Ford P68 is First Produced
The Ford P68, also commonly known as the Ford 3L GT or F3L, is a sports prototype racing car model introduced in March 1968.
It was designed by Len Bailey, a Ford research engineer, funded by Ford Europe and built by Alan Mann Racing at Weybridge, Surrey, UK. The first competition appearance of a Ford 3L prototype was at the BOAC 500 race at Brands Hatch in Kent. Despite apparent pace, the car was criticized for instability at high speeds and, due to mechanical and electrical failures, did not finish any of the races for which it was entered.
For the 1969 season the P68 was used as the basis for an aborted, fully-open Spyder, dubbed the Ford P69. The P69 sported large, free-standing aerofoil wings. However, these were banned on safety grounds early in the season, and without them the P69 was unraceable.
At the end of the 1967 season the FIA redrew the rules for sports car racing. Engine capacity was limited to 3 litres for the lightest, most advanced Group 6 sports prototype class, while a new 5 litre Group 4 Sports Car class was introduced for vehicles of which at least 50 examples had been built. Ford's American headquarters organisation withdrew from sports car racing at the end of 1967, leaving those teams committed to running the aging GT40 without factory support. While some teams, such as JWA, decided to go down the Group 4 Sports Car route and began work on updating the GT40, Alan Mann Racing decided to build a brand new prototype car around Ford Europe's recently-introduced 3.0L DFV V8 Formula One engine.
Raising sponsorship from Ford Europe, as well as Burmah-Castrol and Goodyear, AMR procured the services of leading Ford aerodynamicist Len Bailey, who had designed much of the GT40's bodywork, to work on their new car.
he car was built to Group 6 regulations, with an open two-seat bodywork design. This was perhaps rather liberally interpreted, with only a small hatch in the otherwise enveloping roof being left open to the elements. The hatch also allowed the driver to see the centrally mounted rear-view mirror.
One major advantage of the open prototype regulations was that they permitted a much lower roofline than otherwise would have been possible. Bailey used this to create an extremely low, long, curvaceous, aerodynamically efficient design. With a Cd of only 0.27 and a frontal area of 14ft² the 3.0L engine was sufficient to push the P68 to over 350km/h, faster than contemporary Formula One cars. However, former driver Frank Gardner has criticised Bailey's pursuit of aerodynamic efficiency at the expense of driver comfort. In order to keep the P68 on the road, Bailey incorporated a patented, vortex-generating tail scoop, intended to create downforce without adding to drag. However, although the car has since been shown to produce moderate downforce at speed, this is mostly over the front wheels. The resultant high-speed instability led to both John Surtees and Jack Brabham refusing to drive the car. Over the following months the P68 sprouted ever larger rear spoilers, and small chin spoilers, in an effort to stabilise the car.
Underneath the curvaceous bodywork, the chassis was a riveted, aluminium monocoque, with steel bulkheads onto which the suspension components were mounted. The DFV engine was supported in an aluminium cradle behind the driver. Unlike the Lotus 49 for which the DFV had been designed, the engine was not used as a structural chassis member. In contrast, the suspension layout was almost a direct copy of contemporary F1 practice. Contemporary observers commented on the oversized front hub components, potentially allowing the car to be converted to four-wheel drive at some point. The radiator was mounted in the nose, although cooling problems resulted in a wider opening being incorporated from mid-season. Fuel was stored in two deformable cells, one in each sill.
Following poor results, during the winter of 1968 Len Bailey adapted the P68's monocoque to fully exploit the open-roof regulations. A fully open spyder prototype was produced with almost completely new bodywork panels; even lower and wider, it also included a dramatic reduction in length. Mechanicals were carried over from the P68 in almost unchanged form. This new car was numbered the P69, although differences with the P68 were only skin deep. In an attempt to cure the same stability problems that afflicted the P68, the P69 had an innovative system of interconnected, hydraulically-controlled, partially automatic, adjustable aerofoil wings. However, following several accidents with similar systems during Formula One races, the wings were swiftly banned by the FIA early in the season. Without wings, AMR judged that the car would require a complete redesign to be competitive with the dominant Porsches and therefore, lacking funds, the P68/P69 project was abandoned.