Why did Felipe Massa race with a ‘shark fin’ but Kimi Raikkonen didn’t? How did Fernando Alonso’s ‘under-powered’ Renault out-drag Heikki Kovalainen?
John Beamer of F1-Pitlane has the answers to these questions and more in his technical round-up for Shanghai.
With a couple of long straights the Shanghai International Circuit superficially seemed a Ferrari track. Not so. Lewis Hamilton dominated every session showing just how much progress McLaren has made on the aero front this year ?óÔé¼ÔÇ£ it now, arguably, has a more efficient car aerodynamically than Ferrari does.
With China being the penultimate race conventional wisdom suggest that only the top teams (and the desperate) introduce innovations at such a late stage of the season. Let?óÔé¼Ôäós see what the design boffins had in store.
Perhaps the most dramatic change of the weekend was the appearance of Kimi Raikkonen?óÔé¼Ôäós Ferrari without the ‘shark fin’ engine cover extension despite Felipe Massa electing to run with the device. The shark fin is a an Adrian Newey innovation that improves the efficiency of the rear wing in yaw (ie, when turning a corner).
It primarily works by encouraging air streamlines to traverse the rear wing in a perpendicular direction, which increases wing effectiveness (air hitting the fin is straightened). The net effect is to increase downforce and shift balance rearwards. It is this balance shift that has caused Raikkonen problems and is also why McLaren has not adopted the solution. That Raikkonen, without the fin, was faster than Felipe all weekend suggests that the performance benefit of the device is in any case marginal.
Ferrari and McLaren
Ferrari made a very minor detail change to its barge board pod-fin connectors, making them more curved. This solution was actually introduced for Japan and retained for China. The connectors are designed to help channel air around the side pod undercuts and calm any turbulent front wheel wake that may interfere with the flow.
By speeding up airflow in this region the floor is more efficient because ultimately the diffuser has a lower pressure gradient to overcome. Trying to rationalise the precise purpose of Ferrari?óÔé¼Ôäós solution is difficult as the bargeboard region is intricately complex but presumably the wind tunnel data show improved aero efficiency when the connector is curved.
The most significant alternation to the MP4/23 was a reduction in area of the sidepod inlets. This was achieved by placing pads at the bottom part of the inlet i.e., it wasn?óÔé¼Ôäót a fundamental design shift. The lower temperature in China meant that cooling was less of an issue for the teams and allowed McLaren to run this solution. By restricting the area of the inlet cooling drag is reduced, which obviously boosts aero efficiency.
Renault has probably had the most aggressive development programme out of any of the mid-tier constructors this year, bringing in a new front wing for Singapore and revising the sidepod profiles for Japan.
For China the Enstone-based outfit added blowers for the rear wheels. These blowers channel air from mid-region over. The purpose of this is to interfere with the rear wheel wake and reduce lift. Although Renault ran the blowers in practice it didn?óÔé¼Ôäót use them in the race.
One of the few memorable moments of the Chinese Grand Prix was on the first lap when Fernando Alonso out dragged Heikki Kovalainen on the back straight. Who says the Renault V8 is down on power?
There are a number of explanations for this. One, Alonso was lighter and had better traction out of the corner. Two, Kovalainen?óÔé¼Ôäós tyres were imbalanced which affected his performance and, three, Alonso may have been running a lower downforce set-up.
However, that is to ignore the fact that Renault has been making ?óÔé¼?ôreliability?óÔé¼?Ø modifications to its engine in recent weeks as well as using an improved lubricant mix from Elf, its supplier. Paddock estimates suggest that Renault have found 5-10 bhp from this alone.
On to Interlagos
Interlagos is a fine circuit with which to close the championship ?óÔé¼ÔÇ£ who will it favour, McLaren or Ferrari? Interlagos is a medium downforce track and rewards aero efficiency. China demonstrated that McLaren is aerodynamically strong and given that it has reportedly developed a special Interlagos package the car should be better than it was in 2007.
However, these days track surface and temperature are as much a factor as car design, so it is a safe bet to assume nothing until Saturday qualifying.
Those fretting about Hamilton?óÔé¼Ôäós engine probably needn?óÔé¼Ôäót worry. The Mercedes power plant is ?â??ber-reliable and McLaren will no doubt turn the unit down that little bit more than it might. Plus, Hamilton romped away with the lead at Shanghai and probably turned the wick down quite early on.
Interlagos isn?óÔé¼Ôäót a particularly demanding circuit on the engine with only 57% of the lap at full throttle. The higher altitude isn?óÔé¼Ôäót necessarily a factor as pistons, for example, receive less wear.
Those who worry about writers?óÔé¼Ôäó curse go and put your money on a McLaren engine failure immediately!
This is a guest article by John Beamer. If you want to write a guest article for F1 Fanatic you can find all the information you need here.