Mcdonnell Douglas Helicopter Company

Mcdonnell Douglas Corporation

Robert E Head

Channing S Morse

Thomas G Ashe

A helicopter's main rotor blades are removably attached to a hub, which is rotatably mounted on a mast. The base of the mast is attached to the helicopter's body by unthreaded, expandable bushing bolts. When inserted, the bolts' centerlines lie in a plane which perpendicularly intersects the axial centerline of the mast. The mast is hollow and encases a drive shaft. Splines at one end of the drive shaft removably engage splines on the engine transmission. The hub has a removal fitting for engaging an end of the drive shaft. When the mast is detached and pulled apart from the helicopter body for storage, the removal fitting forces the drive shaft splines to disengage from the tnansmission splines, and keeps the drive shaft inside the mast while the mast is being removed. The main rotor blades' pitch is controlled by a plurality of pitch control linkages. Each linkage is comprised of a first part connected to the mast and a second part connected to the helicopter body. The two parts of each linkage are connected solely by an expandable bushing bolt. Removal of the bolt allows the two parts to be disconnected pursuant to removal of the mast from the body, and keeps the first part attached to the mast during the removal and afterwards. Reaachment of the mast to the helicopter body is accomplished by the reverse of the foregoing operations.

Removable helicopter mast

A roadable helicopter according to various aspects of the present invention comprises a vehicle that drives like a conventional car in its road configuration, and converts to fly like a helicopter in its flight configuration. The operator of the helicopter only needs to press a button to initiate the conversion from one configuration to the other. To facilitate the flight configuration, the helicopter is preferably equipped with a dual, coaxial counterrotating rotor system to provide lift, propulsion, and control in the flight configuration. In the road configuration, however, the rotor system automatically folds into a rotor bay formed in the rear of the helicopter. The roadable helicopter may also include an automatic control/stability/navigation system that permits fully automatic flight.

Roadable helicopter

A low-profile transportation and storage assembly is readily substitutable with a conventional pair of skid landing gear. The low-profile transportation and storage assembly includes a front auxiliary crosstube having low-profile wheels attached to opposing ends of the front auxiliary crosstube, and a rear auxiliary crosstube having low-profile wheels attached to opposing ends of the rear auxiliary crosstube. Both the front auxiliary crosstube and the rear auxiliary crosstube are readily substitutable with the pair of skid landing gear of a conventional helicopter. A pair of front saddle mounts and a pair of rear saddle mounts secure the front crosstube and the back crosstube of the pair of skid landing gear to the helicopter. The pair of front saddle mounts and the pair of rear saddle mounts can be quickly removed from the aft crosstube and the forward crosstube by removal of expandable bushing fittings of the saddle mounts. These same saddle mounts or other saddle mounts can then be used to quickly and conveniently secure the front auxiliary crosstube and the rear auxiliary crosstube to the helicopter to thereby facilitate transportation and low-profile storage of the helicopter. An improved tail skid mount fitting is provided for holding the tail skid in one of an operating configuration and a low-profile storage configuration. The low-profile storage configuration of the tail skid surrounds and protects a portion of the tailboom of the helicopter.

Quick-change skid landing gear

A piezoelectric actuator includes a plurality of linearly axially expandable hard piezoelectric rods located between two plates and are distributed about a central twistable core fastened between the plates, with the axis of the rod skew to the axis of the core, resembling a squirrel cage. The actuator produces a twisting movement between the plates, responsive to voltage induced expansion of those piezoelectric rods. Fly by Wire aircraft control is realized with the actuator in various systems providing all electric control of aerodynamic surfaces, including an electronic helicopter swashplate by which the effective pitch of the main rotor blade is controlled.

Piezoelectric actuator

An engine control system for a helicopter having at least one engine is provided, including an electronic engine control unit for each engine and further including a manually operated system for backing up each electronic engine control unit in the event of a failure thereof or for permitting optional manual engine operation. The engine control system includes at least one collective pitch stick and at least one twist grip rotatably mounted on the collective pitch stick. Each twist grip includes a normal (NORM) position within the range of the operating arc which is coincident with a detent. The system includes means for electronically actuating the detent to retract when the twist grip is rotated out of the NORM position into a manual operating mode, so that the electronic disablement of the detent permits an operator to smoothly operate the twist grip through the operating arc when the engine control system is in a manual control mode. The twist grip further includes an additional arc of travel past the idle stop to an OFF position, wherein fuel flow to its corresponding engine is cut off. Significantly, the system includes an electrically actuated mechanical gate over which the twist grip must pass to enter or exit the OFF position. The gate is normally biased closed, and may be opened electrically by means of a pilot-actuated off release pushbutton to enter the OFF position, or may be opened mechanically by twisting the twist grip against the bias to exit the OFF position.

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Tempe, AZ, United States of America

Robert E Head