Formula One Trend of Design
Steering Gear
The Formula One designers are unanimous on one design feature, and that is the use of an enclosed rack-and-pinion steering gear. Apart from being mechanically efficient this mechanism fits neatly into the front end layout of a single-seater racing car. In the position and mounting of the steering rack there is some difference of opinion; while one designer mounts it behind the centre-line between the front wheels, another mounts it ahead of the centre-line, and while this divergence of opinion is sometimes due to individual ideas on geometry, more often than not it is a question of space requirements. Most of those who mount it behind the centre-line, like Lotus, Tyrrell, Williams and Arrows, have the rack running across the monocoque above the driver’s knees, and the short track-rods at each end of the rack lie directly behind and in line I would have thought the upper suspension members. Ligier and McLaren have their rack mounted a bit lower, with the track-rids in the air steam between the upper and lower suspension members. Ferrari strikes an individual note in having the rack mounted on the floor of the cockpit, under the driver’s knees, but behind the suspension centre-line. The track-rods lie between the suspension members, and near to the lower ones.
Brabham and Renault are agreed that the steering rack should be mounted ahead of the suspension assembly centre-line, and both designs have the track-rods in front and level with the upper suspension members. In all cases the rack housing is clamped to the monocoque and does nothing else than steer the car, but Tony Southgate used a novel layout on the last Shadow design he did, where he used the steering rack casting to carry lugs from which the upper front suspension members were hung. When he left Shadow to start the Arrows team this was one of the design features he took with him and used on the A1 Arrows, and it was part of the lawsuit between Shadow and Arrows A2 design featured a more conventional unstressed rack assembly.
The mechanism for joining the steering wheel to the rack-and-pinion varies according to the space available, the driving position required and the location of the rack. Lotus use a short, straight steering column running direct from the wheel to the rack, with a splined muff joint between the column and the pinion shaft. Ligier and McLaren use a short column running to a universal joint and then another short shaft into the pinion housing. The Arrows A2 uses a similar layout, with a mere stub of shaft out of the pinion housing, Williams use a similar layout to the Lotus. Brabham use a short column from the steering wheel to a universal joint and then another shaft running downwards, at an angle to the primary column, and into the forward mounted rack and pinion. Renault use two universal joints in their steering column, one behind the instrument panel which allows the secondary shaft to run downwards and the second one directly onto the pinion housing.
On the Ferrari there is a very short primary column to a universal joint behind the instrument panel and then a secondary column running downwards almost vertically into the pinion housing under the floor. This secondary column is in the cockpit and the driver sits with this legs on each side of it, the column being virtually between his knees.
Most of the designers use a proprietary steering wheel of about ten inches diameter with a heavily padded rim and three spokes, and many of them are quickly detachable by means of a clamp or locking pin. This is done either to allow easy ingress, or easy egress in the case of an accident. It has on occasion proved a mixed blessing, as for example when a driver spins off into the rough and out of a race and detaches the wheel to get out and does not bother to put it back on again. When the mechanics collect the car after the race the wheel has gone, whisked away by a light-fingered spectator. Pushing a racing car back to the paddock without a steering wheel is a tiresome business, for which the driver gets no thanks. The thoughtful driver brings the wheel with him back to the pits. – D. S. J.