The oil price rise trigged by the 1973 Arab-Israeli War and resulting spiralling of petrol prices had a profound influence on the world’s car makers. Demand for small, economical models soared and the science of aerodynamics, hitherto the preserve of sports and racing-car constructors, began to be applied by the Big Batallions to their passenger models.
One such company was Ford which, in the mid-1970s, began the manufacture of a series of concept cars that were produced under the Probe name. The first of these , was shown at the 1979 Frankfurt Motor Show. It was a sporting two-door, three-seater coupe with roughly the same dimensions as those of the contemporary Mustang.
Hardly a Drag
Significantly, its drag coefficient was an impressive 0.25 at a time when the average American saloon was producing a figure of 0.50! This in turn paved the way for Probe II, a four-door, family sized saloon which incorporated many of the disciplines learnt on Probe I.
In the meantime the company had been developing a new model for the European market to replace the best-selling, but ultra-conventional Cortina. It appeared in 1982 as the Sierra and was significant for incorporating new aerodynamic disciplines learnt on Probes I and II. To prepare the public for what was a radically visual departure from previous principles, with some trepidation Ford unveiled Probe III at the 1981 Frankfurt Motor Show.
Unlike its predecessors developed in America, this was a Ford of Europe project. It attained a remarkably low Cd of 0.22, which was about twice as good as Cortina’s figure. This wind-tunnel-refined shape incorporated aerodynamic features that are today commonplace, all of which were created so as not to obstruct air flow. The usual separate front bumper was replaced by a moulding that was an extension of the front body panel. Headlamps were flush-fitting and the window glasses were positioned as close to the bodywork as possible. Probe III’s rear profile featured a semi-fastback style related to the ‘bustle’ that had featured on Ford’s front-wheel-drive Escort of 1980.
Similarly, the customary wide gaps between the wheels and arches were reduced on the Probe to prevent excessive turbulence.
The Sierra made its debut about a year later, in October 1982, and although outwardly less radical than Probe III, it gave Ford an anxious time as the public took some time to become accustomed to its radical shape. For the record, in America, Ford responded in 1982 to Probe III with the even more futuristic IV, while the radical of 1985 had a drag coefficient less than of a fighter aircraft!
Wood, Jonathan (1997) Concept Cars, Paragon, ISBN 0-75252-084-9.