Roberts 4X In-line 4 Engine
date: label: Date
content: 1912
name: label: Manufacturer
content: Roberts Motor Company (Sandusky, Ohio)
notes: label: Physical Description
content: Type: Reciprocating, 4 cylinders, in-line, two-stroke cycle, water cooled
label: Physical Description
content: Power rating: 48.5 kW (65 hp) at 1,200 rpm
label: Physical Description
content: Displacement: 6.44 L (393 cu in.)
label: Physical Description
content: Bore and Stroke: 127 mm (5 in.) x 127 mm (5 in.)
label: Physical Description
content: Weight: 77.1 kg (170 lb)
label: Summary
content: An important objective of the Roberts Motor Company 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.
label: Summary
content: This engine was purchased by Oscar R. Solbrig of Davenport, Iowa, to power the Curtiss-type pusher aircraft he built in 1911-12. Solbrig, who had received aviation training from Curtiss, soloed in his own aircraft in 1912. He later flew exhibition flights and races with it at county fairs, sports events, and exposition parks in Iowa and Illinois. This artifact is apparently rare because the standard Roberts 4X engine used a 114 mm (4.5 in.) bore, resulting in a 5.21 L (318 cu. in,) displacement.
place: label: Country of Origin
content: United States of America
setName: label: See more items in
content: National Air and Space Museum Collection
creditLine: label: Credit Line
content: Gift of Arthur. J. Hartman
dataSource: label: Data Source
content: National Air and Space Museum
identifier: label: Inventory Number
content: A19560015000
objectType: label: Type
content: PROPULSION-Reciprocating & Rotary
objectRights: label: Restrictions & Rights
content: CC0
physicalDescription: label: Materials
content: HAZMAT: Magnesium
label: Materials
content: Steel, Aluminum, Paint, Textile, Rubber, Copper, Phenolic, Ceramic
label: Dimensions
content: Height 63.5 cm (25 in.), Width 61 cm (24 in.), Depth 102.9 cm (40.5 in.)