Friday, May 30, 2008

Inside the F1 cockpit

Every bit of a Formula One cockpit not occupied by the driver is crammed tight with technology.
  • Buttons: The carbon fibre steering wheel houses controls for the communication radio, the setting of the differential (to change handling characteristics), the fuel mapping (to change the power/economy compromise), the pit lane speed limiter, and the traction and launch control.
  • Controls: Behind the steering wheel are controls for the clutch – needed only to get the car moving when launch control isn’t being used – and the gear change. The driver uses a flipper switch on one side of the wheel to make downchanges and one on the other side of the wheel to make upchanges. Normally the gear changes are made automatically – making these controls redundant – but in some situations, a driver may prefer to change gears manually or may be forced to because of technical glitches.
  • Instruments: In terms of instrumentation, the cockpit display is quite bare. Small digital read-outs tell the driver engine revs, engine temperatures, minimum corner speeds, and instant lap times.
  • Pedals: The cars have only two pedals: a throttle on the right and brake on the left. Most Formula One drivers brake with their left foot.
  • Seat: The driver’s seat is moulded to his own particular shape.

Slick tyres: Why they aren’t used in Formula One

Between 1971 and 1997, Formula One cars used to race on slick tyres – that is, tyres with no tread at all. This lack of tread gave the maximum surface area of rubber on the road, thereby maximising dry weather grip. Most other racing categories still use slick tyres but, since 1998, they’ve been outlawed in Formula One and replaced by the regulatory grooved tyre. The governing body made this change purely to limit the performance of the cars, for reasons of safety. Tyre engineers estimate that slick tyres would make Formula One cars around 3 seconds per lap faster than they currently are.

Understanding F1 tyres

As the cars’ only contact area with the track surface, tyres obviously play an enormously important role in the performance of the machines. So critical, in fact, that the sport’s governing body invariably uses limitations on the specification of the tyres as the key way of controlling the performance of the cars. The limits for dry-weather tyres are currently those of width and tread groove.
  • Width: The front tyres must be between 12 and 15 inches (305–381mm) and the rear tyres between 14 and 15 inches (356–381mm). The back tyres can be wider than the front because the back has more work to do. The weight distribution of the car is rearward-biased, because that’s where most of the mechanical components are. Furthermore, the rear tyres are transferring the engine’s power to the road.
  • Tread groove: Four grooves must run through the circumference of the tyre. The shape and depth of these grooves is also specified by the regulations. The regulations for a wet tyre specify contact area rather than tread pattern or shape.
Formula One tyres grip the track far better than those of any road car could, but this performance comes at the expense of durability. However, a set of tyres on a Formula One car does not need to last any more than the length of a race and more often than not, even less.
Both grip and durability are largely determined by a tyre’s compound, the complex mix of the constituent chemical parts that comprise the material the tyre’s made from. The softer the compound, the better gripping but less durable the tyre. Different circuits place different demands on a tyre, according to the nature of the track surface and the design of the course. Tyre manufacturers come up with compounds tailor-made to each track. The other critical aspect of a tyre’s design is its construction, the way in which its carcass is designed. The stiffer the construction, the greater the load the tyre can withstand and, therefore, the softer the compound can be. A Formula One tyre is very temperature-sensitive. It has virtually no grip at all below its designed operating temperature and would therefore be lethally dangerous if used on the road. Getting the tyre up to temperature requires braking and cornering hard enough that only an accomplished racing driver is able to do it.

