Gnome Monosoupape Type B-2, Rotary 9 Engine

Detached engine components, with 1 cardboard box filled with rings, gaskets, and hardware.

Type: Rotary, monosoupape (single valve), 9 cylinders, air-cooled

Power rating: 75 kW (100 hp) at 1,200 rpm

Displacement: 12.8 L (783.27 cu in..)

Bore and Stroke: 110 mm (4.33 in.) x 150 mm (5.91 in.)

Weight: 123 kg (272 lb)

The first successful rotary engine is generally attributed to the American F.O. Farwell in 1896; but the French Gnome engine, developed by the Seguin brothers, was much more successful in bringing the rotary to a broad aviation market beginning in 1909. The original Gnome engines had two valves, with the inlet in the head of the piston and the exhaust in the in the cylinder head. The monosoupape, as the name signifies, had only one valve in the cylinder head, which eliminated a weak design feature of the earlier design, and was the most numerous model during World War I.

This engine was also manufactured in England, Italy, and the U.S., and used on aircraft types including the: Nieuport 12 and 28; Royal Aircraft Factory B.E.8 and F.E.8; Sopwith Pup and F.1 Camel; Vickers F.B.5 and 6 Gunbus; Airco D.H.2 and D.H.5; Avro 504 E/J/K/M; and Bristol 4 Scout D and 8 Scout S.2A.