By Craig Scarborough, England
Autosport-Atlas Technical Writer
Fewer cars doesn't mean fewer technical evolutions. Technical writer Craig Scarborough looks at the technical issues surrounding BAR's expulsion from last week's Spanish GP, along with a review of solutions brought to Barcelona by the remaining nine teams
Barcelona is fast becoming a classic Formula One track; indeed it could also be described as the definitive circuit such is the amount of testing that goes on there - the mix of long straights, fast corners and heavy braking tests the cars in all aside from low speed cornering. The track demands power, aerodynamic performance and good tyres, and as a result following Spain we have some definitive answers on teams' relative performance.
We can also form a view on how the teams are developing their cars, as most teams presented new parts on their car at some stage over the weekend. Unfortunately the race weekend saw only nine teams competing, as BAR have been excluded following an appeal by the FIA after the weight irregularities in Imola were accepted by the stewards of the race.
If we can ignore the politics, court cases and motivations for the issues surrounding BAR's fuel tank, the evidence presented gave us a rare insight into the car's mechanical layout and how teams operate their cars. Such is the vague wording and disjointed layout of the rule book BAR felt they were able to run a car underweight when it was without any fuel whatsoever, as the car would always have to have a reasonable reserve of petrol to operate the fuelling system, with the weight of this fuel making up the inherent weight deficiency of the car.
There are already precedents set in recent Formula One on residual fuel; the initial clarification on emptying fuel tanks for weighing was set in 1996, but not incorporated into the wording of the rule book. Jaguar also had a fuel pick up issue a couple of years ago, which necessitated the team running over the minimum weight (by the amount of residual fuel required) in a year when the new parc ferme qualifying rules were set out. The extra weight handicapped Jaguar in the single lap qualifying session.
What is clear however is that the BAR fuel system was neither secret, covert nor unique. A Formula One car's fuel system has a lot of factors to take into consideration; firstly the fuel needs to be stored inside a single bladder, known as a fuel cell (i.e. there cannot be separate external tanks). The 100-150 litres of fuel are then subjected to the same loads as the rest of the car, with a constantly changing gravitational load being applied to the fuel, in three dimensions; side-to-side, front-to-rear and even up-and-down depending on the circuit.
With loads of up to 4g the fuel will not sit neatly in the bottom of a flat bottomed tank. The shift in the fuel's location then causes a problem, with the engines needing to be fed a constant stream of high pressure fuel - simply having a pump sat in the base of the tank and sucking up fuel to pump into the fuel rail over the inlet trumpets will not do. The teams have evolved a system of baffles, one-way doors and accumulator tanks to keep a large enough supply of fuel near the fuel pump inlet to keep the engine fed. BAR are no exception, and the system was described in detail in both the FIA's and BAR's submission to the ICA.
Fuel in the main fuel cell is directed towards the first fuel pump, which feeds the collector tank (light blue). This tank is a compartment at the lower front edge of the main cell; this is also the alleged 'secret compartment', and is the one that contained the 'missing' 11kg of fuel. This collector tank feeds the next stage on the fuel collection and pressurisation process.
Via another fuel pump, the fuel within the collector tank is sent to the accumulator (dark grey); this tall carbon fibre tank houses a small amount of fuel that is picked up by the high pressure fuel pump (red line) that feeds the engine itself. Should this accumulator tank be overfilled due to a lower demand from the engine than that being fed from the collector tank there is an overflow pipe (black line); this clear plastic tube was referred to in the stewards' initial investigation. The collector tank also has a breather tube (light grey line) to vent the change in volume within the tank.
Most Formula One fuel cells are manufactured by ATL, and are effectively rubber and Kevlar flexible bags; ATL have confirmed the BAR tanks have followed this design since December 2004, and that other Formula One teams use a similar concept of a collector tank and accumulator. So in design at least BAR do not have an illegal set up, but rather the operation of the car that led to the excess fuel being counted as the cars normal weight, added to the BAR mechanics statement that the tank was empty when being drained. I'll leave the interpretation of those facts to others more skilled in legal terms than myself.
Team by Team
The team appeared with many updates on the car, the main two being the new diffuser and the revised bargeboards. The diffuser now used a secondary panel inside the central tunnel; this panel seems to interact with the extra side channels which are a feature of the F2005. It is these side channels which, as a result of the slim gearbox, allow wider outer channels to feed the central tunnel. The bargeboards now feature a small wing profile mounted a few inches above the axe head on the trailing edge of the main bargeboard.
Rubens Barrichello suffered the majority of the reliability issues at the start of the weekend, with a hydraulic problem on Friday and an engine change on Saturday. Regardless, both Ferraris were off the pace, and the tyre choice was moving them towards harder compounds that would hinder their qualifying.
Barrichello in Q1 lost 1 second in sectors 2 and 3, leaving him just inside the top ten, before Michael Schumacher ran with the harder Bridgestones, having a good opening sector but lost 0.2, then more in sector 2, to end up 0.6 seconds down in seventh. Sunday's second session saw Schumacher lose another place, while Barrichello's penalty kicked in to see him last on the grid.
