The Patriot Air Defense Missile System (formerly SAM-D) is being deployed in Europe. The powerplant supplying electricity to the radar set and to the engagement control station is DOD Model D-424A, powered by the Allison Model GT-404 industrial gas turbine (IGT) engine. Designed as a vehicular engine, the application in a generator set is an interesting one, utilizing many of the following features originally intended to enhance the performance of trucks and buses:
• Dual, rotating disk regenerators dramatically improve fuel consumption by transferring heat energy from the exhaust gas stream to compressor discharge.
• Power transfer, intended to provide part load fuel economy in vehicles, is modified to furnish free-shaft start-fixed shaft run in generator sets.
• Free-shaft starts allow successful operation down to −50°F without auxiliary heaters.
The resultant gas turbine engine driven generator set — 150 kW, transportable, skid mounted, alternating current 400 Hz, tactical — has met the military requirements for performance and reliability.