The introduction to Bonhams auction description for this car captures the essence of this story well: Collectibility covers an enormous range of artefacts. Most are inanimate, contemplative objects of intellectual appreciation. Many drip with cultural significance. Some celebrate the rise of human ingenuity.
Perhaps that inspiringly creative aspect is best demonstrated by mechanical artefacts. Breakthrough technologies highlight man's progress. Historic landmarks earn special regard. And then we can add the animate technologies – landmark artefacts which a mere button-touch can bring to vibrant life...
These can be artefacts into which the collector owner can slip, like easing-on a familiar pair of hand-made shoes. Artefacts which will respond, vibrate and resonate to the owner's command. Flick a switch here, a button there and – say – a toweringly historic landmark-technology Grand Prix car will do for you what it once did in carrying a World-class competitive athlete to his ultimate goal – a record-shattering Formula 1 World Championship title.
The collectible artefact on offer will start up, and run. It will literally come to life ...

This 1992 Williams-Renault FW15B collectible dominated the 1992 season. Nigel Mansell won nine times, beating Ayrton Senna's record of eight Grand Prix victories in a season, against a field that boasted Ayrton Senna and Michael Schumacher. Mansell took five of those wins, plus a second place (at the Monaco Grand Prix, pictured above), in this car before it passed into the hands of his Williams teammate Ricardo Patrese. In total, it contested 13 Grands Prix, winning five and finishing second twice, taking pole seven times.
A revision of this car, the FW15C, gave Alain Prost the Formula One drivers title in 1993 and the 1992-93 titles were the first of designer Adrian Newey's 10 Formula One Constructors' Championship wins (across three marques and six drivers).

Hence, in addition to being Nigel Mansell's sole championship-winning car, it was the first World championship-winning car designed by the winningest designer in F1 history, and Newey's record is unlikely to be beaten. Newey had previously designed the March 86C Indy car that won the Indianapolis 500 in 1986, but this car was his first F1 Championship winner.

The Williams FW15B to be auctioned runs a 3.5-liter V10-cylinder Renault RS3 racing engine with pneumatic valve springs, quoted as producing 700 hp at 12,500rpm at the beginning of the season, and developed to 760 hp at 14,500rpm later in the year.

The RS3 drives through a transverse-shaft Williams 6-speed semi-automatic gearbox, and this particular engine (serial number 240), and the accompanying Renault Sport engine-history document (itself vanishingly rare "out of captivity") confirms it is the actual engine used by Mansell in winning the 1992 South African Grand Prix (pictured above).
The Williams FW15B also had ride-leveling active suspension, and was the first car with active suspension to win a championship, though not the first F1 car to use active suspension. Lotus had pioneered the technology in 1983 with its Type 92, but Williams' computer-controlled 'active suspension' system was the first to use its myriad benefits to win a championship. In addition to improving traction by actively forcing the wheels back onto the road, it provided maximum aerodynamic advantage by consistently presenting the car to the airstream.
The FW15B is hence not just another world championship winning car, but a technological tour-de-force.
Bonhams has not disclosed the estimated price, but given that it sold Ayrton Senna's 1993 Monaco Grand Prix-winning McLaren-Cosworth Ford MP4/8A for €4,197,500 ($5,015,609) last year, somewhere north of $5 million can be expected.
The 2019 Goodwood Festival of Speed will be the fitting venue of the car's auction.
Source: Bonhams