Liberty L-12

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See also Liberty L-8 for the eight-cylinder prototype & Lincoln Liberty engine
Liberty L-12-1
Liberty L-12-1

The Liberty L-12 was a 27 litre water-cooled 45 degree V-12 aircraft engine of 400 horsepower (300 kW).

It was designed by Jesse Vincent and E. J. Hall of the Hall-Scott Motor Co. and manufactured by Packard, Lincoln, Ford, Nordyke and Marmon, and General Motors during the First World War. It was a modular design where 4 or 6 cylinders could be used in one or two banks. 20,478 were built between July 4, 1917 and 1919. A single overhead camshaft for each cylinder bank operated 2 valves per cylinder, in a similar manner to the inline six cylinder German Mercedes D.III engine. Dry weight was 383 kg (844 lb). Two examples of a six-cylinder version, the Liberty L-6, were produced but not procured by the Army. Both were destroyed by Dr. William Christmas testing his so-called "Christmas Bullet" fighter.

An inverted Liberty 12-A was also referred to as the V-1650 and was built up to 1926—the exact same designation later applied, due to identical displacement, to the World War II Packard-built Rolls-Royce Merlin.[citation needed]

The engine was also produced for tank use, including the UK Nuffield Liberty engine in World War II.

Major Henry H. Arnold with the first Liberty V12 engine completed
Major Henry H. Arnold with the first Liberty V12 engine completed

Contents

[edit] Specifications (Liberty L-12)

General characteristics

  • Type: 12-cylinder liquid-cooled Vee piston aircraft engine
  • Bore: 5 in (127 mm)
  • Stroke: 7 in (177.8 mm)
  • Displacement: 1,649.3 in³ (27 L)
  • Dry weight: 845 lb (383 kg)

Components

  • Valvetrain: One intake and one exhaust valves per cylinder operated via a single overhead camshaft per cylinder bank
  • Cooling system: Liquid-cooled

Performance

[edit] Anglo-American or Liberty Tank

The Anglo-American or Liberty Mark VIII tank was designed in 1917-18. The American version used an adaption of the Liberty V-12 engine of 300 hp, designed to use pig iron rather than steel. A hundred tanks were manufactured at the Rock Island Arsenal in 1919-20, too late for World War I. They were eventually sold to Canada for training in 1940, except for two that have been preserved.

[edit] Nuffield Liberty

The Nuffield Liberty tank engine was produced in World War II by the British car manufacturer Nuffield. It had an output of 340 hp (254 kw), which was inadequate, and it suffered numerous problems with cooling and reliability. It was replaced in later British tanks by the Rolls-Royce Meteor, based on their Merlin aero engine.

[edit] Aircraft

[edit] Tanks