Originally designed for military pilots in the mid-1950s, HUDs expanded into commercial aviation in the 1970s, and the late 1980s saw the first production car with a fully integrated HUD. The technology then found its way into Formula One in the early 1990s with Team Lotus, which used a Frazer Nash system where a tiny projector and half-mirrored glass panel were fitted to the inside of the driver’s helmet in front of one eye. It could display information such as rpm warning lights and gear position, but the drivers did not warm to the system because of safety concerns about having hardware in front of their faces; they also seemed to find the system distracting.

The next and so far last time HUDs featured in Formula One was in the 2003 season, when the BMW Williams F1 team developed a system for Ralph Schumacher, and his third place in Hungary marked the first and only time a HUD has been used in race. Specifically designed for Schumacher’s eyesight, the 6 x 8 mm display was integrated into the chin cup of his helmet, and the system worked by storing messages and images in a dataset that could be called up from the pits and then displayed to him by projecting a ‘transparent’ image through his visor.

The display was high-resolution true colour, based on the active matrix liquid crystal display (AMLCD) technology, a type of flat panel display commonly used in mobile phones and televisions these days. The ‘active matrix’ refers to the thin-film transistors and capacitors in the display of the screen that control each individual pixel, resulting in quicker response times and a clearer picture, as opposed to a ‘passive’ matrix that has to alter a full row of pixels to modify a single pixel, and is therefore slower. The active matrix ensures that the system is brighter, more colourful and capable of dealing with faster moving images, and a unique lens element called a free form prism is used to make the picture sharp.

The display was located in the peripheral vision field of Schumacher’s dominant eye, making it easier for him to see, without having to look at the display directly. This offers an advantage over the current display on the steering wheel because when a driver looks at the steering wheel, the horizon becomes unfocused, whereas when the driver focuses on the track ahead, the display remains in focus. Furthermore, unlike the screen on the steering wheel, which rotates with every steering input, the HUD only moves with the driver’s helmet. It also enables the driver to choose when he wants to receive the information, for example when it is safe or on a straight, unlike with radio communications from the pits.

Regarding recent events at the Japanese GP in Suzuka and the reduced radio rules, HUDs may offer an alternative to the steering wheel display. From a safety point of view, critical information such as track status and yellow zones can could be displayed constantly in the driver’s peripheral vision, which arguably is less distracting. Also, as the HUD display can be slightly larger than the display on the steering wheel, the size of the steering wheel can be reduced, which in essence is what delayed the radio rule change until 2015.

Schumacher’s feedback in 2003 was positive, although the system was banned by the FIA because of the safety implications of having the display mounted inside the helmet. One chief technical officer said that, although they are effective, HUDs will only work in Formula One if the focus point is at infinity, to avoid the driver having to refocus, and if the safety of the system is developed further.

Figs. 1 and 2 - The system developed by BMW Williams in 2003 specifically for Ralph Schumacher’s eyesight. A variety of information was displayed to him, and this may be a way of communicating yellow flagged zones and the car’s status without using radio. However, the safety aspect of having the display so close to a driver’s face remains an issue

Written by Gemma Hatton

Fundamentally unchanged in its design for decades, the brake pedal is at in essence a simple part, being a pivoting lever with a plate for the driver’s foot and a bearing housing midway up the lever for the bias adjustment mechanism. However, the detail design and construction have evolved massively into optimised, stiff and light brake pedals.

Since the advent of clutch paddles on the steering wheel, all Formula One cars feature just two pedals, and the driver operates the brake exclusively with his left foot. To this end, modern Formula One pedals feature large footplates with flanged sides, as the driver does not need to slip his foot to operate a clutch or ‘heel and toe’. Each driver has a preference for the design of the footplate, which often has a grippy abrasive material applied to its surface.

Driver preference goes even further with the detail design of the pedal and its interaction with the hydraulic elements of the braking system: teams will optimise the dynamics of both the mechanical and hydraulic elements of the brake bias adjustment mechanism. Ideally the driver wants a bias that shifts during braking, which isn’t possible using active control systems, but by designing the bias bar and valves in the system it is possible to get this behaviour. Everything from the fluid properties, orifice sizes, pipe compliances, bias bar mass, inertia and friction characteristics has an effect. Teams will model these variables in modelling software to design the ideal braking set-up for a specific driver.

One team found an issue when one driver applied the brakes at ten times the velocity of the other driver.

Being only some 240 mm tall, with the bias bar just under half that distance from the pivot, a driver pressing 130 kg with his leg under braking puts great stresses on the pedal; the catastrophic effects of a pedal failure do not bear thinking about. Thus the construction of the pedal has evolved over the decades, from fabricated steel pedals, through the use of titanium, machined aluminium and latterly carbon fibre. With such optimised design the weight of the pedal is now 200-300 g.

