Brake beater - putting the stoppers on Montreal 08 Jun 2011
It may sound counterintuitive, but being quick in Formula One racing isn't just about going fast - stopping well is also a major part of the equation. Montreal's Circuit Gilles-Villeneuve, host of this weekends Canadian race, features seven braking events in all, six of which are considered 'heavy' and four of which involve braking from over 295 km/h. It amounts to one of the toughest tracks of the year on brakes. Getting the system right for Montreal involves fitting revised brake ducts to optimise cooling, and using different pad and disc materials to ensure consistent performance for each one of the event's 70 laps. It's no small challenge, as Mercedes explain
Q: How severe a test is Montreal for the brakes?
A: The energy input to the brakes is roughly double that measured at Spa. At both circuits, the drivers spend around 15 seconds of the total lap time braking. In Montreal this accounts for 20 percent of the lap spent on the brakes, while in Spa it only represents 14 percent.
Q: Where is the heaviest braking event on the circuit?
A: The biggest single braking event comes at Turn 10, where the cars must slow from 295 km/h to just 60 km/h for the corner apex. The cars shed 235 km/h in a distance of just 140 metres. When deceleration is at its greatest, the drivers are subjected to peak forces of some 5.5G.
Q: How hard are the drivers working in the cockpit under braking?
A: The force the drivers exert on the pedal is approximately 2000 Newtons - that's equivalent to lifting 200 kilogrammes. The theoretical stopping distance of a Formula One car from 300 km/h to zero is approximately 135 metres in a straight line, but varies according to drag levels and tyre grip.
Q: What temperatures do the brakes reach?
A: Peak temperatures during a braking event don't occur when maximum force is applied, but later during the braking phase owing to heat transfer rates. The discs can reach up to 1000 degrees Celsius while caliper temperatures stabilise at around 200 degrees Celsius.
Q: What parts of the braking system are altered for a heavy braking circuit like Montreal?
A: The thickness and diameter of the brake discs is limited by the regulations to 28 mm and 278 mm respectively. The brake material - the type of carbon disc and pad - is changed between high and low severity circuits to provide the necessary durability. Large brake ducts are used in order to achieve adequate cooling; these large ducts cost around 0.2s (per lap) compared to the smallest versions run during the year.
Q: What is a typical brake balance at Montreal?
A: A typical figure is a front to rear brake force distribution of approximately 55 percent front/45 percent rear. However, this changes with KERS, which provides significant torque to the rear axle under braking. This means the drivers must run the brake balance even further forward to prevent the rear tyres from locking.
Q: How will the DRS zones, and the resultant higher straight-line speeds, affect the braking demands?
A: Braking energy inputs will be slightly increased when the DRS is activated. However, this will be highly dependent on how often it is activated during the race, and with what fuel load. Its impact will be greater on higher fuel loads.
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