Not fair to criticise the Avro Manchester, Harry. It was a capable machine that would have fared much better had Rolls Royce been able to divert more effort on the Vulture engines. They were unable to as the RAF instructed the firm to concentrate most of its effort on the Merlin and the rest to the Griffon. The Vulture ended production prematurely ( although the quick increase in span and 4 of the Merlins created the sublime Lancaster). The Westland Whirlwind suffered by having no support for the Peregrine engines and consequently only 2 squadrons of them were formed. War is hell!