This engine was built in 1911 by the Roberts Motor Company of Sandusky, Ohio. An important objective of the design was light weight, which was achieved through the extensive use of aluminum and magnesium alloys in the cylinders and crankcase, a hollow crankshaft, and two-stroke cycle operation (to reduce parts count). Between 1911 and 1912, Roberts engines were used by many noted exhibition pilots, and more Roberts engines were said to be built than by Hall-Scott and Curtiss combined.
Historical evidence suggests that this Roberts 4X Serial Number 130 engine artifact powered one of the first American-built Bleriot XI aircraft. That two-seat Bleriot was built for J. Albert Brackett of Boston, Mass. by the American Aeroplane Supply House in Hempstead, New York.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
1911
United States of America
PROPULSION-Reciprocating & Rotary
Roberts Motor Company (Sandusky, Ohio)
Type: Reciprocating, In-line, 4 cylinders, two-stroke cycle, water-cooled
Power rating: 37.3 kW (50 hp) at 1,400 rpm
Displacement: 5.21 L (318 cu in.)
Bore and Stroke: 114.3 mm (4.5 in.) x 127 mm (5 in.)
Weight: 77.1 kg (170 lb)
Length 102.3 cm (40.5 in.), Height 63.5 cm (25 in.), Width 61.0 cm (24 in.)
A19350049000
Gift of Mrs. Flora MacDonald O'Toole
National Air and Space Museum
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