Barrichello's engine change saw him heavily fuelled for the race, while Schumacher's lack of pace in qualifying on the harder tyres also saw him run quite heavy. Barrichello stopped as late as lap 35 for his single pit stop, but this huge fuel load and lack of overtaking opportunities left him trailing down the order and lapped on the same lap. As in Imola Schumacher used the window between the earlier stoppers and his stop on lap 32 to pick up places. This tactic appeared to be working until an unexpected stop on lap 45 to replace a punctured left rear tyre; he rejoined and then suffered a deflated front left tyre heading into turn 1, sending him off the road and requiring nearly a full lap to return to the pits, where he immediately retired.
The cause of the deflations has not yet been clarified; Bridgestone said that initial investigation disproved overworn tyres. With damage or delamination as the most likely causes, the fact that the failures occurred on one side of the car suggest the former, while the unusual V shaped mark across the tread on the front left tyres as he pitched off the road makes the latter also possible. Barrichello reported some blistering, but no related problems were detected on his tyres. He eventually ended up trailing home in ninth.
The team presented their cars at Thursday's scrutineering, but the team's exclusion saw their cars and equipment packed away and they took no part in the race weekend. One change visible on the cars were new rear wing endplates, now featuring the Toyota gills. These seem to be an ever more popular way of dealing with vortex creation at the wing tips. BAR have previously used shaped leading edges to the endplate to create the pressure increase on the outside face of the endplate.
A small addition to the Renault aero specifications were the two small turning vanes / wings on the nose of the car, similar to those introduced last year by Williams and this year by Toyota. They may well create some downforce, but their main aim is to tidy and shape the airflow over the front of the car.
Renault now had two B spec engines for the race, with Fernando Alonso running a fresh engine, and as has been the case with most recent races the Renaults did not complete flying laps in Friday morning, but did complete much longer runs in the afternoon session. Giancarlo Fisichella had a good lap in qualifying but his early slot cost him time for eighth, then Alonso's much anticipated lap finally disappointed with time lost in sector 3. His Sunday lap also failed to seal a front row slot against his lighter fuelled rivals.
Alonso made a blinding start to the race, in contrast to the average starts so far this year, but as the first stint went on his pace waned despite brake bias adjustment and alteration to some controls on the steering wheel. Ralf Schumacher started to close the gap until his stop on lap 24, leaving Alonso out for three more laps before stopping himself for fuel, a front wing adjustment and a rear tyre pressure change.
Fisichella's improving pace saw him stop two laps later, requiring only fuel and a front wing adjustment; the extra laps allowing him to pass Alonso through the pit stop sequence, but his advantage was lost when he had to make an unscheduled stop on lap 40 for a new nosecone and a damaged front floor to be removed from under the car.
A whole range of aero developments were added to the Williams in Barcelona; a new shorter engine cover which featured new flip ups, with the bodywork now ending with two aerofoil profiles, a recent trademark Williams design, probably adding to the rear downforce. Also changed were the winglets, which now mount to the chimneys and are steadied by a small strut attached from the endplate to the flip up and another strut continuing to the floor of the car. At the front the large pair of bargeboards received a small horizontal footplate edged by vertical lips.
Friday went badly for the team; an exhaust valve problem was detected by BMW and the decision was made not to run Mark Webber's car (his engine new for this race) until the newly built engines arrived from Munich. This left Nick Heidfeld, with his one race old engine, to complete the set up programme and then have a new engine fitted and accept the ten position grid penalty. With Heidfeld sacrificed to start back on the grid, Webber went out on a light fuelled race strategy to get past their rivals.
Webber had good opening sectors but, like most Michelin runners, suffered with fading tyres through the demanding last corner sequence. Heidfeld was visibly more attacking on his lap, and posted a time good enough for fifth, just ahead of his teammate. Second qualifying saw Webber jump up to second, While Heidfeld's engine change placed him at the back of the grid with no time posted on Sunday.
Webber's improved grid position was squandered at the start when he was passed by both Alonso and Ralf Schumacher into the first corner. Webber pitted earliest of all at lap 18, belying his improved grid position as a lightly fuelled lap aimed at three stops in the race. His first stop of two also saw a front wing adjustment. Heidfeld meanwhile stopped a whole eleven laps later, but starting from the back still only ended up tenth.
The expected revisions were released at Spain, consisting of new front suspension geometry, a more powerful Mercedes engine, and several aerodynamic changes. These aero changes were more subtle than expected, as the car appeared broadly similar to the Imola specification.
Friday saw a modest number of laps from the race drivers, with Pedro de la Rosa topping the timesheets with the third car. Juan Pablo Montoya had a major shunt when his car swapped ends out of the final turn, sending the car off track for a heavy contact with the barriers. Despite the damage the engine was deemed fit for the rest of the race weekend and did not require a change.
