DELTAWING
the shortened wheelbase, a significant amount having been removed from the front of the chassis. ‘The real car has a 120in wheelbase, but the reason for that is not the use of the AMR-One,’ explained Bowlby. ‘It’s because the ACO requested that our car be no longer than 4.65m, simply because the pit box at Le Mans doesn’t allow a car longer than that.’
THE NISMO CONNECTION While Bowlby’s team worked on the build and development of the DeltaWing in America, Ricardo Divila, technical advisor to NISMO (Nissan Motorsport International Ltd), was performing similar tasks on behalf of Nissan. ‘My initial brief from Nissan was to look over the design concept and see what were the possibilities and if it was a valid project,’ said the Brazilian. ‘To do so meant looking at the initial CFD and 40 per cent wind tunnel data and some dynamic simulations. After liaising with Ben Bowlby, I started receiving the aero maps and car data, and from there did some simulations on my side, and prepared the KPIs (key performance indicators).’
With performance benchmarks
established by Divila for NISMO, he began the validation process that would define the on-track and wind tunnel targets the DeltaWing needed to achieve to activate Nissan’s official backing. ‘The car then had to match these marks in different phases of the project, like the 40 per cent wind tunnel, full-scale matching CFD data, latG, top speed at a given circuit, braking and yaw rates at the same.’ Although the DeltaWing is obviously a very different animal to most racecars, Divila cites first-hand experience and understanding of some Bowlby open-wheel designs as the reason for the easy collaboration between the two men. ‘We had overlapped already, as I had run his F3000 and ChampCars, plus he is someone who is very open. He did a very good job of creating and seeing through the concept and design of the DeltaWing, and it’s nice to work with people with experience and knowledge. It provides an incredible amount of synergy. You don’t have to explain anything, they know what you mean, and know
10
www.racecar-engineering.com • May 2012
With just two four-inch tyres sat close together for frontal grip, that has been the main point of contention from doubters of the DeltaWing concept, but early track tests suggest the unconventional design works. Unusual three-lug front hub arrangement was chosen to save weight
Weight saving and balance were major considerations throughout, with an extremely lightweight EMCO gearbox chosen to back the RML-prepared 1.6-litre, direct injection, turbocharged Nissan engine
dynamics, aero and mechanics.’ After working with his own
simulations and calculations, Divila says he was impressed with the detail work done by the team to maintain the car’s original performance goals after switching to the AMR-One tub,
amongst other things. ‘After getting the project and seeing the data, I can only say there was a very good job done to claw back the L/D, as the use of an existing tub from an LMP1 car reduced the downforce by about 35 per cent through the loss of
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