McLaren M7A
It was sink or swim when a 21-year-old was given sole charge of a new F1 project: Keith Howard talks to the young man who wrote his own rules
Robin Herd CBE is perhaps best known as a co-founder, along with Max Mosley, Alan Rees and Graham Coaker, of March. But his first job in motor racing was as chief designer at McLaren, during the time it successfully battled Chaparral in Can-Am and took its first positive steps in Formula One.
For proof that the past is a foreign country where things are done differently, consider how Herd landed the job. As he tells it: “I got to within two weeks of starting finals [at Oxford] when! realised that I’d be on the dole in four weeks. So I went to the appointments bureau and they sent me to Famborough. I worked there for three years on the development of Concorde, which was fascinating. They treated me marvellously, but! didn’t like working in a large team. Motor racing had been my love from school: Autosport and Motoring News were the highlights of the week.
“It was one of those chains of coincidence: Howden Ganley was working for Bruce McLaren as a mechanic and heard him say that he wanted a chief designer. Howden said that a friend of his had a friend (Alan Rees, the driver, who’d I’d been in the same form as at school) who knew someone with the sort of background Bruce was looking for. Me. I had a phone call from Bruce asking if I was interested — not half! — and we met that evening. The following day I got a phone call from Teddy [Mayer] asking if I wanted to join.
“That was it: I was chief designer at the grand age of 24, having never designed anything, let alone a racing car, in my life. Bruce sat me down at a drawing board and said that Teddy and he were going off to the Tasman series, and would I design a Formula One car for Chris Amon!”
Such lack of experience can be a two-edged sword. The disadvantages are obvious, but ameliorated in McLaren by the corporate design process, involving numerous team members, not least McLaren himself. “It was an extraordinary group at McLaren then — Bruce, Teddy, Eoin Young, Tyler Alexander, Wally Willmott, Don Beresford, Howden Ganley. I don’t think there has ever been one like it, before or since.” Naivety’s upside is that nobody has shackled you with received wisdom about the way things have to be done, which perhaps explains why that initial Herd design, the M2A, was the first Fl car to have a tub constructed of sandwich material (aluminium skins over an end-grain balsa wood core), and was glued throughout — an extraordinarily bold design decision given the knowledge and facilities of the time.
Unfortunately, the M2 was handicapped by its engine. So McLaren’s and Herd’s first ‘proper’ Fl car was the short-lived BRM-powered M5A of 1967; that was followed in ’68 by the Cosworth DFV-powered M7A, featured overleaf. It secured third and fifth places for Denny Hulme and Bruce in that season’s drivers’ championship, and second in the constructors’ title — outstanding for so recent a recruit to the sport’s premier series.
Herd has an odd explanation for this: ‘To go to the toilet at McLaren I had to walk out of the drawing office and pass by everyone. They were all strong characters. That’s why the cars I designed were easy to build, easy to maintain and inexpensive. Because if they’d been difficult to make Don would have collared me on the way past, or if they’d been difficult to maintain Tyler would’ve grabbed me. We set great store by this design simplicity. When Jim Hall saw the M6 he said it was a very simple car but the elegance of that simplicity would make it difficuk to beat.”
Herd: “The oil tank at the rear isn’t exactly elegant, but it’s inexpensive to make, very accessible and you also get cooling airflow around it. And, as I learnt later at Cosworth, you can make it closer to the shape an ideal oil tank should be, which is a narrow-angle V. Plus it balances out the radiator, whose front mounting didn’t make achieving a good weight distribution particularly easy.”
“Mounting the ignition components on the roll hoop’s backstay meant you could get to them easily and they were also cooled. Those days, when the races were not so close, you could actually change a coil or a battery during the race, so accessibility was important, but it was difficult to find a place to mount the ignition components and still ensure this.”
At a time when Fl cars were generally fitted with Girling brakes and solid rotors, the M7A bucked the trend by using Lockheed calipers and discs, the latter ventilated. “I think it was probably down to finance. We had a very good relationship with Lockheed and they wanted to get into Fl. But we pushed for ventilated discs — we wanted very much to have them. Part of this enthusiasm came from our experience with the M6, which originally ran solid discs. You couldn’t keep them cool enough, so we got ventilated discs on in double quick time and the difference was night and day.” Lotus had experienced problems with ventilated discs cracking, but McLaren avoided that by the simple expedient of shielding the discs within the wheel, so that excess cooling didn’t cause large temperature differentials within the disc material.
Although the monocoque was a familiar bathtub design, incorporating three steel bulkheads, it was different from the norm in being adhesive-bonded as well as riveted. In fact, the rivets were there primarily to jig and clamp the structure while the two-part Shell epoxy adhesive cured. It was a technology McLaren carried over from its Can-Am programme. “There was an amicable rivalry between Jim Hall of Chaparral, backed by General Motors, and Teddy [Mayer] and, to a lesser degree, Bruce. Chaparral bonded their cars and used honeycomb; they pioneered it. Our aim was to beat Jim Hall — Can-Am almost rated more highly in importance to the company than Fl — so we felt we had to keep up. It was not a disadvantage in this respect for me to have worked at Farnborough! Our bonding process was very simple. There was no surface preparation except to ensure everything was chemically clean.”
“By machining off the top of the front upright it wasn’t hard to tune the suspension geometry [using packing plates]. The Firestones on our F2 car had stiff sidewalls so you had to have little camber change, otherwise, as the car moved vertically it became difficult to drive. Down the straight at Goodwood the Firestone rears would steer the car over the bumps, whereas with the Fl Goodyears you’d lose lots of camber during cornering, as a result of the soft sidewalls; you had to grab that back by altering the geometry to give more camber change.”
Aside from its remarkable track success, the M7A has also been called the most handsome Fl car of its era. A complete accident, maintains Herd, who was preoccupied with the imperatives of designing a simple, inexpensive car rather than thoughts of beauty. In any case, as he rightly says, ‘The faster a car goes, the prettier it tends to look”.
Trial and aero
Although designed to be fitted with wiwngs, the M7A didn’t get them until mid-season: Yet McLaren had experimented successfully with aerofoils years earlier. “The M2 was built to take an aerofoil and we actually ran it in a test at Zandvoort. On his first lap with it fitted, Bruce was 3sec faster. We took it off again: 3sec slower. Back on again: 3sec faster. It was very difficult to believe, and that’s one of the reasons we didn’t get in earlier with wings in races. Plus there were journalists around during the test and we didn’t want them taking note, so we actually hacked up the wing and put it in the bin to persuade them it didn’t work!
“It was mildly irritating that Ferrari and then Brabham came along with them when we had done it first. I wanted to attach the M7’s wings to the suspension uprights, but the feeling was that that was asking for trouble, which events showed it was.”
Ground effect had been exploited in the Can-Am M6, the success of the inverted aerofoil section under its nose being confirmed in a test at Goodwood where Herd sat alongside McLaren monitoring pressure taps on the car’s underside. Was ground effect ever considered for the F1 car?
‘With the M6 having gone so well, far better than we anticipated, Bruce and I would talk about this sort of thing over dinner. But there’s only so much you can do, and with the M6 there was significant body width and surface area to play with, so you didn’t need to generate much negative pressure. At that stage we thought we should just get the Fl car competitive.”