The Williams FW16

The Williams FW16 will forever be remembered as the car that Ayrton Senna crashed and died in during the 1994 San Marino GP at the Imola circuit near the Italian city of Bologna. An accident at the start of the race when Pedro Lamy's Lotus ploughed into the back of JJ Lehto's stalled Bennetton on the grid spread debris all across the track and brought out the safety car. 1994 was the first season in which a safety car had been used and compared to the vehicles used in modern day F1 those used at the start of this season were under powered and out of their depth trying to keep a field of F1 drivers behind them. They simply could not complete a lap fast enough to stop the tyres of the race cars behind them from becoming dangerously cold.

The aftermath of Senna's accident on lap 7 of the 1994 San Marino GP.

Whilst the exact causes of Senna's accident will never be known it has been speculated that the low temperatures of his tyres after several laps behind the safety car had caused the air pressure inside them to drop so much that this had lowered the FW16's ride height to extremely low levels. When combined with the flat undertray of that generation of Formula One cars and their titanium skid blocks this made the chances that the car might bottom out, or slide along on it's undertray rather than its wheels excessively high. When a car travel along on it's undertray in this fashion control of the vehicle becomes next to impossible and a car's steering momentarily redundant.

It has been suggested that Senna, in his desperation to keep his new rival Michael Schumacher behind him in his better handling Bennetton-Ford had been taking a potentially faster line through the flat out Tamburello kink but one that required driving over a large and destabilising bump in the track to do so. When Senna's Williams clipped this bump it caused his vehicle to spear violently off to the right and slam into the outside wall to the right of the track on lap 7 of the race, the second lap after the restart.

Ayrton Senna being hounded by Michael Schumacher after the safety car period at the beginning ended and shortly before he crashed to his death.

Senna sustained two separate head injuries in the accident, either of which would have been fatal on their own. The first was when a piece of the suspension from the front right hand wheel of his car was pitched backwards during the impact and pierced the front of his skull. The second was a severe fracture of the rear of the skull, caused by his head being flung backwards against the bodywork of his car during the crash.

Various theories of a snapped steering column, broken rear suspension and Senna himself blacking out at the wheel have all been discounted with the evidence available, leaving only a series of coincidental occurrences happening simultaneously to a driver under extreme pressure and in a badly handling car as the remaining possible causes of the accident.

The field gathered before the chicane at the end of the lap after the red flag had been shown following Senna's accident.

But how did Williams, the team who's car had been the class of the field since at least mid 1991 manage to build such a beast of a chassis that even the great Ayrton Senna was having trouble controlling it? The answer to this lies in the banning of what had been Williams F1 team's trump card, their untouchable active suspension system. Using a series of sensors and a real time adjustable hydraulic damper system the team had been able to build a car they could keep perfectly level and stable no matter what it was doing on a race track. Braking, accelerating, turning and going over bumps in the track surface in a car with passive suspension all cause an F1 chassis to pitch, yaw or jolt. This movement of the car will cause it's downforce generating surfaces to be in a sub optimal position and thus provide less grip. A car with active suspension could effectively dial out this movement and keep the car perfectly stable at all times.

When Williams first introduced the system in the FW14B the car was up to two seconds a lap faster than it's nearest rival at any given circuit, but this advantage was steadily eroded as other teams developed their own active suspension systems. At the beginning of 1993 the rules were changed reducing the permitted width of the rear wheels from 18 inches to 15 inches. When the successor to the FW14B, the FW15C was introduced this rule change, along with moving some of the active suspension components at the rear of the car to improve aerodynamic performance upset the vehicle's weight distribution and thus handling. According to Alain Prost this made the it much more difficult to drive on the limit than people realised. Williams were only able to get away with this unpredictable handling profile because the car's inherent speed was sufficient that it need not be driven on the limit very often.

A model  of the Williams FW14B displaying the detailing of the front end active suspension on the vehicle.

When this speed advantage was taken away after the banning of active suspension for the start of the 1994 F1 season it exposed how difficult a car the Williams had become to drive on the limit. This nervousness was compounded by a design flaw in the cars front suspension design that was not detected and corrected until the Imola '94 weekend itself. The team were also at the disadvantage of having to learn how to run their cars on passive, or spring based suspension again after a longer period of running active suspension full time than any other team. This naturally meant that more had changed in the general design of the Williams car over this longer period, making any previous data they had to go on about traditional suspension setups less relevant.

After Senna's fatal accident sweeping rule ranges were introduced to the permitted designs of F1 cars in order to slow them down, but also to make them more stable. The FIA had forced through the banning of active suspension too quickly for such a fundamental piece of technology and the mad scramble that ensued by teams to switch back to passive suspension had created a field of edgey, difficult to drive cars.

Partly in response to trying to maximise performance under the new regulations being progressively introduced during mid 1994 and partly to try and address the nervous handling of the FW16 a substantially updated version of the car was introduced at the German GP weekend, dubbed the FW16B. This updated design featured shorter sidepods in order to accommodate larger barge boards in front of them. These were required to try and recover some of the downforce lost after the banning of trailing endplates running behind the front wheels from the front wings following from the Spanish GP onwards.

The heavily modified FW16B been driven by Damon Hill late in the 1994 season.

The car also featured a longer wheel base to try and add some stability to it's handling. Damon Hill once again proved his worth as driver who excelled at developing a car along with a team and by the time the run in to the 1994 title showdown had begun, Williams once again had a car that was the class of the field. A final, never raced version entitled FW16C was built for use at the beginning of the team's 1994 winter test program. It was used to evaluate the new three litre engine built by Renault for the 1995 season in accordance with FIA rules reducing engine capacity down from the previous 3.5 litre limit from the beginning of '95 onwards.

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