Rotor driven auxiliary power apparatus and method
Apparatus and methods is used for controlling yaw of a rotorcraft in the event of one or both of low airspeed and engine failure. 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. A power take-off engages a rotor and is engaged in response to detecting a loss of engine power.
1. A rotorcraft comprising:
an airframe;
an engine connected to drive the rotorcraft through the air;
a rotor rotatably mounted to the airframe and rotatable about an axis of rotation;
a power take-off selectively uncoupling from the rotor and coupling to the rotor to be driven by the rotor, the power take-off including a drive wheel; and
a power source connected to receive power through the power take-off and comprising at least one of a hydraulic pump and a generator;
a mast extending upward;
a shroud surrounding the mast and being fastened to the mast;
a flange secured to the shroud;
a hub mounted to the mast;
a plurality of blades coupled to extend from the hub; and
a belt encircling the hub and engaging the drive wheel.
2. The rotorcraft of claim 1 , further comprising a tensioner secured to the flange and biased against the belt effective to increase tensile forces within the belt.
3. The rotorcraft of claim 2 , wherein:
the drive wheel is a first drive wheel;
the power source includes both a hydraulic pump and a generator, the drive wheel engaging the belt and the hydraulic pump, the power take-off further including a second drive wheel engaging the belt and the generator; and
the tensioner is positioned between the first drive wheel and the second drive wheel.
4. The rotorcraft of claim 1 , further comprising a hub wheel secured to the hub, the belt engaging the hub wheel.
5. The rotorcraft of claim 1 , further comprising a clutch interposed between the drive wheel and the power source, the clutch adapted to selectively couple torsional forces between the drive wheel and the power source.
6. A method for responding to a loss of power in a rotorcraft, the method comprising:
detecting a loss of power in the rotorcraft, the rotorcraft including
an airframe,
an engine mounted to the airframe,
an auxiliary power generator coupled to the engine and powered thereby,
a plurality of actuators, each being selectively operably couplable to the auxiliary power generator,
a rotor rotatably mounted to the airframe and rotatable about an axis of rotation, and
a power take-off selectively and rotatably engaging the rotor;
in response to detecting the loss of power, selectively operably coupling the power take-off to the plurality of actuators;
the detecting the loss of power, wherein the loss of power is at least one of a loss of power from the engine and a loss of power from the auxiliary power generator.
7. The method of claim 6 , further comprising, in response to detection of the loss of power, activating the power take-off.
8. The method of claim 6 , wherein the power take-off is a hydraulic pump.
9. The method of claim 6 , wherein the power take-off is a generator.
10. The method of claim 6 , wherein the power take-off includes both a hydraulic pump and an electric generator.
11. The method of claim 6 , wherein the power take-off includes a drive wheel operably coupled to the rotor by means of a belt encircling a portion of the rotor.
12. The method of claim 6 , further comprising orienting the rotor to a position with respect to the airframe effective to induce autorotation of the rotor.
13. A rotorcraft comprising:
an airframe;
an engine mounted to the airframe;
an auxiliary power generator coupled to the engine and powered thereby;
a plurality of actuators, operably coupled to the auxiliary power generator
a rotor rotatably mounted to the airframe and rotatable about an axis of rotation;
a power take-off rotatably engaging the rotor; and
a controller programmed to
detect a loss of power of at least one of the auxiliary power generator and the engine;
in response to the detecting the loss of power, operably control coupling the power take-off to the plurality of actuators.
14. The rotorcraft of claim 13 , wherein the power take-off is at least one of a hydraulic pump and an electric generator.
15. The rotorcraft of claim 14 , wherein the plurality of actuators include aerodynamic control surface actuators.