An aircraft wing configuration for a vertical or a short take-off and landing aircraft having a plurality of propeller-blown wings mounted at different longitudinal locations along a fuselage of the vertical take-off and landing aircraft, producing two or more lifting surfaces, fixed at a predetermined acute wing angle greater than 0° and substantially less than 90° relative to a horizontal plane, and having a plurality of flaps disposed behind the wings. The configuration has a plurality of propellers distributed in front of the plurality of wings producing two or more lifting surfaces and mounted such that the wings are externally blown by forced airstreams from the propellers. The propellers produce distributed thrust components, and the plurality of flaps are in the forced airstreams of the propellers when one or more of the flaps is in an extended position.

An aircraft wing configuration for a vertical or a short take-off and landing aircraft having a plurality of propeller-blown wings mounted at different longitudinal locations along a fuselage of the vertical take-off and landing aircraft, producing two or more lifting surfaces, fixed at a predetermined acute wing angle greater than 0° and substantially less than 90° relative to a horizontal plane, and having a plurality of flaps disposed behind the wings. The configuration has a plurality of propellers distributed in front of the plurality of wings producing two or more lifting surfaces and mounted such that the wings are externally blown by forced airstreams from the propellers. The propellers produce distributed thrust components, and the plurality of flaps are in the forced airstreams of the propellers when one or more of the flaps is in an extended position.

Systems and methods to operate an engine in a bowed rotor mitigation mode. An engine starting system includes a starter coupled to the engine and with a compressor. A conduit system communicates a portion of the compressed air from the compressor to the starter. A load control valve controls compressed air from the compressor to the starter and to other loads. A starter air valve controls compressed air through the conduit system to the starter. At least one controller: receives a start signal from the engine; determines whether to initiate a bowed rotor mitigation of the engine; operates either the load control valve or the starter air valve to move to a predetermined static position; and operates the other of the load control valve or the starter air valve to achieve a target speed of the engine.

An engine system for an aircraft comprising a propulsor configured to drive the aircraft, a thermal combustion engine configured to drive the propulsor, an electric motor connected to the thermal combustion engine and configured to drive the propulsor, a power converter configured to apply a torque to the electric motor and generate electric energy from the torque applied to the electric motor, and an engine controller, the engine controller being configured to determine a current power output of the thermal combustion engine, determine an optimum power output of the thermal combustion engine based on current operating conditions, and vary the torque applied to the electric motor so as to vary a load on the thermal combustion engine, wherein the torque may be varied by an amount required to vary the power output of the thermal combustion engine to the determined optimum power output.

An engine system for an aircraft comprising a propulsor configured to drive the aircraft, a thermal combustion engine configured to drive the propulsor, an electric motor connected to the thermal combustion engine and configured to drive the propulsor, a power converter configured to apply a torque to the electric motor and generate electric energy from the torque applied to the electric motor, and an engine controller, the engine controller being configured to determine a current power output of the thermal combustion engine, determine an optimum power output of the thermal combustion engine based on current operating conditions, and vary the torque applied to the electric motor so as to vary a load on the thermal combustion engine, wherein the torque may be varied by an amount required to vary the power output of the thermal combustion engine to the determined optimum power output.

An aspect includes a system for pre-start motoring control for multiple engines of an aircraft. The system includes a first engine starting system of a first engine and a controller. The controller is operable to control a motoring time of the first engine starting system relative to one or more other engine starting systems of one or more other engines of the aircraft by adjusting the motoring time of the first engine starting system within a tolerance of the motoring time of the one or more other engine starting systems in a pre-start motoring sequence.

An aspect includes a system for pre-start motoring control for multiple engines of an aircraft. The system includes a first engine starting system of a first engine and a controller. The controller is operable to control a motoring time of the first engine starting system relative to one or more other engine starting systems of one or more other engines of the aircraft by adjusting the motoring time of the first engine starting system within a tolerance of the motoring time of the one or more other engine starting systems in a pre-start motoring sequence.

A powered aircraft includes at least one thrust producing engine and an engine controller controllably coupled to the at least one thrust producing engine. The engine controller includes at least a first control channel and a drag control channel. The first control channel is configured to control the at least one thrust producing engine via thrust control and the drag control channel is configured to control the at least one thrust producing engine via drag control.

A powered aircraft includes at least one thrust producing engine and an engine controller controllably coupled to the at least one thrust producing engine. The engine controller includes at least a first control channel and a drag control channel. The first control channel is configured to control the at least one thrust producing engine via thrust control and the drag control channel is configured to control the at least one thrust producing engine via drag control.

A structural system for lifting cells, constructed of modular, lightweight framing supporting thin, lightweight, single-ply or laminated, air-impermeable membranes, that maintain near constant-volume under low pressure for aerostatic lift in lighter-than-air aircraft; a system for controlling that aerostatic lift in a single or a plurality of such lifting cells, using electrically-powered vacuum pumps and valves; and a system for recovering electrical energy expended during ascent by using the inflow of air into the lifting cells during descent to generate electricity.