A first power source includes a high discharge rate battery and a second power source includes a high energy battery. An electronically activated switch switches between the first power source and the second power source in response to a control signal from a power controller. If the electronically activated switch fails, it fails with one of the first power source and the second power source in an open circuit position and with the other one of the first power source and the second power source in a closed circuit position. The power controller generates the control signal, including by: during a vertical landing associated with a vertical takeoff and landing (VTOL) vehicle, generating the control signal to switch from the high energy battery to the high discharge rate battery independent of a measured current.

A gas turbine engine arrangement includes an accessory gearbox which is mounted so as to be aligned in an axial direction along the engine. The accessory gearbox may be recessed at least partly into a casing of the engine.

A reconfigurable unmanned aircraft system is disclosed. A system and method for configuring a reconfigurable unmanned aircraft and system and method for operation and management of a reconfigurable unmanned aircraft in an airspace are also disclosed. The aircraft is selectively reconfigurable to modify flight characteristics. The aircraft comprises a set of rotors. The position of at least one rotor relative to the base can be modified by at least one of translation of the rotor relative to the boom, pivoting of the boom relative to the base, and translation of the boom relative to the base; so that flight characteristics can be modified by configuration of position of at least one rotor relative to the base. A method of configuring an aircraft having a set of rotors on a mission to carry a payload comprises the steps of determining properties of the payload including at least mass properties, determining the manner in which the payload will be coupled to the aircraft, determining configuration for each of the rotors in the set of rotors at least partially in consideration of the properties of the payload, and positioning the set of rotors in the configuration for the aircraft to perform the mission.

A method of designing an engine according to an exemplary aspect of the present disclosure includes, among other things, designing an engine and a nacelle assembly together in an interactive process, the engine including a turbine section configured to drive a fan section and a compressor section. The step of designing the compressor section includes the step of designing a first compressor and a second compressor, with an overall pressure ratio being greater than or equal to about 35. The step of designing the nacelle assembly includes the step of designing the fan section to include a fan nacelle arranged at least partially about a fan, with the fan section having a fan pressure ratio of less than about 1.7. The step of designing the fan section includes configuring the fan section to deliver a portion of air into the compressor section, and a portion of air into a bypass duct, and with a bypass ratio equal to or greater than about 5.

A propulsion assembly for aircraft, the assembly including a turbojet having at least one unducted propulsion 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 an airfoil extending transversely between a leading edge and a trailing edge, the trailing edge of the airfoil of the pylon includes a cutout extending longitudinally over a fraction of the trailing edge facing at least a portion of the propeller, the cutout being configured to increase locally the distance between the trailing edge and the propeller, the cutout presenting an outline having a curved shape presenting at least two points of inflection.

An assembly for an aircraft with an engine includes an attachment device intended to support the engine, a pod intended to surround the engine and including a cover, joints intended to allow articulation of the cover and allow movement of the cover relative to the attachment device between a closed position and an open position, and at least one access panel mounted moveably on the cover between a closed position, in which the access panel extends continuously between the cover and the attachment device when the cover is in the closed position, and an open position in which the access panel is remote from its closed position. The assembly includes a handle which can be operated from the outside of the cover between a first position and a second position, and a transmission system provided to move said or each access panel from its closed position to its open position.

Pylon fairings for an aircraft turbojet engine mounted below an aircraft wing are provided with inboard and outboard lateral faces which converge rearwardly to form a trailing edge of the pylon fairing and which are positioned so as to contact a portion of a cold flow exiting a fan duct of the turbojet engine, and a bottom face positioned above a hot exhaust flow exiting an exhaust nozzle of the turbojet engine. The trailing edge of the pylon fairing extends in an upward direction relative to an engine longitudinal axis of symmetry between a lower terminus at the bottom face and an upper terminus located at a lower surface of the aircraft wing. The lower terminus is coincident with a longitudinal midplane of the turbojet engine, and the upper terminus is offset in an inboard direction so that the trailing edge of the pylon fairing is cambered in the inboard direction between the lower terminus and the upper terminus.

A propulsion system for aircraft, in particular lightweight aircraft, provides a low-noise and low-cost aircraft. The propulsion system includes at least two ducted propellers (3, 3). The ducts of are provided laterally on the fuselage (4) of the aircraft in such a way that the common net thrust of the ducted propellers is substantially collinear to the net drag.

Disclosed here are systems for detachable airframe components including detachable nose cones, propeller assemblies and motors. In some example embodiments, the assemblies include a nose cone with a connection receiver, a motor assembly with a rotatable section, where the rotatable section includes torque arms configured to secure with the nose cone connection receiver, and a propeller assembly, configured to connect to the nose cone.

In one example embodiment, a strut for mounting a jet engine to a wing of an aircraft includes a plurality of engine mounts and a space frame truss supported from the wing and comprising front and aft portions, the front portion being coupled to and supporting the engine mounts, the aft portion extending upwardly and rearwardly from an aft end of the front portion. By removing the aft end of the strut from the core exhaust zone of the engine, substantial reductions in the weight and drag of the strut, and a corresponding increase in the specific fuel consumption of the associated aircraft may be achieved.