A Study of the Potential Benefits Associated with the Development of a Dedicated Helicopter Transmission Lubricant

A common oil is now used in both the engines and transmissions of virtually all U.S. military helicopters. While this provides significant logistic advantages, these advantages are attained only by compromising the optimization of the oil for either system.

This paper summarizes the results of two studies undertaken to determine what benefits would accrue through the development of a special oil tailored specifically to meet the unique requirements of high-speed, heavily loaded helicopter transmission systems. These studies, conducted independently by two major helicopter manufacturers under the direction of the Naval Air Propulsion Center, addressed specific problem areas as related to typical production aircraft in order to reach well-documented conclusions. In addition, the effect of the availability of such a special gearbox lubricant on the development of other advanced-technology components was evaluated and documented.