Gnome Omega

Omega
	Gnome 7 Omega on display at the Newark Air Museum
Type	Rotary aero engine
Manufacturer	Société des Moteurs Gnome
First run	1908
Major applications	Blériot XI; Bristol Boxkite
Number built	4,000 until 1914

The Gnome 7 Omega (commonly called the Gnome 50 hp) is a French seven-cylinder, air-cooled aero engine produced by Gnome et Rhône.^[2] It was shown at the Paris Aero Salon held in December 1908 and was first flown in 1909. It was the world's first^[1] aviation rotary engine produced in quantity. Its introduction revolutionized the aviation industry^[3] and it was used by many early aircraft. It produced 37 kW (50 hp) from its 8 L (490 cu in) engine capacity.^[4] A Gnome Omega engine powers the 1912 Blackburn Monoplane, owned and operated by the Shuttleworth Collection, the oldest known airworthy British-designed aeroplane worldwide.^[5] A two-row version of the same engine was also produced, known as the Gnome 14 Omega-Omega or Gnome 100 hp. The prototype Omega engine still exists, and is on display at the United States' National Air and Space Museum.^[2]

Like all early Gnome et Rhône engines the Omega featured a single pushrod driven exhaust valve on the cylinder head; the intake valve was located in the piston crown, opening by inertia on the downstroke and feeding the intake charge from the crankcase into the upper part of the cylinder. No throttle was provided, the pilot controlling his speed by switching off the ignition when necessary.

Variants

Gnome 7 Omega: Single-row 7-cyl. original version; 50 hp (37 kW).
Gnome 14 Omega-Omega: Two-row, 14-cylinder version using Omega cylinders; 100 hp (75 kW).

Applications

Gnome 7 Omega

Gnome 14 Omega-Omega

Engines on display

The very first Gnome rotary engine ever built, Gnôme Omega No. 1, is on display at the National Air and Space Museum, Washington, D.C.^[2]
A preserved production Gnome 7 Omega engine is on public display at the Royal Air Force Museum London.
A restored Omega is on display at the New England Air Museum, Windsor Locks, CT.^[7]

Specifications (7 Omega)

Data from Lumsden.^[4]

General characteristics

Type: 7-cylinder, single-row, rotary engine
Bore: 110 mm (4.3 in)
Stroke: 120 mm (4.7 in)
Displacement: 8 L (488.2 cu in)
Length: 79 cm (31 in)
Diameter: 84 cm (33 in)
Dry weight: 75 kg (165 lb)

Components

Valvetrain: pressure-driven inlet valves were located on the pistons^[1]
Oil system: Total loss, castor oil
Cooling system: Air-cooled
Reduction gear: Direct drive, right-hand tractor, left-hand pusher

Performance

Power output: 37 kW (50 hp) at 1,200 rpm

Footnotes

^ ^a ^b ^c Nahum 1999, pp. 12–14
^ ^a ^b ^c Smithsonian Institution 2018
^ Murphy 2005
^ ^a ^b Lumsden 2003, p. 152
^ Shuttleworth 2018
^ Schiere 1969, pp. 15–16
^ Hurley 2018

References

Hurley, Nick (2018). "Gnome 7 Omega". New England Air Museum. Archived from the original on August 18, 2018. Retrieved Aug 17, 2018.
Lumsden, Alec (2003). British Piston Engines and their Aircraft. Marlborough, Wiltshire, UK: Airlife Publishing. ISBN 1853102946.
Murphy, Justin D. (2005). Military aircraft, origins to 1918: an illustrated history of their impact. Santa Barbara, Calif. [u.a.]: ABC-CLIO. pp. 32–33. ISBN 1-85109-488-1.
Nahum, Andrew (1999). The rotary aero engine. London, UK: Science Museum. pp. 12–14. ISBN 1-900747-12-X.
Schiere, J (1969) [1913]. "Aeroplanes & Dirigibles: Argentine". In Jane, Fred T. (ed.). Jane's All the World's Aircraft. Vol. 1913. New York, NY: Arco Publishing Company Inc. LCCN 69-14964. Retrieved Aug 17, 2018.
Smithsonian Institution (2018). "Gnome Omega No. 1 Rotary Engine". National Air and Space Museum. Washington, DC: Smithsonian Institution. Archived from the original on July 10, 2018. Retrieved Aug 17, 2018.
Shuttleworth (2018). "Blackburn Monoplane". Shuttleworth Collection. Archived from the original on August 19, 2018. Retrieved Aug 17, 2018.