The Junkers L 5 was a six-cylinder, water-cooled, inline engine for aircraft built in Germany during the 1920s. First run in 1925, it was a much enlarged development of the Junkers L2.
The Junkers L5 was a development of Junkers' first water-cooled engine, the L2, but at four times the swept volume was a much more powerful engine. It was a water-cooled upright inline 6-cylinder unit, four-stroke and petrol-fuelled, with a capacity of nearly 23 litres. It adopted some of the L2 features, having twin exhaust and inlet valves in each cylinder[2]driven by an overhead camshaft, twin spark plugs and twin magnetos. The splash component of the L2's lubrication was abandoned in favour of a completely forced recirculating system. The twin carburettors of the L2 were replaced with a single float chamber, dual-venturi model. Like the L2, the L5 was a direct drive engine.[2]
The compression ratio of the standard version was 5.5:1, but variants had other ratios to cope with fuels with octane ratings between 76 and 95. The G series introduced carburettor heating together with an hydraulically damped mounting system. There were also choices of starting system, from inertial or compressed air systems to the traditional hand swinging.[2]
Operational historyedit
The L5 proved to be reliable and became the engine of choice for most Junkers aircraft in the mid-1920s as well as powering aircraft from other German manufacturers.[2] Many of these powered the Junkers F.13 and its derivatives like the W 33, which dominated world air transport in the mid-1920s.[3]
The best demonstration of the reliability of the L5 was given by the unit which powered the single-engined W 33 Bremen in the first fixed wing east to west crossing of the Atlantic in April 1928. For this flight the compression ratio was raised to 7:1 to provide sufficient power for the heavily fuelled aircraft at take off. In July 1925 a W 33 powered by a L5 stayed aloft for 65 h 25 min, with a fuel consumption of 35.6 kg/h.[2]
Variantsedit
L5 many variants including a variety of compression ratios, power output levels and starting systems.
L55 an upright V-12 built from two L5s on a common crankshaft.
L8 a significant 1929 development with the same swept volume but cruising at 2,100 rpm and delivering 354 hp; take off power was 413 hp. The output was geared down at ratios between 2.47:1 and 1.44:1 to enhance propeller efficiency. Only a few were produced, powering early configurations of the Junkers G 38 as outer engines, with two L55s inboard.[2]
L88 an upright V-12 built from two L8s on a common crankshaft.
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The Junkers L 5 was a six cylinder water cooled inline engine for aircraft built in Germany during the 1920s First run in 1925 it was a much enlarged development of the Junkers L2 L5 Junkers L5 on display at the Junkers Museum Type Inline aircraft engine Manufacturer Junkers Motorenbau GmbH Jumo First run 1922 1 Major applications Junkers F 13 Number built gt 1 000 2 Variants Junkers L55 Contents 1 Design and development 2 Operational history 3 Variants 4 Applications L5 5 Specifications Jumo L 5 5 1 General characteristics 5 2 Components 5 3 Performance 6 See also 7 References 8 Bibliography 9 Further reading 10 External linksDesign and development editThe Junkers L5 was a development of Junkers first water cooled engine the L2 but at four times the swept volume was a much more powerful engine It was a water cooled upright inline 6 cylinder unit four stroke and petrol fuelled with a capacity of nearly 23 litres It adopted some of the L2 features having twin exhaust and inlet valves in each cylinder 2 driven by an overhead camshaft twin spark plugs and twin magnetos The splash component of the L2 s lubrication was abandoned in favour of a completely forced recirculating system The twin carburettors of the L2 were replaced with a single float chamber dual venturi model Like the L2 the L5 was a direct drive engine 2 The compression ratio of the standard version was 5 5 1 but variants had other ratios to cope with fuels with octane ratings between 76 and 95 The G series introduced carburettor heating together with an hydraulically damped mounting system There were also choices of starting system from inertial or compressed air systems to the traditional hand swinging 2 Operational history editThe L5 proved to be reliable and became the engine of choice for most Junkers aircraft in the mid 1920s as well as powering aircraft from other German manufacturers 2 Many of these powered the Junkers F 13 and its derivatives like the W 33 which dominated world air transport in the mid 1920s 3 The best demonstration of the reliability of the L5 was given by the unit which powered the single engined W 33 Bremen in the first fixed wing east to west crossing of the Atlantic in April 1928 For this flight the compression ratio was raised to 7 1 to provide sufficient power for the heavily fuelled aircraft at take off In July 1925 a W 33 powered by a L5 stayed aloft for 65 h 25 min with a fuel consumption of 35 6 kg h 2 Variants editL5 many variants including a variety of compression ratios power output levels and starting systems L55 an upright V 12 built from two L5s on a common crankshaft L8 a significant 1929 development with the same swept volume but cruising at 2 100 rpm and delivering 354 hp take off power was 413 hp The output was geared down at ratios between 2 47 1 and 1 44 1 to enhance propeller efficiency Only a few were produced powering early configurations of the Junkers G 38 as outer engines with two L55s inboard 2 L88 an upright V 12 built from two L8s on a common crankshaft Applications L5 editAlbatros L 73 Albatros L 75 Albatros L 83 Adler Focke Wulf A 32 Heinkel HD 42 Heinkel He 50 Junkers F 13 Junkers A 20 Junkers A 35 Junkers G 23 Junkers G 24 Junkers K 30 Junkers G 31 Junkers W 33 Messerschmitt M 24 Rohrbach Ro VIIISpecifications Jumo L 5 edit nbsp Junkers L8 engine on display at the Polish Aviation Museum Data from 2 General characteristics Type 6 cylinder liquid cooled inline Bore 160 mm 6 3 in Stroke 190 mm 7 5 in Displacement 22 92 L 1 399 cu in Length 1 750 mm 69 in Width 650 mm 26 in Height 1 265 mm 49 8 in Dry weight 334 kg 736 lb dry Components Valvetrain Single exhaust and single inlet valves driven by a single overhead camshaft shaft and gear driven from the crankshaft Fuel system Single float dual venturi carburettor twin plugs per cylinder twin magnetos Fuel type 95 octane dependent on compression ratio Oil system forced Cooling system liquid Performance Power output Take off 260 kW 350 hp at 1 450 rpm Cruise 210 kW 280 hp dd dd dd Compression ratio 7 1 Fuel consumption 61 6 kg h 136 lb hr Power to weight ratio 0 78 kW kg 0 47 hp lb See also editRelated lists List of aircraft enginesReferences edit Gunston 2006 p 112 a b c d e f g h Kay 2004 pp 264 265 Kay 2004 p 62Bibliography editGunston 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 amp Engines 1913 1945 London Putnam Aeronautical Books ISBN 0 85177 985 9 Further reading editExternal links edit nbsp Wikimedia Commons has media related to Junkers L5 The Hugo Junkers Homepage http www oldengine org members diesel Duxford germaer1 htm Archived 2007 08 04 at the Wayback Machine Retrieved from https en wikipedia org w index php title Junkers L5 amp oldid 1212082812, wikipedia, wiki, book, books, library,