The braking news

Much of the staggering braking performance of a Formula One car is a result of the enormous download from its wings and other aerodynamic features pressing the car into the ground. This download makes the tyres able to withstand such big braking forces. But the brakes themselves need to be able to fully exploit this force. The key to this exploitation in recent years has been the advent of carbon fibre brake discs and pads.
Carbon fibre discs operate at a temperature range of between 500–800 degrees centigrade. Below that range, the discs are fairly ineffective; above it, they begin to oxidise, that is, they begin shedding their mass in a process very similar to the rusting of metal, albeit faster. Keeping the brakes within this temperature range is a key part to a car’s performance, especially because of the regulation that limits the thickness of a disc to 28mm. (This regulation was introduced to keep a check on braking performance so that overtaking didn’t become impossible.)
The braking forces are the most impressive facet of a Formula One car’s performance. Whilst the best road cars might generate up to 1.5g (g is the force of gravity, so 1.5 times the force of gravity) under extreme braking, a Formula One car can pull over 4.5g. This level of force actually affects the blood flow to the driver’s eyes, and some drivers have noted a momentary effect on their vision. Others have commented on how tears in their eyes get thrown onto the inside of their visors. Such is the downforce and engine compression of the cars that just lifting off the accelerator pedal generates 1g – about the same as a full ABS emergency stop in an average road car. That’s before you have even touched the brake pedal!

Using the suspension to set up F1 car

A Formula One car is almost infinitely adjustable so that it handles according to the demands of the track, conditions, and the driver. The set-up of a car refers to particular settings: wing settings and suspension. The necessary balance between cornering downforce and straight line speed is determined by wing settings (see the section “Wings and underbodies”, earlier in the chapter). But this is only part of the set-up. The more complex part is that of suspension.
In general, the suspension set-up is determined by balancing two aims which are frequently at odds with each other: the need to adequately support the cornering and braking force of the car and the need to achieve the necessary responsiveness of handling. A circuit generating high aerodynamic loadings, for example, generally demands stiffer springing, but this can cause problems in slower corners where the suspension needs to be more supple in order to enable the car to brake well and to ensure good direction-changing response to the wheel. Achieving a good set-up invariably involves finding the best compromise. Achieving maximum grip is obviously important, but getting the best handling balance is even more so.
Driven to its limit, any car will surrender its grip at either the front or the back. There is no such thing as a car with unlimited grip, and any racer worth his salt soon finds where the limit of grip is. This is where the handling balance takes over. Handling balance refers to whether the car runs out of grip at the front first and understeers (that is, tries to run straight-on when asked to turn) or surrenders grip at the rear first and oversteers (turns more than asked). A very narrow window of neutrality exists between these two states, where both ends of the car surrender their grip at the same time, and the car drifts, but this state is rarely seen with modern cars. Driver preferences and the timing monitors determine the best handling balance for a given car and track at a given time. In terms of wing settings, oversteer can be tamed by using more rear wing or less front. Understeer would be countered by more front wing or less rear. But playing with wings is the easy – and usually less efficient – way out of a handling imbalance, because it involves screwing up the ideal downforce/straight line speed trade-off So for a given wing set-up, the handling is usually fine-tuned with the suspension. The suspension components that are used to determine handling balance are the following:
  • Springs: A spring that’s not stiff enough under cornering doesn’t properly counteract the car’s tendency to roll, moving its centre of gravity outwards and quickly overwhelming the outer tyre’s ability to keep a grip on the road. A spring that’s too stiff slows the transfer of load from the inner to the outer tyre too much; as a result, the outer tyre isn’t being loaded enough to achieve its potential before the corner is over. However, the spring rate that’s just right for one corner on the track may be wrong for the next one, because of the corners different shape and speed. To further complicate matters, the difference front to rear must be considered as well. If the spring rate at the rear is just right, both toostiff or too-soft at the front produces understeer. If the front rate was just right, both too-stiff or too-soft at the rear produces oversteer. The driver and his engineer need to find a compromise over the many and varied corners of the track; this compromise may involve surrendering some grip from one end of the car to get the desired balance. At circuits with a wide variation of corners, variable rate springing may be used to give a relatively soft spring at low speeds but a stiffer one at high speeds.
  • Dampers: Dampers don’t determine a car’s grip as much as they determine how much of the grip the driver can access. The dampers offer a very effective way for drivers to fine-tune the car’s handling in the limited time of a practice session. The damper is adjustable in the bump phase of its progression (as it absorbs the initial bump) and in the rebound phase. These adjustments can be made in two ranges – low speed and high – to give four-way adjustment. The damper is also adjustable within the overall range of frequencies in which it works, although this involves fitting different internal valves – not normally something done during practice. A driver might soften the bump rate if the car’s trajectory is being affected by bumps in the braking or cornering zones or if he wants to use more kerb without being thrown off line. Softening the damper’s bump rate allows the spring to smother more of the bump’s effect. A driver may increase the damper’s rebound setting in order to keep the nose of the car down after he has finished braking to help him get the car turned into the corner. In addition dampers include “blow-off valves”. These valves enable the damper to ignore any out-of-range inputs so that, for example, a severe kerb can go undamped beyond a certain range and so not compromise the settings needed on the rest of the track.
  • Arms: The linkage formed by the suspension arms and how they interact front to rear have a direct bearing on the overall handling characteristics of the car. The geometry of the wishbone linkages determine the roll centre of the car. The roll centre is an imaginary, but accurately defined, point on the centre-line of the car around which the car rolls on its suspension. The roll centre can be high off the ground, low, or even underneath the ground (it’s only imaginary, remember). A line connecting the rear suspension roll centre with that of the front is called the roll axis. If the axis runs nose-down, the car tends to oversteer. If the axis runs nose-up, the car tends to understeer. These linkages are intrinsic to the car’s design and can’t be changed during a race weekend, but some adjustment can be made to the car’s ride height (the height above the ground of the car’s underside) via the suspension’s pushrod. The closer to the ground, the more grip but the less the car can tolerate bumps and kerbs. The camber of the wheels can be altered by adjusting the wishbones so that the highly-loaded outer wheel becomes upright under cornering and uses more of the tyre’s width rather than just the outer edge. (Here, camber refers to when the wheels aren’t perfectly upright, but run at an angle to the road surface, usually with the bottom pointing in slightly.) The downside of altering the camber is that it makes the car less good under braking.
  • Roll bars: Roll bars have a big effect on the car’s handling, particularly in the first part of a corner as the driver turns in. The bar’s primary function is to keep roll under control, but the way it does this also results in cornering load being transferred from the inner tyre to the alreadyloaded outer tyre. If the spring rates aren’t too stiff, this detracts from ultimate grip. Taking grip away from the front or the rear by increasing the stiffness of the roll bar gives the driver another tool in adjusting the car’s handling balance.

