Technical Review-Bahrain GP

  Last year the leading cars were often within a few hundredths of a second of each other. But in the first race of this year Fernando Alonso’s fastest lap was a second quicker than anyone else’s and the gap between pole sitter Sebastian Vettel fourth-placed Lewis Hamilton was 1.1 seconds.

How has this happened?

  The new season was billed as one for the ages. But the gulf between the top cars is wider than it has been for some time.

McLaren vs. Ferrari Design Philosophy

  It was clear in testing that the old guard would make a comeback. What was less apparent was whether McLaren or Ferrari would have the upper hand. The first battle easily went to the Scuderia.

  It’s worth reflecting that McLaren and Ferrari took very contrasting design approaches to 2010 – or at least it appears that way. The McLaren technicians seem to be designing for peak downforce. It looks as though they sat down and tried to develop as many innovative schemes as possible to boost downforce. Hence we have the intricate beam wing diffuser, the F-duct, and the slot rear wing. These devices are all a downforce grab.

  In contrast Ferrari has taken a more subtle approach and has focused on end-to-end airflow. There are fewer obvious aerodynamic devices and the car has been designed to manage airflow from front to rear. This has a couple of implications. First is that the red car will generate downforce a lot more consistently. In that way it is similar to Red Bull from last year. Brawn generated its downforce from the double diffuser and aggressive front wing design but the RB5 had better front to back aero efficiency.

  Worryingly for the rest of the paddock this means that Ferrari have a strong platform to build on in the development arms race. The base car is so good it is likely that Ferrari engineers understand the aerodynamic characteristics intimately, which makes development a lot easier. McLaren engineers by contrast need to work from a more peaky base, which is harder. That is partly why Red Bull was able to out develop Brawn last year – the base car was more efficient.

  Let’s take a look at some of the aero innovations seen in Bahrain.

Snorkel (or F-duct)

  The snorkel starts with an opening at the top of the chassis where there is an air intake. The air runs through a tube, past the driver and vents through the engine cover and shark fin. The driver uses his knee to control whether the tube is open or closed. When the tube is closed air blows out over the rear wing which disrupts freestream airflow and reduces drag – this appears to be worth 5-6 kph on the straights. When the tube is open the air from the duct vents into the cockpit and has no effect on the wing allowing normal downforce levels for better cornering.
  The debate is whether the action of the driver constitutes a moveable aerodynamic device. Given that the driver is constantly in motion the ruling seems to be no. McLaren could have this straight line speed advantage for sometime. The monocoque is homologated, which means no changes can be made except for safety and reliability reasons.

  To make the F-duct work teams will likely need to drill a couple of holes in the monocoque which isn’t possible. While legal it will be interesting to see if the FIA outlaw this device for 2011 as it will lead to massive cost increases as teams focus on driving aerodynamic benefit through all manner of drive induced airflow interventions.

Diffusers

  As promised 2010 brought renewed diffuser controversy albeit on a far smaller scale than last year. A few teams, most notably McLaren and Mercedes, added a wider than necessary hole for their starter motors at the bottom of the diffuser. In previous years this was a genuine hole but now looks more slot like. This gave the diffuser another element which made increased downforce and made performance more consistent. Although not strictly illegal the FIA has issued a clarification restricting the starter holes to a predefined maximum dimension. These teams will be forced to make modifications for Australia but the matter isn’t significant enough to force an overall diffuser redesign.

  The McLaren diffuser is probably the most complex in the paddock and extends to the floor region around the rear tyres. Here there is a small duct to allow air to vent through the floor to the diffuser. In addition the diffuser itself consists of a series of planes that build up to the beam wing. In fact the top deck of the diffuser extends the width of the beam wing – effectively producing a multi-element aerodynamic device.

  The challenge teams face with a large, complex diffuser is to feed it with enough air to produce consistent downforce. The longer car allows a narrower coke-bottle zone which partly helps but if airflow separation occurs performance will drop off. It’s interesting to note that Ferrari and Red Bull, the two fastest cars at Bahrain, had among the simplest diffuser designs of the large teams.

Front wing and nose

  Front wing design in F1 is reasonably standardised among the teams although the variety in detail around cascades and endplates is astonishing. There are two board philosophies. McLaren have a long cascade extending from the end plate. On the Red Bull there are smaller cascades which stack more aggressively.

   Renault opted to go the McLaren route and introduced its new front wing in the last Barcelona test and brought it to Bahrain. The extended cascade forms what is now a triple-element device and is ‘twisted’ for increased downforce. In addition the main plane is raised a few millimetres which reduces downforce but will give more consistent performance especially during cornering. There is a large gap between the second element and the endplate adjacent to the main plane to allow air to flow off the top of the front wing through the end plate. This is intended to interact with air on the outer part of the endplate to reduce drag from the tyres.

  Mercedes have gone the Red Bull route with shortened, stacked cascades. It also introduced a new nose that seems to integrate with a turning vane right at the front of the car. This forms and S-profile and is design to gently divert air towards the sidepods. Its a unique solution as diverting the air too early can result in undesirable air-tyre interactions which induce drag. In addition on the top of the nose new splitters were added to the v-nose to prevent air from spilling under the car. This will reduce lift on top of the chassis and should also enhance performance of the bargeboards as less turbulent air from the top of the car reaches them.

Rear wing

  The 2010 season has also seen innovation on the rear wing. Last year Sauber etched an additional small slot in the rear wing to help with downforce. This allows the angle of attack to be increased without creating stall. McLaren extended this concept with a slot across a much wider section of wing, effectively creating a three element device. Williams also adopted a similar slot for its rear wing.

  Expect to see a lot of development around the beam wing. As mentioned earlier some teams (McLaren especially) have elected to integrate the beam wing with bodywork from the diffuser. Force India has taken a different approach and has mounted a second beam wing ahead of the first. Although there are strict regulations about the number of rear wing elements the double decker diffuser loop hole has effectively created a ‘free’ zone in front of the wing where bodywork can extend and this is what Force India has exploited.

Exhausts

   A lot has been made of Red Bull’s revised exhaust positioning which is now below the rear suspension close to the floor. This is classic Adrian Newey, who experimented with using exhaust gases to blow the diffuser when he was at McLaren. A closer look shows that Red Bull has a slot open in the diffuser for the exhaust gasses to blow into. This will help energise flow through the top of the diffuser and produce more downforce from the diffuser.

  As drivers come off the throttle when cornering the exhaust gases do not provide consistent flow and this often disrupts the aerodynamics. As a result previous attempts to use the exhausts to feed the rear wing have been abandoned due to the inconsistent downforce produced. If other teams start copying Red Bull it will be a sign that Newey has solved yet another aerodynamic conundrum, although by placing the exhausts low down there is a higher risk that the rear brakes and tyres will overheat.

  Ferrari also had some innovative bodywork around the exhausts. The F10 appeared with three additional louvres, seemingly contravening the regulations which state that there may only be a single opening for the exhaust pipe. Ferrari has ingeniously created a thin slit originating from the exhaust that traverses each vent so complying with the single opening rule. It’s a neat solution to what is obviously an issue for the F10 given the amount of weaving Alonso was forced to do to cool his engine when following Vettel.

  For more details, click http://www.formula1.com/news/technical

SRi:Red Bull is ridiculously FAST!