Thunderbolt was a British

Land Speed Record The land speed record (or absolute land speed record) is the highest speed achieved by a person using a vehicle on land. There is no single body for validation and regulation; in practice the Category C ("Special Vehicles") flying start regula ...

holder of the 1930s, driven by Captain George E.T. Eyston.

Records held

Between 1937 and 1939, the competition for the

was between two Englishmen:

Captain Eyston Captain George Edward Thomas Eyston MC OBE (28 June 1897 – 11 June 1979) was a British engineer, inventor, and racing driver best known for breaking the land speed record three times between 1937 and 1939. Early life George Eyston was educ ...

and John Cobb. Thunderbolt's first record was set at on 19 November 1937 on the

Bonneville Salt Flats The Bonneville Salt Flats are a densely packed salt pan in Tooele County in northwestern Utah. A remnant of the Pleistocene Lake Bonneville, it is the largest of many salt flats west of the Great Salt Lake. It is public land managed by the Bur ...

. Within a year Thunderbolt returned with improved aerodynamics and raised its record to on 27 August 1938. This record only stood for a matter of weeks before John Cobb's Reid-Railton broke the barrier and raised it to on 15 September 1938, as Eyston watched. This inspired him to take Thunderbolt to a new record of . Cobb had held the record for less than 24 hours. Eyston and Thunderbolt held the record for almost a year, until Cobb took it again at a speed of on 23 August 1939. This was the last record attempt before the outbreak of the Second World War. Although Cobb returned after the war and further developed his car to exceed , Thunderbolt never attempted the record again.

Design

The leading Land Speed Record cars of the period had taken two approaches to obtaining power; using either the latest and most sophisticated aero-engines available or combining multiple engines. Thunderbolt used both techniques to produce an unprecedentedly powerful car. In its day, terms like "leviathan" and "behemoth" were commonly used to describe the 7-ton car, over twice the weight of its competitors. The engines were a pair of

Rolls-Royce R The Rolls-Royce R is a British aero engine that was designed and built specifically for air racing purposes by Rolls-Royce Limited. Nineteen R engines were assembled in a limited production run between 1929 and 1931. Developed from the Rolls-R ...

-type V-12 aero engines, as previously used singly in

Malcolm Campbell Major Sir Malcolm Campbell (11 March 1885 – 31 December 1948) was a British racing motorist and motoring journalist. He gained the world speed record on land and on water at various times, using vehicles called ''Blue Bird'', including a 1 ...

Blue Bird The bluebirds are a North American group of medium-sized, mostly insectivorous or omnivorous birds in the order of Passerines in the genus ''Sialia'' of the thrush family (Turdidae). Bluebirds are one of the few thrush genera in the Americas. B ...

of 1933. In fact, one of Eyston's spare engines for the record attempts was on loan from Campbell. There were so few of these engines built (around 20) that many of them had illustrious careers over several different records. One of the Thunderbolt's had already powered the

Schneider Trophy The Coupe d'Aviation Maritime Jacques Schneider, also known as the Schneider Trophy, Schneider Prize or (incorrectly) the Schneider Cup is a trophy that was awarded annually (and later, biennially) to the winner of a race for seaplanes and flying ...

winner. Each engine was of 36.5 litres capacity, supercharged, and had an individual output power of . Handling all this power through a single driven axle required great innovation in metallurgy and in manufacturing the geartrain, as well as water-cooling the completed transmission. The chassis and bodyshell were built at the Bean works in

Tipton Tipton is an industrial town in the West Midlands in England with a population of around 38,777 at the 2011 UK Census. It is located northwest of Birmingham. Tipton was once one of the most heavily industrialised towns in the Black Country, w ...

. (commercial photo gallery) There were three axles and eight tyres. The two leading axles steered and were of different track, so that each tyre ran on a clean surface rather than following a rut. The driven rear axle used twin tyres to reduce the load on them, a technique already used by Bluebird. Separate panels of polished silver

Birmabright Birmabright is a trade name of the former Birmetals Co. (Birmabright works in Clapgate Lane, Quinton, Birmingham, UK) for various types of lightweight sheet metal in an alloy of aluminium and magnesium. The alloy was introduced by the Birmid Grou ...

, a new aluminium alloy, clad the chassis. The body never had the aerodynamic refinement of the

Railton Special The ''Railton Special'', later rebuilt as the ''Railton Mobil Special'', is a one-off motor vehicle designed by Reid Railton and built for John Cobb's successful attempts at the land speed record in 1938. It is currently on display at Thinkt ...

and was distinctly blocky in appearance. At the rear was a large triangular tailfin, flanked by a pair of hydraulically activated air brakes. includes some images of Thunderbolt

Design changes

When first built there was a large eight-sided cooling air intake at the front, replaced by a smaller oval intake for the 1938 season. Another improvement for this second attempt was to paint a matt black arrow onto the side of the car. During the first attempts, the new photo-electric timing equipment had failed to detect the polished aluminium car body against the brilliant white salt. For the 1939 attempts, the streamlining was increased further. Cooling was now by a tank of melting ice rather than a radiator (as used first by '' Golden Arrow''). A rounded nose now filled the previous radiator air intake and the stabilising fin was removed, all leading to an appearance more like Cobb's Railton.

Fate of Thunderbolt

Thunderbolt was displayed in the British Pavilion at the New Zealand Centennial Exhibition in 1939-40, it also toured New Zealand during the Second World War, but is thought to have been destroyed by a fire in a Rongotai warehouse. Another surviving engine can be seen in the

Science Museum A science museum is a museum devoted primarily to science. Older science museums tended to concentrate on static displays of objects related to natural history, paleontology, geology, industry and industrial machinery, etc. Modern trends in mu ...

in London.

References

External links