Gnome Sigma

The Gnome 7Σ Sigma (commonly called the Gnome 60 hp) is a French seven-cylinder, air-cooled rotary aero engine.^[1]

Sigma
Gnome 7 Sigma as shown in a 1913 Gnome catalog
Type	Rotary aero engine
National origin	France
Manufacturer	Société des Moteurs Gnome

The Sigma produced 60 hp (45 kW) from its capacity of 9.5 L (579.73 cu in).

Specifications (7 Sigma)

Longitudinal elevation of Gnome 7 Sigma, from 1913 Gnome catalog

Data from Société Des Moteurs Gnome^[2]

General characteristics

• Type: 7-cylinder, single-row, rotary engine
• Bore: 120 mm (4.72 in)
• Stroke: 120 mm (4.72 in)
• Displacement: 9.5 L (579.73 cu in)
• Length: 1,125 mm (44.29 in)79 cm (31 in)
• Diameter: 826 mm (32.52 in)
• Dry weight: 79 kg (174 lb)

Components

• Valvetrain: pushrod operated overhead exhaust valves plus pressure-driven inlet valves located in the piston crowns^[3]
• Fuel system: a single static Bloctube carburretor feeding the crankcase
• Fuel type: 40 / 50 octane gasoline
• Oil system: pressure-fed total loss, castor oil
• Cooling system: Air-cooled
• Reduction gear: Direct drive, right-hand tractor, left-hand pusher

Performance

• Power output: 45 kW (60 hp) at 1,200 rpm

See also

Comparable engines

• Clerget 7Z
• Le Rhône Type 7A
• Le Rhône Type 7B
• Le Rhône Type 7B2

Related lists

• List of aircraft engines

References

Notes

1. National Air and Space Museum - Gnome Omega Archived 2012-04-19 at the Wayback Machine Retrieved: 11 November 2010.
2. Moteurs Gnome (PDF) (in French). Paris: Société Des Moteurs Gnome. October 1913. pp. 6–10. Retrieved 26 June 2018.
3. Nahum, Andrew (1999). The rotary aero engine. London: Science Museum. pp. 12–14. ISBN 1-900747-12-X.
4. 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.

Bibliography

• Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.

External links

• Smithsonian/NASM's page on Gnome Omega No.1
• Video of April 2009 ground runup of a restored Gnome Omega in the USA