In Q1 Montoya locked a wheel twice on the warm up lap, then completed a clean but slow lap which dumped him down to twelfth. Kimi Raikkonen ran early in the session then ran wide on the exit of Turn 2 to kick up the dust in a lap otherwise fast enough for provisional third. Come Sunday, the team fuelled Raikkonen lighter to gain pole position; Montoya also improved to seventh.
Montoya made a good start but was forced onto the grass on the approach to the first corner; Raikkonen also made a good start and retained his lead, and was then hindered by the safety car circulating for two laps. As usual Raikkonen was able to slow up the field and then make a break at the restart; from the gap he had already opened up to Alonso he was able to extend his lead.
Montoya's aggressive race start also continued as he was able to pass Schumacher's Ferrari at the restart. The lead he had opened up to Schumacher was lost when he had an unforced 360-degree spin through turn 8. Montoya's first fuel stop was hindered by an electrical fault on the fuel rig; he had to circulate for two more laps while the problem was resolved and the extra stop dropped him down the order. Raikkonen came in on laps 25 and 49 and remained unchallenged for the lead.
The Imola engine cover was run again in Spain, as the team cited it as such a success. The changes to the old engine cover are very subtle; the main shapes of the sidepod and engine cover remain, with only the section aft of the exhaust ports appearing to be changed. This area is now less noticeable due to the larger protruding heat shield, although the trailing edge is believed to be around 5cm lower; this feeds better air to the rear wing and lower beam.
Friday went according to plan for Sauber; both cars competing reasonable lap counts. For Q1 Felipe Massa ran a decent lap which was good enough for eleventh, while Jacques Villeneuve was slow in the opening sector and also struggled through the remaining two sectors, ending up four spots behind Massa.
Villeneuve arrived awkwardly at his grid position and appeared to almost jump the start, but this was not detected by the automated start system. His car was losing water and started to overheat, leading to his retirement on lap 52. Late in the race Massa limped down the main straight with a flat Michelin rear tyre, giving credence to damage being the main issue for Schumacher as his Ferrari was running Bridgestones; in fact the Sauber flat was caused by a cracked wheel.
Development is currently on a small scale at Red Bull; there was a new floor announced, but no visible changes were apparent. Friday saw electronic problems for Christian Klien; both race drivers were happier with the car but felt more was to come through set up.
In qualifying Vitantonio Liuzzi locked up into turn 10 and posted a slower time than David Coulthard, who had a better lap for tenth spot despite being notably slow in sector 3. Liuzzi's difficult weekend ended on lap 10 when his rear tyres locked up and spun him off the track and into the gravel, while Coulthard was able to finish with a point in eighth.
Yet more changes were made to the aerodynamics for Toyota in Spain, with the front of the sidepods coming in for the most changes. Firstly the floor fin changed from a single wide format to a two piece arrangement; Air spills from the front floor over the inner fin and then under the other fin to be flicked up by the gurney on its outer edge. This keeps the flow under the floor tidy and allows the diffuser to be more efficient.
Matching the new floor fin are revised shoulder wings; these also used to be full width, but would contravene the flat bottom regulations if they were so now. Instead the wing is cut short; only the outer section survives, and in plan view matches the shape of the outer floor fin, and the wing is now mounted via a horizontal plate at its lower edge. This wing produces both downforce, for very little drag, and also shapes the flow over the sidepod. The new design now keeps a clean and undisturbed flow along the inner edge of the sidepod tops, which is the flow that feeds the rear wing.
All three cars were on the pace on Friday; Ricardo Zonta's morning was hindered by a hydraulic problem, while Jarno Trulli only completing an installation lap in the morning, but the afternoon session saw a lot more laps from all three cars. Saturday's timed session saw Schumacher down on top speed at only 312kmh, and he also lost time in Sector 3 to end up fourth, while Trulli posted the three fastest sector times to take provisional pole position.
Schumacher kept close to Alonso through the first stint but his stop was earlier than that of the Renaults; meanwhile Trulli's first stop saw a small amount of the fuel spilt from the connector and ignite as the car left the pits, but this resulted in no problems and Trulli even passed Schumacher though the stop sequence.
Problem free opening days allowed the team to have clean qualifying laps; Narain Karthikeyan again was the more aggressive, but was also more controlled and hence faster. Tiago Monteiro says he is now getting used to the car, which was shown by his race finish one place ahead of Karthikeyan.
After a new car in Imola the team brought a new rear wing to Barcelona. Adopting a 3D shape where the outer tips of the leading edge are higher than the centre section, this would produce less downforce but also create smaller tip vortices and hence less drag, which could go to explain the Minardi's high top speed.
In qualifying Patrick Friesacher was fighting the wheel in corners as usual, while Christijan Albers, with a creditable fastest speed of 320kmh, was showing some oversteer but ended up faster.
Both Minardi's struggled at the start, leaving them stalled and forcing out the safety car as the cars were removed from the grid to the pitlane; Friesacher's car was stuck in gear, exacerbated the difficulty of this task. The team cited a programming problem on the MCU, and were able to get them cars going again. After only fifteen laps Friesacher spun off at turn 4 to retire.