This information sheet covers current gear design practices as they are applied to air vehicles and spacecraft. The material included goes beyond the design of gear meshes per se, and presents, for the consideration of the designer, the broad spectrum of factors which combine to produce a working gear system, whether it be a transmission, gearbox, or special purpose mechanism. Although a variety of gear types, such as wormgears, face gears and various proprietary tooth forms are used in aerospace applications, this document covers only conventional spur, helical, and bevel gears.

Application

The working environment of the aerospace gearbox, either air vehicle or spacecraft, has become so diverse that a single set of guidelines will no longer suffice. Herein after, the term gearbox will be used when the type has been defined in that clause of this document. The operating conditions imposed on a high-speed, high-powered, air vehicle gearbox or actuator are quite different than those experienced by the spacecraft mechanism which functions in a vacuum for long periods of time without maintenance. This Information Sheet addresses these differences and provides guidance to the designer for these demanding applications.