These days, Formula One teams are still split between carbon pedals and machined aluminium. One contemporary aluminium pedal seen by the author eschews the simply bar design for an almost semicircular arrangement, where the master cylinders attach to this triangulated shape for even greater stiffness.

It’s also now common for the bias adjuster to be mounted to the bulkhead, and the master cylinders directly to the peal. This frees up space in the footwell for the adjuster cable to reach to the bias mechanism.

Fig. 1 - Moulded carbon fibre and fabricated steel Formula One brake pedals 

Written by Craig Scarborough

When the energy recovery system (ERS) is in harvesting mode, there’s a drag applied through the drivetrain to the rear wheels. This naturally alters the braking bias front to rear. With KERS, until last year the relatively small amount of energy recovered meant that variations around the lap or due to KERS failure were compensated for by the driver via the cockpit brake bias adjuster.

With 2014 allowing up to four times more energy to be harvested in a single lap, however, the impact on brake bias is far more pronounced. It’s unlikely that teams could set up the energy recovery system with a consistent braking effect for the entire lap and/or engineer a brake bias set-up to cope with the frequency and range of adjustments to react to the new energy recovery systems.

So the FIA has allowed the cars’ electrohydraulic control systems to manage the offset between the drivers’ braking demand and the reverse torque provided by their ERS. Controlled by the FIA’s SECU, this system will only take into account the demand at the pedal and the ERS into account. That way, any risk of teams engineering the system to create anti-lock braking or active front-to-rear bias control is prevented.

To achieve the brake-by-wire effect, the pedal and master cylinder set-up remains the same; a dedicated rear braking circuit is still used. However, before the brake lines split to each rear caliper, there is a pressure sensor and a servo valve linked to the SECU. Also linked to the servo valve is a high-pressure feed for the cars’ hydraulic pump, and this feed will power the rear brakes under normal braking. Unless a system failure occurs, the master cylinder pressure is not directed to the brakes.

Under normal braking, the SECU reads the rear brake line pressure as provided by the driver, the pedal master cylinder set-up and the torque being applied by the ERS. An algorithm works out the net pressure required from the-high pressure pump to deliver the driver’s braking demand minus the ERS effect. The servo valve then proportionately opens to deliver this pressure to the rear brake calipers.

With this set-up the brake bias set at the pedal is maintained, and the driver will alter the cockpit adjuster as usual to alter the bias. Although the appearance of brake balance buttons on the steering wheel, means controlling the brake bias offset can now be altered electronically from the steering wheel dials.

In the event of a system failure the servo valve will revert to a safe mode where the rear brake line pressure from the pedal/master cylinder is routed to the rear calipers. In this mode, the driver will therefore have rear brakes, but this will not account for the ERS braking effect. That means there is a risk of a locked rear brake, but that is better than having no rear brakes!

Fig. 1 - In the event of a system failure, the spool in the servo valve will fail safe to manual braking (Courtesy of Moog)

Written by Craig Scarborough

No longer is the pedal simply a means of directly moving the throttles on the engine, as the rules now state that the driver demands torque from the pedal, with the ECU decoupling the traditional relationship between the pedal and throttle with a map. Such maps are now restricted to tyre type, so just three maps are allowed for wet weather, intermediate and dry tyres. Previously, different maps could be selected for the race start and other race situations. The regulations also enforce other restrictions on the pedal, for example no detents or other means can be used to aid the driver in holding a specific position, such as holding revs steady at the race start.

In terms of the foot pedal itself, the part has evolved tremendously over the years, from being a simple metal rod and footplate to operate a Bowden cable to a bespoke carbon fibre moulding operating as a fly-by-wire control. Accelerator pedals are not as mechanically loaded as brake pedals, so their design is far simpler, and this is further aided by fly-by-wire needing sensors rather than a cable. Due to the lighter load on the pedal it is commonly made from carbon fibre, although fabricated titanium or machined aluminium have also been used. 

The pedal is often mounted to a bracket common with the brake pedal and heel rest, which bolts into the monocoque floor, there being different mounting points for different sized drivers. Pivoting at its base on a bearing, the pedal is a simple lever, the driver’s foot modulating the pedal via a footplate. As a driver tends to left-foot brake and no longer slips their foot between accelerator and brake, the footplate can be bounded by side plates to prevent the foot flipping off the pedal. Some teams have these as simple bonded-on sections of carbon fibre; others mould the plate itself into a dished shape in which the foot sits. Abrasive tape is bonded to the footplate to allow the driver’s foot to grip rather than slide over the pedal. Equally key is the spring used to resist the driver’s foot, and these will be tailored to suit the driver’s preference for stiffness and travel. Even with an exotic carbon fibre pedal, a simple bolt and lock nut is still used as a stop to pedal travel.

