Roberts Motor Company

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Roberts Motor Company
  • Roberts Motor Manufacturing Company
  • Roberts Motors
IndustryEngine manufacturing
Founded1905 in Clyde, Ohio
Founder
  • Edmund W. Roberts
  • Benjamin L. Roberts
FateBecame the Johnston Motor Company in 1935
Headquarters Sandusky, Ohio
Key people
  • B. L. Roberts (President, 1905 - 1914)
  • E. W. Roberts (Vice-president and Designer, 1905–1914)
  • William Burke (President, 1914-1915)
  • Earl Johnston (Superintendent, 1915–1918; Owner, 1918–1935)
BrandsRoberts

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. [1] [2] [3] [4]

Contents

Company history

1905 - 1914 (Roberts Motor Company)

The company originated in 1905 in Clyde and moved to Sandusky, both in Ohio, in 1908. [1] 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. [5] [3] 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. [6] [7] [8] [9] Prior to founding his company, Edmund Roberts was chief engineer at the Elmore Manufacturing Company. [1] He was one of the top leading gas engine designers from the 1900-1915 period. [4]

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. [10]

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. [11] [3] According to an Early Bird of Aviation from Sandusky, Reinhardt Ausmus, "the company spent more in national advertizing than they took in on sales." [12] William H. Burke took over as president and the company produced several automobiles in 1915, powered with the company's engines. [1] The name of the company also changed to Roberts Motor Manufacturing Company, and not much was heard from the company after 1915. [4]

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. [13] Earl Johnston, who had taken over as superintendent in 1915, purchased the company in 1918. [9] Subsequently, the company shifted its focus to engines for boats rather than aircraft, and began to operate under the name, Roberts Motors. [8] In 1935, the company became a new incorporation with a new name, the Johnston Motor Co. [14] [9]

Products

Aircraft engines

Model nameConfigurationPowerBore x StrokeWeightYear
Roberts Model 4-X [8] I450 hp @ 1400 RPM4.5"x5"170 lbs.1911-1912
Roberts Model 4-XI465 hp @ 1200 RPM5"x5"230 lbs.1912-1916
Roberts Model 6-X [8] I675 hp @ 1200 RPM4.5"x5"243 lbs.1911-1912
Roberts Model 6-X [8] I6100 hp @ 1200 RPM5"x5"330-350 lbs.1911-1917
Roberts Model 6-X [8] I6100 hp @ 1200 RPM5"x5.5"368 lbs.1916
Roberts Model 6-XXI6125 hp @ 1100 RPM5.5"x6"390 lbs.1912
Roberts Model 6-XXI6165 hp @ 1200 RPM6"x6"650 lbs.1917
Roberts Model 6-XX [8] I6200 hp @ 1400 RPM6.5"x6"690 lbs.
Roberts Model E-12 [8] V12350 hp @ 1200 RPM6"x6.5"990 lbs.1916-1917

Boat engines

Model nameConfigurationPowerBore x StrokeWeightYear
Roberts Model AI125 hp @ 950 RPM - 35 hp @ 1450 RPM4"x5"1925
Roberts Model HI11.5 hp @ 750 RPM - 2 hp @ 900 RPM3"x2.5"50 lbs.1909
Roberts Model 2-HI28 hp @ 1000 RPM3.75"x4"163 lbs.1919-1921
Roberts Model JI48 - 16 hp3.75"x4"1922-1926
Roberts Model OI12.5 @ 750 RPM - 3 hp @ 900 RPM3.5"x3"95-100 lbs.1909
Roberts Model 2-OI26 hp @ 900 RPM3.5"x3"128-135 lbs.1911
Roberts Model 3-PI330 hp
Roberts Model 4-PI440 hp @ 1000 RPM4.5"x5"525 lbs.
Roberts Model 6-PI660 hp
Roberts Model RI116 - 20 hp3.78"x4"1925
Roberts Model SI18 hp @ 300 RPM - 10 hp @ 400 RPM6"x6.5"300 lbs.1917
Roberts Model MI120 hp
Roberts Model 2-MI210 hp @ 900 RPM4"x_240 lbs.
Roberts Model 3-MI315 hp @ 900 RPM293 lbs.
Roberts Model 4-MI420 hp @ 900 RPM450 lbs.
Roberts Model 6-Z100 hp1925

Automobile engines

Model namePowerBore x StrokeWeightYearNotes
Roberts 6-X [1] [3] 60 hp4.5"x5"700 lbs.1912-1915racing engine

Other

ProductSpecificationsWeightSignificanceYear
Engine-compressor unit [4] 30 CFM @ 100 PSI40 lbs.Progenitor portable air compressor1910

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. [10] [8] [15] 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. [3] [8] [10] Despite being two-cycle, they were known for never backfiring due to a cellular by-pass in the crankcase designed by E. W. Roberts. [9] [8]

