2008 Technical Trends Review

As the field is so tightly competitive this year, one of the greatest surprises has been the sheer pace of development. This has allowed teams to adopt each others ideas far quicker, leading to a flurry of copycat designs throughout the pitlane.

With major rule changes in the pipeline for 2009, 2008 will be a swansong for F1 cars with hugely complex aerodynamics. Equally, it will be the last year for grooved dry weather tyres, as Bridgestone will supply slicks in 2009. Although engines, gearboxes, and electronics are far tighter controlled now and not due to change for next year, the teams have still been able to find speed from the limited loopholes in the regulations.

Tyres

For 2008, Bridgestone kept their range of four dry tyre compounds largely the same, although some changes were made to the construction of the super soft tyre in the light of problems in 2007. Thus the teams are still dealing with effectively the same tyres, with the weaker rear tyre and stiffer front tyre constructions. This mismatch leads to the teams aiming to place more load over the front tyres and a lot of work was completed over the winter to move weight and aero balance forwards.

During this year, some teams are still unable to get the front bias they are looking for. Some of the tell tale signs of forward weight bias are the ballast pockets being moulded into the front wings. This is not an ideal place, being ahead of the front axle, but it is as far forwards and as low as possible. Along with the forward weight bias needs to come a forward aero bias, the explosion of triple and now even four element front wings shows the loads needed over the front tyres, albeit some of this load is sacrificed by the multiple flow conditioners adorning the front of the cars.

As well as the static and aero loads, the tyres are sensitive to track layout, ambient temperature and driving style. We have seen very different levels of competitiveness between teams depending on the number of fast corners or as the weather goes from hot to cool. Even within teams we have seen vastly differing fortunes, if one driver has harder driving style than the other.

Classical drivers tending to get better race pace from being careful with the tyres, while the aggressive drivers often see better qualifying pace and struggle on the softer option tyres in the race. This has been most clearly demonstrated within the BMW Sauber team where the smooth driving Heidfeld has struggled in qualifying compared to the harder driving Kubica.

Getting the tyre to work in its ideal temperature range is a tricky business, as well as the aforementioned factors; suspension geometry, compliance and the presence of inerters all make an impact on tyre usage.

Front Wing

To make a front wing work more effectively you either need more wing area, more wing angle or to place it closer to the ground. Each of these approaches has its drawbacks and different teams find their own solution to suit the downstream shape of the car.

Many teams have a deeply swept three-element front wing, this is a balance of the three requirements, the gentler dip prevents the wing being too attitude sensitive, while the three elements create the area and the extra slot gap to allows a steeper wing to be run.

This year a much more aggressive square jawed wing has been run by McLaren, Renault, and Williams, which places more wing area lower to the ground. Careful aerodynamic development has allowed the teams to make the wing insensitive to pitch and roll.

McLaren have gone furthest with a four-element front wing, again the extra gap created between the flaps allows the flap to be steeper without airflow separating from the under surface of the wing. This allied to a slotted bridge wing makes McLaren's wing a stack of six elements at its outer edges.

Bridge wings

Bridge wings have become another near standard fitment across the grid, a logical extension of the endplate mounted cascades of a two years ago, the bridge wing serves two functions, the outer spans create downforce as a cascade with the lower front wing. While the middle section is neutral or creating lift as a flow control device.

Earlier this year there was concern that the bridge wings were flexing at speed, while this was no doubt true it was originally felt there nothing to gain from this flexing. For whatever reason the FIA view changed and from Turkey they were required to be fitted with a support to prevent flexing.

Front wing fences

Once the airflow has passed over the front wing it needs to negotiate the gap between the front wheels, then be directed over the top body and under the floor. The front wheels are a sizeable blockage to the airflow - even more so as the tyres flex and the wheels steer.

This year teams have paid even more attention to the way flow is routed around them. Normally teams fit fences under the front wing to route the air between the wheels, Red Bull and McLaren have now doubled up these fences for a greater effect in steering the flow between the wheels.

Nose hole

A true innovation this year was Ferraris "nose hole", this is a duct let into the nose cone that allows the high pressure air forming above the front wing to escape, letting the wake form underneath the wing. The set up only works with certain wing angles and hence is part of a front wing package not a permanent solution.

