De Dion-Bouton, Langley, In-line 1 Engine

Type: Reciprocating, 1 cylinder, air-cooled

Power rating: 1.9 kW (2.5 hp) at 1,800 rpm

Displacement: Not available

Bore: 8.9 mm (3.5 in.) (approximate)

Weight: Not available

In 1899, the French-manufactured De Dion-Bouton engine powered a tri-cycle vehicle (three-wheel motorcycle) built by the same manufacturer. The higher speed, made possible by timed ignition, and air cooling of this type of engine made it more powerful for its size and weight than earlier automotive engines. Therefore, it was particularly useful for aviation applications, but originally too small for airplanes. However, the small engines were satisfactory for airships, and De Dion-Bouton engines powered Santos-Dumont’s No. 1 and No. 2 dirigibles.

In 1900, Dr. Samuel P. Langley, Secretary of the Smithsonian Institution, purchased this one-cylinder, air-cooled engine from the De Dion-Bouton firm in Paris. The artifact was taken apart, examined, and tested. Charles M. Manly, Langley's engineer, incorporated two features of the engine, namely the lightweight pistons and the ignition system, in his engine. Manly's design became the Langley-Manly-Balzer engine which powered Langley's 1903 Aerodrome.