Tech Analysis: Renault R27

Having won two pairs of world championships in consecutive years, Renault are clearly confident in the pace of their car, as their new offering appears little changed from last year. But when the car was launched in Amsterdam last week, the full picture was not quite revealed.

The machine on display at the launch was only half the car, according to head of aerodynamics Dino Toso, who admitted that there are still "a few add-ons to go on the car" on top of the new nose, wings and floor due for the pre-season test in Barcelona. Some parts that have changed, such as the engine and monocoque, are clearly evolutions of the team's previous ideas, while the main alterations are to the sidepods and the gearbox.

While evolution is key, the team's technical director (chassis) Bob Bell says the car is "completely new" under the skin. "The important thing to remember is there 6000 or 7000 components in the car," he added. "Every one of these we have looked at and said 'can we make it lighter, can we package it more tightly, can we make it stiffer?'"

This procedure is an ongoing process, year-on-year, at Renault and Bell added: "It's more important and time consuming than the visually appealing things like the wing mirrors, although that's the thing people will focus on."

This organic development has served Renault well for the past three years. With this year's regulation change to one make of tyre, Renault's knowledge of the chassis should allow them to rapidly adapt the tyre rules. Additionally the team's focus on reliability should allow them to take advantage early in the season, while other teams work out the unknowns in their packages.

The R27: a view from the top © LAT (Click image to enlarge)

The lack of major technical change in the package, however, could well see Renault running short on development potential through the season. As the team will privately admit, the Ferrari was fastest in the latter part of last year. If the new car has not made enough of a step over the winter, any shortfall on pace will be immediately obvious.

Bell has also commented that although the R27 has enough front-end downforce, it does not currently have any capacity for more. "We need to find more," he said. "We can get the aero balance where we want it. We always like a margin there and what we need to do is keep developing the front of the car, not just the front wing but the front of the car in general."

The new Bridgestone tyres demand a more forward weight bias, so the ex-Michelin teams are having to re-site their ballast to put more weight over the front. But this weight issue needs to be balanced by the aerodynamic centre of pressure (CofP).

This is the aerodynamic equivalent of weight distribution, the point where front and rear downforce are equal. Its position is usually a few percent behind the centre of gravity - and if the CofG is moved forward the CofP must follow. This has left Renault hard pushed to create enough front end downforce, the updates due in a few weeks are expected to remedy this.

Putting aside the new ING livery, the new R27 is very much the son of the R26. The new car features the same mechanical layout of the R26 in terms of wheelbase, gearbox/monocoque length and keel design, where a V keel is retained. Its front end will be altered before the first race, so the nosecone, front wing and bargeboards are all provisional designs, carried over from last year.

But it is the sidepods that are all new, based around new radiator and exhaust packaging. The monocoque is now wider to accommodate the side penetration panel (6mm thick) but the sidepod bodywork is in fact narrower, visible the by the fact the flip up stands proud of the sidepods by a few cm. In terms of undercut shape and inlet the car follows last years design.

The mirror is integrated into the pod wing which extends to form the flip up © Scarborough (Click image to enlarge)

Causing the most fuss amongst the fans and media are the new pod wings and mirrors. While the integration of the pod wing and mirror is a simple idea it is not the most significant part of the sidepod add-ons and Bell downplayed the design as "a nice touch, a signature." Dino Toso added: "The sidepod is visually the biggest change, but aerodynamically probably not. The things that you don't tend to see like the wings and diffuser are where we get the gains from."

Toso confirmed the mirrors are sited in the wake of the front wheels, an aerodynamically untidy area. This minimises the impact of the mirrors' turbulence on other parts of the car, and Toso did suggest the driver's rear view has not been compromised, while the view of the tyres is actually improved.

One downside of the mirrors' position is that they are prone to buffeting, something that has been shown in testing. However, it seems their position further from the driver may offset this. "They are still vibrating, but if you have something near or something over there that vibrates rapidly, the one further away will allow you to actually see more," said Toso. No doubt the lay up of the carbon fibre in the wing will eventually offset the vibration.

But the more interesting point about the pod wing is the continuation of the pod wing mounting into the flip up along the sidepod. This whole assembly becomes one surface, despite being split to allow the engine cover to be removed. It accentuates the pod wings' function of splitting the flows into one clean flow inside the wing and one untidier flow outside of the wing, providing more rear downforce.

The new car has also retained the shapes of the lower flip up, the chimney and winglet from 2006, but the exhausts now protrude through the bodywork rather than being cut flush as they were on the 2006 car. Everything around the sidepods and engine cover is tucked in a little tighter and lower, but the overall look is very in keeping with Renault's evolutionary philosophy.

A new curved element now spans the floor between the diffuser and wheel © LAT (Click image to enlarge)

At the rear, the car's rear wing and diffuser are carried over from 2006 and due to change for the pre season test at Barcelona in a few weeks. Renault has followed a unique design of diffuser with an aggressively steep middle tunnel and outer channels aided by the position and shape of the lower wishbones.

The new floor seems to be aided by two unusual curved devices spanning the floor between the diffuser and wheel. Its not clear quite how these devices work, or what they aim to do, but they are probably limited in their benefit, unlike similar larger devices other teams fit over their diffuser roofs.

Underneath the bodywork the gearbox is a new development. Again it uses a cast titanium casing with small amounts of carbon fibre bonded to it in critical areas, and Bell commented: "I think we are reasonably unique in that and we get more adventurous each year."

But the gears and selection mechanism have been changed for a seamless design. This is a Renault-developed technology, which they have termed instantaneous gearshift (ICG). It keeps Renault in line with their rivals, none of which have launched a 2007 car without such a system.

On top of the gearbox, the rear suspension set-up retains the familiar vertical torsion bar design, placing the dampers behind the axle line. This year a truncated engine cover leaves the ends of the dampers exposed to the airflow. This is an unusually untidy design, but perhaps some of the Barcelona updates may hide away the ends of the dampers.

Being amongst the class of the field in 2006 bears well for the revised engine © LAT (Click image to enlarge)

This year's engine has to follow the engine development freeze regulations and as such differs little from the 2006 RS26. Engine head Rob White is clearly frustrated by the regulations, having only been allowed to do the tuning to accommodate the new 19,000 rpm limit and some revision to the engines installation in the car.

Last year's engine, however, was often remarked as amongst the most powerful as well as being stronger on fuel consumption and demanding smaller radiators. Such facets suggest that Renault have an enviable unit to race in 2007.

So, with a clear link to the past, the new R27 has a strong chance of setting the pace early in the new season. The team's addition of new aerodynamic parts and a seamless gearbox should keep pace with their rivals and, with these developments based on a well known chassis and solid engine, Renault could do well early in the season. Their bigger task will be keeping the package competitive as the other teams find their feet.