In view of the rapid progress in military aeronautics, the necessity for the development of a high-powered motor adaptable to American methods of quantity production was early recognized. The result of the efforts to meet this need was the Liberty motor—America’s chief contribution to aviation, and one of the great achievements of the war. After this motor emerged from the experimental stage, production increased with great rapidity, the October output reaching 4,200, or nearly one-third of the total production up to the signing of the armistice. The factories engaged in the manufacture of this motor, and their total production to November 8, are listed in Table 21.

Table 21.—Production or Liberty Motor to November 8, 1918, By Factories:

Packard Motor Car Co 4,654
Lincoln Motor Co 3,720
Ford Motor Co 3,025
General Motors 1,554
Nordyke & Marmon Co 433
———
Total 13,396

Of this total, 9,834 were high-compression, or army type, and 3,572 low-compression, or navy type, the latter being used in seaplanes and large night bombers.

In addition to those installed in planes, about 3,500 Liberty engines were shipped overseas, to be used as spares and for delivery to the Allies.

Other types of service engines, including the Hispano-Suiza 300 horse-power, the Bugatti, and the Liberty 8-cylinder, were under development when hostilities ceased. The Hispano-Suiza 180 horse-power had already reached quantity production. Nearly 500 engines of this type were produced, about half of which were shipped to France and England for use in foreign-built pursuit planes.

Table 22 gives a résumé of the production of service engines by quarterly periods:

Table 22.—Production or Service Engines in 1918:

Name of engineJan. 1 to
Mar. 31		Apr. 1 to,
June 30		July 1 to
Sept.30		Oct. 1 to
Nov. 8		Total
Liberty 12, Army 1221,4934,1164,0939,824
Liberty 12, Navy142633 1,7101,0873,572
Hispano-Suiza 180 h.p.......185284469

Later the Statistical Department of the War Department issued the following. The number of planes and engines shipped by the Bureau of Aircraft Production to depots and storehouses from the date of the armistice to February 14: