The 2007 Technical Review (part I)

Despite few rule changes, 2007 provided a major technical challenge for the teams. For once aerodynamics were largely unchanged, as were the engines - albeit restricted in development.

Thus, the season was largely directed by the teams' reaction to the new Bridgestone tyres. The tyres demanded different weight distribution, and also affected the aerodynamics.

Thus, the order of teams established over the past few years was upset, leading to several outfits having to go back to the drawing board in terms of understanding how their cars worked.

Visually, the cars gradually started to adopt similar solutions, with pod wings on the sidepods and extra elements over the front wings. There was also controversy regarding how teams used their rear wings and floors for aerodynamic effect. In many respects, the year had a lot of technical interest, but it was much more in the detail rather than major visual changes.

Rule changes

Single tyre supplier

The switch to a single tyre supplier was probably the most significant rule change for this year. The most important step for the teams was not learning how to manage the tyres over the course of a weekend, but in the design decisions made when planning their new car.

How the teams were able to get their car to work with the tyres probably shook the field up more than any other regulation change. The Bridgestones of 2007 had a very different stiffness to the preceding Bridgestone or Michelin tyres. This put the emphasis on putting weight forwards and altering spring damper settings.

Also, the tyres deflected differently. This affected the suspension geometry, and more importantly, the aerodynamics. The front wing and its endplates are greatly influenced by the way the tyre changes shape through the course of lap - the tyres deflect sideways during cornering, and vertically under braking.

Many teams were not able to adequately recreate this effect in the windtunnel or in CFD simulations. Thus, the highly influential front wing was not able flow as predictably or effectively as teams had envisaged. Honda, Renault and Toyota struggled in this regard.

One ex-Michelin team that thrived on the new tyres was McLaren - it's probably not a coincidence that the McLaren had a particularly narrow front wing, sending the wake well clear of the front wheels.

Meanwhile Red Bull, amongst other teams, suffered by not being able to alter their weight distribution to suit the tyres. There simply wasn't enough adjustment in the car's ballast to put the required load over the font wheels. This year, teams were adding ballast in the front wing main plane and nose cone in an effort to put weight onto the front wheels.

Qualifying format change

Changing the qualifying system produced yet more unwanted confusion. The so-called fuel burn period did little to excite fans, nor to broadcast the sport's aspiring green credentials.

Times in the third qualifying session had less to do with who was fastest, and more to do with how drivers planned to execute their race strategy.

The vagaries of the rules meant that drivers could be rewarded with extra race fuel if they could get enough laps completed in the final qualifying session. Thus, we saw a queue of cars waiting to leave pits minutes before the session had started. This led the teams to develop clever idling strategies to maintain low engine temperatures while queuing up.

Engine freeze

Having already made engines last two weekends, then restricting them to smaller capacity V8s with material and dimensional restrictions, the FIA went further this year and restricted the engines to 19,000 rpm, and then effectively homologated their design for the whole year.

Only development to airboxes, exhausts, electronics and ancillaries was allowed. Many teams downsized their operations, and Ferrari even sent their previous engine department head, Paolo Martinelli, back to the road car division.

Engine development was therefore much more muted through the year, with only small increments being possible when the engines were replaced after every two races.

Without being able to increase the engine speed, it wasn't possible to increase peak power. Therefore, it was left to the teams to make improvements to the engines' drivability to improve lap times. On the plus side, engine failures were rare, there being less than a handful of grid penalties and race failures.

Wing slot gap separators

In a move to prevent flexible wing elements, the FIA mandated slot gap separators to be fitted to rear wings. These needed to fit tightly around the wing profiles to prevent the slot gap between the two rear wing elements altering at speed, which would reduce drag and improve straight-line speed.

There was pre-season confusion as how many separators were allowed, be it a single or pair of separators. In the end the FIA didn't seem to mandate the quantity, nor their relative positions across the wing.

Teams switched between single or pairs of the separators, depending on how their wing worked. Although they prevented the slot gap altering near the separator, they did not satisfactorily prevent any form of wing flexing, and in some cases the separator allowed the teams to fence off sections of wing - which would have been illegal under previous rules.

Not withstanding the separators and other FIA deflection tests, footage suggested rear wing endplates were still deforming at speed to lessen wing angle on the straights. Yet more tests were devised by the FIA to work around these loopholes.

