With slick tyres, significantly reduced downforce and energy recovery systems giving them temporary boosts of extra power, Formula 1 cars are going to be very different animals next year.
In his latest feature for itv.com/f1, Mark Hughes analyses what effect this trio of changes is likely to have on lap times and overtaking opportunities.
Last week’s Barcelona F1 tests were only partly about this coming weekend’s Spanish Grand Prix. Teams were also making their first on-track attempts at simulating 2009 packages, with several of them running drastically reduced downforce and/or 2009-spec slick Bridgestone tyres in place of the normal grooved rubber.
Bridgestone had made nine sets of the slicks available per day for each team to try, and any testing on these tyres was not counted as part of the teams’ 2008 limited testing mileage.
Prior computer simulation suggested that the much reduced downforce of the ’09 regulations would cost the cars around three seconds of performance but that the new slick tyres that replace the grooved tyres next year would claw around two seconds of this back.
The Barcelona tests tended to confirm this as a good approximation of reality.
No teams were running with an actual 2009 aero package. Instead, they simulated expected downforce/drag levels with the current packages.
The ’09 aero regs include a front wing with a standardised middle section that will be much less aerodynamically effective than current wings, as well as restrictions to upper body downforce-generating barge boards and winglets, all slightly offset by a more powerful underbody diffuser.
The net effect will be a significant reduction in downforce, with a greater proportion of the total generated by the underbody, which is less affected by turbulence – the idea being to make overtaking more feasible.
Teams are still running simulations of this package in their wind tunnels and on their CFD programmes. The lift:drag numbers they are seeing there will have guided them in their Barcelona simulations.
The teams chose differing methods of making the comparisons over the three days of dry-weather testing (a fourth day was run in wet conditions).
But taking McLaren as an example, they ran the first day with simulated 2009 downforce and slick tyres – in other words a full ’09 simulation. On day two they ran with this year’s aero package and grooved tyres. On their final day they tried simulated 2009 aero with 2008 grooved tyres.
Although the day three combination is not one that will ever be raced, it helped give an approximate indication of the performance losses from the new aero regs and the performance gain of the new slick tyres.
The picture looked as follows:
Day 1 ’09 aero/slicks 1m21.6s (3.3s off fastest)
Day 2 ’08 aero/grooves 1m20.5s (1.6s off fastest)
Day 3 ’09 aero/grooves 1m20.6s (4.2s off fastest)
However, it is not possible to directly compare lap times on each of the three days as the track tends to become significantly faster as it rubbers in.
What is more important is the comparison to the quickest times of each day – and even this is just an approximation.
On day one the comparison is to a Ferrari running the most advantageous combination of ’08 aero and ’09 slicks.
The fastest cars on days two and three were also running this combination – but were respectively a Honda and a Renault.
To date this season the Honda and Renault have been around 1s off Ferrari’s pace. So adding 1s to McLaren’s deficit on days two and three would give a more realistic picture.
Doing that, the deficits are as follows:
Day 1 ’09 aero/slicks 3.3s
Day 2 ’08 aero/grooves 2.6s
Day 3 ’09 aero/grooves 5.2s
Which would suggest that the 2009 aero simulation was costing McLaren around 2.6s (5.2s minus 2.6s) and the slick tyres were finding them around 1.9s (5.2s minus 3.3s) – leaving the net figure of an increase in lap time of 0.7s from a pukka 2008 car to a pukka 2009 car.
More significant than this small increase in lap time will be (hopefully) better overtaking opportunities caused by the different way the lap times are generated.
The reduced aerodynamic efficiency should allow chasing cars to get closer to the car ahead in fast corners leading onto straights, allowing them to be better positioned to attempt outbraking moves at the end of the straight.
The greater mechanical grip from the slick tyres once the downforce has reduced in the slower corners should enable the pursuer to try that outbraking move that would not be feasible with the current generation of cars.
However, one part of the 2009 regulations that was not simulated at Barcelona was the planned KERS (kinetic energy recovery system) devices that will be fitted to the cars next year but which are not yet ready.
These recover and store energy from braking which can then be released to give a power boost.
They will store up to 400 kilojoules of energy, which will allow a boost of an extra 80 horsepower for 6s per lap.
As well as making more efficient use of energy, the idea is that this technology will also aid overtaking by giving the driver a ‘push to pass’ button.
With the input/output limits of the devices set by the governing body, the KERS would add the equivalent of an extra 23bhp to the wheels without the energy store of the devices being depleted – there would be as much energy going in as coming out.
Only when the driver presses the boost button will there be the 80bhp boost, but this will use up more energy than has gone in from the braking and so the energy store will be depleted. It will then take around one lap to boost itself back to equilibrium.
So there will be an element of tactics about when to use the button.
It’s clear that the Barcelona tests last week gave us the first glimpse of a very different future for F1.