To allow the nose cone to vent its flow most effectively, a small chamfer is moulded into the front of the monocoque and when the "nose hole" is not run there is a blanking piece for this area.

With the demand to crash test the new nose, and its interaction with the rear of the car's aerodynamics, it's not surprising that others have not followed this path, especially as new aero rules are planned for 2009.

This is not to be confused with the small slot all teams run in the tip of the nose cone, which is mainly for cooling purposes, the footwell and cockpit area contain hydraulics and electronics which emit heat, making life uncomfortable for the driver

Brake ducts

The inside face of the wheel creates disturbance to the flow. Bucket-like brake ducts have helped to seal this flow and teams often fit small flicks and tabs on the duct to aid airflow.

This year, Renault went a lot further and mounted a turning vane to the brake duct. This is legal as the rules only dictate the area in which bodywork can sit around the wheel, not what their purpose must be.

Wheel fairings

On the other side of the front wheel, Ferrari's lead has been followed by nearly every other team in adopting static wheel fairings. Again legal under the bodywork rules, these devices do little for brake cooling but do make a big impact on the flow passing down the flanks of the car.

Pod wings

Pod wings have also become standard fitment to F1 cars this year. Vertical fins mounted to the shoulders of the sidepod, they act to collect the flow and divide it into clean flow to the rear wing and dirtier flow passing over the flip up and around the rear wing.

Their purpose has become joined with one of the dual functions of the cooling chimneys. Many teams now retain chimneys even if they are closed, because they are part of the cascade of devices splitting the flow around the rear wing.

McLaren joined their pod wings to the chimneys to create a single dividing surface and, again, this has become this season's fashion.

BMW have extended this thinking by merging the pod wing with the bargeboards to provide a little extra bodywork area to turn the flow around the sidepod. Just as with McLaren's innovation, this has been copied throughout the pitlane.

Diffuser

While the flows over the top of the car are important, the most important is the flow under the car. Surprisingly, the flow approaching the diffuser under the car is shaped by the bargeboards, or more correctly, their footplates. The greater pressure that can be fed under the floor and expanded by the diffuser, the greater its downforce.

The footplates along the bottom of the bargeboards are stepped and have curled up edges, which all help send high energy flow under the floor to feed the diffuser.

At the rear of the car, anything that can help lower pressure behind the exit is useful, so the team fit large gurney flaps, place the wishbones and drive shafts in a cascade above the exit, and create bulbous brake ducts to help.

One other strategy employed by the teams is to maximise the exit area of the diffuser. The taller centre tunnel rises to the height of the beam wing and a smaller channel is created in a legal loophole above the roof of the side channels.

The exit area creates a problem to prevent separation inside the larger tunnels, thus teams with these high expansion diffusers tend to run sizeable fins around the rear brake ducts to act as extensions of the tunnels to keep the flow expanding beyond the diffuser's exit.

Shark Fins

To aid the onset flow, the engine cover has been extended from a simple hump or raised spine to the Shark fin design first seen on the Red Bull in winter testing. These fins provide a greater surface area to resist any yawing moments and to straighten the flow to the rear wing.

Their unusual shape exists to allow the greatest possible surface area (up to the maximum 850mm height) while still providing some feed to the rear in yaw, which is why the fin has the large undercut.

Rear wings

One area teams have converged in recent years has been the addition of slots into the endplates ahead of the flap\endplate junction. These slots bleed high pressure air toward the wing tip to reduce the pressure difference, thus reducing the vortex formed. This reduces drag created at the wing tip.

Renault used to merge their flap and endplate into a blended join. This worked in a similar way to the slots as high pressure would bleed off towards the wing tip to reduce the tip vortices. Although Renault use this solution more rarely now, it has been taken almost permanently by McLaren and occasionally by Honda.

Inertia dampers

One element un-tunable by the race engineer is the tyre's natural 'spring'. Thus a degree of energy is put into the chassis by the tyres, which is different in both bump and rebound. In 2005, Renault raced a front "tuned mass damper" (TMD) to offset these inputs, but unbeknown to most, McLaren were already racing a much more integrated system packaged into their suspension system.

This was the Inerter or J-Damper in McLaren-speak. An Inerter is a mass that spins in a different plane to the load applied to it; this absorbs energy of the input. The beauty of the Inerter is that it only responds to the acceleration applied, so the different forces given out through the tyres is always counteracted with an equal and opposite force.

