Thunderbolt (car)
Encyclopedia
Thunderbold is a British Land Speed Record
holder of the 1930s, driven by Captain George E.T. Eyston
was between two Englishmen: Captain Eyston and John Cobb
. Thunderbolt's first record was set at 312 mi/h on 19 November 1937 on the Bonneville Salt Flats. Within a year Thunderbolt returned with improved aerodynamics and raised its record to 345.5 mi/h on 27 August 1938.
This record only stood for a matter of weeks before John Cobb's Reid-Railton broke the 350 mi/h barrier and raised it to 353.3 mi/h on the 15th September 1938, as Eyston watched. This inspired him to take Thunderbolt to a new record of 357.5 mi/h. 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 369.7 mi/h 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 400 mi/h, Thunderbolt never attempted the record again.
The engines were a pair of Rolls-Royce R
-type V-12
aero engines, as previously used singly in Malcolm Campbell
's Blue Bird of 1933. Indeed 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 Thunderbolt's had already powered the Schneider Trophy
winner. Each engine was of 36.5 litres capacity, supercharged, and had an individual output power of 2350 bhp. 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
. There were three axles and eight tyres. The two leading axles steered and were of varying 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
, a new aluminium alloy, clad the chassis. The body never had the aerodynamic refinement of the Railton Special and was distinctly blocky in appearance. At the rear was a large triangular tailfin, flanked by a pair of hydraulically activated air brakes.
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.
both from
Another surviving engine can be seen in the Science Museum
in London.
both from
Land speed record
The land speed record is the highest speed achieved by a wheeled vehicle on land. There is no single body for validation and regulation; in practice the Category C flying start regulations are used, officiated by regional or national organizations under the auspices of the Fédération...
holder of the 1930s, driven by Captain George E.T. Eyston
Records held
Between 1937 and 1939, the competition for the Land Speed RecordLand speed record
The land speed record is the highest speed achieved by a wheeled vehicle on land. There is no single body for validation and regulation; in practice the Category C flying start regulations are used, officiated by regional or national organizations under the auspices of the Fédération...
was between two Englishmen: Captain Eyston and John Cobb
John Cobb (motorist)
John Rhodes Cobb was a British racing motorist. He made money as a director of fur brokers Anning, Chadwick and Kiver and could afford to specialise in large capacity motor-racing...
. Thunderbolt's first record was set at 312 mi/h on 19 November 1937 on the Bonneville Salt Flats. Within a year Thunderbolt returned with improved aerodynamics and raised its record to 345.5 mi/h on 27 August 1938.
This record only stood for a matter of weeks before John Cobb's Reid-Railton broke the 350 mi/h barrier and raised it to 353.3 mi/h on the 15th September 1938, as Eyston watched. This inspired him to take Thunderbolt to a new record of 357.5 mi/h. 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 369.7 mi/h 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 400 mi/h, 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
Rolls-Royce R
The Rolls-Royce R was a British aero engine 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...
-type V-12
V12 engine
A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft....
aero engines, as previously used singly in Malcolm Campbell
Malcolm Campbell
Sir Malcolm Campbell was an English racing motorist and motoring journalist. He gained the world speed record on land and on water at various times during the 1920s and 1930s using vehicles called Blue Bird...
's Blue Bird of 1933. Indeed 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 Thunderbolt's had already powered the Schneider Trophy
Schneider Trophy
The Coupe d'Aviation Maritime Jacques Schneider was a prize competition for seaplanes. Announced by Jacques Schneider, a financier, balloonist and aircraft enthusiast, in 1911, it offered a prize of roughly £1,000. The race was held eleven times between 1913 and 1931...
winner. Each engine was of 36.5 litres capacity, supercharged, and had an individual output power of 2350 bhp. 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
Bean cars
Bean Cars were made in factories in Dudley, Worcestershire, and Coseley, Staffordshire, England, between 1919 and 1929.-Origins:The company traced its origins beck to two auto-industry component suppliers, A Harper and Sons and Bean Ltd., both based in England's Black Country...
in Tipton
Tipton
Tipton is a town in the Sandwell borough of the West Midlands, England, with a population of around 47,000. Tipton is located about halfway between Birmingham and Wolverhampton. It is a part of the West Midlands conurbation and is a part of the Black Country....
. There were three axles and eight tyres. The two leading axles steered and were of varying 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
Birmabright is a trade name of the former Birmetals Co. for various types of lightweight sheet metal in an alloy of aluminium and magnesium. The constituents are 7% magnesium, sometimes 1% manganese, and the remainder aluminium...
, a new aluminium alloy, clad the chassis. The body never had the aerodynamic refinement of the Railton Special and was distinctly blocky in appearance. At the rear was a large triangular tailfin, flanked by a pair of hydraulically activated air brakes.
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
Golden Arrow (land speed racer)
Golden Arrow was a land speed record racer. Built for Major Henry Segrave to take the LSR from Ray Keech, Golden Arrow was one of the first streamlined land speed racers, with a pointed nose and tight cowling...
). 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.
both from
Thunderbolt today
Thunderbolt toured New Zealand during the Second World War, but was destroyed by a fire. Engine remains can be seen in the Museum of Transport and Technology, Western Springs, Auckland, NZ.Another surviving engine can be seen in the Science Museum
Science Museum (London)
The Science Museum is one of the three major museums on Exhibition Road, South Kensington, London in the Royal Borough of Kensington and Chelsea. It is part of the National Museum of Science and Industry. The museum is a major London tourist attraction....
in London.
Sounds of the Salt Flats
These recordings were made on August 24, 1938 (three days before the record) and broadcast by Salt Lake City's KSL radio news.both from