Mcdonnell Douglas Helicopter Company

Daniel A Nyhus

Stephen S Osder

The present invention comprises a feedback-controlled braking apparatus that applies a modulated braking force that smoothly decelerates a rotating shaft such that it comes to rest at a precise location. According to a preferred embodiment of the present invention the rotor hub of a rotor/wing aircraft is coupled to a hydraulically actuated friction brake, such as a conventional disk brake. The disk brake caliper is supplied with fluid pressure from an electrically actuated servo valve which, in turn, is controlled by an electronic controller. A sensor monitors the angular position and velocity of the rotor main shaft. The velocity and position information is provided to the controller, which modulates the brake pressure as required to bring the rotor to a stop at exactly the right orientation relative to the aircraft. By providing active brake control, the present invention enables the rotor of a rotor/wing aircraft to be decelerated and stopped smoothly and precisely in the desired position in the minimum time possible.

Active brake control for rotor/wing aircraft

The present invention comprises an apparatus for locking the pitch axes of the rotor blades of a rotor/wing aircraft so as to form a rigid wing. In one embodiment of the present invention the rotor blades of a rotor/wing aircraft are locked to each other to form a rigid wing assembly having a common pitch axis. This wing assembly is then locked in position about its pitch axis by means of a pitch lock apparatus that engages the lower end of the pitch link of the rotor blade that is oriented at the leading edge of the fixed wing. In another embodiment each rotor is independently locked about its respective pitch axis by means of two separate pitch lock apparatus. By locking the rotor blades into a rigid assembly by means of an independent rigid pitch lock apparatus, it is possible to provide a rotor/wing aircraft having a fixed wing with more predictable and controllable response to aerodynamic forces.

Rotor pitch lock for rotary/wing aircraft

The present invention comprises an apparatus for locking both rotor blades of a rotor/wing aircraft at a common point to form a rigid wing having a uniform bilateral aerodynamic response. In one embodiment of the present invention the rotor blades of a rotor/wing aircraft are locked together to form a rigid wing assembly. This is accomplished by locking the blades together by a locking mechanism that engages when the rotor speed drops below a certain threshold. With the rotor blades locked together, the wing assembly can then be locked in position with the appropriate pitch angle simply by securing the pitch link of the rotor blade that is oriented at the leading edge of the fixed wing. In another embodiment of the invention the blades are locked directly to the rotor by two locking mechanisms that engage the hub directly. By locking the rotor blades into a rigid assembly having a common control point, it is possible to provide a rotor/wing aircraft having a fixed wing with more predictable and controllable response to aerodynamic forces.

Rotor blade lock for rotary/wing aircraft

An articulating and telescoping duct is provided for use in a helicopter reaction drive flow path for ducting the exhaust and/or bypass gases from the aircraft engine into the flow ducts of the rotor blades. In a preferred embodiment the telescoping duct comprises a tubular member having a bead formed at each end. Each of the beads has an outside surface formed into a spherically curved sector that is centered radially about the axis of the tubular member. The receiving duct at one end comprises a complementary spherical bore that seals against and retains the spherical outside surface of the tubular member while permitting the tubular member to articulate relative to the receiving duct. The receiving duct at the other end comprises a complementary cylindrical bore that seals against the spherical outside surface of the tubular member while permitting the tubular member both to articulate relative to and telescope in and out of the cylindrical bore. By incorporating an articulating and telescoping duct into the flow path of the reaction drive it is possible to route the exhaust gases from the engine to the rotor blades with less total duct length and with fewer bends than was heretofore possible, thereby reducing the total losses associated with the ducting with a concomitant increase in aircraft efficiency.

Articulating/telescoping duct for reaction drive helicopters

The present invention provides a slotted cam control system for controlling pitch angles of fan blades of a relatively low-pressure-ratio fan within a fuselage of a helicopter. The stream of air generated by the fan is directed into the tailboom of the helicopter, and is selectively discharged through the circulation control tailboom and left and right openings of a direct jet thruster. A force-receiving arm of a slotted cam control system receives left and right forces from corresponding left and right foot rudder pedals. An end of the force-receiving arm fits into a V-shaped cam. When the pilot depressed a left foot rudder pedal and releases a right foot rudder pedal, for example, the end of the force receiving-arm is first moved along a first predetermined distance of the V-shaped cam in order to decrease the pitch angles of the fan blades while the opening of the direct jet thruster corresponding to the released foot rudder pedal is closed. Next, the end of the force-receiving arm passes the pheochrome of the V-shaped slot and passes along a second predetermined distance of the V-shaped slot in order to increase the pitch angles of the fan blades as the opening of the direct jet thruster corresponding to the depressed foot rudder pedal. A force-applying arm is connected to the end of the force-receiving arm that moves within the V-shaped slot, and this force-applying arm applies to each of the fan blades to change the pitch angles.

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Gilbert, AZ, United States of America

Daniel A Nyhus