Along with flexing wings, we had the issue of the flexing floors. This appeared to be resolved quickly with a new deflection test at a higher loading, only for the test to be made even stricter a few races later.

The well-engineered spring set-ups adopted by Ferrari and BMW, amongst others, were effectively outlawed, and the teams switched from very heavy front floor sections to chassis-mounted ballast - a sure sign that any advantage from a flexing floor was negated.

Summary

This season will be marked first by the teams that made a step backwards in reacting to the new tyres, and then the comparison between the Ferrari and McLaren in the fight for the championship.

If the races were always headed by McLaren or Ferrari, the midfield was much tighter - although BMW Sauber established itself as the clear leader chasing the top two teams.

In many respects the two championship-leading cars cannot be separated. Both the McLaren MP4-22 and the Ferrari F2007 succeeded in splitting the wins, podiums, poles, fastest laps, points and retirements equally. Whichever way the statistics are sliced and diced, there's no clear better car or team over the course of the season.

But the two cars were as different in concept and execution as they could be. Thus, the cars competed closely, but each had a clear advantage at different types of tracks.

At the opening race however, this situation was not yet clear. Ferrari had a traction advantage, both under braking and acceleration, while McLaren were believed to have the fast corner advantage. The following races sent results McLaren's way, reinforcing the belief.

Only by mid-season did the true picture emerge. After the opening three flyaway races, both teams had time to re-engineer their cars. McLaren made progress on engine and aero, while Ferrari focussed on tyre wear and aero.

Spain showed Ferrari to be dominant, but then came a run of very different circuits that swung the advantage towards McLaren. Having analysed these races, it was clear that Ferrari didn't handle slower turns and kerbs as well as McLaren. McLaren, conversely, didn't cope with fast turns and tyre wear as well as Ferrari.

The mid-season string of races backed this theory up; Hungary and Monza being McLaren circuits, as were the wet races at the Nurburgring and Fuji.

Quite how the teams arrived at such a neat split in competitiveness was possibly more coincidence than design. McLaren have always ridden the bumps and kerbs well, with comments from the team suggesting that the car's aerodynamics are designed to be less sensitive to attitude changes.

This meant the McLaren may not have had the most downforce, but was able to exploit what they had even if the car was rolling, jumping or yawing around slower turns.

Ferrari's strategy appeared to be geared towards a higher peak downforce, but the car was more sensitive to attitude changes. Thus the car's aerodynamics struggled when it needed mechanical grip and hence a softer set-up to work.

Team by team

Renault

Having been in the ascendancy for over three years, 2007 marked a sudden reversal of fortune for Renault. After securing the championship in 2006 with a car that was fastest for the majority of the season, the same synergy with the Michelin tyres that gave Renault the edge for two years proved to be part of the reason for the struggle in 2007.

But that is not to say the reason for Renault's lack of pace this year was a simple as the switch to Bridgestone tyres. In comparison to most other teams, the R27 was closely modelled on its predecessor. Although they voiced concerns over whether the car had enough downforce at its launch, the teams were content that it was a step forward from the previous car.

However it transpired that the wind tunnel figures that Renault were basing their predictions on were suspect. As with several teams this year, the performance of the wind tunnel model did not translate into the same pace on track.

Part of the discrepancy was the change in the tyres. Not only do tyres affect the car's mechanical set-up, their shape and deformation characteristics also fundamentally affect the aerodynamics.

All the various aero solutions that Renault had optimised over the past few years did not appear to work as well with the Bridgestone tyres.

To their credit, Renault went back to the factory and systematically worked through the problems. The flaws were not only in their car's designs, but more importantly in the testing and validation the design team go through to agree upon the designs.

This process took time, and Renault did not rush through new unproven parts until it was clear where the problems were. Thus, the season passed the team by before they could respond with new suspension and aero parts.

The problems with the car were subtle, and developments that made it onto the car were equally subtle - only the new split-element front wing and move away from the complex rear wing endplate solution suggested that the team were searching for more downforce at the cost of some efficiency.

If the team struggled for pace on occasions, at least the car always rewarded them with reliability.

Ferrari

Ferrari came into 2007 having lost the championship twice in two years as well as saying farewell to its key driver and some senior technical staff.

The launch of the F2007 brought some consternation to the media and fans. The new car was longer, heavier (unballasted) and eschewed the single keel of its successful forebears.

With the anticipated surge in their rivals pace, many believed Ferrari had got it wrong. Clues to the reason for the longer (by some 10cm) monocoque were first revealed in the cars aerodynamics, but later statements from Nigel Stepney suggested much cleverer ideas were at work.

To make the car longer, Ferrari extended the footwell section of the monocoque. If completed alone this would have taken weight off the front axle, at a time when everyone else was moving more weight forwards. But Ferrari were able to place more ballast forwards (hence the heavier car) to recover the ideal weight distribution.

Why the team chose to engineer this complexity into the car has not been clarified by Ferrari. Certainly, the area around the front wheels allows for bargeboards to be more efficient, but evidence given at the World Motor Sport Council hearing into the spy case suggested that the plan was to create a longer splitter, and make the floor affect aerodynamics and mechanical grip.

According to Stepney, the front splitter was heavier than it needed to be and mounted such that it was able to move under certain conditions. This lead to the flexible floor scandal that blew up early in the season.

As had been known for some time, most teams employed a sprung floor support, which allowed the floor to remain undamaged should the splitter hit the ground - as long as it passed the FIA deflection test.

What was not known at the time of the floor scandal was that the Ferrari floor was allegedly flexing in other ways too, firstly in an 'up and down' motion, having been sprung both ways to create a mass damper effect. This tuned flexing of the heavy floor would have offset the bounce of the tyres, and improved mechanical grip.

Secondly the floor would droop at high speed. This cut flow off to the floor, reducing some drag and also lowering the bargeboards - which could lead to even less under-floor flow.

Although unproven, Stepney's suggestions could be plausible. The longer floor that Ferrari used would have provided the car with additional grip in slow corners, and less drag for more top speed on the straights, which would have offset the length and complexity that it added to the car.

Aside from the longer car, Ferrari also followed the aerodynamically-preferred zero keel arrangement. By moving the lower wishbone off a central single keel to the lower edges of the sidepods, the flow around the car could be improved.

This gain comes at the cost of the control over the wheel geometry. Keeping the front tyres at the ideal camber angle to the ground is important, but can be compromised if a greater gain in lap time can come from the aerodynamics. If both demands can be met with a zero keel, the lap time gains would be nearly doubled.

Unseen until Raikkonen's Monza practice crash, Ferrari have adopted a unique method of arranging their front suspension. The main problem with zero keel suspension is that the upper and lower wishbones are much the same length, which means that the tyre tends to lean at the same angle as the chassis when the car rolls in the corner.

This changes the angle of the tyre to the ground in a movement called 'camber gain'. Traditionally, racing cars have wishbones of unequal length to create less change in wheel angle as the car rolls.

By making the top wishbone shorter, the wishbone has a tighter arc to pass through than the longer lower wishbone. This tends to bring the top of the wheel in towards the car in roll, reducing the change in camber.

Ferrari aimed to keep the upper wishbone shorter by a similar proportion to the lower one as used on the single keel set-up. But in moving the lower wishbone outwards, the upper wishbone needed to be moved outwards by a similar amount. Thus, Ferrari has mounted the upper wishbone on a metal extension to the chassis.

Somewhat similar to a horizontal keel, this means Ferrari can have a short upper wishbone to manage camber gain, and also have their aero advantage.

There are some compromises in this design. The side extensions add weight in order to maintain stiffness, and the shorter wishbones also tend to scrub the wheel sideways as it goes up and down. But Ferrari have done their simulations, and have found this set-up to be the best solution for them.

In this horizontal keel set-up, Ferrari mount the carbon fibre upper wishbone to a metal extension which is bolted to the monocoque. The upper wishbone employs these extensions for both the front and rear legs. The arrangement was kept secret with fairings added around the inner ends of the wishbones, hiding the extensions. Only when Raikkonen damaged the wishbones in Monza did the structure underneath become clear.

This horizontal keel also demands that the steering rack be wider, thus the rack extends into the fairings to place the steering joint in line with the wishbones flexures.

Lastly, as the lower wishbone is now mounted higher, the mounting for the pushrod is compromised. As with most teams, Ferrari mount their pushrod on the upright rather than the wishbone. But other teams have spaced their pushrod out farther, and inline with the front stub axle. This creates yet more compromises in the weight transfer and spring/damper operation.

Ferrari has chosen to pass the pushrod through the lower wishbone to keep the mounting close to the steering axis, and maintain a steep installation angle to operate the spring dampers inside the nose of the monocoque.

Elsewhere around the car, the Ferrari employed new solutions. The airbox snorkel over the engine was given a secondary purpose, with a hydraulic oil cooler being mounted atop the gearbox fed by the duct.

This was visible externally by the exit in the tail of the engine cover. Why Ferrari needed such a large cooler is not clear, but placing it in this spot did save space in the sidepods for the main engine cooling matrices.

The gearbox itself was new, both with its titanium skeleton construction, reinforced with carbon fibre skins, as well as the new seamless shift mechanism. The gearbox and hydraulics did cost the team results this year - in both qualifying and a race the set-up failed, while the only other mechanical retirement were electrical and a suspension failure in Monza.

The latter failure was attributed to the third damper, but speculation is still ongoing as to why a conventional and usually bullet-proof damper would fail in such a way to force a retirement.

Ferrari was the first to exploit fairings installed on the wheel last year in the wake of the FIA easing the definition of brake ducts. This year, they went a step further with the static front wheel fairings. These reduced drag not only by streamlining the wheel, but also by directing the hot air from the brakes back behind the wheel.

The extra complexity these added to pit stops, where the mechanics were required to use had a special wheel gun, did not create the expected problems.

McLaren

A major push by the post-Newey design team over the previous season and through the winter delivered what was in many ways a better car than the previous run of McLarens.

The MP4-22 was a very sophisticated car, yet not in the same vein as the over-complicated, still-born MP4-18. The MP4-22's defining features were in the aerodynamics - the finely detailed area around the rear suspension, the diffuser and the curious conjoined pod wing/chimneys.

Also, the car sported larger wings than most, especially the huge three-element front wing, which was later joined by the bridge wing, creating a fourth element.

Early in the year the car lacked straight-line speed compared to its rivals, possibly due to the high amount of downforce the car carried, and also partly from the engine being in an early stage of development.

It was noted by rival designers that McLaren had made a major step for this year in their aerodynamics. In the opening races, just as it became apparent which teams had struggled with the technical rule changes over the winter, it was equally clear that McLaren were on the pace, and reliable to boot.

Podiums first time out and wins in the season's second and third races proved that the car was a major step forward.

Making the car's championship challenge possible was the team's huge leap in reliability, which was probably a bigger challenge than the aerodynamic improvements. With McLarens having been fast but fragile in recent seasons, the MP4-22 gained a reputation as a solid finisher.

The car did fail on a few occasions however, once with a hydraulics problem, and also with a wheel gun-induced suspension failure that affected the car in qualifying. But only the gearbox problem for Lewis Hamilton in Brazil affected race results.

Offsetting the mechanical reliability was the fact that the car was harder on its tyres, and twice the team overstepped the mark, leading to major problems (chunking in Turkey and over-worn wet tyres in China). But the car's tendency to be harder on its tyres led to strong qualifying pace, naturally offset by compromised race pace.

One trump card played by McLaren early in the season was its cooling package. Having seen a succession of McLarens greeted in the pitlane by squirt of fire extinguisher and burnt carbon fibre, or hastily modified cooling outlet s at hot races, the MP4-22 was able to run with surprisingly few cooling outlets.

The lack of grills, chimneys and louvers added to the team's pace at the first flyaway races, as did the car's ability to idle in the pitlane for several minutes, giving McLaren a monopoly on a clear track in qualifying.

Cooling packages are far more than just the radiators. The volume of water and the temperature the engine can withstand, plus the way the electronics manage traction control and idling are just as important.

McLaren were able to engineer this year's cooling set-up to run cooler, and for longer. The changes gave them a head-start, and also recovered points when Hamilton spun off at the European race and was able to keep the engine running for long enough to get the car craned back onto the track.

As with any advantage this was short-lived, although the car's bodywork was still notably closed up for hot races through out the season.

