A few weeks ago, Autosport ran a nice piece on 'F1 cars that never raced', which included the Williams six-wheeler. Whilst the Tyrrell P34 of 1976 famously pioneered the idea of six wheels on a Formula 1 car, the Tyrrell employed four small wheels at the front, and, given that the rear wheels on a 1970s Formula 1 car were much bigger than the fronts, this failed to reduce the frontal area of the car. In contrast, the Williams six-wheelers of 1981 and 1982 had four driven wheels at the rear. This reduced frontal area, and, by virtue of splitting the torque amongst the contact patches of four tyres, rather than two, improved traction into the bargain.
The Williams FWo7s of 1979-1981 were, to my mind, the most beautiful of Formula 1 cars. They were simple, effective, and elegant. Scalextric duly brought out a model of the Fw07, one instance of which enjoyed many happy hours hurtling around my own 'figure-of-eight' track, clattering along the plastic armco, the aroma of over-heating electric motors diffusing through the air of the dining room.
By good fortune, I stumbled across this article on the internet today, in which an enthusiast describes how he converted a conventional Scalextric FW07 into a six-wheeled version. The casual ingenuity of this type of thing is fantastic: