Top: Three-quarter left front view of De Havilland D.H.106 Comet (background) at Hatfield Airfield, England; in foreground is the third prototype de Havilland D.H.108, which was used to calculate wing resistance, stress, and strain for the Comet. Bottom: (left to right) Grp. Capt. John Cunningham, test pilot; Sir Frank Whittle; and Major Frank Halford, designer of the Comet's engines; August 1949.