Armstrong Whitworth submitted its "AW.56" proposal against Operation Requirement (O.R.) 229 under specification B.35/46. The requirement ultimately called for a swept-wing, jet-powered medium-class bomber fitting four turbojet engines and having a speed of no less than 575 miles-per-hour, able to reach an altitude of 55,000 feet. The requirement was eventually filled by the classic Avro "Vulcan" and Handley Page "Victor" bombers and, together with the Vickers "Valliant", the trio went on to form the potent "V-bomber" nuclear-capable force for the British Royal Air Force (RAF) force covering decades of service during the Cold War period (1947-1991).
The proposed AW.56 was not advanced beyond its paper stage.
The requirement arose in the immediate post-World War 2 period which saw a war-weary world progressing towards an unsettled peace. The turbojet engine was the way of the future concerning combat warplanes and designs were being thrown about, centered on all-new concepts of faster aircraft flying higher than ever before. With the Soviet Union having now become the new "enemy-of-the-day" for the West, high-flying bombers were in great demand - particularly those capable of hauling nuclear loads over distance.
The AW.56, as it appeared in 1946, was designed largely around a "flying wing" configuration in which the mainplane's wing surface area provided strong inherent lifting properties and extended operational ranges while also supplying more internal volume. This also allowed an unconventional tail unit to be used - in this case a single vertical fin with no horizontal planes as part of its makeup. To this point, large flying wing designs were not all that proven, particularly those being jet-powered and capable of achieving high Mach numbers in flight.
The design was centered along a tubular fuselage which held a heavily-glazed frontal section making up the cockpit. The cockpit was well-streamlined into the shape to maintain maximum aerodynamic efficiency in all speed aspects, the section protruding just a short distance ahead of the wing roots. The roots incorporated slat-style intakes for the four turbojet engines buried within. The wing structure was to blend efficiently into the upper section of the fuselage and contain the aircraft's main collection of powerplants, main landing gear legs, bomb bay, and fuel stores. Ground running was to use a tricycle undercarriage involving a twin-wheeled nose leg and twin-wheeled main landing gear legs. The bomb bay, encompassing two sections, was to be featured at the ventral line of the fuselage running from just ahead of midships to near the base of the tail unit. Instead of hinged doors opening outward (and disrupting airflow at speed), the covers slid away from midships to maintain aerodynamic efficiency. The end-result was a clean, massive aircraft measuring a length of 80 feet with a span of 120 feet.
The mainplane of AW.56 held considerable sweepback along its leading edges. The wingtips were rounded and the trailing edges were straight nearer the fuselage and swept back outboard of the landing gear wells and engine compartments. The turbojets would be installed as pairs in a side-by-side arrangement, each pair straddling the fuselage section at center. A short run of ductwork would funnel air to the engines from the wing roots and the systems would exhaust through ports found at the straight section of trailing edge. As there were not horizontal tailplanes, jet wash was of little concern near the rear of the aircraft.
The four fuselage-based engines were to be 4 x Rolls-Royce "Avon" AJ.65 turbojet types of 6,500lb thrust (each) slipped into the wing-body section while a fifth turbojet of same make, model, and output power was to be installed in the aft-section of the fuselage to provide additional thrust. As this remained an air-breathing engine, the unit was to have been aspirated through a small, semi-circular intake positioned along the dorsal line of the fuselage near midships.
With this arrangement, engineers estimated their 113,000lb medium jet bomber to reach a maximum speed of 640 miles-per-hour with cruising held closer to 580 mph. Its service ceiling would have reached 50,000 feet requiring pressurization of all crew sections. Range was estimated at 3,855 miles with a full war load.
At the internal bomb bay, support was to have been given for both conventional and nuclear bomb loads. This would have entailed 19 x 1,000lb bombs, 3 x 6,000lb bombs, or 1 or 2 x 10,000lb bomb(s).
In 1947, this same aircraft was revised some and this work involved removal of the fuselage-mounted turbojet engine (which, in turn, allowing the intake to be deleted as well). The nose section was completely reworked to provide a "tear-drop" style canopy for the pilot only (the rest of the crew to reside within the fuselage proper). His position was now set towards the port side of the fuselage. The wing planform was also slightly revised though the elegant shaping remained. The Rolls-Royce RB.77 turbojet of 7,500lb thrust (each) was also introduced as an alternative propulsion scheme. The aircraft was shortened to 75 feet and lightened some to 101,105lb. Estimated maximum speed dropped slightly to 575mph.