HINDSIGHT 1971 MARCH 711 w A 2011 re-appraisal
Racecar Engineering asked Dr Mark Handford, who was chief aerodynamicist at Benetton and Jaguar and has worked on racecar aerodynamics for more than 20 years for his assessment of the March 711. ‘A streamlined body with
everything tucked out of the way can make a big drag reduction,’ he said, ‘but as March found with the 711, it’s also an easy way to make life difficult for yourself with cooling the engine. As a result they ended up removing large parts of the bodywork and fitting larger radiators, which spoiled the original concept. ‘Given that an early ’70’s
Cosworth DFV was only producing around 450bhp, Frank Costin’s performance claim seems excessive and somewhat optimistic. It would probably have been possible to cut drag by about 10 per cent with the ‘streamliner’ approach and, at 150mph, that might work out as a 30-40bhp gain, but if you then have to add bigger coolers
and remove large parts of the bodywork you could easily lose the whole lot. ‘Looking at the car with full
bodywork as it was launched, they seem to have done a good job in reducing the drag resulting from the structure around the driver’s head. There’s a fairing behind the cockpit, but it’s
duct on the 711 is just behind the driver’s helmet and so I doubt that there’s low turbulent flow in that area. That would result in quite poor pressure recovery, compared to an airbox with a forward facing scoop inlet. ‘The elliptical front wing looks
distinctive, but I would question its use on a racecar. With an
“The elliptical front wing looks distinctive, but I would question its use on a racecar”
curious to see that the fairing is not swept down towards the rear of the car to make the wake of the car as narrow as possible. Instead, it just stops. Also, the apparent inlet to the engine is a single NACA duct on the top of the head fairing. NACA ducts work well when they are operating in a thin boundary layer and in low turbulent flow.But the NACA
aircraft wing the target is not an elliptical shape but elliptical loading distribution. If you plot a graph from the centreline of a wing to the tip you ideally want to see a gradual reduction in the amount of lift produced the nearer you get to the tip. ‘Racecar wings are limited on span and, as a result, tend to have a very low aspect ratio. That
means that a lot of tip spillage will occur unless end plates are fitted. ‘If you put end plates on a
racecar wing you will create a given amount of downforce at a shallower angle of attack. You actually have less drag because you have more uniform loading across the span of the wing. From a 2011 perspective, not
using front wing end plates was quite a large mistake. Worse yet, it seems that the front wing was run desperately close to stall angle, so whenever the driver accelerated on corner exit, he probably lost most, if not all, of the front-end downforce. ‘It’s intriguing to think how
the car might have performed if the nose wing support had been inverted, coming off the underside of the nose so that the wing itself ran in ground effect. The car would then probably have had all the downforce that it could use. It would have been more efficiently generated too, and would also have made the rear wing work better.’
was devised, but the track tests required to validate the figures never happened due to a shortage of budget. After the Italian Grand Prix Costin made calculations based on data from Monza, and showed a 60- 70bhp improvement. March disputed the claim and Costin was not paid for his work on the car. Chastened by the experience, he never worked on another F1 project.
So near, yet so far With his 711 restored to its usual aero spec
In ultra low drag form, the 711 came close to winning the 1971 Italian Grand Prix, the last F1 race held at Monza before chicanes were added.
Peterson scored another second place finish behind Stewart in the wet Canadian Grand Prix at Mosport and, by the end of the season, had gained a total of 33 world championship points, securing the Swede second place in the driver’s championship, and March fourth in the constructors’ table. A championship race win eluded the
711, but it did score one race victory in 1971 at the non-points Oulton Park Gold
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www.racecarengineering.com • August 2011
Cup with Henri Pescarolo winning the first of two races in Frank Williams’ chassis. ‘It was a good car everywhere really,
and we were unlucky with the pitch sensitivity issues relating to the front wing, but the big disappointment of the 711 was that it wasn’t actually any quicker in a straight line than the 701, and it’s still not clear why that was,’ says Herd. ‘The 711 had a relatively long wheelbase, a low moment of inertia and was always very easy to set up. The 701 was the opposite.’ For a design so rooted in aerodynamic
theory, the March 711 was devised with no use of a wind tunnel and never saw one until it had been raced several times. ‘There was no wind tunnel model of the 711 before we built the full-scale car. What wind tunnel testing there was came after that. Compared to modern-day Formula 1 we were living in a completely different world.’
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