Avro 730

Origins Following the end of the Second World War and facing the threats of the newly emerging Cold War, the Royal Air Force (RAF) was keen to not only preserve but to strengthen its strategic capabilities. In particular, RAF Bomber Command sought to replace its inventory of wartime bombers with more capable models that would take advantage of the latest technologies, such as jet propulsion and nuclear weapons. During the late 1940s and early 1950s, an entirely new jet-powered bomber fleet comprising three aircraft, the Vickers Valiant, the Avro Vulcan, and Handley Page Victor, which were collectively known as the V-bombers, was developed and introduced to service with the RAF. The V-bombers were purpose-built to be armed with the first generation of Britain's nuclear weapons, designated as Blue Danube, and served as the airborne carriers of Britain's nuclear deterrence for many years. As such, the Air Staff set about formulating an Operational Requirement, and in 1954 Specification OR.330 was issued with the specified required performance attributes. The envisioned reconnaissance aircraft would be capable of successfully entering the airspace of the Soviet Union while avoiding the sophisticated hostile air defences. The aircraft would have to be capable of maintaining Mach 2.5 at an altitude of , along with the ability to attain at least Mach 3 and operate at a maximum range of 5,754 mi (9,260 km). By operating at such a high altitude and speed, along with assorted advanced electronic systems on board, it was believed that the specified aircraft would be capable of evading the threats posed by Soviet interceptor aircraft and newly developed surface-to-air missiles. As an aid to development, the Bristol Type 188 aircraft was built to test the compound-delta wing shape, and later, the effects of prolonged supersonic flight on metal. Up to 10 prototype aircraft were proposed, necessitated in part by a decision made part-way through the development process to give the aircraft a bombing capability. The initial version of the aircraft had been intended strictly for the aerial reconnaissance role, using its "Red Drover" side-looking airborne radar to find targets for the V bomber force that would follow. As development progressed, it became clear that the radar could use a smaller antenna, which resulted in freeing up considerable internal space. It was suspected that by the time the aircraft came into service a decade later it would have been vulnerable to Soviet advances in anti-aircraft missile technology. Effort was instead transferred to the Blue Streak medium-range ballistic missile, while the sole 730 test fuselage was cut up. ==Design==

The Avro 730 was originally designed solely for aerial reconnaissance purposes. In order to achieve the desired high speed performance, the aircraft consisted of a long, slender fuselage with a high fineness ratio and a small, tapered, almost rectangular wing that was mounted centrally on the fuselage. The aircraft adopted a canard configuration; this approach had the effect of greatly reducing trim-drag, while also generating increased lift at slower speeds. roll control was provided by the nose-mounted tail plane via trailing edge elevators, pitch control was enacted by ailerons located on the wing's trailing edge, and yaw control was achieved by a conventional rudder. All four primary flight control surfaces were actuated by a quadruple-redundant electro-hydraulic control unit, designed by Boulton Paul. As originally envisioned, a crew of three would be carried: pilot, navigator and radar operator. In order to increase wing area, extra "winglettes" were added outside of the engine pods and the entire planform was re-shaped to be more of a classic delta wing. The wing inside the engine pods, about two-thirds of the overall span, was swept at about 45°, the smaller area outboard of the engine was more highly swept at about 60°. The forward sweep on the trailing edge was removed. The engine pods were now specified to carry four Armstrong-Siddeley P.176 engines each, for a total of eight. The pods were circular at the front and mounted a single large shock cone, growing progressively more "square" to the rear, where they ended flush with the rear of the wing. Much of the layout was generally the same as the earlier version, with the rectangular canards, buried cockpit and large cropped-delta vertical fin at the rear. In the new version, the crew was reduced to two. The bomb bay was narrow, but very long at , and was intended to be armed with a nuclear-tipped stand-off missile. A suitable warhead had started development as Blue Rosette. ==Specifications==