New car technical round-up

Last week saw the penultimate pre-season test, for most teams in Jerez. Despite it being initially marred by rain, as the weather improved the teams were able to focus on longer runs and introducing new developments.

At this stage of any season the development rate is very high, as teams discard their launch bodywork for the parts that have benefited from more development time. But with this year's major rule changes, the cars are changing more substantially than ever before.

With just this week's Barcelona test before most teams pack up their equipment for the FOM flights to Australia, there is little time left to test new parts.

Some teams are planning another test, thus having to make their own transport arrangements to Australia and no doubt a lot of new parts will have to wait until Fridays practice in Melbourne to make their debut.

Williams

Williams came to the test with perhaps the most numerous and innovative changes. Almost every panel of bodywork on the car saw some alteration. But while the skate wings caught the most attention, Williams had far more interesting parts on their car.

One of the most interesting new features, and going almost unnoticed, was a unique snow plough-like device mounted below the nose. Just visible below the nose cone in unpainted carbon fibre, the 'snow plough' starts with vertical edge and diverges either side, the lower edges being horizontal to form a foot plate and void formed behind.

Sitting this high up, the snow plough is legally above the bargeboard exclusion area between the wheels outlined in article 3.11.2. Having switched to a shallower nose cone soon after the launch, at first it seemed that the aerodynamic effect of the bulbous nose was not desirable. However, the new device appears to mimic both the bulbous nose shape and act as a turning vane.

This device was aided by two small extra turning vanes dropped from the front of the monocoque. Thus the effect is both to create low pressure behind the middle front section and divert air around and under the car. Unlike their diffuser, this is quite a specific solution and tied closely in with the team's front wing, sidepod and under floor strategy, and it's unlikely many teams will immediately copy this device.

If the snow plough avoided media attention, then the teams other addition certainly caught the headlines. Two vertical fins added to the side of the cockpit, have been termed 'Skate fins'. These come from the same family of solutions as the Viking and Antler fins used last year, as they aim to divert flow to the rear wing, particularly when the car is at angle (yaw) to the airflow. With the new rules creating exclusion zones above the sidepods for this sort of bodywork, the fins are in the only place left free for something this far outboard and high up.

Unlike the Viking format used by Honda, BMW and McLaren in the past, the Williams fins have a rounded tip shape; where as the sharp edge on the Viking wings was more aggressive in creating the tip vortex (which is the aim part of the device). As yet, these devices have to be scrutineered in Melbourne, the FIA may accept they are legal within the bodywork rules, but may view them as a safety hazard being so close of to the cockpit.

Other new parts fitted towards the front of the car included a brief run with Red Bull-like bulbous fairings on the top edges of the monocoque, and then permanently fitted were new wing mirrors with broader mounting stalks to influence the airflow; plus a small cooling outlet set into the side of the cockpit side.

At the rear of the car new rear brake ducts forming a turning vane-like shape were added, along with new rear wheel fairings, rather than being fully closed off the fairings featured four large apertures to vent the hot air from the brakes.

Then the team brought a major revision to the sidepods. The tall wide shoulder of the sidepods that lead into the coke bottle area has gone; instead, the sidepods sweep from their leading edges more smoothly to the rear. Many teams are taking altering their sidepods to create less internal ducting aft of the radiators. It seems that the sidepods need less volume to send the hot air from the radiators to the exit of the sidepod; the sleeker sidepods are then less obstructive to the flow towards the lower rear wing and diffuser.

Lastly but probably most importantly, at the rear of the car the 'double decker' diffuser seen on the launch car has had a major overhaul. Unlike the 'M' shape exit to the launch diffuser, the new set-up makes full use of the 175mm high exit area and is now completely rectangular.

As well as this, the team have created a 150mm wide centre diffuser, albeit not reaching beyond 350mm in length, unlike Toyota's longer middle tunnel. The greater diffuser area needs to be fed with higher pressure air upstream, without the benefit of large bargeboards. As in 2008 this is difficult in 2009 so it's possible that the work with the 'snow plough' and turning vanes around the nose have aided airflow heading under the car.

Despite the innovative approach in design, Williams have yet to convert this into top times in testing. This may reflect their testing strategy, but at over a second off the fastest times each day, Williams still have to prove their pace.

