Junkers L55

Junkers L55

Company type	Aircraft piston engine
Industry	Aerospace
Predecessor	Junkers L5
Founded	1927
Successor	Junkers L88
Products	Aircraft engines

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The Junkers L55 represented Junkers' inaugural V-12 powerplant, introduced in 1927 and constructed by combining two six-cylinder L5 engines. A supercharger was incorporated in 1928 to enhance performance. This engine powered one or two early Junkers models but was soon supplanted by the geared L88 V-12 in 1929.

Design and development

Among Junkers' range of six-cylinder inline four-stroke engines, the L5 was the most extensively utilized, debuting in 1922. In 1927, the design evolved into the 665 hp L55, featuring two banks of six cylinders arranged at a 60° angle. These cylinder banks retained the same bore, stroke, camshaft-driven twin intake and exhaust valves per cylinder, water cooling system, and other features as the L5, but were connected to a newly designed common crankshaft housed within an updated crankcase. To boost high-altitude output, a supercharger was fitted one year later.

Operational history

The L55 is definitively documented as powering only two aircraft: the early versions of the Junkers G 38 and the Junkers A 32. Initially, the first G 38 was equipped with two inboard L55 engines alongside two L8 units. It is possible that the high-altitude experimental Junkers Ju 49 employed the L55 during its initial flight tests. The L55 was quickly phased out in favor of the L88 in both the G 38 and Ju 49 models.

Applications

• Junkers A 32
• Junkers G 38
• Junkers Ju 49, potentially