Abstract: An air turbine flow restrictor comprises a sensor for determining the rotational velocity of the turbine wheel. In response to a detected speed above a predetermined threshold, particles are injected into the inlet airstream. In one embodiment of the invention, the particles are metal disks. The disks, carried by the airstream become lodged in the nozzles of the air turbine, thereby restricting the flow of air to the turbine wheel.

Abstract: An air turbine starter containing a liquid lubricant is provided with a passive hydraulic capacitor which is charged by operation of the starter. Charging the capacitor partially drains the lubricant reservoir contained in the starter. This partial drainage decreases drag on internal, rotating components of the starter, thereby decreasing parasitic loss in output torque. The capacitor discharges the lubricant back into the starter when the latter discontinues running, thereby satisfying lubrication requirements of an internal overrunning clutch.