Peak Transient Torques In Pneumatic Starter-Engine Systems

A method for calculating the peak transient torques in pneumatic (air turbine) starter-engine systems subjected to running engagements is illustrated. The procedure couples the inlet air-valve flow characteristics with the starter performance characteristics. Calculated time-based speed, torque data, and knowledge of the system's backlash establish initial conditions and the applied-torque function necessary for predicting the transient response of the coupled starter-engine system.

The three major contributions to transient torque are discussed and the relative magnitude and the contributing parameters of each are explained. Results using the analysis compare well with the test data.