McLaren

While many teams have been going for fast lap-times during differing phases of their test schedules, McLaren appear to be unperturbed and are continuing on their usual pre-season schedule of running the car with a reasonable level of fuel and used tyres. With this approach, McLaren have been absent from the top of the testing timesheets and for some this appears to be a sign of problems.

These concerns are multiplied by the constant re-appearance of the 2008 rear wing and further flow-vis tests.
It would be unwise to discount McLaren's pace, as the team devoted some time to testing in preparation for the 2010 regulations (no tyre warmers and no refueling), while this test is critical in preparation for next year, the time would not have been spent if McLaren were in crisis with their new car.

Additionally the team released their new front and rear wings, which are a major step beyond what other teams have done with their wings so far.

Thus, the MP4-24's new front wing develops the outer spans, free from the regulatory middle wing section, and splits them into four elements joined to far more complex endplates.

As with McLaren's 2008 front wing, the extra slots between the elements allows the wing to be more aggressive to create more downforce. Aiding the wing are new endplates that take cues from Ferrari with a footplate mounted vane, but also use clever little aerofoil elements both above and below the leading edge of the wing tip.

Hardly visible below the outer tips of the wing are numerous fences, while many teams use one or two fences to direct the flow and maintain pressure differences across the wing, McLaren have adopted five fences each side.

As these sit directly in front of the tyre, McLaren might be using them near the tyre to seal the low pressure under wing, but as the front tyres steer they could become less effective, making the front wing sensitive to steering angle.

Clearly, McLaren would not introduce a development that would make the car less predictable to drive, so they must have worked out how to use these parts without introducing sensitivity. All this extra shaping helps direct airflow around the tyre.

Lastly, the wing is joined to the nose cone with a slightly more 'bow legged' pair of mounting pylons.

Although the front wing was a late arrival at the test, the team also ran with two new rear wing designs, although both share the same basic philosophy. Both wings use a dihedral profile, with the wings' leading edge rising up towards the centre. One of the wings takes the dihedral a step further and the whole flaps inclines upwards towards the centre.

A higher leading edge reduces the wing's angle of attack and thus reduces downforce, but also drag. Also reducing drag was an additional slit in the rear wing endplate, McLaren now using five slits as well as the merged endplate flap design. At its base the new rear wing is joined to the diffuser by small slight twisted vanes.

The wing was used in conjunction with the smaller middle diffuser section, suggesting McLaren are not seeking rear downforce but focusing on a heavily front biased aero split, this allowing the team to work towards better aerodynamic efficiency with their car.

Ferrari

Surprisingly even at this late stage in pre-season testing, this was Ferrari's first open European test, so this has been the first chance to gauge their performance relative to the other teams. Clearly Ferrari have matched the pace of the other teams and some observers feel they have a small advantage, but the test was not without its problems, largely KERS related as they were in the Bahrain test.

For this test Ferrari had their new sidepod and exhaust design, the launch version was fixed earlier in the cars development, around the time that the technical working group agreed to include the exhaust as part of the bodywork.

As the original sidepod concept did not allow space to package the longer exhausts, the team have now taken a McLaren-like approach and formed a rear facing exit around the exhaust, which can also serve to vent hot air from the sidepod.

With this revised shaping to the rear of the sidepod was a revised coke bottle shape, the bulged flank of the sidepod has been flattened and the general line of the sidepod profile has been streamlined.

The new front and rear wings taken to Bahrain were also used in Jerez, with the rear wing flap being slimmer towards the endplates, as with most team's rear downforce does not seem to be an issue and the shorter chord the flap in this area will also serve to reduce drag.

Curiously, Ferrari have chosen to run the fake camera pods in both the optional locations (one on the nose and one low down on the roll hoop) at every test. While these pods are neutral in aerodynamic profile their positioning may actually help the car's aerodynamics if they can be placed in strategic point in the airflow around it.

Renault

After a difficult opening test, at Jerez Renault came out towards the top of the timesheets as the weather dried. At first the car remained in its previous testing guise, with the curtain vanes under the nose, albeit now painted black to improve their aesthetics.

The car soon sported revised sidepods with a subtly altered coke bottle 'cooling bulge'. Renault also conducted a flow-vis test at Jerez, the coloured oil being added to the floor and its route through the diffuser tracked.

