Archive for July, 2011

Six Wheels On My Wagon

July 1, 2011

I have always had an unaccountable fascination for six-wheeled cars and since the only decent page on F1-cars with more than the usual four wheels has disappeared, I decided to fill the gap.

Pre-war, Auto Union, Mercedes Benz amongst others would affix two extra wheels on the back axle, mostly to adapt their cars for hill-climbs, such as for this Auto Union Type-C at Shelsley Walsh in 1936.

Post-war, the Pat Clancy Special was entered in the 1948 and 1949 Indianapolis 500s.

The extra traction made it faster on the straights but the four at the rear also made the car want to go straight for the turns creating understeer that negated any advantage. It finished twelfth (ten laps down) in ’49 and failed to finish the year after.

The only six-wheeled car to enter the Formula One World Championship, and indeed to win a race, was the famed Tyrrell P34.

Jody Scheckter, Germany, 1976

Patrick Depailler, 1976

Patrick Depailler, France 1976
The Cahier Archive)

The P34 (short for Project 34) debuted at the fourth round of 1976, the Spanish Grand Prix at Jarama, for Patrick Depailler, with Jody Scheckter also on six wheels by the next GP. Designer, Derek Gardner, had worked on the four-wheel-drive turbine-powered Lotus cars that raced in the 1968 Indianapolis 500, which were fastest but failed to finish. The only way found to have the cars handle at all well was to send most the power to the rear wheels, so Gardner had the idea to have four wheels at the front, two of which were powered, but 4wd and turbine engines were banned before the 1969 event. The idea inspired the P34 (which was only rear-wheel-drive).

The point of the four smaller wheels at the front was not to reduce drag by reducing frontal area, as the air would instead hit the huge rear tyres. It seems the spinning tyres in the airflow create lift. I am not sure of the physics, please comment if you can cast light on this, but I am guessing the top of the tyre travelling backward at the speed of the car relative to the oncoming airflow creates faster airflow over the tyres (the way wings work is that faster airflow is lower pressure than slower airflow), thus ‘sucking’ the tyres upwards. The principle was that four smaller tyres created less lift, therefore less front-wing could be used, which did reduce the drag making the car faster in a straight line without losing performance in the corners.

Depailler was very enthusiastic about the experimental concept, but Scheckter hated it, despite scoring the P34’s only win in his third outing with it in Sweden, with four second places and five other top-sixes propelling him to third in the title chase with his then highest points tally. His main complaint about the car was that it was too easy to lock a front-wheel. Scheckter also relates an incident in one practice when he saw a wheel bouncing along, wondered whose it was, and found out on reaching the next corner it was his. On returning to the pits, he was asked what the problem was and replied, “Understeer.”

Patrick managed five podiums with the six-wheeler in ’76 for fourth overall. Jody left for Wolf to be replaced by Ronnie Peterson in 1977. The year saw a high rate of retirements by both Tyrrell drivers but also netted a few podiums. That was the last of the P34, as whilst Goodyear had considered the expense of making the 10″ tyres had proved to be fantastic value for money with the initial huge publicity the car had created, they failed to develop the smaller tyres as they did with the front tyres for other teams, which gave Tyrrell little choice but to revert to four wheels in 1979.

March designer, Robin Herd, took much interest in the Tyrrell P34, coming to the conclusion that four wheels at the back was the more effective way to reduce drag, as well as improving the airflow to the back wing and giving better traction. Team manager, Max Mosley, was more inspired by that publicity created by the six-wheel concept, and in its potential to help attract sponsors at a time the team were struggling financially. Thus in late 1976 team engineer, Wayne Eckersley, was assigned to adapt a 1976 March 761 as cheaply as possible into essentially a show car. However, the unveiling in November/December (depending on source) caused extensive press excitement including the car making the front cover of Autosport. Below is the March 2-4-0 presented, Mosley in the middle, Herd to the right, with the exotic backdrop of sun-kissed Bicester.

(The “2-4-0” refers back to the designation of the wheels on steam locomotives, whereby, for example, a 4-6-2 would have four smaller un-driven wheels at the front, then six large powered wheels, then two smaller trailing wheels behind.)

A full test for the car was announced for (I believe) the last day of the year with the team throwing itself into rushing out a working version, as shown below at Silverstone.

The budget-limited build meant the gearbox casing had not been strengthened as required for the new four-wheel-drive, causing the cogs sending power to the very back wheels to un-mesh soon into the first lap as the gearbox flexed. The team quietly removed the offending parts sending Howden Ganley back out to complete the test with only the forward rear wheels powered (2-2-2). Fortunately for March, it was a wet day so slow times could be blamed on un-indicative conditions without needing to let the press on.

By the time Ian Scheckter tested the car in February on another wet day at Silverstone the gearbox had been strengthened. Scheckter described the traction as incredible but was not so happy with the heaviness and power-delivery in the turns. Again the car made the front cover of Autosport. The next picture shows the car sporting the new season’s Rothmans sponsorship as was the case at that test, although this does not look like Silverstone to me.

After that, development of the March 2-4-0 ceased and never came close to being raced by the team. Never the less it turned out to be highly profitable, with Scalextric paying to produce what became a very popular slot-car, and the car being hired out (probably with myriad liveries) for trade shows and other business promotions.

In 1979, Roy Lane bought a March 771 and was loaned the kit to convert it to 2-4-0 configuration which he used for the British Hill Climb Championship that year. He won events, notably in the wet, but overall it was uncompetitive and, even for such short-distance events, it was on the fragile side.

Shortly after March’s six-wheel media launch, in December ’76 Ferrari joined the fun with their own announcement generating another gigantic wave of publicity. The story went quiet until March of 1977 when the Ferrari 312 “T6” (a semi-official designation) broke cover in a test at Fiorano.

