Avro Lancaster B.VI British Heavy Bomber
The Avro Lancaster B.VI was a development of the B.III fitted with Rolls Royce Merlin 85/87 engines which had two-stage superchargers, giving much improved high-altitude performance. The engines were fitted with annular radiators similar to the Lincoln and had three-bladed paddle-type propellers. The B VI could achieve a maximum speed of 313 mph (504 km/h) at 18,200 ft (5,500 m). Only nine were built, converted from B.IIIs and only seven of these served with squadrons (7,83,405 (RCAF) and 635 squadrons). The two remaining aircraft were retained by Rolls Royce for testing.
The Merlin 85/87 proved unreliable in service and all B.VIs were withdrawn from squadron used by November 1944. The remaining machines were used by Rolls-Royce, the Royal Aircraft Establishment and the Bomb Ballistics Unit (BBU) for various testing and experimental duties.