Disclosed is a system for controlling acoustic radiation from an aircraft. The system comprising a plurality of rotor systems (one or more) and a noise controller configured to regulate acoustic radiation from the plurality of rotor systems. The noise controller can be configured to regulate a commanded flight setting from the flight control system and to output a regulated flight setting to the plurality of rotor systems. Based on the regulated flight setting, the plurality of rotor systems are configured to generate, individually and in aggregate, acoustic radiation having a target acoustic behavior. The target acoustic behavior may be achieved using beamforming techniques to, for example, change the directionality of acoustic radiation from the plurality of rotor systems, or otherwise tune the acoustic radiation to reduce detectability and/or annoyance.

Herein provided are methods and systems for controlling operation a first propeller of an aircraft, the first propeller associated with a first engine, the aircraft further comprising a second propeller associated with a second engine. A first requested engine power for the first engine is obtained. A second requested engine power for the second engine is obtained. The first propeller is synchronized with the second propeller by setting a first propeller command for the first propeller based on the first and second requested engine power, and the first propeller command is sent for the first propeller.

Herein provided are methods and systems for controlling operation a first propeller of an aircraft, the first propeller associated with a first engine, the aircraft further comprising a second propeller associated with a second engine. A first requested engine power for the first engine is obtained. A second requested engine power for the second engine is obtained. The first propeller is synchronized with the second propeller by setting a first propeller command for the first propeller based on the first and second requested engine power, and the first propeller command is sent for the first propeller.

An aircraft is provided and includes one or more main rotors, one or more and propellers including blades that are rotatable about a rotational axis, a pitch of each of the blades being controllable, and a flight control computer disposed to control the pitch of each of the blades to reduce propeller blade pitch angles in an event of an engine failure.

Methods and systems for operating a turboprop engine having a high pressure spool and a low pressure spool rotating independently from one another. Each spool contains at least one compressor stage and the low pressure spool is connected to a propeller. The method comprises determining a target temperature-corrected rotational speed of the low pressure spool for a given set of operating parameters; and controlling a mechanical speed of the low pressure spool to maintain the temperature-corrected rotational speed of the low pressure spool substantially constant throughout at least a portion of a range of a power demand on the turboprop engine.

A method for providing peak efficiency propeller control includes determining an optimal propeller blade angle via a control system having settings and readings including advance ratio, propeller RPM, and electric motor torque. If any limits, such as maximum propeller RPM, allowable blade angle, or motor torque are violated, then a non-optimal blade angle may be found which does not violate any of the limits. The controller connects to sensors to measure the speed and altitude of an aircraft, and using advance ratio, is able to determine thrust and power contours for a blade-angle domain such that the optimum blade angle is determined in real-time for a wide range of flight conditions.

A method of operating a propeller system for an aircraft. The method includes: receiving propeller speed information, the propeller speed information indicating propeller speed; receiving a target propeller speed; performing a propeller speed threshold adjustment process, the propeller speed threshold adjustment process comprising adjusting a propeller speed threshold as a function of the target propeller speed; comparing the propeller speed to the propeller speed threshold; and in response to propeller speed exceeding the propeller speed threshold, performing an overspeed protection process.

A turboprop control system 10 for use with a turboprop 2 having a turbine engine 12 operably coupled to and rotationally driving a propeller 14 having variable pitch blades 16 to control the engine speed, propeller speed, and propeller pitch. The pilot provides, by a single power control lever 30, the control input used to control the engine and propeller.

A single input engine controller and system are provided for translating a single input indicative of the amount of fuel to be supplied to an engine from a fuel control interface into separate signals for controlling the amount of fuel supplied to the engine and the RPM of a propeller powered by that engine. The single input controller translating the single input into the separate signal for the RPM of the propeller according to a fuel efficiency relationship between the fuel amount and the propeller RPM.

A hybrid electric aircraft propulsion system includes both a turbine engine and an electric motor. A power management system controls operation of the electric motor and a pitch angle of a propeller associated with the propulsion system. A disconnect switch is provided to isolate the electric motor by mechanical decoupling the electric motor from the aircraft propulsion system.