Roberts 4X In-line 4 Engine

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.

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.

• Type: Reciprocating, 4 cylinders, in-line, two-stroke cycle, water cooled
• Power rating: 48.5 kW (65 hp) at 1,200 rpm
• Displacement: 6.44 L (393 cu in.)
• Bore and Stroke: 127 mm (5 in.) x 127 mm (5 in.)
• Weight: 77.1 kg (170 lb)

Where this page came from

This page was imported from Smithsonian National Air and Space Museum. Released by the Smithsonian Institution under CC0 through Smithsonian Open Access.

Nobody has written it yet — it is the source material at a new address, which is why search engines are asked to skip it and why no one earns from it. It is up for grabs: take it on, and it is yours to rewrite and to earn from.