Tail fan apparatus and method for low speed yaw control of a rotorcraft
AssigneeGroen Brothers Aviation, Inc.
InventorCody Brandon Yarger
Life of this patent
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Abstract
Apparatus and methods for controlling yaw of a rotorcraft in the event of one or both of low airspeed and engine failure are disclosed. A yaw propulsion provides a yaw moment at low speeds. The yaw propulsion device may be an air jet or a fan. A pneumatic fan may be driven by compressed air released into a channel surrounding an outer portion of the fan. The fan may be driven by hydraulic power. Power for the yaw propulsion device and other system may be provided by a hydraulic pump and/or generator engaging the rotor. Low speed yaw control may be provided by auxiliary rudders positioned within the stream tube of a prop. The auxiliary rudders may one or both of fold down and disengage from rudder controls when not in use.
Claims17
A rotorcraft comprising:
- an airframe;
- a rotor rotatably mounted to the airframe and rotatable about an axis of rotation;
- a vertical stabilizer mounted to the airframe offset from the axis of rotation;
- an emergency power supply mounted to the airframe;
- a fan mounted to the vertical stabilizer;
- and
- a controller selectively coupling the emergency power supply to the fan effective to drive the fan in forward and reverse directions;
- wherein the emergency power supply includes an air reservoir containing compressed air;
- wherein the air reservoir is in fluid communication with a hydraulic reservoir containing hydraulic fluid;
- wherein the fan is coupled to a hydraulic motor;
- and
- wherein the hydraulic reservoir is in selective fluid communication with the hydraulic motor.
A method for controlling a rotorcraft during an emergency loss of power, the method comprising:
- urging the rotorcraft translationally under power of an engine, the rotorcraft further comprising:
- an airframe,
- a rotor rotatably mounted to the airframe and rotatable about an axis of rotation,
- a vertical stabilizer mounted to the airframe offset from the axis of rotation,
- an emergency power supply mounted to the airframe, and
- a fan mounted to the vertical stabilizer;
- maintaining the fan unpowered while urging the rotorcraft translationally under power of the engine;
- detecting loss of power of the engine;
- and
- in response to detection of loss of power, coupling the emergency power supply to the fan in proportion to yaw control inputs;
- wherein the emergency power supply includes an air reservoir containing compressed air.
A rotorcraft comprising:
- an airframe;
- a rotor rotatably mounted to the airframe and rotatable about an axis of rotation;
- a vertical stabilizer mounted to the airframe offset from the axis of rotation;
- an emergency power supply mounted to the airframe;
- an engine adapted to propel the rotorcraft translationally;
- a fan mounted to the vertical stabilizer;
- and
- a controller programmed to
- propel the rotorcraft translationally under power of the engine responsive to pilot inputs,
- maintain the fan unpowered while urging the rotorcraft translationally under power of the engine,
- detect a loss of power of the engine, and
- in response to detection of loss of power, couple the emergency power supply to the fan in proportion to pilot inputs;
- and
- the emergency power supply further comprising at least one of :
- an air reservoir containing compressed air in selective fluid communication with a pneumatic motor coupled to the fan, and
- an air reservoir containing compressed air and positioned within a hydraulic reservoir, the hydraulic reservoir being in selective fluid communication with a hydraulic motor coupled to the fan.
Dependencies are inferred from the claim text.