 It had a blended wing tailless design and he successfully tested several models, including a six-foot scale model at speeds of up to Mach 2, in the 1950s, but in 1957, government backing was withdrawn for many aeronautical research and development programs, including Wallis' work.One outcome of Wallis's work was a visit to the US during which he collaborated with the NASA Langley Laboratory team of Alford, Polhamus on a design study for a variable-sweep fighter.Although it used the pivot mechanism he had developed, NASA also insisted on giving it a conventional horizontal stabiliser to ease the issues of trim and manoeuvrability.