Thursday, May 8, 2008

Formula One suspension components

The suspension is made up of the following components:
  • Springs: The springs absorb the basic loadings. Sometimes these are in the classic coil shape that most people associate with the word spring. More usually, however, they are things called torsion bars, a sort of straightened-out spring, that makes for easier changing and lighter weight. Changing the stiffness of the spring – how much it deflects for a given load – is a key way to change the handling of the car.
  • Dampers: Once a load is released from a spring – like when the car has finished cornering or braking – the spring oscillates. Dampers damp out the oscillations, enabling the car to recover its equilibrium quicker. The stiffness of the dampers is adjustable, and they form another key variable in establishing the driver’s preferred set-up.
  • Arms: Arms are the connections that transfer the loadings from the wheels to the spring/dampers. In a Formula One car, arms are almost always arranged in what is known as the double wishbone formation. Two upper and two lower arms stretch horizontally in a vee shape from the wheel to pick-up points on the chassis. In between is a pushrod, a single arm that stretches (at an angle from the horizontal) from the wheel to the spring/damper attached within the main chassis. As the wheel moves up and down supported by the wishbones, the pushrod translates the loadings onto the spring and damper. The arms are connected to the wheel via an upright, a cast piece of metal (usually titanium) onto which the wheel hub is bolted on one side and the suspension arms on the other. The front suspension arms (and sometimes the rear suspension arms, too) are usually made from carbon fibre. But the heat from the exhausts can have a damaging effect on the strength of the material, requiring that an exotic lightweight metal might be used instead.
  • Roll bars: The roll bar is a metal bar linking one side of the suspension to the other. It limits how much the car rolls during cornering. The thickness of the bar determines its stiffness. There is a roll bar at the front and another at the back of the car.

