The Avro Manchester originated with an Air Ministry specification dating from November 1936 for a bomber capable of carrying a load in excess of 8,000lbs over more than 2,000 miles. This aircraft would be powered by a Rolls-Royce X-Type engine, which was then still under development. This engine, soon renamed Vulture, was the cause of most of the type’s problems. It was basically two Peregrine engines joined together (one inverted on top of the other) driving a single crankshaft. The engines were prone to overheating and fitted with a complex lubricating system, which also gave constant trouble.
A total of 1,200 aircraft were ordered even before the prototype made its first flight on 25 July 1939. Tests showed that handling was poor, and this was only partially rectified by increasing the wingspan and fin area of later aircraft. The Manchester finally entered service with 207 Squadron in November 1940, but the type’s first bombing missions were not made until February the following year.
The new bombers were highly unpopular. One pilot recalled that: ‘The engines never were and never did become reliable. They did not give enough power for the aeroplane, so we ended up with two extremely unreliable 1,750hp engines having to haul a 50,000lb aircraft. We should really have had 2,500hp engines. You felt that if you’d lost one, that was it – you weren’t coming home.’
The pilot continued: ‘It didn’t matter if you feathered the propeller or not. There was only one way you went and that was down. I have seen an aircraft doing a run-up on the ground and have two pistons come right out through the side of the engine. The original bearings were made without any silver as an economy measure, so they weren’t hard enough. The bearings would collapse the connecting rod and the piston would fling out through the side of the engine and – bang! – your engine just destroyed itself.’
Inherent unreliability Although several more squadrons were equipped with Manchesters, their inherent unreliability was so bad that only 200 or so aircraft were ever completed. A total of 77 were lost on operations, with an additional 44 destroyed in accidents – at least 61 of these were due to engine failures. To the relief of its crews, the type was finally withdrawn from operation in June 1942.
Avro had quickly recognised that the Vulture’s problems might be insoluble and, even before orders were placed for the Manchester, the firm’s chief designer, Roy Chadwick, started work on a feasibility study to assess the possibility of fitting different engines. He quickly established that the most promising option was to extend the wings to accommodate four Merlin engines and, after some wrangling with the Air Ministry, the project was approved in November 1940, with this new version designated the Manchester III.
In this case, going ‘back to the drawing board’ worked far better than anyone anticipated: the prototype first flew on 9 January 1941, and immediately demonstrated vastly improved handling and overall performance. An initial order for 1,070 aircraft – soon renamed Lancaster – was placed almost immediately, and the type went on to become one of the mainstays of RAF Bomber Command. A total of 7,377 were completed by the time that production ended in March 1946. •