Grand Prix Details
Technicalities of the 1968 Formula One Cars
To the casual eye all Formula One or Grand Prix cars look the same, in as much as they have multi-cylinder engines mounted behind the driver, a gearbox stuck out of the back of the car, long sleek glass-fibre nose cowlings and wide fat tyres. To the initiated, Grand Prix cars are vastly different in almost every aspect, unlike Formula Two where 99% of the entry use Cosworth FVA engines, or Formula Three where almost 100% use Ford engines. It is agreed that Grand Prix cars follow a general pattern in having the engine/gearbox aggregate forming the rear of the car, either mounted in a space-frame, on a monocoque structure, or forming the rear part of the chassis itself. In detail there are as many variations as there are makes and some such details are in aero-dynamic spoilers, oil tanks, brakes, exhaust systems, accessories, windscreens and regulation details such as crash bars, oil catch tanks and so on.
It was almost universal for Grand Prix cars to carry the tank for the dry-sump oil system in the nose of the car, usually just behind the radiator where it added to the general heat discomfort of the cockpit. McLaren has started a new trend by carrying the oil for his Cosworth V8 engine in a functional cylindrical tank mounted at the back of the car on the left of the gearbox; where it is out in the open air. Lotus have experimented with a much more complicated affair in the form of a welded saddle-tank mounted over the gearbox. Both layouts have transferred 50 or 60 lb. of weight to the extreme rear of the car, but at the same time affording additional cooling by radiation, the tanks being uncovered by bodywork. Since air-flow “spoilers” were thought up by Ferrari to cure bad handling on his sports cars, trim-tabs and spoilers have appeared on all manner of cars, both likely and unlikely. They are now appearing on Grand Prix cars, having been experimented with by the Indianapolis car builders and in U.S.A.C. racing, while they had quite a vogue on 200-m.p.h. Dragsters. Different people have different ideas, both as regards shape and size. Matra being content with very small bits of aluminium stuck on the “cheeks” of the nose cowling as afterthoughts, while Lotus have a sheet like a chinstrap on the Lotus 49. However, B.R.M. are much more definite on the V12-cylinder cars, having steeply inclined blades on each side of the nose, mounted on a tubular cross-member. In the Tasman races Lotus fitted a small wing-stabiliser on the rear of one of their cars, but did not race with it, while Brabham has fitted a trim-strip on the rear of his Formula One car that hardly looks deep enough to reach into the aero-dynamic turmoil around the rear of the car, let alone have much effect. So far no Grand Prix designer has followed Chaparral along the principle of directing all your aerodynamic problems to a point above the tail of the car and controlling them with an adjustable aero-foil.
There is a manufacturing regulation for Formula One cars that says that the exhaust pipes must not project more than a certain number of inches beyond the extremity of the car. The Cosworth engine uses very long tail-pipes so the Lotus has a tubular structure bolted on to the rear of the gearbox in order to extend the official length of the car. This has also been done on the Matra MS10 that Stewart drives, and Colin Chapman refers to these tubes as “legalisors.” The V12 B.R.M. engine has very short tail-pipes so that this problem does not arise, but on the M5A McLaren, what appears to be a “legalisor” is in fact a protection for a fuel pump mounted on the rear of the gearbox. On the V12 Ferrari there is so much equipment mounted around the rear of the gearbox that the extremity of the car is a long way back and the central exhaust system presents no problem, in spite of being long. This equipment comprises coils, battery, ignition equipment, alternator and oil catch-tank, the whole lot being carried on a chromium-plated tubular structure, which also gives some slight protection.
Crash bars or head-protection structures behind the cockpit very enormously, some being adequate, others merely being legal. Among the most effective looking are the Lotus 49 and Matra, which have two tubular hoops joined at the top, one leaning backwards and one forwards. Other cars have single tubes, not always mounted vertically, which might support the weight of the car if it was lowered on to the crash-bar very gently, but would almost certainly fold flat if it hit the ground obliquely at speed, and there are some that are not higher than the top of the driver’s head, which must defeat the whole object.
Cooling air scoops are popular on things like brake discs, shock absorbers and the driver’s feet. Brakes and shock-absorbers are doing work and this means heat, so cooling must be provided, but the driver’s feet need cooling for a different reason. Although there is usually a bulkhead between the pedals and the front suspension a lot of unwanted heat gets into the cockpit, so some form of ventilation is required. Heat comes from the water radiator, the oil tank, water and oil pipes passing along the cockpit and is aggravated by the pencil-slim cockpit dimensions. Radiator air usually escapes on either side of the front bulkhead, blowing on the suspension units, and in warm climates the steering mechanism and pedals can become uncomfortably hot. McLaren has used Prototype Sports Car practice on his new Grand Prix cars, by letting the air out through large openings on top of the glass-fibre nose cowling.
Disc brakes are universal now but there are some variations as to mountings, especially for rear brakes, the discs being mounted outboard of the hub-carriers as on the Lotus, or just inboard of the hub-carrier as on the B.R.M., or completely inboard, on each side of the gearbox, as on the Ferrari. This last mounting is advantageous from the point of view of unsprung weight, but can present heat transfer problems to and from the gearbox, but this has never bothered Ferrari, although some designers have tried the fully inboard mounting only to give it up later. At the front most designers are content to mount the discs on the hub, outside of the hub-carrier, only Cooper going to the trouble of mounting the discs inboard of the hub-carrier with a short stub axle shaft passing through it. No-one has deemed it worthwhile to follow the lead of Lancia, on their sports cars, and Mercedes-Benz on both sports and Grand Prix cars, where the brakes were chassis mounted in the centre of the car, with shafts joining them to the wheel hubs. However, with Ford and Lotus probing the 4-w-d field, fully-inboard front brakes may come back into fashion.
Although the basic conception and layout for a Grand Prix car would appear to be pretty set in general, there is little conformity in details, which makes each car very individual when studied closely, and with 8-cylinder, 12-cylinder and 16-cylinder engines in Formula One there is plenty of variety, while the fundamental differences in the V12 engines of Ferrari, Honda, Weslake and B.R.M. are almost unlimited.
Anyone who thinks that Grand Prix car designers slavishly follow each other should take a closer and longer look at the 1968 Formula One cars.—D. S. J.