An aero-engined car is an automobile powered by an engine designed for aircraft use. Most such cars have been built for racing, and many have attempted to set world land speed records. While the practice of fitting cars with aircraft engines predates World War I by a few years, it was most popular in the interwar period between the world wars when military-surplus aircraft engines were readily available and used to power numerous high-performance racing cars. Initially powered by piston aircraft engines, a number of post-World War II aero-engined cars have been powered by aviation turbine and jet engines instead. Piston-engined, turbine-engined, and jet-engined cars have all set world land speed records. There have also been some non-racing automotive applications for aircraft engines, including production vehicles such as the Tucker 48 and prototypes such as the Chrysler Turbine Car, Fiat Turbina, and General Motors Firebirds. In the late 20th century and into the 21st century, there has also been a revival of interest in piston-powered aero-engined racing cars.
Background In the early 20th century, automotive engines were fairly limited in terms of revolutions per minute (rpm), with 3,000 rpm constituting an upper limit. This meant that the easiest way to increase the power output of an engine was to increase its displacement. In the decade of the 1900s, engine construction necessitated extremely large displacements in order to simply reach the mark. Furthermore, while it was difficult to fit such a large engine into a car, it was very much possible, and the fact that most of the aircraft engines of the period were liquid-cooled made them more adaptable for automotive use.
Racing
Pre-World War I A number of early European automobile manufacturers experimented with the automotive use of aircraft engines, including Hispano-Suiza, Renault, and Rolls-Royce, although it was Fiat that made perhaps the first true aero-engined car when it created the Tipo S76 in 1910. Nicknamed "The Beast of Turin", the vehicle consisted of a 1907–08 Fiat production chassis mated to a four-cylinder Tipo S76DA airship engine that had a displacement of and developed at 1,500 rpm. Daryl Murphy speculates that the car was built to capture the world land speed record, which at the time stood at after the Blitzen Benz had established the mark at the English track Brooklands in 1909. While the Tipo S76 did race at Brooklands, it never exceeded more than about . It later returned to continental Europe and ultimately disappeared during World War I.
Sunbeam also manufactured aircraft engines before World War I, and at the suggestion of chief designer Louis Coatalen it decided to install one of its flathead V12 engines (which would later be developed into the Sunbeam Mohawk) into an automobile chassis in 1913. Nicknamed "Toodles", the car achieved at Brooklands before it was shipped to the United States, where it was raced by Ralph DePalma. DePalma later sold Toodles to the Packard Motor Car Company, which used the car's engine as the inspiration for its Twin Six, which became the world's first production 12-cylinder engine in 1916, as well as a , V12 aircraft engine in 1917.
Sunbeam also developed a second aero-engined car before World War I, which began life as an Indianapolis 500 racing car before Warwick Wright augmented it with a V8 Sunbeam Sirdar airship engine. The car developed at 2,200 rpm, which enabled it to achieve a top speed of approximately . By 1923, this Sunbeam was listed for sale for £1,000.
Interwar period
1920s By the 1920s, after the end of World War I, interest in and development of aero-engined cars reached a new level. Coatalen built another aero-engined racing car, the Sunbeam 350HP, which featured a Sunbeam Manitou engine that had been designed to power Royal Naval Air Service flying boats. With an engine displacement of and the ability to generate at 2,100 rpm, the 350HP achieved a top speed of in 1922.
In 1923, Ernest Eldridge began building the Mefistofele, which consisted of a Fiat SB4 chassis and a Fiat A.12 bis aircraft engine that produced at 1,800 rpm. On 12 July 1924, Eldridge drove the car to a world-record speed of on public roads in Arpajon, France, which marked the last time that a land speed record would be set on public roads. The car's name was bestowed upon it by the press due to the tremendous amount of noise and smoke generated by its engine.
Argentine racer Adolfo Scandroglio built his Fiat Botafogo Special in the image of the Mefistofele, using a 1917 Fiat chassis and the same Fiat A.12 engine that had been chosen by Eldridge. The car, which was named after a famed racehorse, was capable of producing at 1,800 rpm. In 1949, Scandroglio was killed while racing the Botafogo Special, and the car was presumed to have been lost before its engine was rediscovered in the 1990s. After its rediscovery, the Argentine company Pur Sang, which is noted for creating exact replicas of Alfa Romeo 8C 2300s and Bugatti Type 35s, reconstructed the Botafogo Special. In 2011, the rebuilt car was purchased from Pur Sang by Jay Leno.
In 1923, the Sunbeam 350HP was purchased by Malcolm Campbell, who made modifications to the coachwork as well as the engine in his endeavor to increase its speed. He also renamed the car Blue Bird, and on 25 September 1924 used it to set the official world land speed record with a speed of at Pendine Sands in Wales. The next year, on 21 July 1925, Campbell returned to Pendine, where he became the first person to exceed as he set a new record of .