The spy affair gave some insights into the troubles McLaren faced this year with the change to Bridgestone tyres. They were constantly seeking to improve their weight distribution. The late season lightweight gearbox gave us clues to the direction the team was heading in its weight bias.

Lightening the rear end allowed weight to be moved forwards in the form of ballast. Equally, the car's braking system struggled to stop the rear wheels from locking. Subsequent changes to the Akebono braking system cured these maladies.

Toyota

Having gone through two compromised seasons with much-modified B-spec cars, the TF107 was launched as the team's clear aim to capitalise upon their strong end to 2006. Although not as cloaked in the voguish sidepod shapes as other cars, the new car was striking, with an extreme raised nose, plus clever detailing around the front and rear wings.

Toyota maintained a bi-plane wing from its launch, the wing being neatly blended into the tip of the nose. Likewise at the rear, Toyota launched with a pyramid shape over the rear crash structure to rejoin the flows passing up from the diffuser around the new lower structure.

But it was clear at an early stage in the year the car was not performing as expected. A lack of downforce was suspected and the car made poor use of the tyres, despite being one of the few teams to carry over from last year with Bridgestone.

Developments aimed at adding grip were presented throughout the year. The front wing went through several versions along with a new rear wing, engine cover and lots of bargeboard details. Late in the season a new drooped nose was introduced, as well as a diffuser that reportedly wasn't as successful as hoped.

At least through the season the car was reliable, aside from a curious issue where the uprights failed, leading to two retirements at Silverstone. The team found the car's set-up had gone so far as to overstress the design, and the team switched from MMC to cast titanium to improve the durability of the upright.

Honda

Perhaps the most spectacular failure this year was Honda. The new car appeared with an off-beat aero concept that very soon appeared not to work.

Again, a problem in the relationship between the actual car and the new wind tunnel was identified, and the tyres clearly played a critical role in how the whole aero was working.

A lack of grip from the rear and an unpredictable front was the main issue. This made the car difficult to predict under braking, ruining the drivers' confidence and lap times.

Before the season began the team started to alter the car to recover some pace. The complex sidepod winglet set-up was removed, and inefficient dive planes placed on the nose to add some downforce.

As the season progressed, frequent updates were added for races or extreme solutions run in testing, such as the suspension which had three or four upgrades at each end. The diffuser and wings had also been altered an equal number of times.

While inspiration for many designers comes from other cars, Honda appeared to repeatedly adopt McLaren-like solutions. The launch car's oversize pod wings were altered for conjoined pod wing/chimneys, a large three-element front wing and a bridge wing - not to mention the outlandish elephant ears tested early in the year.

Additionally, the diffuser was simplified and beam wing changed accordingly. Late in the season the team tested an interim car, completely devoid of the team's trademark forward turning vanes and pod wings. Instead, the car ran larger bargeboards mounted towards the sidepods.

To many aerodynamicists outside the team, the philosophy of forward-mounted vanes has now been superseded by the more widely adopted practice of using larger rear-placed boards, as nowadays the bargeboards do as much for flow under the car as they do around it.

Therefore, having the vanes so far ahead of the floor makes them less efficient in getting the correct pressure and distribution to feed the diffuser. Although the test was inconclusive, it is perhaps the first sign that Honda are going to change their philosophy for 2008.

BMW Sauber

Heading into the team's second year and with the benefit of a full season of the extra resources BMW have provided, BMW Sauber have turned around to be the third top team.

The new car was a development of what has gone before, but was preceded by a lengthy series of CFD studies to ensure areas such as the nose format and cooling layout were the optimum solution.

Thus, the car started from a well-judged position. The low nose of last year was eschewed for a more typical raised version, and from it hung their own innovation - the split front wing flap. The car then rapidly developed and grew complex shaped wings and viking wings.

Detail work, along with a lot of bargeboard development, kept the team on pace with the rest of the field.

Early season fears for the quick-shift gearbox reliability were well-founded, as the team struggled with gearbox and hydraulics issues throughout the year, leading to five related retirements.

Additionally, a late-season engine failure cost Robert Kubica ten grid positions in Spa. It was a credit to the team's consistent pace at all tracks that it was able to maintain its championship position with this level of reliability.

That said, the team never really threatened to beat the top two teams on pure pace, but they were always there to collect podiums should one of the leading four cars fail.

