A method and apparatus for controlling an airflow. The method draws air through a group of inlets. The group of inlets is located in a group of locations on the vehicle such that the group of inlets actively controls the airflow relative to an aircraft when drawing the air. The method compresses the air drawn by the group of inlets in a group of air compressor units located in an aircraft structure to form pressurized air. Further, the method sends the pressurized air through a group of exit ports in the aircraft structure. The pressurized air flowing out of the group of exit ports actively controls the airflow for an aircraft, enabling an improved performance of the aircraft.

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 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.

An apparatus for determining a movement direction of a component of a mechanism. The apparatus includes an acoustic emission sensor arranged to detect acoustic emission from the mechanism, and a processor arranged to determine a Doppler shift in a frequency characteristic of the measured acoustic emission and to determine a movement direction of a component of the mechanism on the basis of the determined Doppler shift. A method of determining a movement direction of a component of a mechanism including detecting acoustic emission from the mechanism and determining a Doppler shift in a frequency characteristic of the measured acoustic emission and, determining, based on the Doppler shift in the frequency characteristic, a movement direction of the component of the mechanism.

An aircraft includes an airframe, an engine mounted to the airframe, and an engine inlet for receiving an ambient airflow and providing the ambient airflow to the engine. An amount of airflow provided to the engine inlet is controllable.

A gas turbine engine comprises a housing having an inlet leading to a fan rotor. A bypass door is mounted upstream of the inlet to the fan rotor, and is moveable away from a non-bypass position to a bypass position to selectively bypass boundary layer air vertically beneath the engine. An aircraft is also disclosed.

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.

An aircraft is provided and includes fuselage having a nose, a main section aft of the nose and a tail aft of the main section, an engine nacelle partially embedded in the tail and including a boundary layer ingestion (BLI) propulsor with an inlet directly adjacent to the fuselage and a nozzle element disposed upstream from the inlet and configured to accelerate boundary flows flowing toward the interior side of the engine nacelle.

Fluid systems are described herein. An example embodiment of a fluid system has a first body portion, a second body portion, a plurality of supports, a plurality of fluid pressurizers, and a plurality of ducts. The first body portion and the second body portion cooperatively define an injection opening, a suction opening, and a channel that extends from the injection opening to the suction opening. The fluid pressurizer is disposed within the channel cooperatively defined by the first body portion and the second body portion. Each duct of the plurality of ducts is disposed within the channel cooperatively defined by the first body portion and the second body portion.

Fluid systems are described herein. An example embodiment of a fluid system has a first body portion, a second body portion, a plurality of supports, a plurality of fluid pressurizers, and a plurality of ducts. The first body portion and the second body portion cooperatively define an injection opening, a suction opening, and a channel that extends from the injection opening to the suction opening. The fluid pressurizer is disposed within the channel cooperatively defined by the first body portion and the second body portion. Each duct of the plurality of ducts is disposed within the channel cooperatively defined by the first body portion and the second body portion.