The R.C. Allen Direction Gyro Model 15 "K" has been designed with extended life and reliability foremost in mind.
The design incorporates high quality aluminum castings for the frame and gimbals. All gimbal bearings are high grade permanently lubricated instrument bearings, shielded against possible contamination and loss of lubrication. As part of the assembly process, these bearings are aligned with special tooling to assure minimum friction and proper control of bearing endplay. The gyro motor operates on bearings of similar quality properly preloaded to assure long life and smooth operation.
To insure maximum stability, the inner axis is aligned perpendicular to the azimuth axis and maintained in that position by means of an improved air torquing system. The air flow for this system is supplied by a turbine pump which is integrally coupled with the gyro motor and has no parts that can wear out. Position reference of the azimuth gimbal is transmitted to the display card by means of precision machined gears, thus minimizing friction and dither.
The heading adjust knob allows selection of the desired heading. Upon depressing this knob the gyro inner axis is automatically aligned perpendicular with the azimuth gimbal, thus assuring the most favorable position for maximum stability. All models have an AC (brushless) motor. The DC versions have a hybrid inverter which converts the aircraft DC power to the required voltage and frequency for motor operation. A power failure flag drops into view whenever the supply voltage is lost or when the voltage has dropped below a level of acceptable for proper operation of the gyro.