Armstrong Whitworth AW.52

The Armstrong Whitworth AW.52 was a test vehicle for a possible future airliner.

Development
Since the development of powered flight there have been many efforts to produce pure flying wing aeroplanes. During the 1940s the most high profile attempts to produce this type of aircraft came from the American Northrop company, work which resulted in the XB-35 piston and YB-49 jet bomber programmes. However, the British Armstrong Whitworth Aircraft company (AWA) also looked in some depth at flying wings and the AW.52 represents the most important result of that work. It was envisaged that a passenger airliner weighing about 180,000|b or more could be the result.

A September 1943 report from the Tailless Aircraft Advisory Committee noted that tailless aircraft had been built at almost every stage in the history offlying. They had flown reasonably well, but in general had failed to hold their own against other aircraft types. The reason form this was simple - the reduction of drag was not sufficient to outweigh the disadvantages introduced by difficulties of trim, control and stability. But there were two main arguments in favour ofthe tailless aircraft - drag was low and in military types the field of fire to the rear was excellent. The saving in drag over conventional types was very little if the aircraft was small because of the relatively large body, but it would increase as size increased. The tailless type also lent itself to the fitting of gas turbine engines and thus enabled full advantage to be taken of laminar flow wings. As far as the U K was concerned, research had moved forward very little from where it had stood in 1934 when development of the Hill Pterodactyl was abandoned.

Since the abandonment of the Pterodactyl only two small tailless aircraft had been flown, the Handley Page HP.75 Manx and a Muntz-Baynes glider. By September ‘I943, however, a number of tailless projects had been put forward by British aircraft firms and the Ministry of Aircraft Production (MAP) had decided that flight test experiments should be put in hand immediately to obtain data, particularly on the problems of trim and control, using two types of flying wing, one V-shaped and the other U-shaped, and these were built as gliders by General Aircraft. It was at this point that a proposal for a tailless glider model of a large type was also put forward by Armstrong Whitworth.

Research glider
Armstrong Whitworth began its investigations into the possibilities of tailless aircraft and laminar flow wings in 1942, the objective being high performance and economical long range. This was in response to a request by the Directorate of Scientific Research to design a full-scale wing section that would be suitable for laminar flow drag tests in the National Physical Laboratory (NPL) wind tunnel. The resulting specimen was roughly 6ft chord by 8ft span and proved satisfactory in that proﬁle dragwas reduced by a half and the wing maintained laminar flow for up to 60% of the chord. In due course discussions between the firm and members of the Tailless Aircraft Advisory Committee were made under the aegis of N.E. Rowe, the director of technical development at MAP (the committee was formed in July 1943 to assess and provide information on tailless and tail first aircraft). The first AWA design was the unsolicited AW.5O bomber of December 1942, which had a swept wing and no horizontal tailplane, and this was followed by a project for a one-third scale model glider to go with it called the AW.51. However, during 1943 work moved on to the AW.52G (glider) as a half-scale model for the bomber or for a larger power—driven tailless aeroplane.

For the AW.52 family longitudinal and lateral control was to be achieved using two surfaces in tandem on each outer wing called the "corrector" and the "controller". The corrector was the forward surface and with power operation its function was to provide a course~trimming device capable of counteracting major changes of longitudinal trim such as occurred when the landing flap was lowered. The controller served an elevator and aileron and was hinged behind the corrector. Another vital aspect when designing high speed tailless aircraft, or indeed any sweptback wing, was to provide adequate ﬂexural and torsional stiffness to prevent aileron reversal and wing-aileron flutter. The bending stiffness of a swept wing was vitally important since pure bending distortions produced changes in incidence, something that did not occur in a normal unswept wing.

AW.52G airborne
The AW.52G was given the military serial RG324 and was towed into the air for the first time on March 2, 1945, from the manufacturer's Baginton facility. One of the firm's own Whitley bombers (LA95l) was a tug and the glider's take-off speed using 10° of flap was 75 m.p.h. Charles Turner-Hughes was the glider pilot and he performed almost all of the aircraft's early flying, but later the AW.52G programme was shared by AWA pilots R. Midgley and Eric G. Franklin; observers to fly in the AW.52G were a Mr Kent of A.W. Hawksley Ltd and later W.W. Barratt of AWA. The chief designer at AWA from 1923 to 1948, and who was responsible for both AW.52G and AW.52, was John "Jimmy" Lloyd.