Detecting the pedal travel has equally evolved since fly-by-wire was introduced. Initially, linear or rotary since sensors between the chassis and pedal were used and, owing to the critical nature of the sensor, these were doubled or even tripled up for redundancy. In recent years, for simpler packaging the linear sensors have been replaced with non-contact sensors, such as Hall effect or induction types, the sensors being built into the pivoting plate and the target magnet being embedded into the base of the pedal. As the teams cautiously start to take up these new sensors, the pedal may use two or more different sensor types for redundancy.

Accelerator pedal-related retirements are rare, but in qualifying for the 2012 US Grand Prix, Jenson Button suffered a complete loss of drive due to a pedal failure. It seems the electronics were the problem, and he was unable to complete the session. This serves to highlight how critical such an apparently simple part can be.

Fig. 1 - Carbon fibre throttle pedals are now common, but can use different sensor technology

Written by Craig Scarborough

Preparation for the race start begins with the warm-up lap, with the driver being instructed to complete a number of burn-outs, and this brings the tyre and clutch up to operating temperature. Having the clutch at the right temperature is critical in order to have a consistent start, both for the friction qualities of the carbon clutch plates and the thermal expansion of the clutch plates moving the bite point. The team can monitor the clutch temperature from the telemetry system, via a simple infrared sensor pointed at the clutch. 

The bite point is the other significant factor. Towards the end of the warm-up lap the driver will conduct a Bite Point Find (BPF), a process initiated from a button on the steering wheel, where the clutch is released and the electronics detect the drop in revs and the clutch position is recorded in the software. Clutch position is sensed by either LVDT or non-contact sensors. With this data the team may instruct the driver to alter clutch settings from the steering wheel to tailor the clutch paddles to the bite point position. On this lap the car’s electronic mappings are set to ‘Race Start’ mode, which is simply an amalgam of other settings controlled via one switch. So engine mixture, rpm limit, gearshift and pedal maps are all set to their optimum for the best start.

As the car arrives on its grid slot the car will be left in neutral until the final countdown to the start. The driver will then draw in both clutch paddles and select first gear, while also holding the revs at around 13,000 rpm. In the final moments before the start, both clutch paddles are partially released to a preset position, such as in line with the gearshift paddles, which moves the clutch to the bite point. 

To initiate the start the driver will release one clutch paddle, which releases the clutch part way between the bite point and fully released, and they can now modulate the throttle to manage wheelspin or avoid stalling. Bogging down off the start or stalling is prevented by an anti-stall system, an electronic process that detects the drop in revs and automatically pulls in the clutch and raises revs. Once the car is moving and wheelspin has subsided, the second clutch paddle is released and the clutch is fully engaged, with full engine power passing into the transmission. 

Despite its low-rpm torque from the electric motor, the additional 80 hp KERS power cannot be used at the start. Only once the car reaches 100 kph is KERS allowed to be deployed, and it will be fully charged either from recharging in the pit or from harvesting power around the parade laps. The driver may use this tactically into the first turn or for other strategic points around the track to either defend or attack for position.

 Also, around the lap the driver needs to reset the Race Start mode switch on the steering wheel to return to the individual controls on the steering wheel for powertrain set-up. 

Fig. 1 - For its all its complexity, the start process relies on a pair of fingers on the clutch paddles (Photo: Craig Scarborough)

Written by Craig Scarborough

The ‘wheel’ itself tends to be carbon fibre, with the grips being either suede or the more common silicone mouldings. Attached to the steering column via a quick-release mechanism, it also serves as the connector to the car’s CANbus. From here the steering wheel’s design diverges from the norm to incorporate the paddles and buttons to control the various electronic and hydraulic systems on the car. Inside the wheel is a standard Interface unit, a circuit board that takes the inputs from the wheel’s controls and passes them back to the car’s CANbus. The board accepts 18 switch inputs and 11 variable inputs (0-5 V), which is a lot, but does limit the potential for even more controls on the steering wheel for the more technically minded driver.

Gearshift is controlled via paddles behind the wheel, usually a pair left and right, mounted to common yoke, such that pulling one paddle has the same effect as pushing the other. This movement is picked up by sensors at the paddles’ hinge point. Either Hall Effect or microswitches are used, doubled or even tripled up for redundancy. The paddle is sprung, and features bump stops to give the driver the positive feeling of the paddle requesting a gear.

