Avco Corporation

George S Hudson

Kimball J Rumford

John W McClure

Avi Ben-Porat

Madan M Roy

A gas turbine engine which includes a starter/generator mechanically coupled thereto and an electric oil pump motor for driving an oil pump is started in a manner which assures a continuous and uninterrupted supply of lubricating oil to the moving components of the engine. According to one method, first and second motor controllers initiate operation of the oil pump motor. Thereupon, the second motor controller is re-directed to initiate operation of the starter/generator and the gas turbine engine itself, after which, the second motor controller again joins the first motor controller to accelerate the oil pump motor up to idle speed. The oil pump motor may then be electrically coupled to the starter/generator for continued operation. In another mode of operation, a second motor controller may not be used at all. In that event, the alternating electric power supply for the vehicle powered by the gas turbine engine may be used as an interim source for controlling the speed of the oil pump motor.

Gas turbine motor drive

A plurality of accessories operatively associated with a gas turbine engine are driven by electric motors. A first motor controller initiates operation of a starter/generator mechanically coupled to the engine. After the engine has been started, the motor controller is used to accelerate other accessory motors at a predetermined rate after which they are each electrically coupled to the starter/generator for continued operation. Throughout this operation, the first motor controller serves as a back up for a second motor controller which is dedicated to the operation of a fuel pump motor. Other modes of operation can be achieved as well by reason of the flexibility provided by motor driven accessories.

Management of electrically driven engine accessories

A test stand for measuring the thrust produced by a jet engine includes a base and a floating frame having the engine connected thereto, with the floating frame being disposed in spaced, parallel relationship to said base. The base and floating frame are interconnected by a plurality of elongated support flexures, each of which is provided with a first and second elongated generally planar webs, disposed in axial alignment and with the plane of the first web being orthogonal to the plane of the second web. The flexures are disposed such that the plane of the fist web is perpendicular to the logitudinal axis of the jet engine. In operation, the thrust of the jet engine causes movement of the floating frame relative to the base thereby resulting in a corresponding bending of the flexure, with the bending being localized in the first web to facilitate its measurement. A control circuit is provided which includes a plurality of transducers that are bonded to the flat surface portion of the first web. The transducers are interconnected in a Wheatstone's bridge arrangement to produce an accurate measurement of thrust.

Thrust measuring test stand

A torque correlation ring is disclosed which forms a part of a test stand useful in measuring performance of aircraft turboshaft engines. The torque ring assembly comprises two annular rings separated from each other by four short equally spaced beams. One of the annular rings is fixedly attached to the frame of the test stand. The engine casing is attached to the second ring. Attachment is such that the engine is axially suspended within the annular rings with the propeller shaft on one side and the turbine exhaust on the other. Torque reaction forces on the engine casing stemming from supplying power to a propeller will be passed from the second annular ring to the frame mounted, first annular ring via the four beams. The magnitude of this torque is measured by means of strain gages mounted on each of the four beams. The electrically combined signal from the strain gages represent an accurate measurement of the torque forces being supplied to the propeller by the engine under test.

Torque correlation ring

The disclosure illustrates a closed loop aircraft transmission test set comprising a variable speed DC motor driving a speed changing gear box whose output shaft is coupled to the input of the transmission under test, the main output shaft of the transmission being coupled to a DC generator load, the output of the generator being used to supplement the input electric power used to operate the DC driving motor thus assuring power drain from the supply busses is only the amount needed to overcome system friction and efficiency losses.

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Hamden, CT, United States of America

George S Hudson