‘This car was born from the regulations. It was a variant of the successful BT49. By then the car was so reliable – we knew it inside out. At that point, way ahead of other teams, I’d started introducing an organised ‘lifing’ system so we’d change parts before they showed signs of wear.

‘We even had an early computer programme in those days where we changed parts just down to the mileage that they’d done and the abuse that they’d had. This was run by one of our guys called Pete McKenzie, and [the BT49] became one of the most reliable grand prix cars of all time.

‘I was very friendly with David Phipps, the photographer, who in turn was very friendly with Colin Chapman. In fact, David was the one who first came up to me and offered me the job [at Lotus] in 1974, on behalf of Chapman, after we won the United States Grand Prix. So that was my connection with David; we stayed good friends.

‘The fine-tuning of the rear suspension on Formula 1 cars was very, very important, because the tyres were ridiculously wide – 18in-wide rims. Of course, we had quite a bit of camber change and were running the cars quite soft in those days, so you could very easily end up coming out of a corner trying to use all the tyre but, due to the squat under acceleration, only using half the tyre.

‘Because the cars were quite lightly loaded at somewhere like Monaco, your contact patch went down to half and you’d blister the tyre or damage the tyre. So, designing the right geometry and the right roll control with springs, dampers and anti-roll bars was very important. But there was no telemetry in those days, so it was very difficult to try to assess what was happening, apart from looking at the tyre and talking to the driver.

‘So, I came up with this concept of sending a photographer out to a certain bend – high speed, medium speed, low speed – and he would take photographs of all the cars from exactly the same angle and exactly the same spot.

‘He would have them developed quickly and I would get them back and I could check what camber compensation other people were using on their geometry for that particular circuit and how the tyre was being used, and compare it against our cars. One of the spy shots was our car, and the others were Ferrari, Williams, whoever. If he couldn’t develop them in time from the first day of practice, I’d take them home and do the analysis anyway. Then I would adjust either the suspension geometry, if I thought we were wrong, or more usually just the settings for camber, static camber and the ride-heights, and the amount of anti-squat that we used. I think I was the only person, and certainly the first person, to do that.’

‘That winter the two of us set about designing a hydro-pneumatic system and luckily we had pull-rods still operating the suspension. We just broke into the middle of the pull-rod with a little piston and cylinder. We had a valve that fed hydraulics to one side of the cylinder, and we had a valve that had the tiniest, tiniest port, and a filter to stop anything blocking that port, which the hydraulic fluid had to go through.

‘So the car went out slowly with the 6cm ride height. The driver took a lap with the downforce pushing on the springs. The springs pushed the fluid up out of the piston in the rod, which lowered the car slowly. Tuning the size of the hole was the trick. The final hole was so small that we had to find an extremely fine filter to ensure that the valve hole could not be blocked – from memory, the filter material was some form of volcanic rock!

‘It had to be a lap’s worth of running, roughly, until all the fluid was on the other side of that valve. The pull-rods were all longer by a certain amount, which meant we then had only a very small gap under the skirts and we were making twice the downforce of everybody else.

‘Then, after the driver finished the race, he did one slowing-down lap – very slow, like 40mph – which you were allowed to do before you came into the pits. Without the downforce, the spring pressure pushed the fluid back through the valve and raised the car back up to 6cm.

‘We arrived in Argentina and people immediately saw these four cylinders on the push-rods with tubes coming off and people like [Gérard] Ducarouge, who was with Ligier, went absolutely bananas with the scrutineers and he said, “Come and look at this – these guys are cheating.” And I invited them all into the garage. The valve body was just a little milled aluminium thing with a tube that just came in one side and out the other. You couldn’t see what it was; it just looked like a junction. It didn’t look as though it did anything.’

With his wicked sense of humour, Gordon had incorporated a red herring.

‘I’d said to the mechanics, “You must leave the top bodies off all the time.” In one of the sidepods we had a big 20-gauge aluminium box, which we’d made with electronic wires and hydraulic pipes going into and out of it, and that went to the same system and looked like it all joined in. So it looked like we had some sort of big hydroelectric thing that operated the suspension cylinders.

