Technical review: Australia and Malaysia

How much of Brawn's performance is down to their controversial diffuser?

How much of Brawn's performance is down to their controversial diffuser?

F1 Fanatic guest writer John Beamer examines the technical changes and controversies over the first two races of 2009.

Formula 1 never changes. We’re not even two races in and controversy continues to rage around the paddock – as it has done so every year since 1954 and will do so until we humans are extinct. Putting McLaren’s astonishing fib aside most of the brouhaha is down to the revamped technical regulations.

‘Diffusergate’ continues to gobble column inches; Toyota was booted out of qualifying because of it flexing rear wing; and the podwings on the Red Bull and Ferrari were called into question by Williams.

Diffusers

One outcome of the first race was that a date was set for finally resolving diffuser gate. The FIA meets on 14th April to arbitrate on the legality of the device.

For the uninitiated let’s remind ourselves how a diffuser works and what the kerfuffle is about.

The diffuser is the device attached to the back of the car (starting at the rear axle) that manages air under the floor. This air has been squeezed under the floor so is going fast. In order to maximise downforce this flow must be transitioned back to freestream (normal) speed. Failure to do so creates unwanted turbulence at the rear, which feeds back into the diffuser harming downforce. The larger volume of the diffuser (compared to the floor) allows the air to slow down to freestream speed – this is what creates rear downforce. Generally the larger the diffuser volume the more effective it is.

It will come as no surprise that the reason that the double diffuser creates more downforce is because it has a larger volume. Brawn, Williams and Toyota are taking advantage of three loopholes:

(1) The rules don’t prevent double-decking as the diffuser is defined in the articles labelled ‘bodywork facing the ground’ – the upper tier does not face the ground.

(2) The reference plan and step are not treated as a single continuous surface so holes can be carved in the step transition to feed more air to the diffuser.

(3) A longer, higher central section that integrates with the rear crash structure is allowed – Toyota exploits this (think of this as a narrower version of the central section allowed last year).

The prevailing view in the paddock is that the FIA will not outlaw the double-diffuser, at least not this season. Expect 75% of teams to be running them when the F1 circus lands in Europe.

Other controversies

Toyota's flexing rear wing gave them a headache in Melbourne

Toyota's flexing rear wing gave them a headache in Melbourne

It’s not all about diffusers. In Australia there were two further points of contention. First, Toyota was found guilty of having a flexing rear wing after qualifying and was excluded.

Flexing wings are outlawed because at high speed the main plan will flex upwards and close the ‘slot’ to the flap. This causes stall over the rear wing, which reduces drag and allows the car to go faster.

Given the tight rules around flex-testing it appears to be a manufacturing glitch on Toyota’s part rather than anything malicious.

The second controversy surrounds the podwings of Red Bull and Ferrari. Williams protested the legality of these devices after Melbourne qualifying. The protest was later withdrawn so it isn’t 100% clear what Williams’ gripe is but Red Bull and Ferrari’s podwings are unique in that they sprout up from the axehead in front of the sidepod unlike a traditional podwing.

Aero Innovations – Red Bull and Williams

Most teams finalised their Melbourne/Sepang package in late preseason so there weren’t a huge number of innovations for the opening two races. For this article we’ll look at two of the more innovative teams over winter: red Bull and Williams.

Red Bull has probably the most radical looking car on the grid. The design philosophy is to make the nose as small as possible to minimise disturbance and feed the floor. Look closely at the chassis and you’ll see raised section along the front edge. This is required so the chassis meets the cross-section area requirements and also help funnel air to the rear of the car to feed the rear wing.

The other noticeable feature of the Red Bull is its tiny sidepods. This allows air to be channelled under the sidepods to the coke-bottle zone and over the diffuser. This ‘pumping’ of the diffuser leads to considerable downforce benefit as it creates a lower pressure above the diffuser – in other words the diffuser is working against a less adverse pressure gradient, which makes it more efficient.

Williams has also innovated over the winter – it pioneered the skate wings (now dropped) and the snow plough (effectively a splitter under the nose). In Melbourne the Didcot-based outfit ran revised axe-heads. The axe-head now curls up at its leading edge and has a couple of horizontal fins. The curl helps to funnel more air under the floor which is then transitioned into a vortex by the fins. This vortex acts as a virtual skirt sealing the floor and increasing downforce.

Tyres

In Melbourne we witnessed the sort of havoc that the new tyre rules will bring into play. Not only must teams get used to slicks but the option and prime are two compounds from each other – super-soft and medium in Australia. From what we saw the super-soft needs work. Although it was the fastest qualifying tyre its performance degraded to such an extent that within 8 laps it was virtually un-drivable. It made for a fun end to the race but a tyre that causes a 3 second a lap difference in time shouldn’t be used in a race.

Malaysia had the opposite problem. The soft was the tyre of choice by a mile as teams struggled to get the hard compound ino its operating window.

KERS

Much has been about the fact that the cars at the front of the grid are KERS-less while those at the back have KERS. Is KERS to blame? No – I don’t think so.

Let’s clear up one common misunderstanding. KERS doesn’t add to the weight of the car – all it does is move the weight distribution back and raises the centre of gravity.

Granted, neither of those are benefits, but the 80bhp boost will more than offset that loss. The teams that run it believe they gain two-tenths a lap from KERS depending on the track. These data will have been borne out in testing as team alternate between using and not using KERS.

We’ve seen that KERS is especially useful at the startline and for passing/defending. Once the large teams master the technology it will make a difference.

However, had the boffins at McLaren, Ferrari, BMW and Renault focused on aero rather than KERS perhaps they too would be at the front of the grid.

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29 comments on Technical review: Australia and Malaysia

  1. HounslowBusGarage said on 9th April 2009, 13:06

    And these guys are not jokeys. They should not be disadvantaged by their physical build. They are athletes and need to watch their weight to be fit, but they should not have to slim their self to borderline unhealthy levels.

    Sorry Polak, but if they are *athletes*, then their physical build has everything to do with their relative advantage or disadvantage.
    And actually, I think the term ‘jockey’ fits them very well as the combination of rider and horse, driver and car operating to mutual advantage is similar.

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