the tunnel size. The only surprise to me was the exceptional straight-line stability. With a narrow front track, the car does not tramline over bumps in the way a conventional car would.’ In addition to Divila’s technical input, the France-based designer’s experience at La Sarthe should also benefit the team in June. ‘I’ve been racing at Le Mans for decades and have a considerable amount of experience in the set up, preparation and running of a car there, so this is an area that could also be beneficial.’ After incorporating more
detail changes related to using the AMR-One tub, Bowlby’s DeltaWing design team, including Simon Marshall and Zack Eakin, along with AAR’s Justin Gurney and John Ward, worked through the manufacturing list to complete the car. With Eakin’s
Fortunately, the fuel, which is located right next to the engine now, doesn’t change the weight distribution because it’s working with the c of g.’
Once the DeltaWing heads
to Le Mans, Bowlby anticipates having lighter bodywork on the car. ‘For the bodywork, I think the budget was about 43kg. When we first put the car on the ground, it was 9kg (20lb) overweight. That was not because it was bad, it’s just that the interim engine hadn’t got the new crank, or new block. Also, our wind tunnel bodywork was heavy. It was the first lot out of the mould, and the car weighed 472kg (1040lb) dry. Now we have the proper bodywork which is lighter, although it’s still not absolutely finished. We’re down to, well, let’s say we’re below our target weight.’
“the car does not tramline over
bumps in the way a conventional car would”
15kg (33lb) gearbox design being built at EMCO, and Ray Mallock Ltd preparing its 1.6-litre, direct- injected, turbocharged engine for the car, AAR began bringing the rest of the DeltaWing to life. ‘Every single component of the car was new,’ said Bowlby. ‘Actually, there is a ChampCar shift lever and shift cable because we are manual shifting and want to do the testing on the electronic shift in a properly controlled condition. I don’t think there is a single other component from another car.’ The team exploited the
recess in the tub’s rear bulkhead, moving the Nissan-badged RML engine inside the cavity as far as possible. ‘In order to get the weight of the tub and the driver appropriately positioned so that we still gained 28 per cent front weight distribution, we had to sink the engine into the oil tank that was in the AMR-One chassis. We didn’t make it any deeper than the existing divot, but we did make it wider. So that’s an area where we did a lot of FEA work and we’ll have to do some re-testing of the car in that area.
REAR SUSPENSION The DeltaWing’s rear suspension is a visual feast. It doesn’t have a name, but falls somewhere in the range of being a swing arm-push- pullrod system, for lack of a more precise term. ‘It’s very simple,’ remarked Bowlby. ‘The car has all of its roll damping from the rear axle. You can imagine the roll circumstances in a traditional car. It has both front and rear suspension and flexing and roll so all of our roll damping has to come from the rear. The mass of the vehicle has to be damped and rolled by the same amount and ratio as always. So what we did was to come up with a way to overdrive the shocks in roll but not in heave so we have optimum damping in heave. That translates to an increase in damping and roll so we get a decent amount of roll damping of the overall car, but it’s all achieved at the rear without giving away grip.’
FRONT SUSPENSION Up front, the DeltaWing’s suspension has an F1 look to it, with short links from the upright to the tub limiting camber gain
May 2012 •
www.racecar-engineering.com 11
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