electric propulsion assembly having an electric motor and a propulsor, the propulsor powered by the electric motor. The propulsion system also includes an electric power bus electrically connecting the electric power source to the electric propulsion assembly. The electric power source is configured to provide electrical power to the electric power bus, and the electric power bus is configured to transfer the electric power to the electric propulsion assembly at a voltage exceeding 800 volts.

Provided are flight control mechanisms, such as omnidirectional thrust mechanisms (OTMs), and methods of using such mechanisms. These mechanisms may be positioned in wings, tails, or other components of aircraft. A mechanism may comprise a center member and top and bottom panels. The center member may comprise two curved segments joint at a center edge. The top and bottom panels may be independently pivotable relative to the center member. At high speeds, the top panel and/or the bottom panel may be pivoted outward to change the lift, drag, roll, and/or other flight conditions. The mechanism may also include a gas nozzle to direct compressed gas to the center member. The center member and/or the top and bottom panels redirect this gas resulting in forces in one of four directions, which are used for controlling the aircraft at low speeds, down to hover.