Some of the Roberts engines were used by prominent exhibition pilots, including Tom Benoist, Willie Haupt, Joseph Richter, Clifton Hadley, and Weldon Cooke. [16]

Engine modelPowerRoberts engines in early aviation historyDate
Roberts 4-X50 hpPowered one of the first Bleroit XI aircraft built in the United States. [10] 1911
Roberts 4-X50 hpPowered the aircraft built by the first South Dakotan pilot, Saxe Pitts Gantz. [17] March 9, 1911
Roberts 6-X50 hpPowered the Ecker Flying Boat which is on display at the Smithsonian Institution. [18] 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. [19] 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. [9] January 1, 1914

References

  1. 1 2 3 4 5 Beverly Rae Kimes , Henry Austin Clark Jr.: Standard catalog of American Cars. Krause Publications, Iola 1989, p. 1255.
  2. ↑ George Nicholas Georgano (ed.): The Beaulieu Encyclopedia of the Automobile. band 3 : P–Z . Fitzroy Dearborn Publishers, Chicago 2001, ISBN 1-57958-293-1 , p. 1342.
  3. 1 2 3 4 5 Grayson, Stan (1999). Engines Afloat, from Early Days to D-Day: The Gasoline Era. Vol. 1. Devereux Books. ISBN   0964007045.
  4. 1 2 3 4 Wendell, C. H. (1983). American Gasoline Engines Since 1872. Crestline Pub Co.
  5. ↑ "Engine Designer Succumbs; After Distinguished Career; Son of Civil War Surgeon". The Cincinnati Enquirer . March 14, 1947. p. 14. Retrieved July 7, 2025.
  6. ↑ Underwood, Paul (July 18, 1942). "Engineer Recalls Experiment with Steam-Powered Plane, Once Hiram Maxim Helper". The Cincinnati Enquirer . Cincinnati, OH. p. 16. Retrieved July 6, 2025.
  7. ↑ Knue, Paul F., ed. (October 27, 1987). "Bicentennial Capsule: Prince Hill Inventor's Ideas Soared". The Cincinnati Post . p. 10. Retrieved July 7, 2025.
  8. 1 2 3 4 5 6 7 8 9 10 11 Angle, Glenn D. (1921). Airplane Engine Encyclopedia. Dayton, Ohio: The Otterbein Press. pg. 427 - 429
  9. 1 2 3 4 5 Harmon, Mel (January 6, 1967). "Flying Very Popular Here; Pioneers Started in 1909". Sandusky Register . p. 8. Retrieved July 7, 2025.
  10. 1 2 3 4 "Roberts 4X, In-line 4 Engine | National Air and Space Museum". airandspace.si.edu. Retrieved 2025-08-02.
  11. ↑ "Roberts, Edmund Willson". Rutherford B. Hayes Presidential Library & Museums. Retrieved June 28, 2025.
  12. ↑ Reinhardt, Ausmus (1969). "Reinhardt Ausmus Speech on Aviation in Sandusky". ohiomemory.org. p. 7. Archived from the original on 2022-06-21. Retrieved 2025-07-06.
  13. ↑ Roos, Frederick W., "The Brief, Bright Aviation Career of St. Louis's Tom Benoist," American Institute of Aeronautics and Astronautics, Inc., 2005. Archived December 21, 2010, at the Wayback Machine
  14. ↑ "Sandusky Listed With Pioneers in Aviation". Sandusky Register . November 24, 1947. p. 82. Retrieved July 8, 2025.
  15. ↑ Von Muffling, E. Adrian (June 1912). "The New York Aero Show" (PDF). Fly Magazine: The National Aeronautic Monthly. 4 (8): 13 – via Internet Archive.
  16. ↑ Hankins, Hobart Bishop (December 1911). "The Latest Engine Product of E. W. Roberts". Fly. The National Aeronautics Monthly. 4 (2). Philadelphia, PA: Aero Publishing Co.: 20–22 – via Internet Archive.
  17. ↑ Kraemer, Norma (2010). South Dakota’s First Century of Flight. Arcadia Publishing Inc. – via South Dakota Pilot's Association.
  18. ↑ Ogden, Bob (2007). Aviation Museums and Collections of North America. Air Britain Historians Ltd.
  19. ↑ Mason, Paul B. (September 16, 1945). "Along Aviation Lanes". The Cincinnati Enquirer . p. 13. Retrieved July 7, 2025.

Roberts Motor Company Aircraft Engines

Roberts 6x Aeroplane Engine

Smithsonian Collection of Roberts Aircraft Engines

Ohio museum: E. W. Roberts collection

Ohio museum: Reinhardt Ausmus collection - Roberts Motor Company catalogs

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