 During the mid-1930s, George Eyston set many speed records with his Speed of the Wind car, powered by an unsupercharged Rolls-Royce Kestrel. In 1937 he built a massive new car, Thunderbolt, powered by two R engines to attempt the absolute land speed record. At first Eyston experienced clutch failure due to the combined power of the engines. Nevertheless, he took the record in November 1937, reaching 312 mph (502 km / h), and in 1938 when Thunderbolt reached 357.5 mph (575 km / h). When first built at Bean Industries in Tipton, the nearside engine fitted to Thunderbolt was R27 which had powered S1595 when it set the air speed record in 1931. The other was R25, used by the same aircraft to win the Schneider Trophy two weeks earlier. Eyston had also borrowed R17 from Sir Malcolm Campbell and, with the continuing support that Rolls-Royce extended to both Campbell and Eyston, he also had the option of using R39.
