High Speed Transmission Shafts for Gas Turbine-Driven Remotely Mounted Accessories

Remotely mounted gearboxes and complete auxiliary power systems, including hydraulic pumps, engine starters, and electric generators, may be driven from gas turbine engines through power transmission shafts that use material flexure to accommodate misalignments. Since the diaphragm type of flexible coupling does not require lubrication, it offers long life maintenance free operation, and long TBO's while operating at high speeds, high torque, and ambient temperatures in excess of 800 F. Many transmission shafts have an “on condition” TBO; others range from 1500-3000 hr. Location of the accessory with respect to the engine is of major importance to the weight and complexity of the transmission shaft. Transmission of power over long distances can now be achieved by using supercritical shafts that employ simple hydraulic viscous dampers to control the dynamic response, even at each critical speed.