FORGET ABOUT MONSTER TRUCKS, funny cars, and NASCAR. Sure — they’re fun — but if you’re looking for a shot of adrenaline from the sheer beauty of sophisticated, high-tech design, Formula One is where it’s at. As the world’s most technologically advanced racing category, the sport is constantly pushing the limits of design creativity and component evolution, including body and brake materials, software programs, and advanced sensor technology.
Since the late 1980s, CAD/CAM has been used to speed up the design process, with the predominant software being CATIA (used by eight of the 11 teams), originally developed by Dassault Systems for designing its Mirage fighter planes. Dimensional errors are eliminated well before the prototype stage. When the design team is happy, a 50% scale drawing is given to the team’s model-making division, which uses it to produce a wind tunnel model. The model is tested and findings are used to fine-tune later CAD/CAM iterations. The goal? To get the design right — as aerodynamically effective as possible. Once the wind tunnel model is perfect, the shape of the monocoque body can be finalized, with the team’s construction expert deciding just how many layers of carbon fiber to use.
From Monaco to Monza
The next challenge comes from the track itself as no two circuits are the same. Setting up the car for twisty Monaco is a very different job from getting it ready for flat Monza. The setup will be almost completely opposite in wing settings and the amount of compliance in the suspension. Designers must consider factors such as their experience at the track 12 months earlier, rule changes, and computer modeling back at base with circuit coordinates plugged in, where they play with the theoretic impact of setup changes. Six major variables designers must contend with include aerodynamics, brakes, gearing, ride height, suspension, and tires. Oh yeah, and the weather. The car’s handling is affected by changes in temperature, wind direction, and humidity. Final adjustments are made during several test sessions at the track during the Friday and Saturday prior to Sunday’s big race.
Back seat driver
We’re talking glamour here, not comfort. The physical demands on drivers begin as soon as they slide into their cars. The actual driving position is optimized with aerodynamics in mind, so that drivers are almost flat on their backs. They must drive with their feet on the same level as their hips, with arms squashed in by their sides. Drivers are crammed into this little position and must also deal with cockpit heat, the car bashing on the ground, and significant g forces during the 300 km race. Then there’s the pit crew. These guys have a maximum of 11 seconds to do their jobs during a pit stop, often making four-second tire changes. Drivers do a pit stop around four times during a race. The crew has been working long hours each day over the race weekend and is fatigued by race day. Year-round fitness training for both drivers and mechanics is becoming an increasingly important aspect of Formula One racing.
Sensational sensor technology
IF YOU’VE NEVER THOUGHT OF DISplacement sensors as sexy, think again. These babies are widely used in Formula One racing to control and monitor a number of critical control functions that will trim a few tenths of a second off lap time — the difference between success and failure. The use of displacement sensors and a computerized data logging system allow race engineers to perfect a car’s performance for individual circuits during pre-race practice. Data is transmitted after each lap via an onboard telemetry system and is displayed on a computer screen so that engineers can advise drivers about performance issues during various parts of the circuit. Pit mechanics can then make immediate adjustments to the suspensions, wing settings, and more.
Throttle control is achieved with a closed loop electro-hydraulic system (fly-by-wire) that requires a displacement sensor on the driver’s pedal and on the actuating mechanism mounted on the engine. This allows faster acceleration and preserves engine life by restricting over-revving during the race. The pedal sensor is usually a twin output linear potentiometer with a measurement range of 50 mm (the pedal displacement). The enginemounted sensor is either a high performance rotary potentiometer or rotary variable differential transformer (RVDT). Rotary sensors are spec’d for the throttle actuating mechanism because carburetors are rotary in design and have relatively small angles of movement (90° rotation).
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The clutch also works via a closed loop electro-hydraulic system, with the driver operating it by moving a finger paddle mounted behind the steering wheel. This arrangement improves handling through corners as drivers can keep their left foot on the brake pedal to control speed. Because steering wheel space is limited, one of the sensors that can be used is a miniature rotary potentiometer. This is fitted directly to the driver’s wheel with connections to the system made through the steering column via a multi-pin connector, which carries signals for the gear select switches, radio, and steering wheel dash LCD display. The sensor mounted on the clutch actuating mechanism is a short stroke linear variable differential transformer (LVDT). This sensor has a measurement range of 6 mm and a short body-to-stroke-length ratio.
Getting in gear
Most race cars are designed with a sequential gearbox with the gear change operated from the steering wheel by a simple pushbutton switch. This is known as a “semiautomatic gearbox” and allows for quick gear change and more control of gear selection through software. Cars can go from sixth gear at top speed straight into second gear at the push of a button. The sensor used to position the gearbox actuator is a high performance twin output rotary potentiometer, which is preferred to a RVDT because of its angular range capability of 350°.
Suspension and braking
Every race car is affected by even the slightest change in suspension. The more information a racing team has, the better their chances of winning. The signal from a linear or rotary potentiometer is fed into a data logger mounted on the car, which transmits the signal to the pit via radio or is downloaded when the car returns to the garage. Race engineers examine the data on their computers and calculate any needed adjustments to the suspension.
Brake disc wear is another area where sensors prove their worth. Disc wear is monitored by mounting a miniature linear sensor (LVDT) in the brake caliper. Brake disc width and diameter is governed by the rulebook (28 mm in Formula One) and hard braking circuits can wear a disc by as much as 50%. This is the harshest environment a sensor must deal with on a race car, as disc temperatures can reach 800°C during braking.