The Liberty L-4B was an experimental water-cooledinlinefour-cylinderaircraft engine developed in the United States during World War I.[1] The 102 hp (76 kW) engine was designed and manufactured by the Hudson Motor Car Company and was mainly intended for use in training airplanes.[2] Only two examples of the L-4B were produced, since other types of engines were available and in production. While the engine was ground-tested, it is unknown if the L-4 was ever test-flown. The L-4 was created as part of a US aircraft engine development effort which also created the six-cylinder Liberty L-6, eight-cylinder Liberty L-8 and twelve-cylinder Liberty L-12.
