Wednesday, September 28, 2011

Renault: Forward-facing exhausts have been our downfall 28 Sep 2011


Renault's early-season podium finishes were but a distant memory in Singapore at the weekend, with drivers Bruno Senna and Vitaly Petrov crossing the line a lowly 15th and 17th respectively, two laps down on the Renault-engined Red Bull of winner Sebastian Vettel.
But there is one glimmer of hope for the team. Rather than being stuck in limbo not knowing what has caused their form to dip, Renault believe the issues lie in their innovative forward-facing exhausts. Although initially envied up and down the pit lane, technical director James Allison believes that the concept is flawed - at least at low-speed tracks like Singapore.

"We entered the race knowing that our pace would be poor and our tyre degradation high - this is what we had seen on Friday and Saturday," Allison told the team's official website. "There is always a bit of you that hopes, irrationally, that it might be different in the race, but as events showed, free practice and qualifying were accurate portents of the grim two hours that unfolded on Sunday.

"Anybody can spot that we have suffered very poor performance at Monaco, Hungary and Singapore. The simplest explanation is that there is not enough downforce in low-speed corners. We know from our experiments with rear blowing exhausts earlier in the year that they do offer a lot more rear downforce - especially at high rear ride heights.

"We know that slow speed tracks allow the rear to be held up high in all the corners and we know that rear downforce is a prized asset for coping with the traction demand at these tracks. We also know that the forward exhaust, by contrast, performs more strongly once the rear ride height starts to compress - something that cannot be avoided in medium- and high-speed corners. It is probably reasonable to conclude that this is the basic mechanism behind the way that we shed so much competitiveness at slow-speed tracks."

Allison believes that the car's inherent sensitivity to set-up changes has also contributed to the recent slackening off of performance.

"Even at Spa and Monza, where our performance was acceptable, we still had to tweak the aerodynamic setup during the weekend," Allison explained. "Our car is very sensitive and extremely unforgiving of even the slightest geometric misalignment. This weekend, we were plagued by rear wing and floor issues that all seem to be even more sensitive at very low speeds than they are at the higher speeds where our car is more comfortable."

The Briton, however, is confident, given the nature of the tracks coming up on the calendar, that more points can be scored in 2011. He is also sure the team won't face the same issues next season.

"Of course (we can get rid of these problems with the 2012 car)," he concluded. "Each of these problems we can engineer out of the R32. However, at this stage of the season it is much harder to address these underlying problems for the R31.

"(But) several of the remaining races offer a range of medium- and high-speed corners where we ought to be able to get the car back into the points. We need to - Force India is starting to breathe down our neck and we need a few good results to stay ahead."

Renault are currently fifth in the constructors' standings on 70 points, with Force India just 22 adrift on 48. The team will be back on track in Japan at Suzuka from October 7-9.

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