Early Manchester in flight
The Rolls-Royce Vulture engine, despite its ambitious design, is often remembered as a significant failure, much like other “lemons” in various industries. Developed starting in 1935, the Vulture was a liquid-cooled, X-configuration engine with four banks of six cylinders, aimed to provide substantial power for heavy aircraft. However, it faced numerous issues throughout its development and service.
Key aspects of the Vulture included its shared bore and stroke dimensions with earlier Rolls-Royce engines like the Kestrel and Merlin, although it was a new design. It featured single-stage, two-speed supercharging and a complex gear train designed to manage the high torque from the crankshaft. The engine also had contra-rotating propeller drives developed for the Hawker Tornado aircraft.
The Vulture suffered from significant mechanical failures, particularly with its connecting rods and main bearings. The design of the connecting rods, initially using a master and link rod configuration, led to frequent failures. Problems with fretting in the connecting rod and crankcase joints further exacerbated these issues, despite several design iterations and attempted fixes, such as the introduction of dowels in the crankcase to prevent fretting.
The engine’s cooling system also had design flaws, particularly cavitation issues in the dual coolant pumps, which could cause overheating. This problem was eventually resolved with a balance pipe, but not before causing several critical failures.
These mechanical problems led to significant losses of aircraft and crew, and by 1941, the ongoing issues with the Vulture were too great to continue. The decision to discontinue the engine in 1942 was also influenced by the redesign of the Avro Manchester bomber, the primary aircraft using the Vulture, to use four Merlin engines instead, leading to the successful Avro Lancaster. The Lancaster’s surprising performance further underscored the inadequacies of the Vulture, which had its power output downgraded due to reliability issues .