2006 Italian GP Technical Review

It seems fitting that the Italian Grand Prix is the last circuit on the European calendar, as the classic track, situated just north of the city of Milan, is the last of the historic super-fast Formula One circuits.

Monza stands alone in F1 as the only track that demands its very own set-up for the cars. This is down to the track's layout, which all about long straights and open corners, punctuated only by a few low speed chicanes. As the track demands such a unique set-up, teams are allowed to test at the track in the week before the race - the only circuit allowed such an exemption.

To achieve the ideal lap around Monza, the first requirement is power and a low drag aerodynamic set-up, in order to gain speed on the straights. The second requirement is a set of good brakes, which are able to withstand the long hard stops from 200mph+ into the chicanes.

To achieve this second requirement, softer compound tyres and a sympathetic mechanical set-up are required. In fact, it is only through the chicanes that driver can make a real difference to the lap time - such is the circuit's emphasis on acceleration and top speed. But the vicious Italian kerbs are renowned for breaking suspension, gearboxes and even engines.

Monza aerodynamics

Preparations for Monza start a long way ahead of the pre-GP test. Such is the lead time for the major new bodywork required, that the teams are working on a Monza set-up from early in the season.

With the cars having much lower power outputs from the V8 engines this year, the initial lap time predictions will have been of even more importance. Only by having the data on how the potential lower-power outputs will affect the car's lap time will the teams be able decide what compromise will be required for the best performance.

A team's lap simulation maps the car and track to find the best set-up. On all circuits a compromise is required for the aerodynamic set-up, between downforce for corners and low drag for the straights. Teams will find that a higher downforce set-up helps them get around the corners, but this benefit is lost with the lower speed on the straights. Conversely, a lower downforce set-up brings lower drag for speed on the straight, but time is lost in the corners.

This graph, of the effect of downforce over a lap, is known as an aero map. Most tracks have an equal measure of straights and corners, thus the graph is quite flat. Therefore, a car can get similar lap times with very different levels of downforce/drag, and this allows the team a wide range of options in setting the car up.

However, Monza is largely made up of straights or long curves, and any time lost on these with high downforce/drag set-ups cannot be made up in the few slow corners. Thus, the circuit is deemed to have a peakier aero map. So the set-ups for best lap times tend to be in the lower downforce/drag end of the range.

Confusingly, however, the much slower Monaco circuit - which is the diametric opposite to Monza - also has a peaky map, with the best lap times coming with an emphasis on high downforce.

Often Monza aero specification cars are called low downforce set-ups, but this is in fact slightly incorrect. The teams are actually only seeking low drag to boost top speeds; as consequence of this, downforce is also reduced.

The balance of downforce/drag is known as aero efficiency, which is a ratio of the device's downforce-to-drag. If an F1 car can have low drag and still good downforce at Monza, then the driver will have an easier time, with both good straight-line speed and grip for braking/corners.

From the team's simulations, the car's ideal top speed will have been determined. The aerodynamicists then find a set-up that will allow the car to reach that top speed. The critical component in setting the top speed of the car is the rear wing. As the rear wing is mounted high up in the airflow, it produces the most drag and hence affects top speed the most.

With the rear wing specification set, the next job is to balance the car front to rear. This time, it is the front wing being the main tunable device; front downforce is reduced until it balances that of the rear.

Lastly, as the rear wing is easily able to produce the small amount of downforce that is required, a lot of the devices that are there to improve flow to the rear wing are not required. Although these devices keep the car working better when more downforce is required, they do come at the cost of some drag and so are removed.

All sorts of the little appendages are removed; in the image to the right, the yellow area shows parts that have been removed to improve the car's top speed. From the winglets around the rear chimneys to the flip-ups, shelf and mid wings, even the fashionable shoulder fins are taken off.

Aesthetically, Monza spec cars are much easier on the eye, as the demand for as much as 40% lower drag keeps the cars free of the clutter that few fans find attractive.

Last weekend, some teams ran extremely small wings. With engine outputs from the current breed of V8s believed to be quite equal between the teams, those running quite large wings presumably have very efficient aerodynamics, as their drag levels allow them to reach their top speed with more downforce.

Furthermore, over the weekend, changing track conditions affect the car's behavior under braking, and this may force the team to alter the downforce level slightly. But, again, this will be done initially by selecting a different rear wing setting or adding a gurney flap and balancing the front accordingly.

