The F1 Cars Behind Honda’s Glory

Unprecedented 3L Air-Cooled F1 Car

1968Honda RA302

Unprecedented 3L Air-Cooled F1 Car

For the 1968 F1 season, Honda introduced the RA302 powered by an air-cooled V8 2987.5 cc RA302E engine in a chassis that was Honda-designed and built.

The RA302 was a very distinctive racing machine in the history of F1 Grand Prix racing, because the RA302E was the first large-displacement racing engine in the history of F1’s 3-liter era to be completely naturally air-cooled.

The RA302’s structure and design were specially designed to accommodate the naturally air-cooled engine, which was a complete departure from F1 cars of the same era which were powered by water-cooled engines.

As an example, the car lacked a large front radiator and water-cooling system such as air intakes and water piping that were needed for water-cooled engines. This made it possible to achieve an extremely compact and lightweight chassis. However, cooling a large-displacement air-cooled engine with wind alone required a great deal of ingenuity in its design.

The prospect of a prolonged research and development period for the RA302 also presented the opportunity to plan for incorporating numerous advanced ideas into the design. While waiting for the technological evolution of the engine’s development, the advanced ideas incorporated in the chassis could be refined into real-world technology.

The RA302 debuted, as a futuristic, avant-garde F1 car.

The first RA302 had a magnesium alloy monocoque body. Until then, all Honda F1 cars had been made of aluminum alloy, but Honda decided to use magnesium based on advanced technology. The structural design of the body was also unique, starting with the engine mounting method. In order to direct as much air as possible to the naturally air-cooled mid-ship engine, an extension frame was positioned from the upper rear end of the monocoque between the 120-degree V8’s V-banks, suspending the engine from the frame. This was done to direct a large amount of air directly to the air-cooling fins in the lower section of the engine. The rear member was attached to the rear edge of the extension frame, to support the engine’s rear and the rear suspension’s upper arm. The rear suspension’s lower arm was supported by a short sub-frame fixed to the engine crankcase.

In order to realize this innovative engine mounting, the rear end section of the monocoque body needed to be a sturdy box-like structure, in which the fuel tank was placed so that the engine and fuel tank could be concentrated in the center of the chassis. The cockpit was positioned toward the front of the car, immediately in front of the fuel tank, and the steering wheel was positioned close to the front tires.

F1 cars at the time had a cigar-shaped silhouette with a large radiator in the front nose and wide gaping air intakes, but the RA302 had a pointed front nose design because it did not need a radiator. The wedge-shaped, or jet fighter silhouette, as it was called at the time, together with the air intakes on both sides of the chassis and engine, and the advanced cockpit position, was a bold and innovative silhouette that was well ahead of its time.

The Honda engineer in charge of structural design was the same person who, at the age of just 26, was responsible for the structural design of the 1964 Honda RA271. After that, he handled the structural design of the 1966 RA273, and was a member of the design team for the 1967 RA300 and 1968 RA301, before taking charge of the RA302 at the age of 30.

The schedule for the RA302’s actual debut progressed at a furious pace.

After its shakedown at the Honda Arakawa Test Course, the RA302 was immediately transported to Haneda Airport for a press conference at an adjacent hotel, where it was then loaded onto an air cargo plane for its flight to London, England, on June 29, 1968.

After receiving the RA302, the Honda F1 team in London installed an oil cooler in the front nose and conducted a test run at the Silverstone Circuit. The driver in charge was John Surtees, the only F1 driver to have won both motorcycle and automobile world championships. The RA302E engine overheated within its first lap or two. The test run ended with issues that could not be fixed or corrected by the team on site. After implementing the fixes, Honda France entered the French GP on July 7 with the RA302. The car qualified 17th, out of 18 cars, and burned in an accident early in the race.

Honda R&D in Japan hurriedly prepared the second RA302, and the Honda F1 Team entered the RA302 as a spare car for the #14 RA301, which was powered by a liquid-cooled V12. In the official practice on September 6, the RA302 participated as number 14T, but the team determined that it was too early to participate in the race, due to a significant drop in power output caused by overheating. The car did not participate in qualifying or the race.

This second RA302 had an aluminum alloy monocoque body, a small spoiler on either side of the front nose, and an oil cooler behind the cockpit.

At the end of the 1968 season, Honda announced a “temporary suspension of F1 activities,” and development of the RA302 had stopped.

RA302E