Forgotten F1 Friday: Williams FW15C CVT

29 November 2019 - 16:54 By Motoring Reporter
Alain Prost test driving the Williams FW15C
Alain Prost test driving the Williams FW15C
Image: Steve Etherington/EMPICS via Getty Images

OK, so the Williams FW15C isn't exactly forgotten. Campaigned during the 1993 season it was the car in which French driver Alain Prost won his fourth and final Formula 1 world championship. Packed with a plethora of driver aids (active suspension, ABS brakes, traction control, telemetry, fly-by-wire controls, pneumatic valve springs, power steering and a semi-automatic transmission) it also remains the most advanced F1 car ever built.

So what gives? Well take a rummage through the sport's history books and you'll discover that Williams built a special test-mule version of the FW15C that was fitted with a continuously variable transmission (CVT). Sounds strange, I know, but apparently this modification let the 3.5-litre Renault V10 operate at its peak efficiency more of the time.

With no actual gears to shift through the FW15C was, according to test driver David Coulthard, also smoother and more stable through corners. In fact there was speculation in and around the paddock that this Williams was a good few seconds quicker around a racetrack than its sibling fitted with the conventional six-speed semi-automatic gearbox.

Once the FIA caught wind of this they immediately drafted a new rule for the 1994 season stipulating that all Formula 1 cars must have between four and seven fixed gears. They also added a cheeky subclause banning all together the use of CVT technology. And so that was that: this unique FW15C never saw a race and was instead stowed inside the Williams museum where it remains to this day — mostly forgotten.