Roberts Motor Company


Roberts Motor Company was an American manufacturer of lightweight, high-speed engines for aircraft, boats, stationary, and automobiles, based in Ohio during the early 1900s.

Company history

1905 - 1914 (Roberts Motor Company)

The company originated in 1905 in Clyde and moved to Sandusky, both in Ohio, in 1908. It was cofounded by Benjamin Leacock "B. L." Roberts and his brother, Edmund Willson "E. W." Roberts, a mechanical engineer, engine designer, inventor, patent agent, and prolific author of gas engineering books. E. W. Roberts was known for being chief assistant to Hiram Maxim in his 1894 'flying machine' project in Kent, England and a designer of a large wind tunnel for Maxim. Prior to founding his company, Edmund Roberts was chief engineer at the Elmore Manufacturing Company. He was one of the top leading gas engine designers from the 1900-1915 period.
According to the Smithsonian Institution, which has a few Roberts engines in its collection, the Roberts Motor Company produced more engines during this pre-WWI period than Hall-Scott and Curtiss Motor Company put together.

1914 - 1917 (Roberts Motor Manufacturing Company)

Roberts left the company in 1914 when the company faced financial trouble, and became editor of The Gas Engine magazine before starting a private consulting practice for engine design. According to an Early Bird of Aviation from Sandusky, , "the company spent more in national advertizing than they took in on sales." William H. Burke took over as president and the company produced several automobiles in 1915, powered with the company's engines. The name of the company also changed to Roberts Motor Manufacturing Company, and not much was heard from the company after 1915.

1918 - 1935 (Roberts Motors)

The Roberts Motor Manufacturing Company ceased operations upon the tragic death of Thomas Benoist in 1918, who had been affiliated with the company. Earl Johnston, who had taken over as superintendent in 1915, purchased the company in 1918. Subsequently, the company shifted its focus to engines for boats rather than aircraft, and began to operate under the name, Roberts Motors. In 1935, the company became a new incorporation with a new name, the Johnston Motor Co.

Products

Aircraft engines

Boat engines

Automobile engines

Other

Significance

The Roberts engines were designed to be as lightweight as possible by using Germany-imported aluminum and magnesium alloys for the cylinders, pistons, and crankshaft, an alloy which the company called 'aerolite,' as well as a hollow crankshaft. All the Roberts engines operated on a two-stroke cycle for parts reduction and thus lighter weight, though four-stroke cycle engines were introduced after WWI. Despite being two-cycle, they were known for never backfiring due to a cellular by-pass in the crankcase designed by E. W. Roberts.
Some of the Roberts engines were used by prominent exhibition pilots, including Tom Benoist, Willie Haupt, Joseph Richter, Clifton Hadley, and Weldon Cooke.
Engine modelPowerRoberts engines in early aviation historyDate
Roberts 4-X50 hpPowered one of the first Bleroit XI aircraft built in the United States.1911
Roberts 4-X50 hpPowered the aircraft built by the first South Dakotan pilot, Saxe Pitts Gantz.March 9, 1911
Roberts 6-X50 hpPowered the Ecker Flying Boat which is on display at the Smithsonian Institution.1911-1912
Roberts 6-X75 hpPowered a Benoist biplane used in the first parachute jump from an aircraft, performed by Captain Bert Berry and piloted by Anthony Jannus in St. Louis, Missouri.March 12, 1912
Roberts 6-X75 hpPowered the Benoist Type XIV during the first commercial passenger airplane flight, flown by Jannus, in St. Petersburg, Florida.January 1, 1914