There are several possible layouts for an inerter, the original version as proposed by Malcolm Smith used a toothed rack to spin a mass via pinion gear, the rack attached to one side of the axle and the mass\pinion to the other. The relative movement between the two sides of the axle spin the mass to negate the input force.

This has been described as a bicycle bell design and the analogy works well as the effort put into the thumb is absorbed into the rotary motion of the bell ringer. Most likely in F1 is the concentric solution, a threaded rod on one side and a mass threaded to it and supported on bearings on the other side. As the threaded end moves, the mass spins creating the same effect and bicycle bell.

As the Inerter makes use of mechanical advantage in the gearing of the spinning mass it is overall much lighter and hence easier to package. This also makes the inerter harder to spot is it can be shaped like a conventional heave damper.

Teams are now starting to fit Inerters both front and rear, so far McLaren have had them since Imola 2005, Williams for over two seasons, and Ferrari since Monza 2007. In 2008 Renault, Red Bull and Force India have all announced Inerters, with it being unclear how long BMW Sauber have run them (they had them at Silverstone as the rear 'fourth' damper was changed according to the FIA scrutineers notes). Honda's Hungary rear suspension also included an extra bulge, potentially for an Inerter.

Electronics

With the introduction of the single ECU (SECU) for this year, The FIA have been able to enforce a driver aids ban. This encompasses traction control as well as adaptive engine braking, which provided stability, and an element of antilock braking on corner entry.

In addition to the ECU's standardisation, teams now have a more restricted set of drivetrain maps. These used to be adjustable both by the car's GPS satellite positioning system, to alter the mappings for each corner, as well as the more visible options adjustable from the steering wheel.

In spirit, this rule puts the driver on a single map for the whole lap, unless he adjusts the knobs on the steering wheel, as commonly done around the lap with braking bias.

McLaren realised that with the driver having to adjust a less than ergonomic button in between corners, they could set up gear paddles with differing maps. Thus an extra set of gear paddles (four in total) has been provided, each with a different map to suit different sections of the track. This provides the driver with a greater degree of control. Renault and latterly Ferrari have appeared with a second set of gear paddles.

Seamless shifts

Now that Force India have got their seamless shift working, all the teams have this technology.

Contrary to popular belief, most seamless shifts do not use double clutches, Zeroshift, or any clever dog ring set ups. Nor does the power remain uninterrupted (i.e. full throttle, full engine load shifts).

In fact, the shift is simply controlled by two selector drums, each operating alternate gears. Thus the engagement of the next gear can be progressing as the old gear is disengaged, this can occur as the engine\gearbox load is momentarily eased with an ignition\throttle cut and clutch disengaged.

In a normal gearbox, the adjoining gears are controlled by a single selector, thus the old gear has to be disengaged before the selector can engage the next gear. Reducing this undriven time is where the "seamless" element is brought in and saves time on shifts. This seamless shift is only possible with highly accurate hydraulics and electronics, one timing error and the gearbox will engage two gears simultaneously with destructive results.

The SECU's introduction is believed to be responsible for some winter gearbox woes, as teams struggled to get the control code working as well as it had on their old ECUs.

Engines

Now that engine development is limited to just the fluids inside the engine as well as the exhaust and upper airbox, there is limited scope for development. But that is not to say there is no development going on.

Teams have found sizeable gains with revised oils, leading to McLaren's hotter running engine and smaller aero inlet. Fuel is a more obvious way to create more power without mechanical changes, simply new mapping within the engine. Also, as teams learn to use the SECU, the issues with part throttle opening has been improved for more drivability.

Some mechanical changes are allowed to the engine despite the engine freeze. These have sparked off some "cheat" rumours, but the underlying process is quite legal. If a team suffers reliability problems, they are allowed to submit a request to the FIA for the parts design to be changed. The team has to back this up with documentation of the problem and solution.

All the teams are aware of this rule, but are fearful of using it as the documentation is circulated to the other teams and thus they are revealing facts about their engines to their competitors. No doubt teams will seek to provide any performance advantage in redesigning a part, but any excessive requests for design changes can still be rebuked by the FIA.

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- The Autosport.com Team

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