Learning new tricks: How McLaren crafted James Hunt's title winning M23

Scheckter, who was winning the UM Formula 5000 series Stateside, returned to F1 in Canada in September, and qualified third, admittedly behind Revson. Sure, Peter was good, smooth and capable, but McLaren knew which way the wind was blowing. They wanted Jody for 1974, easing Revson into a third, Yardley-backed (Texaco/Marlboro would sponsor the other two) car to make way for Fittipaldi. Still grouching over their carambolage, however, Emmo vetoed Scheckter. A put-out Revson had already switched to Shadow, so Mike Hailwood landed the Yardley drive, and Denny ‘The Bear’ was out of the woods for one more year.

Fittipaldi and McLaren would win the titles, the team’s first, that year, justifying these choices, but did so via consistency and car-sorting prowess rather than speed. Emerson felt he had the best team, if not the best car, and because DFV-vs-Ferrari was at its most competitive, he (and the team) decided handfuls of points on bad days would be the key. They were. Just.

The next season was ultimately disappointing despite three wins, two of them admittedly garnered in foreshortened races at Montjuic and Silverstone. And despite an eventual second place for Emerson in the title race, he had seemed disenchanted in the early part of the year. So here’s the rub: no-one drove M23 as hard as rough-edged Jody did in 1973, until the equally fiery James Hunt rocked up in ’76. And had Jackie Stewart, maybe even Ronnie Peterson, been in the M23 in ’73, McLaren’s title wait would have been one year shorter. For the car was on the pace the moment it turned a wheel and was setting poles five seasons later.

Yet remarkably, it was Gordon Coppuck’s first F1 design. He had learned the ropes under Robin Herd on M7 (1968), been in cahoots with Jo Marquart on M14 (70), and had wowed Indy with his M16 while Ralph Bellamy penned M19 (’71). M23 was Coppuck’s response to the deformable-structure regs in force as from the 1973 Spanish GP. Tyrrell and Lotus doffed their caps to the wording, bolting and riveting onto existing cars; McLaren were more thoughtful, strategic. How much more they surely could never have guessed.

“We had always hoped M23 would be a two-year car,” admits Coppuck. “As well as meeting the new regulations, we wanted to build a much stiffer chassis. It was a bit of a risk in that the chassis extended right out to the extremities of the radiator duct, integral with the chassis, but it paid off.”

M23’s build was complex — its monocoque double-skinned 16 gauge aluminium sheet sandwiching injected foam — but at its core lay a rugged simplicity. An amalgam of M19 rear end and M16 wedge front and hipster rads, it was tidy, well-built and, crucially, possessed of a bigger footprint than the 72 and 005-006. It was, basically, F1’s way forward. A solid foundation upon which to pile two seasons of continuous, Fittipaldi-led development, from where to launch a feverish, Hunt-inspired title bid.

That foundation was even bigger in 1974, a bell-housing spacer adding 3in to the wheelbase, the rear track being widened by 2in. This was done in the main to clean up the airflow around the rear wing. One of M23’s strengths was that it proved adaptable to aerodynamic changes. This was vital, because McLaren and Coppuck were just beginning to feel the tug of ground effects. They weren’t alone, and they didn’t grasp the opportunity in the way Lotus eventually would, but the side-skirts that appeared on M23 during 1975 were the most professional-looking and effective of their type.

That large underbody area (previously considered a design no-no) was paying increasing dividends, too, especially when the sidepods were extended to the rear wheels in 1975. Suspension movement was consistently reduced to keep the track/car interface as close and as consistent as possible. And a NACA duct was let into the floor under the driver to create an area of negative pressure inside the cockpit.

“We weren’t particularly aware of ground effect in 1973,” admits Coppuck. “We knew we were generating downforce from the underside, but had no accurate measurement. All we could do was try an idea and see if the driver liked it. We had, though, always found that bigger was better. The bigger the plan area, the more downforce.”

The proof? M23 was usually the car to have in the quick stuff: Kyalami’s Jukskei Sweep (pole 1973, 76 and ’77), Paul Ricard’s Signes (pole and win 1976, fastest lap ’73 and ’75), the ‘Glen’s Chute and Loop (win and pole 1976, fastest lap ’75 and ’76), all of Mosport (win 1973, ’74 and ’76, pole ’74 and ’76), Interlagos’ old outer loop (win and pole 1974, pole ’76 and 77, fastest lap ’73 and ’77), and the long, long Curvon at Buenos Aires (win 1974 and ’75, pole and fastest lap ’77). M23 bombed at Monaco, though.

“Because it was as heavy as a pig,” explains Alastair Caldwell, one of the forthright hands-on Kiwis who drove this team. He’d joined McLaren in 1967, became F1 team manager in ’72, and stayed until ’80. “It was only when I moved to Brabham that I discovered that most teams spent half their life trying to get their cars heavy enough to be weighed. And McLaren always tended to have big drivers. Even though midgets like Jackie Stewart were trotting around the paddock, the importance of it escaped me at the time.”

McLaren left few other stones unturned, though. During 1974/75, M23 rarely appeared in the same spec in back-to-back races. In the first of these years, however, the team was gunning for the title; in the second, they were striving to prolong the life of a car they feared might be past its sell-by date. A subtle but important shift.