Team developments

Renault

Renault presented their Monza spec car with apparently very little wing. The car ran without the cascades over the front wing and featured a single element rear wing. The endplates are simple, devoid of the slots and integrated joint to the flap.

Renault's rear wing is quite unusual. The single element is possible, as the wing is set at such a flat angle. This means the flow passing under the wing is not pulled up so aggressively, and hence the slot gap is not required to keep the flow attached, saving yet more drag.

The wing's profile alters over its span: in the middle, the leading edge of the wing is much higher in respect to the trailing edge. This is primarily done to reduce drag. Moreover, the wing is steeper nearer the endplates, and this is where the wing generates most of its downforce.

McLaren

Like Renault, McLaren used a single element rear wing and combined it with a simple two element front wing. The team opted to remove the winglets behind the chimneys, but they did retain the Viking wings on the roll structure.

Ferrari

Ferrari appeared to be running more wing than the other leading teams, with two element rear wing and the bi-plane front wing, albeit both suitably reduced in chord and angle. The shallower wing was mounted to a cut-back endplate, making the wing falsely appear higher up than usual.

Also, most of Ferrari's other aero add-ons were retained, such as the chimney winglets and shelf wing. Towards the front of the car, the bargeboards were altered with one less step along the top edge than appeared in Turkey and also devoid of the extra turning vane.

On the nose, a new pair of fins was installed. These fins were quite high and forward mounted, to such an extent that they nearly met across the nose cone.

Toyota

In the testing at Monza preceding the race, Toyota ran new flip-ups. These sported an inner fence (marked in yellow) and a longer flip reaching further forward around the sidepod. However, these revisions did not appear on the car for the race weekend.

Toyota ran a two-element rear wing and a very slim front wing. The front wing sported an unusual flap arrangement, where the flap is much longer at the endplate.

In theory, this design should create more drag, but probably creates its downforce without upsetting the flow around the centre of the car and hence improved the cars total aero efficiency.

Williams

Again Williams brought major bodywork changes to the Grand Prix. Further revised sidepods were run, without the complex stack of flip-ups between the rear wheels and cooling chimneys.

The large flip-up (marked in yellow) remained, and this gained an extra slot. This should ease any flow separation under the surface, as the oncoming flow is no longer curved by the flip ups.

At the front, the nose gained a pair of fins; and at the rear, the rear wing endplates were slimmed in a similar fashion to Ferrari's.

Honda

Honda appeared to make few aerodynamic alterations for the Monza race. The flips were cut back in front of the rear wheels, and the simpler winglets were run behind the chimneys. Unlike the team's Canadian GP rear wing, the Italian wing was simple and flat and without the Renault-style curved endplate flap junction.

While the team's aero was unchanged, Honda rushed through changes to the engine, which were planned for 2007, to Monza. With the specification of engines being frozen after China, Honda wanted the best possible specification ready for the next races.

The new engine uses a lot of new major parts and apparently requires some alteration to the car to make it fit. The unit made its debut in the pre-race test but suffered some reliability issues.

The decision was made to bring the engine to the race and run it initially in the third car on Friday. However, two reportedly similar major failures led the team to switch back to the old power unit for reliability.

Images of the engine being removed from the car showed that the failure was catastrophic. As the floor was removed, remnants of the broken crankcase fell out - one particularly large chunk was stuck to the floor's moulding.

Judging by the shape and location of the debris, a major reciprocating part towards the front pair of cylinders failed at high revs, sending bits of the crank or rods through the sump.

Super Aguri

With familiar front and rear wings simply run at a shallower angle, Super Aguri's main novelty were a pair of nose fins (yellow) attached to the small covers that go over the pushrods. These were only run briefly on Takuma Sato's car.

BMW-Sauber

Having had several races with BMW making major strides in their aero development, Italy provided more opportunities for the team to alter their bodywork.

Almost all of the car's aero add-ons were removed. They also had a new rear wing profile (yellow) with a pronounced kick-up in middle. Beneath the rear wing, the old "stinger" wing (Yellow) over the crash structure was removed for the race.

BMW-Sauber were the only team to also remove the axe heads mounted to the floor ahead of the bargeboards. At the front, the normally curved wing was replaced with a much flatter profile.

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