Later in the test came the major development of a revised diffuser and front wing. The diffuser is not a complex device like on the Williams or Toyota, but instead the transition of the underfloor step is now continued up in to the centre of the diffuser, whereas before it was curved up abruptly to keep a clear diffuser. The new shape probably helps to keep the flow from the step attached to the diffuser.

A more visual change was to the front wing, the large nosecone remains the same, but the front wing sections now rise up from the centre section before dropping to the lower ride height at the outer tips, as demanded by the rules. A higher ride height would make the wing less effective, as a low front wing works in 'ground effect'. As the wing rides lower to the ground, it exponentially produces more downforce.

If Renault have opted to raise the front wing it might be to reduce sensitivity, making the car easier to drive, by being more predictable albeit with less overall downforce. Allied to the new front wing were revised endplates taking a more outswept shape rather than the boxy original design with its large flip ups.

All these changes to a more fluid design and comments by Bob Bell suggest the team are trying to make the car more drivable. Although comparisons are difficult, the car did not perform well in the wet in the hand of Piquet. The changes and a switch to dry weather saw the cars top the timesheet sin the hands of Alonso.

BMW Sauber

Although BMW were the first team to test a 2009 configuration and have tested for several weeks since its launch, the F1.09 has not appeared to have gained any major upgrades. Instead, the team seem to have focused on reliability, with long runs and the continued development of their KERS system. It would make sense to presume that the team will have a major update ready just in time for Melbourne, thus adding it to an already proven and reliable platform.

The only change to the F1.09 appears to be a small fence added to the front wing between the middle section and the outer spans; the large strut that supports the front wings flaps extends forwards to the wings leading edge. This probably maintains the pressure difference between the neutral centre section and the downforce producing outer spans.

A curious feature of the BMW has been its KERS solution. The wedge shape attached to the monocoque ahead of the sidepod inlets has again been run, with the inlet open to cool the KERS hardware. It has been suggested that the BMW-developed set-up uses mainly air cooling over the water-cooled solution of its rivals. This might be a simpler and lighter solution, but this has negative impacts on car packaging as the car needs such large cooling inlets and outlets, not to mention the space for the internal ducting over the power controller and batteries.

One quirk of the car's edge shape inlets is the gap left between the wedge and the sidepod. Although the path into the main radiator inlet is continuous, there remains a small void behind it plus an opening above and below it. The purpose for this does not appear to be aerodynamic; in fact it would appear to be a hindrance to smooth airflow.

Perhaps the gap is to allow hot air to exit the sidepods while the car is stationery, which would be useful for the stop\start routine of testing, but is less attractive for a race weekend. It will be interesting to see if this feature remains in the future.

Red Bull

It was rewarding to see the innovative RB5 set the pace during the test, but the car's reliability still appears to be its weakest point. Only one, albeit highly visual development was noted during the test. The shark fin engine cover brought to F1 last year by Red Bull but absent from the launch car, made its return.

With the revised rear wing rules, the space allowed for the fin is in much closer proximity to the rear wing: the new fin now meets the rear wing. The fin is joined to the rear wing all the way back to the rear edge of the flap, yet it does not reach below the wing.

Last year these fins grew in popularity as they improves stability in fast corners by both smoothing flow to the rear wing and preventing yaw (tail slides) by presenting a larger surface area to the airflow. Few teams have adopted them thus far in testing. But as the season progresses many teams might find they benefit from them.

Toyota

Toyota continues to show promising pace and the car continues to see small developments. For the Jerez test, the major visual change were the pod wings: the simple rectangular fins seen since its launch were replaced with floor-mounted vanes featuring a curved slot where the upper part of the vane mounts to the sidepod's shoulder.

Less visible was a flat plate running along the top of the shark-finned engine cover. Just a few centimetres wide, this plate may prevent airflow spilling over the top of the fin as the car is yawed to the airflow.

As with Williams, Toyota ran complicated new rear brake ducts - the increased space between the ducts and the rear wing endplate give greater freedom for the team to use the 120mm wide space allowed for brake duct bodywork.

Teams do not have to prove this bodywork is used for brake cooling and thus most teams exploit this area for general aerodynamic benefit.

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- The Autosport.com Team

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