Design and Development of a Modern Transmission: Baseline Configuration of the CH-53K Drive System

The three-engine CH-53E SUPER STALLION helicopter is currently the largest, most powerful marinized helicopter in the world. It is deployed from United States Navy amphibious assault ships to transport personnel and equipment and to carry external (sling) cargo loads. The CH-53K helicopter will maintain virtually the same footprint as its predecessor but will double the payload to 27,000 pounds over 110 nautical miles under "hot/high" ambient conditions. This paper provides a detailed description of the CH-53K power transmission configuration including the nose, main, intermediate, and tail gearboxes; the engine and tail drive shaft systems; the rotor positioning capabilities and the Integrated Vehicle Health Management Systems (IVHMS). Powered by three General Electric GE38-1B 7,500 shp rated engines, specially designed for the CH-53K heavy lift helicopter, the drive system transmits up to 6,158,000 in-lb of torque to the main rotor and 262,000 in-lbs of torque to the tail rotor. The Main Gear Box (MGB) also drives two main generators, two permanent magnet alternators (PMA), three hydraulic pumps, and an oil cooler blower. Designed for military applications, the CH-53K drive system is equipped with emergency lubrication systems that are capable of sustaining operation of the transmission for 30 minutes after the first indication of oil pressure loss. The challenges and design solutions that led to the final drive system configuration, which is designed to operate at 35% higher power than the CH-53E transmission while still meeting the stringent weight requirements, are included.