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.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date 1911 Country of Origin United States of America Type PROPULSION-Reciprocating & Rotary Manufacturer Roberts Motor Company (Sandusky, Ohio)
 Physical Description 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) Dimensions Length 102.3 cm (40.5 in.), Height 63.5 cm (25 in.), Width 61.0 cm (24 in.)
 Inventory Number A19350049000 Credit Line Gift of Mrs. Flora MacDonald O'Toole Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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