‘We invited everybody into the garage, the FIA and the other competitors. They all spent time looking at that and nobody saw the little valve blocks. Ducarouge was furious and some of the other people were really upset as well – Lotus and Tyrrell, the usual suspects. They went back to the FIA and said, “We think they’ve got a driver button, not a lever, and the button operates something in that box and that lifts the car up and down.” I told them all to come back in again and said to the guys, “Clear the cockpit, take the seatbelts out, show them the cockpit. Now, find me the lever or the button that the driver operates. Here you go. Spend an hour, if you like, looking for it.” They all did and of course they couldn’t find anything at all because they kept looking at this electronic box.’

Fiendishly clever though this set-up was, it was not without its teething problems. At the end of the year, Gordon told Doug Nye that, at the season-opening Long Beach race, ‘The car went down and wouldn’t come up. Then it came up and wouldn’t go down. Then one end went down and the other jammed up. It was awful. We were using plastic hydraulic lines to save weight. They blew off or melted on hot parts, the fluid leaked, the car sank and stayed sunk. It looked as if Nelson wouldn’t qualify so we took the system off his car and ran with conventional twin-rate springs.’

Piquet finished third behind the two Williams. To the consternation of their teams, Goodyear had pulled out of racing during the winter and Brabham was now using Michelin’s radial-ply tyres.

Piquet was on pole for his home grand prix at Rio but could finish only 12th, the wrong tyres having been chosen. In the fortnight between this race and the following Argentine Grand Prix, Gordon flew back to the UK to redesign the lowering system. At Buenos Aires, Piquet qualified on pole. Williams and others protested the Brabham to establish exactly what was legal and what was not.

“Do you want us to disqualify the whole field? Nobody will win”

Gordon commented, ‘Everything flexes to some degree. How do you define it?’ He and Ecclestone offered to back down if everyone agreed to have marker paint on their fixed skirts on the understanding that, if any such paint was found on the ground at any point round the circuit, they would be disqualified. There were no takers!

Piquet won the race with team-mate Héctor Rebaque holding second for much of the grand prix until his distributor rotor arm stopped playing the game.

‘So Ducarouge and the other guys go bananas and say, “OK, look at the underside of their skirts.” The scrutineers get down and sure enough our skirts are scuffed all the way along where they’ve been touching the ground. They said, “You must have been less than 6cm at some point because the skirts are scuffed.” And I said, “Yep, sure. I told you that before the season started.”

‘So I said, “Now will you go along to all the other cars that finished the race and look at their skirts?” And of course they’d all been over kerbs – everybody was scuffed. So they went back to the other competitors, Ducarouge in particular, and said, “Do you want us to disqualify the whole field? You won’t have a winner for the Argentine Grand Prix.”

‘Then of course other people were trying to find out what we did. Everybody thought we had some sort of thing that could, when the springs were compressed, hold the car down somehow. And Williams in particular were trying all sorts of things. They couldn’t suss out what we were doing. We had all these cars going round Brands Hatch, coming down the pit lane and down past the pits, springing up and down with them trying to hold the car down. And of course none of them were working.’

A front spring and cylinder were stolen from the team’s garage in Argentina and the Brabham crew were intrigued as to who would have a similar system at the next race at Imola. There was considerable bitterness directed towards Brabham. “It was a bad feeling – all the blokes you’d always chatted to, all your friends, suddenly not talking to you,” Gordon told Doug Nye. Piquet won the San Marino Grand Prix but accidents then eliminated him from the next three races.

‘We got to Monaco, which was in May, only a third of the way through the season, and the other people were really pissed off because obviously we had so much more downforce we were just going to walk away with the Championship. So the FIA, because they couldn’t work out what we had, changed the rules at Monaco and said, “From now on you can have a lever that lowers the car down when you’re on the circuit and you have to raise it after the race.”

‘I was incensed. Can you imagine? So we made a big false lever in the car with “FIA cheat” on it. Obviously then people caught us up very quickly because they could just mechanically get round the rules, which we weren’t doing. Then we had a much tougher job. In the end, though, we won the Championship, in spite of that. But that car was significant because it was hydropneumatic. It had carbon brakes, carbon monocoque, machined bulkheads, and was easy to work on. So the 1981 version was a very significant car.’

The title the team won was the drivers’: The team finished second to Williams in the constructors’, which had Carlos Reutemann second in the drivers’, by a point.

Book extract taken from One Formula: 50 years of car design
by Gordon Murray & Philip Porter. Published by Porter Press.