Junkers L2

The Junkers L2 was Junkers' first water-cooled four-stroke engine and the first to be built on a production line, though only 58 were made. It was a six-cylinder inline engine and powered many Junkers aircraft until replaced by the more powerful L5.

Type 4-stroke petrol 6-cylinder water-cooled inline aircraft engine
National origin Germany
Manufacturer Junkers Motorenbau GmbH (Jumo)
First run 1925
Number built 58

Design and development

The Junkers L2 (the L signifying a four-stroke petrol engine rather than a two-stroke diesel) had some features in common with their first petrol engine, the L1, both six-cylinder upright direct drive inline engines with four overhead camshaft driven valves per cylinder, but was water-cooled rather than air-cooled and had a much greater swept volume.[1] It initially developed a cruise power of 195 horsepower (hp) (145 kW) at 1,550 rpm but was developed to 220 hp (164 kW).[2]

Operational history

The L2 powered early versions of several Junkers aircraft. It was soon replaced in these models by the more powerful Junkers L5 and only 58 L2s were built.[1]


  • L2 initial version.
  • L2a refined L2, 230 hp.[1]


Early versions of[1]


Specifications (L2)

Data from Kay (2004), pp. 263–264

General characteristics

  • Type: 6-cylinder upright water-cooled inline 4-stroke piston engine
  • Bore: 150 mm (5.906 in)
  • Stroke: 180 mm (7.09 in)
  • Displacement: 19.1 L (1,166 cu in)
  • Length: 1.58 m (5 ft 2¾ in)
  • Width: 0.555 m (1 ft 9¾ in)
  • Height: 1.085 m (3ft 6¾ in)
  • Dry weight: 310 kg (684 lb)


  • Valvetrain: Two inlet and two exhaust valves per cylinder, overhead camshaft operated
  • Fuel system: Twin carburettors
  • Fuel type: Petrol
  • Oil system: Combined splash and pressure
  • Cooling system: Water-cooled
  • Reduction gear: Direct drive


  • Power output: cruise 195 hp (145 kW) at 1,550 rpm, take-off 230 hp (171 kW)
  • Fuel consumption: 31.82 kg/h (70.16 lb/hr)

See also

Related lists


  1. Kay (2004), pp. 263–264
  2. Gunston (2006), p. 112
  3. Kay (2004), p. 44


  • Gunston, Bill (2006). World Encyclopedia of Aero Engines: From the Pioneers to the Present Day (5th ed.). Stroud, UK: Sutton. ISBN 0-7509-4479-X.
  • Kay, Antony (2004). Junkers Aircraft & Engines 1913–1945. London: Putnam Aeronautical Books. ISBN 0-85177-985-9.

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