Liberty 12 Model A (Packard), Moss Turbosupercharged, V-12 Engine

Type: Reciprocating, V-type, 12 cylinders, air-cooled, supercharged

Power rating: 334 kW (449 hp) at 1,940 rpm

Displacement: 27 L (1,649 cu in.)

Bore and Stroke: 127 mm (5 in.) x 178 mm (7 in.)

Weight: 382.8 kg (844 lb)

The Liberty engine was America's most important contribution to aeronautical technology during World War I. Jesse G. Vincent of Packard and Elbert J. Hall of Hall-Scott co-designed it in mid-1917 for the U.S. government, which wanted a standard design in 4-, 6-, 8-, and 12-cylinder versions that could be quickly mass-produced to equip U.S. combat aircraft. Automakers Ford, Lincoln, Packard, Marmon, and Buick produced 20,748 Liberty 12s before the Armistice, which insured their widespread use into the 1920s and '30s.

Details of the turbo-supercharger design were based on experience of the turbine and centrifugal compressor departments of the General Electric Company, where the first one was built at its facility in Lynn, Massachusetts, led by Dr. Sanford Moss.

The Packard Motor Car Company built the engine, and GE built the turbo-supercharger assembly. Turbo-supercharged Liberty engines powered aircraft such as the: LePere LUSAC-11, Martin MB-2 (NBS-1), de Havilland XDH-4BS and DH-4M-2S.