In January 1947 the British Air Ministry issued a specification for a new bomber that would be able to deliver a nuclear bomb from high altitude and within a fraction of the speed of sound. At this time the only people to have researched high speed flight in any depth had been the Germans, whose engineers had observed that to cruise close to the speed of sound without encountering excessive air resistance meant using very thin and swept wings. Unfortunately there was a problem with this, as it was known that such wings would have to be designed to produce only a limited amount of ‘lift’ if serious airflow problems were to be avoided near the speed of sound.
A.V.Roe, a company with a vast amount of experience in the construction of heavy bombers during the War years, wasted no time in studying the thin swept-wing aircraft and quickly discovered that in order to carry a heavy load at high altitude meant building an aircraft twice the size and weight of that which would be acceptable by the Royal Air Force. Worse still, such a machine would not be capable of achieving the full range and speed demanded by the specifications. Thus the AVRO project team, under the leadership of the brilliant Lancaster designer, Roy Chadwick, realised they would have to design an aircraft that bore no relationship to any existing design principles of the time.
After a number of ‘Flying Wing’ style designs had been considered and rejected, the design team came up with the novel idea of the Delta Wing. With mounting enthusiasm the project team soon realised that this type of wing promised a dramatic reduction in structural weight due to the obvious strength of its great width and short span. In addition the Delta Wing would provide the thinness and sweep back for very high speeds as well as the low wing loading required for high altitude flight. The design team also discovered that the Delta Wing provided other significant advantages: the low wing loading allowed reasonable take-off and landing speeds without the encumbrance of flaps or other high lift devices and, furthermore and possibly most important, the Delta Wing formed a large, rigid structure capable of housing engines, undercarriage, extensive military equipment and of course, a very substantial quantity of fuel-all, without any interference to the aerodynamic shape of the aircraft.
Being a new and untried concept the Delta Wing naturally required a great deal of research to be carried out to ensure the success of the proposed bomber (which would eventually become the famous Avro Vulcan). AVRO built a number of research aircraft, the AVRO 707 series, with one objective only- to prove the design of the Vulcan. All other research work was given second place. The AVRO 707 made its maiden flight from Bosombe Down on the 4th September 1949 with Eric Esler at the controls. Although the 707 was lost in a flying accident a month later sufficient knowledge of the flight characteristics of the Delta Wing had been gained, and development of the Vulcan was hardly interrupted at all.
AVRO’s unorthodox Delta Wing concept would soon be recognized as having great potential for other ultra high speed jet-powered aircraft. In the USA, France and Sweden other aircraft manufacturers seized on this innovative concept for such high speed jets as the B-58 Hustler, A-4 Skyhawk, Dassault Mirage and eventually probably most famously of all - the world first supersonic airliner-the beautiful Concorde.
