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.

L2
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. It initially developed a cruise power of 195 horsepower (hp) (145 kW) at 1,550 rpm but was developed to 220 hp (164 kW).

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.

Variants

• L2 initial version.
• L2a refined L2, 230 hp.

Applications

Early versions of

• Junkers F 13
• Junkers A 20
• Junkers G 23
• Junkers G 24
• Junkers W 33

Re-engined

• Junkers Ju 21

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)

Components

• 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

Performance

• 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

• List of aircraft engines

Bibliography

• 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.