The Liberty L-12 was a 400 hp (298 kw) 12-cylinder, water-cooled, V-12 aircraft engine. The crankcase was cast aluminum and split horizontally at the main bearing centerline. The cylinders were forged steel with cooling jackets welded to the cylinders as was common at the time. Each cylinder bank had a single overhead-camshaft that would operate both intake and exhaust valves. The camshaft was driven by vertical rods, driven off the crankshaft, and placed at the back of each cylinder row. It had a 7” bore and 5” stroke and a direct drive to the propeller. It used an automotive Delco ignition system and a Zenith carburetor. |
Production during the war totaled 13,574 engines with continued production after the war for a total production of 20,478 engines. Other versions of the Liberty engine available were the V-8, 6-cylinder inline, and a 4-cylinder inline. |
Specifications: | |
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Liberty L-12 | Date: | 1917 |
Cylinders: | 12 |
Configuration: | Liquid-cooled, Vee |
Horsepower: | 400-420 hp (298-313 kW) |
RPM: | 1,800 |
Bore and Stroke: | 5.00 in. (127 mm) x 7.00 in. (179 mm) |
Displacement: | 1,649 cu. in. (27 liters) |
Weight: | 845 lbs. (383 kg) |
Endnotes:
1. Herschel Smith. A History of Aircraft Piston Engines. Manhattan, Kansas: Sunflower University Press, 1993. 103. 2. Howard Mingos, ed. The Aircraft Year Book for 1929. New York: Aeronautical Chamber of Commerce of America, Inc., 1929. 86. |