Williams FW15C

The original FW15 was designed in 1991 to incorporate active suspension changes developed by Frank Dernie, originally implemented on the FW14B. Because the FW14B had been adapted to active suspension after the fact rather than designed for it from the outset, it was a relatively overweight package. The FW15 was conceived as an active car from the start, enabling a tidier design closer to the minimum weight limit. The success of the FW14B in 1992 meant the FW15 was not required that year. The FW15B was a 1992 FW15 hastily converted to 1993 regulations, featuring narrower front suspension, narrower rear tyres, a raised nose, raised wing endplates, and narrower wings, used for early-season testing.

The FW15C was the first all-new car produced by Patrick Head and Adrian Newey in collaboration. Head had designed many of Williams's earlier cars; Newey had previously designed cars for March and Leyton House Racing. Newey's aerodynamic input produced a narrower nose, a sleeker airbox and engine cover, and carefully sculpted sidepods. A larger rear wing with an extra element ahead and above the main wing — similar to winglets seen in Grand Prix racing in 1983 and 1984 — was used at high-downforce circuits.

The car was ready in August 1992 but its debut was delayed to the 1993 season-opener in South Africa due to the continued reliability of the FW14B. Because of the significant size difference between Alain Prost and Damon Hill — Prost was nearly half a foot shorter — Williams built two slightly different FW15C tubs. Hill had repeatedly complained of cramp around the pedals, so his tub was designed to accommodate his size 12 feet.

The FW15C had 12% better aerodynamics (downforce-to-drag ratio) and 30 additional horsepower compared to the FW14B, with a 210-litre fuel tank against the FW14B's 230-litre unit. Newey noted that the FW14B's aerodynamics were compromised by the switch from passive to active suspension; the FW15C was an aerodynamically cleaned-up version.

The Renault RS5 67° V10 engine was in its fifth year with Williams, producing at least 760–780 bhp (570–580 kW) — at least 80–100 hp more than the Ford V8 units used by Benetton and McLaren. Renault had acquired a reputation for near-bulletproof reliability, though Williams suffered three engine failures during races in 1993; the sister car won on each occasion. The French Grand Prix was a 1–2 finish for Williams with a French driver leading, and Hill's win at the Belgian Grand Prix was Renault's 50th Formula One victory.

The FW15C used a semi-automatic transmission similar to the FW14B, with modifications to the hydraulic activation system. A push-button starting device bringing the clutch under automatic control was tested but not used in races, as drivers preferred the psychological reassurance of the clutch pedal. An auto-up function could be engaged at any point on the circuit to initiate automatic gear changes until the driver next requested a manual shift; the software recognised early driver input and immediately returned control to the manual system.

By 1993, the car featured active suspension, anti-lock brakes, traction control, telemetry, drive-by-wire controls, pneumatic engine valve springs, power steering, semi-automatic and fully-automatic transmissions, and a continuously variable transmission (CVT) — the last used only in testing. Prost described the car as "a little Airbus." CVTs were explicitly banned from Formula One in 1994, just two weeks after successful testing in 1993. The car required three laptop computers every time it was started: one each for the engine, telemetry, and suspension.

A push-to-pass system (yellow left button on the steering wheel) used the active suspension to lower the rear of the car, eliminating diffuser drag, while simultaneously setting the engine for 300 additional revs and raising the active suspension, giving extra speed for overtaking.

An entirely new driver lineup was fielded for 1993. Triple World Champion Alain Prost signed with Williams after a year's sabbatical from motorsport. Nigel Mansell, the reigning champion, left for the American CART series following a dispute with Frank Williams over No. 1 driver status and Prost's signing; Williams would not guarantee Mansell the No. 1 role over the three-time champion. Riccardo Patrese, who had raced with Williams since the last round of the 1987 season and won 4 races with the team, moved to Benetton-Ford. He had signed with Benetton believing both Prost and Mansell would be Williams drivers in 1993, and did not learn he could have stayed until after Mansell's departure was announced.

Damon Hill, son of the late two-time World Champion Graham Hill, was signed as the second driver on the recommendation of the team's engineers, citing his speed and two years' work as team test driver. Hill had made only two previous Grand Prix starts, both for Brabham in 1992. Mika Häkkinen was considered but was largely expected to sign with McLaren. Williams retained Prost and Hill for all 16 races of the season.

Ayrton Senna, who had lost his Honda engine supply after the Japanese company withdrew at the end of 1992, repeatedly sought a Williams seat and offered his services for free, but a clause in Prost's contract specifically forbade Williams from signing Senna as Prost's team-mate. After Prost announced his retirement at the Portuguese Grand Prix, it was confirmed that Senna would join Williams for 1994.

Williams established dominance from the opening race. Prost won in South Africa by nearly a lap over Senna's McLaren. The FW15C consistently qualified 1.5 to 2 seconds ahead of rivals. At the Brazilian Grand Prix, Prost out-qualified Hill by a full second; Hill then finished second to Senna after Prost retired mid-race following a collision. At Donington Park, Senna produced a dominant display while Hill finished second and Prost inherited third from the Jordan-Hart of Rubens Barrichello after the Brazilian retired with fuel pressure failure.

Prost moved into the championship lead with wins at Imola and Spain, though Senna briefly regained it with a victory at Monaco. After nine wins in the next ten races, Prost secured his fourth World Drivers' Championship at the Portuguese Grand Prix and announced his retirement. Hill won his first Grand Prix in Hungary — aided by Prost stalling on the warm-up lap and starting from the rear — then won in Belgium and Italy. Hill's win at Spa, along with Prost's third, secured Williams's sixth Constructors' Championship. In the final two races in Japan and Australia, Prost followed Senna home, dropping Hill to third in the final standings.

The primary criticism of the FW15C was inconsistent handling arising from computer systems misinterpreting sensor data, or air in the active suspension hydraulics. The car was slightly more responsive than its predecessor but more nervous at the limit, exhibiting rear-end instability under braking particularly on high-speed, low-downforce circuits such as Hockenheim. This was especially problematic for Prost, whose smoother driving style suited cars with even handling characteristics. Prost noted that an active suspension car with traction control benefited from being driven aggressively, whereas his preference was for more sensitive throttle use. In wet conditions, the car momentarily locked its rear wheels during downshifts, a fault cured at Imola by fitting a power throttle system to match engine revs during clutch engagement.

The 1993 season was the final year of title sponsorship from Canon, who had sponsored the team since 1985, and cigarette brand Camel since 1991. Camel logos were used at most rounds but replaced with either a Camel emblem or "Williams" text at the French, British, German, and European Grands Prix. Japanese video game company Sega joined as a major sponsor; related livery details included a Sonic's foot on the pedal, and Sega decals on shifting and race-winning trophies on the rear wing.

In early 1994, two FW15C chassis were modified to run without the electronic driving aids banned for that year. The FW15D ran passive suspension and no traction control. Senna and Hill tested the car in January 1994; it was considered far from optimal as it had been designed around an active suspension system. The car was used at the Rothmans Williams Renault launch at Estoril on 19 January 1994 — driven by Hill, not Senna as is often assumed — and retired once the FW16 became available. Despite its limitations, the FW15D was the faster car of the two in early-season testing.

The level of technology prompted the FIA to ban several "driver aids" with immediate effect following the British Grand Prix. The resulting "Weikershof Protocol" postponed the ban to the start of the 1994 season. CVTs were separately banned in 1994, two weeks after successful testing in 1993.

This article is based solely on the supplied corpus. No external sources were consulted; claims that could not be substantiated against the corpus were omitted under the drop-the-claim rule.