Methods and systems for slowing down an aircraft having a propeller. The method comprises operating the propeller at a reference speed with the propeller blades in a first position, applying a load to the propeller to slow down a rotational speed of the propeller when the propeller is in a windmilling state or just before the propeller enters the windmilling state, adjusting the propeller blades to a second position in response to the load being applied, to increase the rotational speed of the propeller back towards the reference speed, and operating the propeller at the reference speed with the propeller blades in the second position.

A gas turbine engine control system is disclosed having a model and an observer that together can be used to adjust a command issued to the gas turbine engine or associated equipment to improve performance. In one form the control system includes a nominal model that is adjusted to real time conditions. The adjusted model is used with a Kalman filter and is ultimately used to determine a perturbation to a control signal. In one form the perturbation can be to a legacy controller.

A vertical take-off and landing aircraft using a hybrid electric propulsion system, according to an embodiment of the present invention, includes: a first control step (S1) of changing a destination when an engine (10), a power generator (20), an engine control unit (30), a power management device (40), a control unit (50), a battery management system (60), a main battery (62) and the like malfunction, thereby causing a normal flight to be difficult; a second control step (S2) of performing control so that an aerial vehicle (1) glides to a point (T), at which same has entered a first space (CEP-1) required for landing or a wider second space (CEP-2) considered safe, and maintains lift and has minimized flight air resistance after passing through the point (T); a third control step (S3) of performing control so that lift is increased and performing control so that a nose cone is switched into an upward direction; and a fourth control step (S4) of performing control so that lift is gradually reduced, and controlling a second variable-pitch control device (122) so that thrust does not act on the aerial vehicle at the moment the aerial vehicle lands, and thus the present invention can vertically land while minimizing impact to be applied to the aerial vehicle.

A propeller system includes a rotatable housing having at least one propeller blade mounted thereon and an electric pitch control motor within the rotatable housing. A pitch control member is coupled to the propeller blade and extends through a wall of the rotatable housing. The pitch control motor is configured to move the pitch control member and to thereby vary the pitch of the propeller blade.

An electronic control system for a turbopropeller engine having a gas turbine and a propeller assembly coupled to the gas turbine is provided. The control system implements a propeller control unit to control propeller operation using an actuation assembly designed to adjust a pitch angle of propeller blades. The control unit engages a mechanical lock determining a minimum flight value for the pitch angle during a flight operating mode, and disengages the mechanical lock and controls the pitch angle below the minimum flight value, up to a minimum ground value lower than the minimum flight value, during a ground operating mode. The propeller control unit, during a transition from the ground operating mode to the flight operating mode, engages the mechanical lock. The control unit anticipates the increase of the pitch angle before the mechanical lock engagement when transitioning from the ground operating mode to the flight operating mode.

In one aspect, described herein is an aircraft capable of carrying at least 400 pounds of payload. An embodiment has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor systems is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems.

The method can include, while the airplane is on the ground: entering a disking mode including positioning the blades at a disking pitch including rotating each blade around the length, the disking pitch oriented parallel to the plane of rotation; maintaining the blades at the disking pitch; and exiting the disking mode when a disking mode exit condition is met, including rotating each blade around the length, away from the disking pitch.

An electronic controller for an engine and a propeller, a control system and related methods are described herein. The controller comprises a first channel and a second channel independent from and redundant to the first channel. Each channel having a control processor configured to receive first engine and propeller parameters and to output, based on the first engine and propeller parameters, at least one engine control command comprising instructions for controlling an operation of the engine and at least one propeller control command comprising instructions for controlling an operation of the propeller. Each channel also comprises a protection processor configured to receive second engine and propeller parameters and to output based on the second engine and propeller parameters, at least one engine protection command comprising instructions for protecting the engine from hazardous conditions and at least one propeller protection command comprising instructions for protecting the propeller from hazardous conditions.

A powertrain for an aerial vehicle may include a mechanical power source and a propulsion member coupled to the mechanical power source and configured to be coupled to the chassis and convert at least a portion of the mechanical power supplied by the mechanical power source into at least one of a thrust force or cooling. The powertrain also may include an electric power generation device configured to convert at least a portion of the mechanical power into electrical power. The powertrain further may include a powertrain control system associated with the powertrain and configured to at least partially control at least one of an output speed of the mechanical power source or a pitch angle associated with the propulsion member, based on at least one of an operation, a status factor, or at least one component characteristic associated with the aerial vehicle.

A method of reducing noise includes: driving a first propulsor using one or more of the first electrical motor and the first thermal engine, and driving a second propulsor of the second hybrid power plant using one or more of the second electrical motor and the second thermal engine; receiving a signal indicative of an initial combined noise signature; determining, from the signal, that an initial amplitude variation of a periodically fluctuating amplitude of the initial combined noise signature is greater than an amplitude variation threshold; modulating a thrust produced by the second hybrid power plant, by changing a power output of the second thermal engine or the second electrical motor, to produce a modulated combined noise signature having a modulated amplitude variation less than the initial amplitude variation; and compensating for a difference in thrusts generated by the first hybrid power plant and the second hybrid power plant.