Perhaps the most well-known aero-engined cars of the interwar period were the series of amateur, chain-driven creations of Louis Zborowski that were each known as Chitty Bang Bang. They later attained fame as the namesake for the children's book Chitty-Chitty-Bang-Bang, written by Ian Fleming, as well as the film and musical of the same title. Although the origin of the name is unknown, it is thought to derive from either a lewd World War I soldier's song or simply the sound of the aircraft engines that powered the cars. The first car, Chitty 1, featured a customized pre-war Mercedes chassis and a , six-cylinder Maybach airplane engine that had powered a Gotha G.V bomber before it was surrendered by Germany as a war reparation. The engine could produce at a relatively modest 1,500 rpm. Chitty 1 achieved celebrity status at Brooklands in 1921, where it won races at speeds in excess of . In 1922, Zborowski returned to Brooklands to achieve his highest ever speed in the car, , although that autumn Chitty 1 was destroyed in a racing accident.
Zborowski began working on a second car of the same name, Chitty 2, in 1921. While its use of an older model Mercedes for its chassis made it similar to its predecessor, this iteration of Chitty Bang Bang was powered by an Benz Bz.IV engine that manufactured . Chitty 2 placed second in its only race at Brooklands, although it did record a speed of over . In 1922, Zborowski and his wife took the car on a lengthy excursion across France and Algeria, all the way to the edge of the Sahara, where a dearth of sufficient radiator water caused such substantial engine damage that he was forced to retire the car from racing. Zborowski himself was killed at Monza while competing in the 1924 Italian Grand Prix, and Chitty 2 passed through a series of owners (including Arthur Conan Doyle) before being acquired by the Crawford Auto-Aviation Collection in Cleveland.
The third of Zborowski's cars, Chitty 3, was also built around a modified Mercedes chassis, this time mated to a six-cylinder Mercedes aircraft engine originally rated at that had been tuned to develop . Once again, this car raced at Brooklands, where it achieved a top speed of .
Zborowski's fourth and final aero-engined car was the Higham Special, which he named in a nod to his manor, the Higham House. Created in 1924 for the purpose of making an attempt on the land speed record, the car was powered by a World War I V12 Liberty L-12 engine with a displacement of , which made it the largest-capacity engine to ever race at Brooklands. With an engine producing and the gearbox and chain-drive of a pre-war Blitzen Benz, the Higham Special achieved a speed of with Zborowski at the wheel. After Zborowski's death at Monza, racing enthusiast J. G. Parry-Thomas bought the car and, after streamlining the body and modifying the engine, rechristened it "Babs". In 1926, Parry-Thomas took the car back to Brooklands, where he set a new world record with a speed of . He then took Babs to Pendine, where he achieved on the sands. After Malcolm Campbell took back the record with a run in his Blue Bird, Parry-Thomas returned to Pendine in 1927 with a more streamlined Babs. However, on his first run, he was killed in a crash. Parry-Thomas' crew buried Babs in the sand, where it remained until Owen Wyn Owen began excavating it in 1969. Wyn Owen ultimately restored the car to working order by 1985. In 2013, Babs was placed on display at the National Waterfront Museum in Swansea.
In 1927, Henry Segrave broke Campbell's world speed record with a run of at Daytona Beach, Florida, in his Sunbeam 1000 hp, which was powered by two V12 Sunbeam Matabele aircraft engines. The new record made him the first person to surpass the mark. The following year, Campbell raced at Daytona to retake the record with a speed of , only to have it eclipsed just two months later by Ray Keech and his Triplex Special, which was powered by three V12 Liberty engines. On 11 March 1929, Segrave captured the world record once more at Daytona with a speed of in his Golden Arrow, which was powered by a W12 Napier Lion aircraft engine with a displacement of that manufactured at 3,300 rpm. The very next day, while attempting to re-take the record with the Triplex Special, driver Lee Bible lost his life in a fatal crash that also killed a film cameraman.
1930s In 1931, Campbell returned to competition with an upgraded Blue Bird that was sleeker and lower than its predecessor. Fitted with a Napier Lion engine, the car successfully set a new land speed record with a run of . By 1933, Campbell had created another Blue Bird that was powered by a Rolls-Royce R, which had achieved fame as the engine that helped the Supermarine S.6B seaplane win the Schneider Trophy. With this engine, which produced and had a displacement of , Blue Bird achieved a speed in excess of at Daytona. However, as performance continued to increase, the relatively limited area of Daytona Beach began to prevent cars from reaching their true top speeds. In September 1935, Campbell took Blue Bird to Utah's Bonneville Salt Flats, where it exceeded .
Ab Jenkins, who in October 1935 had set speed records for one hour and for 24 hours in a factory-modified Duesenberg SJ on a circuit marked out in the Bonneville Salt Flats, realized that it was no longer possible for a modified production car to compete against aero-engined cars for long-distance speed records. Jenkins had his SJ special further modified, replacing the modified SJ engine with a Curtiss Conqueror engine. The Conqueror-engined special was named "Mormon Meteor" by a contest held by the Deseret News. In 1936 the Mormon Meteor set the record at (breaking a record set by George Eyston), the 24‑hour record at , and the 48‑hour record at . The Mormon Meteor set another 24‑hour record in 1937, averaging . Jenkins then commissioned August Duesenberg to build a chassis that was better able to handle the weight, power, and torque of the Conqueror engine. The result was the Mormon Meteor III, which broke the 12‑hour record in 1939 and set a 24‑hour record of in 1940.