A little acorn …

Any short list of the great aircraft of World War II must include the Royal Air Force’s Avro Lancaster, which was not only the prime lifter in the RAF’s night bombing offensive but also carried out a number of spectacular missions, notably the “Dam Busters” and the sinking of the German battleship Tirpitz.

But unlike other successful bombers of the era, the Lancaster was not the result of long development and evolution. Rather, it was an attempt to save a failed earlier Avro bomber, the Manchester – “Mighty oaks from little acorns grow.”

The Manchester was designed to meet a 1936 RAF specification for a twin-engine medium bomber powered by the new Rolls Royce Vulture engine, carrying a bomb load of 8,000 pounds or two 18 inch torpedoes, and capable of executing shallow (30 degree) dive bombing attacks.

The Manchester was conventional looking: twin engines underslung on mid-mounted wing and twin vertical tail fins. The fuselage was straight from nose to tail and contained a very large, unobstructed, single celled bomb bay that took up two thirds of the fuselage and could carry more than 10,000 pounds of bombs.

 The flight deck was mounted high in a large canopy that provided good all-around visibility. It carried a crew of seven and was heavily armed with three power-operated turrets carrying a total of eight .303 Browning machine guns.

On the strength of design alone, Avro received an order for 200 Manchesters on July 1, 1937, but the first prototype did not fly until July 25, 1939. Tests on the new aircraft revealed some minor problems, notably directional instability, which was reduced by adding a fairly large fin on the top of the rear fuselage.

But there was one major problem – the complex Rolls Royce Vulture engine, basically two engines joined together driving a single crankshaft and with an intricate lubricating system. When development began in 1935, the engine showed promise, but over time it proved unreliable and produced much less power than promised. Rolls Royce continued to work on the Vulture, but the company had more urgent jobs in 1939 and 1940 than fixing the Vulture – specifically, developing its Merlin that was powering Hurricanes and Spitfires.

With orders for 1,200 Manchesters and Rolls Royce concentrating on the Merlin, Avro feared the Vulture would never be combat ready. As a precaution, it took a Manchester, added a longer wing and mounted four Merlins on it.

This “Manchester III” was essentially the first Lancaster and received the Lancaster name after its first flight on Jan. 9, 1941. Meanwhile, Avro persisted with the Vulture-powered Manchester, which entered service with No. 207 Squadron of RAF Bomber Command in November 1940. The squadron’s work-up was severely hampered by the unreliability of the Vulture engines and the fact it often left a trail of sparks – an undesirable feature in a night bomber. It also had a disturbing tendency to catch fire in flight.

Their first combat operation came on Feb. 24, 1941, against a German cruiser in Brest harbor, then two nights later the squadron attacked Germany for the first time as part of the RAF’s night bombing offensive.

Continued problems with the engines led to frequent groundings, and in April 1941 all Manchesters were grounded to have engine bearings replaced because the Vultures were repeatedly overheating.

In theory, the Manchester could fly on one of the low powered Vultures, but generally the failure of one engine put such a load on the other it usually (and quickly) led to a forced landing. Another problem was, because of Vulture’s low power, the Manchester, while it had an advertised service ceiling of 19,200 feet, had a maximum ceiling with a full load of 10,000 feet – in range of light German AAA.

Nevertheless, the RAF’s desperate need for relatively modern night bombers kept it in front line service. By April, a second squadron had formed with Manchesters – No. 97 – and during the summer of 1941, No. 61 Squadron became the third Manchester squadron and the first to receive the Mk IA, which dropped the fuselage fin for new, taller twin fins and rudders. The larger fins and rudders were mounted on a new tail plane that was 11 feet longer than the original.

By the fall of 1941, the reliability of the Vultures increased and, in percentage terms, Manchesters losses to mechanical failure were the same as other bombers in the command. In response, four more squadrons were re-equipped with the aircraft, which eventually equipped eight bomber squadrons. Still, of the 1,200 Manchesters ordered originally from Avro, only 202 were produced. Production ended in November 1941, and the last Manchester mission was flown on June 25, 1942.

 Manchesters flew 1,269 operations, dropped 1,826 tons of bombs and lost 78 of their number – 45 were from non-operational losses, and 30 of which involved engine failure.

Meanwhile, the Lancaster moved into quantity production and showed the basic Manchester design had many excellent features; in fact, the fuselage was little changed throughout the war.

 Because of its dive bomber ancestry, it was very strong and could take a great deal of damage, the bombardier position was the best of any Allied bomber, its armament remained basically unchanged, and the huge bomb bay could carry any Allied bomb, including the 22,000 pound Grand Slam.

Dr. Michel is currently deployed downrange.