Gnome Lambda

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Gnome Lambda - Moteurs Gnome October 1913.png
Gnome 7 Lambda as shown in a 1913 Gnome catalog
Type Rotary aero engine
Manufacturer Gnome et Rhone
First run c.1916
Major applications Avro 504
Bristol Boxkite
Bristol Scout
Number built 979 (British production)

The Gnome 7 Lambda was a French designed, seven-cylinder, air-cooled rotary aero engine that was produced under license in Britain and Germany. Powering several World War I era aircraft types it was claimed to produce 80 horsepower (60 kW) from its capacity of 12 litres (720 cubic inches) although recorded figures are lower.[1]

Just under 1,000 units were produced in Britain, the majority (967) by the Daimler Company of Coventry. A 14-cylinder variant was known as the Gnome 14 Lambda-Lambda.

In Germany Motorenfabrik Oberursel license-built the seven-cylinder engine as the Oberursel U.0 and later copied the 14-cylinder design and designated it as the Oberursel U.III.


Gnome 7 Lambda
Seven-cylinder, single-row rotary engine.
Gnome 7 Lambda (long stroke)
Increased stroke of 145 mm (5.7 in) to raise the compression ratio to 3.87:1, and total displacement to 12.26 litres.
Gnome 14 Double Lambda
14-cylinder, two-row rotary engine using Lambda cylinders. 160 hp (120 kW).
Motorenfabrik Oberursel U.0
German production of the Gnome 7 Lambda - had a 124mm cylinder bore and 140mm piston stroke for a total displacement of 11.52 litres, external diameter of 1.020 meters.[2]
Motorenfabrik Oberursel U.III
:German production of the Gnome 14 Double Lambda


List from Lumsden

The Sopwith Tabloid replica on display at the Royal Air Force Museum is fitted with an original Gnome 7 Lambda[clarification needed] engine.

Gnome 7 Lambda[edit]

Gnome 14 Lambda-Lambda[edit]


An original Gnome 7 Lambda engine is installed in the Sopwith Tabloid replica aircraft on display in the Grahame-White hall of the Royal Air Force Museum London.[4]

Specifications (Gnome 7 Lambda)[edit]

Oberursel U.III, a copy of the 14-cylinder Gnome Lambda-Lambda

Data from Lumsden.[1]

General characteristics

  • Type: 7-cylinder, single-row, rotary engine
  • Bore: 124 mm (4.9 in)
  • Stroke: 140 mm (5.5 in)
  • Displacement: 11.8 L (721.2 cu in)
  • Length: 112 cm (44 in)
  • Diameter: 93 cm (36.6 in)
  • Dry weight: 96 kg (212 lb)


  • Valvetrain: Automatic centre-piston inlet valve, overhead exhaust valve (one each per cylinder)
  • Cooling system: Air-cooled
  • Reduction gear: Direct drive, right-hand tractor, left-hand pusher


  • Power output: 50.3 kW (67.5 hp) at 1,250 rpm (maximum power)
  • Compression ratio: 3.75:1

See also[edit]

Comparable engines

Related lists



  1. ^ a b Lumsden 2003, p. 151.
  2. ^ "Obsah fóra :: Zbraně a vybavení :: Výzbroj, zbraňové systémy, vybavení a příslušenství :: Motory :: Letecké motory :: Pístové :: Německo (DEU) :: Oberursel U.0". (in Czech). Retrieved July 19, 2013.
  3. ^ "The Borel Hydro-Monoplane". Flight: 450. 19 July 1913.
  4. ^ RAF Museum - Sopwith Tabloid replica history[permanent dead link] Retrieved: 11 November 2010.


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