L7279 EM-B, No 207 Squadron, RAF Bomber Command, Waddington, Lincolnshire, November 1940

Air Ministry specification P.13/36, issued in 1936, called for a twin-engined medium bomber (occasionally referred to as “heavy” in official documents) capable of being used throughout the world and having the highest possible cruising speed to reduce time spent over enemy territory. Defence was to be at least nose and tail power-operated turrets. Cruising speed at two-thirds maximum power 275mph with normal loading. Also at normal loading, takeoff 500 yards, to carry 1,000lb of bombs for 1,000 miles minimum range at 15,000ft whilst cruising at maximum cruising revs. The airframe was to be stressed for catapult launching, the idea being that fully loaded with bombs and fuel the plane wouldn’t be able to take-off with engine power alone from a standard RAF runway of the time. It was assumed engines of around 2,000hp would be required for a large twin-engined design. At the time of the specification issue in summer 1936, at least three engines in that class were under development, from Rolls-Royce, Napier and Bristol. The aircraft had to carry up to 16 250lb or 500lb or four 2,000lb armour piercing bombs; provision also to carry two 18in torpedoes. Also included in the specification were the functions of general reconnaissance and general purpose, with the idea the aircraft could carry personnel and equipment if required — the new design was to be a Swiss Army knife of an aeroplane, if you like.

The Avro 679 was a step into the unknown by the company. It was one of the biggest and heaviest aircraft ever conceived by Avro, had the highest wing loading and incorporated a stressed-skin all-metal structure. The entire fuel load was carried in the wings, and the bomb bay was clear of obstructions and nearly two-thirds the length of the fuselage. Compare this with everything that went before: the Wellington had a long bay, but divided into four longitudinal strips, as did the Stirling; the Hampden had a clear bay, but it was short; the Whitley had several bays and wing cells; the Stirling also had wing cells. Reasonable bomb loads, yes, but limited in the size of the ordnance that could be loaded.

Emphasis in the new design was placed on comfort and protection for the crew. The flight crew was housed together in a forward cabin enclosed by a glazed canopy, warmed by ducted air passing through a small coolant radiator housed within the wing. Both pilots were provided with armoured backplates, and a pivoted armour-plated bulkhead was located just ahead of the front spar. There was a comfy reclining armchair amidships, so crew could take a rest on long flights. Hydraulics were used to retract the landing gear and operate flaps, radiator, air intake shutters and the bomb bay doors.

Napier, Bristol and Rolls-Royce were considered as providers of engines for the new bomber. Napier had been working on an advanced design with the 24-cylinder block in an “H” configuration, but it was still at an early stage of development. Bristol had the Centaurus, an 18-cylinder radial sleeve valve design, again at an early stage of development. The only engine close to production status was the Rolls-Royce Vulture.

The supercharged Rolls-Royce Kestrel and its derivative, the Rolls-Royce Peregrine, were fairly standard designs, with two cylinder banks arranged in a V-form and with a displacement of 21 litres. The Vulture was, in effect, two Peregrines joined by a new crankcase turning a new crankshaft, producing an X-engine configuration with a displacement of 42 litres. The Vulture used cylinders of the same bore and stroke as the Peregrine, but the cylinder spacing was increased to accommodate a longer crankshaft, necessary for extra main bearings and wider crankpins.

There is said to be a maxim in aircraft design that it is unwise to marry a new engine to a new airframe.

Early flight tests of the Manchester prototypes showed the high wing loading made the plane difficult to handle. The wingspan was increased by almost ten feet to improve the situation. There was some noticeable lateral instability, alleviated in the first place by fitting a central vertical fin. Later, the problem was cured by fitting a wider tailplane and taller fin plates and rudders. The ventral FN21A turret introduced drag, somewhat fixed by installing a Frazer Nash FN7 dorsal turret instead, though that was also not without problems. Once in full squadron service, issues such as hydraulic failure, defective propeller feathering controls and tail flutter began to plague the Manchester. The biggest problem, though, was those Vultures.

While the Vulture engines promised much, they showed intractable problems. The engine suffered from an abbreviated development period because Rolls-Royce suspended Vulture development in 1940 during the Battle of Britain to concentrate on the Merlin. As a consequence the reliability of the Vulture when it entered service was very poor. Apart from delivering significantly less than the designed power, the Vulture suffered from frequent failures of the connecting rod big end bearings, which was found to be caused by a breakdown in lubrication, and also from heat dissipation problems. Rolls-Royce were initially confident that they could solve the problems, but the company’s much smaller Merlin was already nearing the same power level as the Vulture’s original specification, in part because of its accelerated development in 1940, and so production of the Vulture was discontinued after only 538 had been built.

The Ministry felt it imperative to get as many new bombers into squadrons as soon as possible before any likely conflict broke out. An order for 200 Manchesters was placed before the prototypes had even been built. Two prototypes were sent for testing, and the first two production aircraft were also used for tests — including the catapult launch system. Numerous changes were recommended after the testing was done, which were applied to the production line aircraft, and retrospectively to the aircraft already beginning to enter squadron service.

The first squadron to receive the Manchester was No 207 Squadron, which reformed at RAF Waddington on 1 November 1940. The first aircraft they received, on either 6 or 10 November depending on what you read, was L7279, code EM-B. The aircraft was given camouflage Scheme A. The intention was to paint alternate serial numbers in Scheme A or B, but it was decided to settle on Scheme B for future production.

I’ve wanted a Manchester in my life since I first read about the type in the 1980s. It is so often regarded as a failure, something to be forgotten, overshadowed by its more illustrious descendant. Almost ninety years on since the Manchester first flew, I believe it is time to remember Avro’s problem child, give the design its due, and honour the crews that flew them.

My 1/72nd scale Manchester started life as an Airfix Lancaster MkII, with a conversion kit in cast resin by Blackbird Models. Propellers and spinners, plus the main wheels, were kindly provided by a friend and 3D printed. The photographic vignette features “set dressing” models from Ace Models, PH Designs, Airfix and Modelu3D.