Tech Notes: Decoding secrets of the midfield pack

Force India

A chilly Silverstone hosted the launch and shakedown of Force India's new car, the VJM05.

Although employing the McLaren-Mercedes powertrain once again, the chassis marks a complete departure for the team: clearly lacking any similarity to its forebears, the design emanates from a new philosophy in front-wing layout. From this, the nose, turning vane and sidepod thinking have followed suit.

Although new to Force India, the wing aligns with common thinking in F1 front-wing design: it's a three-element unit, with diverging endplates to send flow around the front tyres. This hangs below a typical 2012 flat-topped nose, Force India taking a high-chassis and high-nose route, with slight V-shape to the front bulkhead.

By taking the high-nose approach, Force India risks having the centre of gravity too high. To lower the C of G, the team has switched back to a more conventional, lighter rollhoop, replacing last year's blade design.

Along the car's flanks is the other big change in design approach, the undercut sidepods, which are similar in concept to the 2011/2012 Toro Rosso solution.

By undercutting the entire length of the sidepod, more airflow can be directed at the diffuser for more downforce. Tapering in smoothly, the sidepods vent their hot air through an outlet above the gearbox, that leader of the design team Andy Green terms a 'tulip' outlet.

This was run closed for the freezing Silverstone shakedown, but larger outlets will be used in the opening races.

This area also includes the exhausts, which are mounted inboard and directed inwards for a less aggressive approach, Green saying that the team was looking for a less sensitive but still beneficial use of the exhaust plume.

Sauber

In the frenzy of launches preceding the first day of testing, Sauber was first off the mark by launching its car in front of the assembled media.

As another one of the teams supplied with an entire powertrain, Sauber has developed its chassis around the Ferrari engine, KERS and gearbox. Its new C31 is a clear evolution of the 2011 car, with the necessary changes to meet the new nose and exhaust regulations. If externally similar to the outgoing car, the new C31 does sport some clever aerodynamic details.

As the launch car was fitted with a front wing similar to the late-2011 wing, we can move straight to the nose design: along with all teams bar McLaren, Sauber has opted for the maximum nose and chassis height allowed under the rules.

Having a flat-topped nose and chassis creates problems in keeping the flow attached along these long, flat surfaces, especially after the step between them. So Sauber has adopted a slot in the rear face of the nosecone to help keep this flow attached. This is a clever interpretation of the wording in the rulebook.

Sauber's sidepods have traditionally been well shaped, and the C31 follows that approach. The sidepod entries are high and extremely undercut, then the entire sidepod curves tightly inward and appears to have a very small volume, this being aided by the inevitable tail-funnel cooling exit, albeit Sauber's version being a pair of tall vertical slots, rather than a rounded outlet.

Cooling is further aided by a small inlet under the rollhoop, which probably feeds the KERS or gearbox coolers.

In contrast to its engine supplier's solution, Sauber's exhausts are very simple, being quite far back and on top of the sidepod. In this position their effect would be more neutral and less peaky than Ferrari's more radical solution.

One of the other neat aero solutions on the car is the beam wing mounting. In order to keep the harder working underside free from obstruction, the wing is secured from above by a swan-neck mounting. This is quite thick and could form a duct; however, it joins to the gearbox in the same place as the rear suspension. Sharing this position suggests no air could be routed through the mounting.

Although rocked by the departure of technical director James Key, the design team headed by Matt Morris and head of aero Willem Toet has shown it can create a solid and innovative car.

Toro Rosso

Ending the pre-testing day of launches, Toro Rosso unveiled its new STR7 in front of the garage.

Having been independent of Red Bull's design team for several years, Toro Rosso's design office has forged its own philosophy. This line of thinking progresses for 2012 with a continuation in the undercut sidepod, as well as some neat interpretations on nose and rollhoop design.

As with Sauber, the team employs the entire Ferrari powertrain (engine, gearbox and KERS).

With the aerodynamic rules being largely the same from 2011, the front wing bears a strong similarity to the team's old device. Above this, it has followed a straightforward interpretation of the new rules, the flat-topped chassis and nose forming a step with a slight V-shape to the cross-section, thus creating the distinctive bulges atop the nose.

Back in 2010, with the loss of the double diffuser, Toro Rosso followed a design path of an extreme-undercut sidepod similar in concept to the 1992 double-floor Ferrari, which removes the obstruction of the sidepods from the flow approaching the diffuser.

This is a logical approach, albeit with a C of G height penalty and loss in sidepod volume. As this is the second year with this sidepod shape, technical director Giorgio Ascanelli feels its aerodynamic benefits are enough to offset these drawbacks.

Another unusual feature is the rollhoop design. Although the undercut airbox inlet is not uncommon, this uses a metal internal structure to create the strength. Beneath this is a large oval inlet that feeds air to the KERS or gearbox coolers.

Both of the other Ferrari-engined teams have a sizeable additional cooling inlet along the centreline of the car, whereas all their sidepod inlets are relatively small.

Having a headstart with its sidepod design means Toro Rosso should be quick off the mark as the season begins. Last year its development rate was impressive, but out of step with other teams. It will need to keep up its in-season development to keep ahead of the midfield pack.

Lotus

Despite this being its first year as Lotus F1, the team is clearly a continuation of the Renault, hence the E20 designation signifying the 20th chassis designed at the Enstone factory.

In design terms, the new car's lineage clearly follows that of the Renault team. Although the 2011 R31 chassis, with its front-exit exhaust, was not a success, the new car bears a remarkable resemblance to it, the comparison of new car to old being made difficult by the use of a show car at various media events on the launch day.

However, the car that took to the track at Jerez was the new chassis and features several departures from the launch spec.

As one of the teams with the greatest number of front-wing iterations during the season, it was no surprise that the complex wing sported new features, the new most notable being the P-shaped vanes midway across the wing, directing airflow around the inside of the wheel.

Last year's Renault marked a departure on nose shape after the boxy versions raced in 2009 and 2010. Despite the new nose rules for 2012, the rounded shape has been integrated into the new flat-topped design.

Considering the switch to a rear-exit exhaust, the sidepods also resemble the 2011 car, featuring a peak above the inlet that encloses part of the crash structure. From there, the sidepods sweep back inwards and downwards, the exhausts exiting through a small bulged fairing near the rear suspension.

At this early stage it seems the car is just a simple evolution of the outgoing version. However, technical director James Alison confirms that it has a lot of new parts yet to be bolted on. With other midfield teams making a larger step in design terms, Lotus may need these parts to break clear and chase the leading pack of teams.