Abstract: A special purpose helicopter based on an existing airframe, power train, and engine, modified to provide greatly enhanced performance, payload, speed and maneuverability. The modification consists of modifying an original helicopter universal transmission center case for installation of twin drive shafts, at 180.degree. apart, and mounting a second engine on the airframe structure, at 180.degree. to the first engine, and forward of the transmission. An exhaust system for the second engine is split into two units for directing the exhaust outwardly and upwardly.

Abstract: A method of converting an existing helicopter airframe, such as a UH-1H/V or a UH-1D, to a special purpose use such as, for example, a gunship or a firefighter, and a helicopter constructed thereby. The process takes a conventional, multi-passenger, helicopter from a primary design use to a second, un-anticipated use after the primary function has ceased. The invention converts the helicopter from a dual-piloted, multi-passenger aircraft to a helicopter gunship flown by a single operator/pilot. Modifying the aircraft involves stripping the entire shell from the basic boxlike airframe, removing all of the equipment and accessories, and re-assembling the aircraft with a slimmer profile, reduced weight, and improved performance.

Abstract: A rotor blade recorder system for accumulating the total number of hours that the rotor blades of a helicopter have been rotating at operational speeds. An hour meter and a switch are attached to the outer surface of a mounting rod running through the root end of each of the two blades comprising the main rotor. The switch has a calibrated weight at the end of the switch arm to close the contacts of the switch when the main rotor reaches operational speed. Closing the contacts energizes the self-contained power source in an hour meter. Remote readout terminals permit the hour meter to be read from outside without disturbing the blade assembly. As long as the rotor continues at the operating speed, the hour meter continues to record the time at work.

Abstract: The principle utility of the blade modification tool is as a work holder for holding a helicopter blade in a firm position and a process for cutting at least two feet from the end. More specifically, in conformity with FAA regulations, a Bell Helicopter Model UH-1H rotor blade assembly may be modified for FAA approved installation on the Bell Helicopter Model UH-1B.