Below these, two more paddles are used for clutch control, using rotary pots to detect the clutch paddle movement so that the clutch actuator can accurately reflect the movement.

Teams may use other paddles to serve multiple functions based on driver and team preference, such as operating the KERS or DRS (drag reduction system). For example, Mercedes AMG F1 had an overtake control called the ‘magic paddle’, which provided maximum engine power (mix and rpm) and DRS activation settings on just one control.

On the front of the steering wheel there’s a standard display panel and a plethora of buttons and rotaries. The display panel is another standard homologated part, and provides the usual range of shift lights, gear position indicator and alphanumeric displays. But it also has two sets of three LEDs linked to the circuit’s marshalling system, to display an LED coloured to match the flags around that sector of the lap (blue/yellow/red).

The buttons are grouped into two main types – pushbuttons that can be toggle or latches via the software, and the multi-position rotary controls. A few teams used toggle switches for the RS (Race Start) mode, which requires the driver to flick them back into normal mode after the race’s start.

Every team and most drivers have their preference for what the buttons and rotaries do on their steering wheel; this is a list of the more common controls.

Rotaries

Diff Entry – Alters the gearbox differential setting on entry to turns; this will alter the car’s handling

Diff Mid – Alters the gearbox differential setting at the midpoint of a turn; this will alter the car’s handling and traction

Diff Exit – Alters the gearbox differential setting at the exit point of a turn; this will alter the car’s handling and traction

KERS Mode – Alters the way KERS energy boost is delivered

KERS Recover – Alters the way KERS energy is harvested under braking

Revs – Alters the rev limit up to 18,000 rpm

Mix – Alters the engine power setting; more power uses more fuel

Multifunction – This controls less frequently used functions that don’t warrant a dedicated control. The driver will use this in coordination with the ‘+1’, ‘-1’ and ‘OK’ buttons listed below

Tyre – This tells the ECU what tyres are fitted: dry, intermediate or wets. It can also be used to inform the team of the state of tyre degradation

Pedal – Alters the relationship between pedal movement and the engine’s throttles. 

Buttons

Acknowledge – Confirms that a verbal instruction was understood

Oil – Release additional oil into the engine

+1, -1 and OK – Used with the ‘Multifunction’ rotary to alter settings

Drink – Operates the driver drink system pump

DRS – Opens the rear-wing drag reduction system

Overtake - Sets engine mix and revs to maximum for overtaking

KERS – Discharges KERS boost

BPF – Bite point find for the clutch

Pitlane – Engages the pit lane speed limiter

Radio – Push to talk on the car-to-pits radio

Neutral – Selects neutral gear

Reverse – Selects reverse gear

A typical Formula One steering wheel has one dash display, six paddles, nine rotary controls and more than 12 buttons

Written by Craig Scarborough

Safety in the cockpit, aside from the fundamental function of the monocoque as a survival cell, is largely about driver restraints and fire protection. Each driver is held in place by a six-point harness system, the wide 3 in belts wrapping around sturdy mountings bolted into the monocoque. The central buckle that twists to undo the belts is completely detached when undone, and teams will often stick this to the cockpit side with Velcro when the driver is out of the cockpit to prevent losing it. Now that a head and neck support (HANS) device is mandatory, the shoulder belts feature a secondary strap that goes over the collar, thus the main shoulder straps are against the driver’s shoulders and not the HANS device itself.

The driver’s seat itself is no longer a simple A-B foam mould taken at the seat fitting. Instead, a similar seat fitting process is completed, but the foam ‘seat’ is then 3D-scanned so that a seat mould can designed in CAD, complete with mountings and accommodation for the straps to allow the seat to be lifted out complete with driver in the event of a crash. Finally the seat is moulded in carbon fibre with some limited padding and/or covering added for a tiny degree of driver comfort. Although minimum cockpit dimensions are now specified in the rules, the cockpit is surprisingly wide around the driver’s waist, although the resulting seat will often feature an open bottom and other cut-outs for clearance around the insides of the tub, to the detriment of driver comfort.

While rarely used, a critical system is the onboard extinguisher; a small carbon fibre fire bottle is custom made to fit into the recess in the monocoque under the driver’s thighs. The extinguisher will have one outlet under the dash and another in the engine bay, and it must discharge 95% of its contents in no less than 10 s and no more than 30 s.

Nowadays there is no requirement for the car to carry a medical oxygen supply on board. The sight of the drivers needing a breathing tube hooked into their helmet in case of fire disappeared in the 1980s.