Fittipaldi’s 1975 Silverstone win, though a little fortuitous, lifted the team, and strong drives in Italy and America suggested Emmo was back in the groove. But with an out-of-the-blue call from an airport, he kissed goodbye to his hard work. And with a phone call from his Esher home, McLaren boss Teddy Mayer turned Hunt’s career around. It was late November. Testing would be minimal. It could’ve been a poisoned chalice. It was, though, a match made in motor sport heaven.

Smart in a new dayglow paint job, and minus a few pounds (thanks to Kevlar panels and — from Kyalami on — a battery-obviating onboard air-starter), what M23 needed was a balls-outer for a final fling: Hunt All Hunt, a boiling-over, pent-up winner, needed was a release valve: M23. He slapped it on pole at Interlagos. Game on.

Ferrari had the grunt and Lauda, but McLaren had an open forum of straight-talkers. “We were harsh on each other,” says Coppuck, “but never lost sight of what we were trying to do. I was the only professional designer, but there were lots of others with ideas and opinions.”

Caldwell had been banging on for a couple of seasons about the need for a six-speed gearbox. Now, finally, he had got his way: “I had developed it in my own time using an existing Hewland casing. I got rid of the huge sliding gear used to engage reverse, moved reverse to the rear of the ‘box, outside the casing, and fitted sixth into the space I’d created. Hewland told me it was a stupid idea but were soon making their own, which was longer and heavier than mine.

“We used to spend hours talking about ratios and changing them, but that all stopped once we had the six-speeder. The drivers could not even tell you which gear they were in; ‘The right one,’ they’d say.” On the engine front, McLaren bypassed Cosworth conservatism via offshoot engine sellers Nicholson McLaren, and (initially) secret batches of lightweight, higher-compression pistons from Mahle.

“The mistake we made was to stop buying Cosworth pistons,” says Caldwell. “That alerted them to what we were doing, and they blackmailed us into using their pistons again.”

The catalyst for such subterfuge was that Texaco was on the case. F1 cars were allowed to use 101-octane (plus or minus one per cent) pump fuel, often sourced from whichever five-star pump was in the paddock.

“Texaco analysed some of it, came back to us and said it was crap,” explains Caldwell. “It was 100-octane, but its motor number was low compared to their own. I’d never heard of the motor number, but it’s the one the matters. The research number, the one on the pumps, is the speed at which the fuel burns; the motor number concerns its detonation.

“Texaco stopped a refinery in Belgium and made us a batch of 101.8octane [inside the theoretical 102.1 maximum] fuel with a very high motor number, which allowed us to run higher compressions.” This caused a fuss at Monza but was legal, as the CSI, the governing body, admitted to Texaco two weeks after Hunt had been forced to start from the rear of the grid.

So the 1976 M23 had the most powerful DFV, and a gearbox to make the most of it. But it didn’t stop there. Driveshaft angles were pushed to their limit to stretch the wheelbase further. The case for the skirts was argued successfully — further debate on the topic stymied by the headline-grabbing controversies of Spain (McLaren too wide, courtesy of fatter Goodyears), Britain (Hunt’s right to restart) and Italy (said octane ratings). McLaren, ignited and united by their flamboyant number one, were ahead of the technical game and full of fight — but short of luck and points.

And then, suddenly, M23 was all over the place — and nowhere — in Belgium, Monaco (as usual) and Sweden. It wasn’t until a test at Paul Ricard, just before the French GP, that the reason for this was discovered.

Caldwell: “Because of the fuss in Spain, we had decided to go to the next race with an absolutely legal car. We didn’t want Ferrari to have the smallest thing to pick us up on. Which is why we moved the oil coolers to the tail: they had been in the sidepods, but this meant they broke some rule about maximum length of oil pipe from the centre-line of the car.”

This change seemed insignificant, but the resized coolers upset the hard-won smooth airflow over, and negative pressure under, the wing. Once restored to their more propitious place, Hunt promptly won in France — and Britain (in the eyes of the world at least), Germany, Holland, Canada and America, before securing the most dramatic of championships at Fuji.

M23 would never win again, but it would sit on pole for the first three races of 1977, the last at Kyalami, five seasons after Hulme’s one-and-only. It wasn’t until Hunt qualified eighth, behind Fittipaldi’s Copersucar, at Long Beach, that the pressing need for M26, which had been on Coppuck’s books as long ago as 1975, could no longer be ignored.

So what’s it to be, Lotus 72 or McLaren M23? I agree, the automatic reaction is to plump for the Lotus, which has an allure and star quality no McLaren has ever possessed. The reasoned reaction is to look again, more closely this time.

The Lotus won over a period of five seasons, but drew a blank in 1971 and fizzled out horribly in 1975. The McLaren won in four consecutive seasons and was still competitive when it was eventually replaced. The Lotus took three drivers to victory: Jochen Rindt, a bright-eyed Fittipaldi and Peterson. Not a bad line-up. The McLaren took five to victory: Hulme, Revson, Mass, a latterly distracted Fittipaldi and Hunt. Not quite such a good line-up. The Lotus required three seasons to set a fastest lap, the McLaren needed two races. A fading 72 ushered (with all due respect) Jim Crawford and Brian Henton into F1. A fading M23 ushered in Gilles Villeneuve and Nelson Piquet.

See, not so clear-cut, is it?