X-ray spec -- Fittipaldi F6
One small flaw crippled this Brazilian project, as designer Ralph Bellamy tells Keith Howard
By late 1977 Ralph Bellamy had had enough of Lotus. Having been a key member of the team which created the revolutionary Type 78, he'd then been banished to the Hethel factory for a year to work on the company's road cars. So when Emerson Fittipaldi, having watched the 78 trounce the opposition from the sidelines at Monza in 1977, invited Bellamy to Brazil to design a new car for his Copersucar-sponsored team, he leapt at the idea. He and his wife Anne moved there in early 1978.
"We enjoyed our time in Brazil," he recalls. "It was a wonderful opportunity to live and work in a fantastic country. I look back on it as one of the more pleasant experiences in my life, but professionally it was a disaster. You can't just walk away for over 12 months and do your own thing. You have to be on the scene, to see what other people are doing and where the technology is going.
"Having said that, the Fittipaldis had a terrific factory in Säo Paulo. The Interlagos circuit was the other side of the road and my office looked over to it. They had all the machinery and equipment needed and skilled craftsmen to operate it, and I had an engineer and draughtsman to help me draw the car. Up-country, Embraer — the aircraft manufacturer — had a wind tunnel, although it wasn't as sophisticated as the Imperial College tunnel that we'd used at Lotus. So we weren't that badly off. The project didn't fail because we were trying to make a Formula One car in the jungle or anything like that."
In fact it failed, as Bellamy candidly admits in his comments on the car, because one component of his F6 design — something few racing spectators would even consider — was not up to the job: the wheelbearings.
"You have to remember that, because of the sudden increase in downforce, we were in an era when design solutions that had been perfectly adequate for many years suddenly weren't anymore. You can design the most brilliant, most advanced racing car within the rules for its class, but if you make one small mistake that car can be a clunker. That's the awesome thing about designing racing cars, the knife-edge you live on: that something will not be up to snuff and it will crucify the car."
Cue the F6...
"The sidepod was designed with this flexible-skirt system in mind. Most people were then using sliding boards which tended to stick and jam. Teams had one if not two people whose entire role was to maintain them -- they were forever stripping and servicing them -- and the skirt mechanisms became more and more complex as the years went by. The F6 had these Kevlar fabric skirts which were attached to a bottom runner that ran on the road. It was located by four vertical rods passing up through tubes in the outer wall of the sidepod. There was nothing to jam or stick and it was low maintenance."
"The tub was designed to be as narrow as possible to maximise the body's wing area. It had a flat floor and then the sides -- aluminium honeycomb panels made by Embraer -- went up and out at an angle of about 15 degrees to the vertical. So across the bottom the car was only about 12 inches wide, although it had to taper out to the engine. It was quite neat underneath -- I was very happy with the way all that worked."
Again to maximise the wing area formed by the body, the back of the car was also completely enclosed.
"I was keen to carry the top deck right through to the back of the car and make the whole bodywork as near to a wing profile as possible. What doesn't show up in this drawing is that there was bodywork beneath the gearbox too, an undertray right back to the trailing edge of the upper deck. Everything was panelled in."
One of the most obvious visual differences between the F6 and its F5A predecessor was the length of its sidepods. Whereas the F5A's reached forward to the front wheels, the F6's began much further back.
"The sidepods were short because I wanted to move the centre of pressure backwards. It is very easy to get front downforce with the front wing and, because it is ahead of the front suspension and tyres, this doesn't increase the drag of the overall package, whereas putting more rear wing on does give more drag, because it's at the back of the car and controls the wake behind it. I wanted to get as much underbody downforce on the rear as I could and use less rear wing."
Bearing on the issue:
As Bellamy designed it. the F6 ran only once in 1979, at Kyalami, finishing 13th.
"It took a long time to diagnose the bearing problem. Your drivers tell you a car is spooky to drive, but what's the cause? We put extra stiffening in the front, all sorts of things. It wasn't until a test at Donington that I fully understood. Meanwhile Fittipaldi had a consultancy agreement with a small Italian company and Wilson Fittipaldi gave the car to them to fix, so that was it as far as I was concerned. They took it away and rebuilt almost everything -- things that didn't need rebuilding. But it was never much of a car even after that, and by then I'd left." When the F6 returned from its six-race makeover, during which the F5A ran instead, it still underperformed. It retired in Germany. Austria and Holland before finishing eighth at Monza and Montréal and seventh at Watkins Glen.
Three years later, at the end of the '82 season, the Fittipaldi team closed its doors. Ralph Bellamy, after a short time at Ensign, did design work for March and rediscovered his winning touch, first with the '82 F2 car which took the European championship, and then the 85B F3000 car in which Christian Danner won the inaugural championship in 1985.
"Designing an Fl car is to a large extent a packaging exercise. You have certain pieces -- the driver, fuel tank, engine and transmission -- over which you don't have a lot of control because they have a particular volume and place. It was clear to me that the area around the rear axle was a critical one aerodynamically that you had to keep clear so that the underbody air could expand behind the sidepods. To put the exhaust system through there was going to clutter the whole area up, so I thought I'd do something different. The exhaust system is quite bulky and there are quite specific requirements in terms of pipe diameter, pipe length and where the collector box has to be. But as you can see there's actually plenty of room in the sidepod for it all. People hated it, though, because it made the engine sound like a four-cylinder -- it didn't sound like a Cosworth V8 at all as it drove by."
"In the Lotus 78 we had a unique wheelbearing system which has gone largely unremarked. A British bearing company called RHP made special hubs for us integrating hub and bearing. I wanted the same for the F6 and tried to get a Brazilian bearing company to do it. But even with the influence of the Fittipaldis we didn't succeed, so I had to use ordinary large diameter, small section, angled contact wheelbearings instead. I designed the hubs and bearings and at the end of the day they were no good. We couldn't assemble them in such a way that we got the level of stiffness we needed. So under racing loads the car had wobbly wheels, particularly at the rear. And if you didn't have control of those big rear tyres then you had no control at all. That's why the car didn't handle well."