A near-permanent fixture now though is the drinking tube passing into the helmet. Every car has a small drinks systems installed, usually consisting of a small flexible bladder containing a litre or so of liquid that is pumped into the driver’s tube via a windscreen washer-like pump controlled from the steering wheel.

Cooling inlets also pass into the cockpit. As the driver’s feet are just behind a hot hydraulic steering rack, and his seat is surrounded by electronic boxes, the cockpit generates enough heat on its own to stress the driver, even without high ambient temperatures. The rules permit a driver cooling opening in the tip of the nose cone, and in extreme temperatures teams will fit other openings in the hatches on top of the monocoque. There are vents in the helmet to get this cooling air to the driver’s skin without sacrificing fire protection, and modern Nomex race suits are surprisingly thin, allowing some airflow despite their fire protection.

Fig. 1 - Seat belts, a moulded seat and fire extinguisher all tightly packed into the cockpit area (Photo: Craig Scarborough)

Written by Craig Scarborough

Drivers have been able to adapt the braking bias from front to rear throughout the race, to compensate for changing conditions. This allows the driver to ensure the rear brakes do not lock up prematurely, to give better stability into corners, and this can make the driver’s lap times more consistent.

Although it has appeared occasionally in Formula One car cockpits over the past ten years, it was Michael Schumacher who really put the rapid bias adjustment system on the map. Since his return to Formula One the field has been tighter, with qualifying ever more important, and the introduction of KERS has greatly affected braking performance.

These factors all affect the distribution of braking effort between the front and rear axles. With ABS or any form of active braking control banned since 1994, the bias set-up at the pedal remains the same through the lap and largely through the race, with only minor adjustments being by the driver from the cockpit.

The distribution of braking effort between the front and rear braking circuits is largely dictated by the relationship between brake pedal and the master cylinders, the force from the pedal being apportioned to each master cylinder by a bias bar passing through the pedal. The bias bar can be moved by means of a threaded adjuster to alter the force applied to either of the master cylinders and thus the front or rear braking circuit. A simple cable operated by the driver on the dash bulkhead finely adjusts the bias bar.

This does not, however, provide rapid or larger adjustments to suit individual corners, changing conditions such as tyre degradation or the loss of the KERS assistance to the rear braking effort.

Although not unique in his use of a rapid bias adjuster, Schumacher found he could gain lap time with a different bias level for different corners, such as braking on gradients and different braking levels for corners of different speeds. So a relatively simple lever arrangement inside the cockpit was devised, which operated the same balance bar as the fine bias adjustment.

With several different bias positions identifiable by detents in the lever mechanism, the German found he could set up the brake bias for specific corners. Often in qualifying and sometimes in the race, he could be seen taking his left hand from the steering wheel and moving the lever before arriving at a corner. But while he clearly found some benefit in the system, which could be adopted by other drivers, it does not fully explain its recent widespread adoption.

The introduction of KERS is one explanation; since 2009 it has affected braking bias braking by harvested energy at the rear axle. KERS is still not completely consistent throughout the race though, either because of different harvesting levels or parts of the KERS being unreliable. Each of these issues will alter the braking effort that KERS adds to the rear axle; for the driver to maintain a constant brake bias through the race, they will need to make more than fine adjustments to the bias bar. Thus the simple control used previously would need several turns of the adjuster to make the required bias shift. The lever arrangement allows the driver to make larger and quicker adjustments, so that if KERS is not harvesting at its full rate then a lever adjustment will quickly compensate. That will still leave the driver with scope for fine tuning using the conventional adjuster.

Most teams now integrate the fine adjuster into the lever arrangement, the assembly typically being sited on the left-hand side of the cockpit, allowing the driver to take his hand from the wheel momentarily to make an adjustment. Both the fine and rapid adjustments are translated into movement at the pedal’s bias bar with a shaft passing from the mechanism down to the pedal.

Although it’s down to driver preference, the lever will feature from three to five detents, tuned to either a KERS compensation – which will shift the bias rearwards to match the lost braking effort from a failed KERS – or with different bias presets to suit specific corners. Thus the mechanism will need to be tuned for different tracks to make the requisite bias adjustment for a specific lever position. As with any driver control its use is largely dictated by the driver’s preference, and can be used in different ways with many different uses.

Next time you see onboard footage of a driver, spare some time to consider the fact that Formula One has found lap time even in the humble brake bias adjuster.

Fig. 1 - In this Red Bull RB6 the brake bias bar can be seen behind the brake pedal (Photo: Craig Scarborough)

Fig. 2 - Williams places its rapid bias adjuster to the left of the cockpit with both a lever and dial for rapid and fine adjustments (Photo: Ionut Pascal)

Written by Craig Scarborough