<P> Initially, the aircraft was to use Frank Whittle's latest engine, the Power Jets W. 2 / 700, which would only reach supersonic speed in a shallow dive . To develop a fully supersonic version of the aircraft, an innovation incorporated was a reheat jetpipe--also known as an afterburner . Extra fuel was to be burned in the tailpipe to avoid overheating the turbine blades, making use of unused oxygen in the exhaust . Finally, the design included another critical element, the use of a shock cone in the nose to slow the incoming air to the subsonic speeds needed by the engine . </P> <P> Although the project was eventually cancelled, the research was used to construct an unmanned missile that went on to achieve a speed of Mach 1.38 in a successful, controlled transonic and supersonic level test flight; this was a unique achievement at that time which validated the aerodynamics of the M. 52 . </P> <P> Meanwhile, test pilots achieved high velocities in the tailless, swept - wing de Havilland DH 108 . One of them was Geoffrey de Havilland, Jr. who was killed on 27 September 1946 when his DH 108 broke up at about Mach 0.9 . John Derry has been called "Britain's first supersonic pilot" because of a dive he made in a DH 108 on 6 September 1948 . </P> <P> The British Air Ministry signed an agreement with the United States to exchange all its high - speed research, data and designs and Bell Aircraft company was given access to the drawings and research on the M. 52, but the U.S. reneged on the agreement and no data was forthcoming in return . Bell's supersonic design was still using a conventional tail and they were battling the problem of control . </P>

Who was the first british pilot to break the sound barrier