Formula One suspension

Suspension is demanded by the technical regulations. Technically, a Formula One car could get by without it – it would be like a big go-kart – but the drivers’ spines would take damaging punishment. The role of suspension in a Formula One car isn’t just to give the driver a smoother ride though. It is also a vital tool in adjusting the handling of the car to suit individual circuits, track conditions, or driver preference.
The suspension needs to be compliant enough to allow the driver to shave vital hundredths of a second from his lap time by cutting across kerbs, but it also must be stiff enough to withstand the huge aerodynamic loads that press the car down to the track surface. Sounds like a near-impossible demand? Hey, if it was easy, we’d be out there doing it!

End plates and barge boards

Getting the air to separate cleanly between upper- and under-body is vitally important to the effectiveness of the aerodynamics. Endplates, the complex shapes at the sides of the front wing, are designed to do this. Further back, low on the side of the bodywork, behind the front wheels, are the barge boards. Barge boards pull the air coming over the front wing along more quickly – and thus increasing the downforce – and then channel it where needed.

Saturday, May 3, 2008

Formula One 2008 So Far: The End of Something New?

by Benjy Sanford
What 2007 brought to the main stage of the worlds greatest motorsport is nothing short of an unexpected miracle. F1 fans all over the globe were left dillusional over what to expect once the king himself, Herr Michael Schumacher, stood down from his forever pole position in drivers him or hate him. But what the sport received in the 2007 season unquestionably left every fan wanting for more.

Formula one was graced by the presence of the young rookie Lewis Hamilton, a young boy from the Hertfordshire town of Stevanage. Like all British "sensations", Hamilton was overhyped and branded the next greatest thing; how right they were.

All of a sudden, we were plunged into a world of McLaren versus McLaren, mano on mano. No longer did the commercial side of the sport shine through as we had seen previously with teams instructing other drivers to pull over for team mates, but instead, drivers re-discovering their own thrive and lust to any cost.

Formula one became the testosterone-fuelled sport that it once was and with it capturing the eyes and imaginations of numerous new spectators around the world. Yes, the pit-babes used to get the main attention from the flashing bulbs of the media, but not any more. Pit-lane scandals, nose cone to diffuser action and disastrous weather brought the season to be one of the greatest of all time.

As for Lewis. All of the hype has proven to have much substance behind it with an impressive championship from the youngster. He has used his British charm and mannerisms to secure a fond spot in the eyes of not only British spectators but in the eyes of the world as he embarks on what is only his second series in top-flight racing.

Let not the scandals of "Spygate", the antics of a certain Mosley and the commericialism of the sport put you off this season. The drivers are racing fuelled on bio-passion and hunger to win no matter what is yelled at them down the team radio. They, along with some of the best racing tracks in the world will ensure an epic season in this majestic sport.

Lets just pray nothing will get in its way...

Understanding Formula One Diffuser

Wings work the air that passes over the car’s body. But air travelling beneath the car is also harnessed. The regulations state that the underbody of the car must be flat up to the rear wheel axle line, but, from that location to the rear extremities of the car, anything goes. This rule has allowed designers to incorporate an upward-sweeping device, called a diffuser, beneath the engine and gearbox. The diffuser’s shape causes air to be sucked into its narrow opening which then opens out into a bigger area. Air fed through a shape such as this creates a pressure change that induces a suction effect.

Understanding Formula One Wings

The most visually obvious of the car’s aerodynamic features are the front and rear wings affixed onto the car’s chassis. These wings work on a principle similar to that used on aircraft wings – except Formula One wings are upsidedown and provide downforce instead of lift. If air passes a longer distance over the lower surface of an object than an upper one, it creates a downward pressure. The wings are shaped so as to create this effect, pressing the tyres into the ground.
In increasing downforce the wings also create a lot of air resistance, slowing the car in a straight line (a Formula One car without wings would be able to reach around 300 mph rather than the 220 mph it can currently reach). If the wings could be lowered into the body of the car until they were needed, you would see a big performance gain. But moveable aerodynamic devices are banned and have been since 1969. The angle of the wings can be set to varying levels of effectiveness, and changing the balance between front and rear downforce is a key way of adjusting the handling of a car.