With two extra wheels attached to a single back axle, this was reminiscent of the pre-war hill climb cars. Nicki Lauda gave no statement after this test. The next was at Nardò Ring, a FIAT owned high-speed banked testing facility, from which little public feedback emerged. Carlos Reutermann had a big accident at its next outing back at Fiorano, and by standard Ferrari policy of the time was entirely blamed until mechanical failure was established a few days later. Lauda conducted further tests but any near-future race-debut of the car was pooh-poohed. In May, the project was shelved, Enzo Ferrari stating that it was until Goodyear provided special tyres, but that was probably a convenient face-saving tactic bearing in mind front tyres were utilised.

It is difficult to see where Ferrari intended to go with the concept, almost questionable whether it might have just been again about the publicity. The extra rear tyres caused the car to exceed the maximum width regulation. Ferrari’s success in 1975 to 1977, when Lauda would have won three consecutive titles but for his terrible crash at the Nürburgring in ’76, was founded on the decision to adopt a transverse gearbox (which was aligned parallel to the back-axle instead of the more conventional longitudinal arrangement along the length of the chassis), which made moving the wheels inwards impractical without a fundamentally major re-design. It would have been an enormous obstacle to configure suspension that would have prevented the outer wheels wobbling with greater than usual amplitude to maintain consistent contact patches. It was surely physically impossible to have a differential (which splits the power between the (normally) two back wheels allowing the outer wheel in corners to turn faster than the inner wheel as the outer wheel has further to travel, otherwise the outer tyre would spin and/or the inner tyre drag, causing loss of grip, high tyre wear, and more difficulty in persuading the car to turn) that could cope with a much more significant difference between the distances travelled in corners between the inside of the inner tyre and outside of the outer one on each side. Ferrari without commercial sponsors and the cost of producing their own engines were not that well funded in this period, but it is difficult to see how the publicity of a dead-end project would help to alleviate this.

In 1981, the writing was on the wall for the normally aspirated customer-affordable Ford Cosworth DFVs that had powered all the driver World Championships, apart from three for Ferrari, since 1968. Rumour was that Williams had a future deal with Honda (which transpired by 1984) but what to do until then? Patrick Head decided that the March six-wheel configuration offered great potential advantage in the ground-effect era that had arrived since. The first foot in the water was to adapt the FW07, with versions of which the team had won races in 1979-81 along with the 1980 World Championship (Alan Jones). Initially tested in October 1981, I suspect this photo of the FW07E was from later in the year.

The FW08 introduced for 1982 was specifically designed to be adaptable to racing with four wheels and conversion to six when the necessary engineering changes were proven and reliable. This was why the cars that raced appeared stubby for having short wheelbases. The team continued to test the six-wheeler in private tests, with reports emanating during the summer of stupendous speed. Meanwhile, Keke Rosberg in the four-wheeler was unexpectedly on his way to winning that season’s title, although it would have been Ferrari’s year but for the death of Gilles Villeneuve and the career-ending accident Didier Pironi had at Hockenheim.

Unlike March, Williams had the engineering resources to develop the FW08D properly. The additional weight involved with the extra parts needed was not a huge handicap as their usual cars without ballast were significantly below the minimum weight limit. The same advantages of extra traction, better airflow to the rear wing, less drag over smaller rear-wheels, less lift from those wheels, and being able to use what would normally be front tyres with their continued development all applied as (at least in theory) for the 2-4-0. The hugely significant difference was that this was the era of full ground effects. There were no flat bottoms with diffusers at the rear doing the best they could to pull air from under the car. As much as possible, the whole underside of the car acted as a gigantic diffuser with skirts along the bottom outer edges of the sidepods to contain the low pressure under the floor with the main body of the chassis effectively being a huge wing.

The skirts were only allowed to run back to the rear axle so the six-wheeler enabled greater exploitation in this aspect, as well as the skirts not having to awkwardly deviate inside the conventional rear wheels with the new arrangement giving wider airflow out the back of the car. The main and acceptable disadvantages seemed to be an increase in mechanical complexity and higher friction losses in the transmission to four wheels.

Williams planned to run the six-wheeled cars in 1983, but FIA banned six-wheel cars AND four-wheel drive! (After twenty-eight years, this still makes me angry. If it had been Renault or Ferrari…)

Jonathan Palmer drove the FW08D up the Goodwood hill in 1994, setting an unofficial record that stood for a few years. His observation on the car was that if lateral forces caused the back-end to begin to slide, when the first tyre lost grip the driver had 75% adhesion left to save it, whereas with a conventional layout, he only had 50% left.

With the six-wheel craze in 1976, word was that Lotus being unhappy with the 77 were planning to copy the Tyrrell P34 for the Lotus 78 with this prototype photograph emerging.

They did not have Photoshop back then so it probably involved double-exposure or combining negatives to create this fake shot. However, the shot below, also from 1976, of Clay Regazzoni at Fiorano aboard the Ferrari 312 “T8” is completely un-doctored.

I think this is quite clever, as at first glance the brain assumes the car is moving with it being on a track when it is in fact stationary, and although there is no trick photography, it can be spotted on scrutiny that the extra wheels look a little larger than the matching expectedly positioned ones, being slightly closer to the camera because they are just sitting in front of the car. This was a Ferrari-orchestrated hoax not long after the “T6” was canned, renewing my half-suspicion that that project might have been most about the publicity. Like the March 2-4-0, the “T8” spawned a slot-car.

Do have a look at the Spanish-language forum article Cuando sólo cuatro… no bastan  (When Just Four… Are Not Enough), for even more pictures as well as bigger versions of many I used. Avoid auto-translate or you will discover where much of my “research” came from…

(Short link: