Image of the Air Force wings with the museum name underneath

Open daily from 9 a.m. to 5 p.m. 
FREE Admission & Parking

Liberty 12-A Inverted

The inverted Liberty is a conversion of the famous Liberty 12, one of America's greatest technological contributions during World War I. During the war, 20,478 Liberty 12s were produced in the United States and used primarily in U.S.-built DH-4s, the only American-made airplane to get into combat over the Western Front.

Initial attempts to invert the Liberty engine took place in 1918-1919, but technical problems delayed the first flight until 1923. Inverted Liberty 12-As, produced until 1926, were conversions of the standard engine. Most were used in the Loening OA-1 amphibians, designed specifically for the inverted engine. Among the advantages were high propeller position (for hull clearance in the amphibian), better visibility and easier access for the mechanics.

The Liberty on display was manufactured by the Lincoln Motor Co., Detroit, Mich., on Oct. 18, 1918. It was converted to the inverted configuration by Allison Engineering Co., Indianapolis, Ind., on Nov. 16, 1926. It represents the engine used on the Loening amphibian.

Model: Inverted Liberty 12-A (V-1650)
Type: 12-cylinder, liquid-cooled, Vee (inverted)
Displacement: 1,650
Rated rpm: 1,700
Rated hp: 425
Original cost: $2,500
Conversion cost: $1,472

Click here to return to the Early Years Gallery.