Williams

As the leading independent team, Williams had yet another new engine to integrate, and in return the team provided a quick-shift gearbox design to Toyota.

Despite the added workload, the FW29 car was a major step for the team. The cars design was well considered and well executed. Early season pace backed this up, but with development the car maintained its pace.

Some of this development has been highly visible, with the team sporting two major revisions to its nose treatment, initially with a flatter bi-plane wing, then their own take on McLaren's bridge wing.

Late in the season Williams tested Ferrari-like static wheel fairings, but these are yet to race. Reliability has been impressive too, with only a few engine installation issues and none of the gearbox hydraulic problems that most other teams have posted.

Red Bull Racing and Scuderia Toro Rosso

We can consider both teams cars together as they were jointly developed by parent company RBT. The RBR team largely got the benefits of development first, and had the better pace throughout the year.

Each team constructed and operated their own car, and its clear the ex-Minardi facility struggled compared to the better-run RBR Milton Keynes factory.

The Red Bull car was clearly the child of Adrian Newey's mind - the similarity to McLaren designs was obvious, and the previous Mark Smith Renault influence was diminished.

This meant the entire car was new - even the Renault engine supply for RBR was new. Thus, the design team started earlier than other teams, and many decisions were made before the tyre rules were confirmed and the demands of the new tyres were understood.

As a result the layout for the RB3/STR02 was premature, and ultimately compromised the car's development. This led to two major issues. Firstly, the car struggled with reliability problems all year. The quick-shift gearbox was adopted late by RBR, and hydraulics were never reliable.

The two teams posted the most retirements in the field, largely as a result of hydraulic/gearbox failures. However, the car's inconsistency in qualifying often put it back among the pack and made it vulnerable to accidents while trying to recover during the race.

The car's pace was also hindered by a lack of forward-biased weight and downforce. The car developed through the year, but the changes needed to get the car to the correct layout were not viable during the season.

Development work through the year resulted in new wings, revised pod wings and mirrors. The initial outboard position of the mirrors on the RBR cars was changed to a more conventional configuration, but in testing the old format mirrors were continually assessed.

Spyker

Starting the year with an evolved car was a hindrance for the team. Already at this early stage a major B spec upgrade was planned by the new technical head Mike Gascoyne.

The 2007 car adapted the 06 monocoque, now using a zero keel suspension whose structure was much more to designer John McQuillan's liking. The rest of the aero and mechanical set-up was largely developed from the previous car's B-spec configuration, only a switch to a McLaren-like keel fairing/bargeboard was adopted.

Clearly, the car was not capable of escaping from the rear of the grid. The B-spec version was pencilled for the Turkish GP, but Gascoyne wanted the car rushed through for the preceding European race. When it was clear that this was not going to be possible, the Turkish date was reinstated.

Eventually he had to wait as late as Monza after the car failed the rear impact tests. The revised car left only the monocoque and engine in place - the rest of the aero, cooling suspension and gear case were new. The new, lighter car also allowed a forward weight bias with the use of more ballast.

There was a distinct step in performance, as witnessed at Spa. Such are the revisions to the B-spec car that it will form the basis of their 2008 car, with only the monocoque to be lightened and the aero slightly revised.

Super Aguri

By basing their design on the Honda RA106, Super Aguri had a newer base to start compared to the old Arrows chassis used last year. However, the RA106 was not the best F1 car of the 2006 season, although its late surge was impressive.

The Honda factory team clearly have some limitations in their understanding of the car's workings, yet the small Aguri team were able to develop the chassis with the help of Honda R&D in Japan. They fitted it with the same Honda V8 and quick-shift gearbox as the factory cars, and work started to revise its aero, lead by the in-house aero team.

No major revisions were made to the car, but detail work did produce revised wings, diffuser and pod wings, and having the back catalogue of Honda designs allowed the team to run the Renault-esque low-drag rear wing in Canada.

The car showed glimpses of great pace with some surprising qualifying positions and race results. But development was hindered by the team's budget. A non-paying sponsor effectively halted major development on the car by May.

As the car did not have such great pace in qualifying, race results were tainted by accidents, as well as a small number or mechanical retirements. But one race ended in a retirement caused by one of the year's few engine failures.

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