Features - Technical
JANUARY 11, 1996
Formula 1 Preview-1996
BY PETER WRIGHT
In the aftermath of Senna's accident, urgent steps were taken to curb the performance of the cars. A long term programme was started to identify and research car and circuit safety improvements (Sid Watkins' Advisory Expert Group on Safety) and to identify and "make safe" the key dangerous corners (combined high speed and high g) on the circuits.
Twelve months on and we can see that the cars' performance has been checked rather than reduced, with the same teams getting it right as previously. The drivers quite like the dynamic characteristics of the reduced downforce cars, Johnny Herbert and his Benetton B195 excepted. Monza realised that it was better to cut down a few trees around the Curva Grande than to lose the Italian Grand Prix, and Silverstone found out that it had over-done the slowing of some of its corners - Stowe and Copse - and is opening them out again.
But it is the new co-operation between the Teams, drivers and the FIA that is most significant. With the teams that could afford to do so actively participating in the research programmes initiated by Sid Watkins' Group (see .....), the involvement of GPDA members, Schumacher and Berger, and the results as they mature, being introduced via the Formula 1 Technical Working Group, any points of dispute are thrashed out before the regulation is published.
The Technical Regulation changes for 1996 focus almost entirely on driver protection, with the head receiving the most attention. In any open cockpit formula, the driver's head will be vulnerable. But it is a delicate balancing act to devise measures that combine controlling the deceleration and rotational acceleration of the brain; the likelihood of impact with parts of the vehicle or track-side barriers; and the bending and shearing forces on the neck. Improve one and it is likely that another will be made worse. For these reasons Sid Watkins counselled a delayed introduction of mandatory changes until rigorous HyGe sled testing at MIRA, using a McLaren monocoque and a fully instrumented Hybrid III dummy, had indicated that an actual net improvement was possible.
The resulting modifications: a longer (775 mm versus 650 mm) and wider (520 mm versus 420 mm) cockpit opening, with raised sides that must pass a 1000 daN squeeze test, provide space for Confor foam padding around the sides and rear of the cockpit opening. In side and rear impacts this foam padded cockpit surround will restrain the head, providing controlled deceleration, and prevent head rotation that could potentially damage the neck.
There are more safety changes in the pipeline for 1997 and 1998 - a rear impact absorbing structure; redefined side impact test specification to move the impact point forward; and an increased size survival cell with 28% more space around the legs for greater strength and room for padding. Where possible the changes are being introduced at a rate that allows teams to use a monocoque design for two seasons.
The wide, high cockpit sides will inevitably adversely affect the airflow to the rear wing. Along with the elimination of the aerodynamic devices (winglets) mounted outboard of the rear wing endplates and around the rear wheels, there will be a reduction in rear downforce. My guess is that it will about cancel out the development gains yielded by a winter's wind tunnel testing. There are small changes to the front wing end plates (minimum thickness of 10 mm, and minimum radius of 5 mm) to reduce the risk of puncturing the rear tyres of a leading car, in the event that it's driver stages a brake test. The aerodynamic effect of this change is negligible.
None of the other major changes to the regulations will substantially affect the design of the cars - they set out to ban technologies that would escalate the costs of engine development for small gains in RPM and power: variable geometry exhaust pipes; crankshafts and camshafts in any material other than steel or cast iron; and composite pistons, cylinder heads and cylinder blocks, using carbon or aramid (Kevlar) fibre reinforcement. Some will mourn the lost opportunities....
So what is there to look forward to in 1996? What will be taxing the brains of the leading engineers and designers? Will there be any new hardware or software on the cars to puzzle over?
Best driver Ferrari
Best team Benetton
Best car Williams
Best Engine Williams and Benetton
There are of course wild cards: how will Ferrari's V-10 perform? Will it be reliable? Can Benetton change the dynamic characteristics of their new car to suit drivers other than Schumacher and perhaps Alesi? Will Benetton still be the best team without Schumacher, or can Williams sort out their race strategy and achieve Benetton levels of reliability? Will Schumacher change the Ferrari from the sweet handling car it was in 1995, and turn it into a blindingly quick one, when he is at the wheel? Will McLaren rise again from their four year plunge (see Figure 1 of John Barnard interview) with Alain Prost's help? Will Peugeot get their act together and start to show the sort of dominating performance they managed in World Rallying and Sports Cars?
With the performance aspects of the Technical Regulations temporarily stabilised, the chassis performance of the cars will converge, differentiated by aerodynamics more than anything else. Schumacher extracted the maximum from the Benetton by being prepared to drive an unstable car and gain the benefit from as much aerodynamic downforce as Rory Byrne could give him. Few others are able to do this, and track testing will be as much about matching aerodynamic characteristics to driver skill, as anything else.
However, given two equal chassis/driver combinations, it is the engine that determines which is the quicker. The most remarkable feature of the new crop of 3-litre engines is their low weight: around 100 kg. Generating 7 bhp/kg using standard specification fuel, up from 6 bhp/kg less than 2 years ago, is impressive for a normally aspirated engine. The weight released from behind the Centre of Gravity gives the chassis designer increased freedom to use ballast to adjust the CofG position. I would not be surprised to hear of Active CG systems this year. A couple of litres of mercury, weighing 27 kg and capable of being pneumatically moved up and down the length of the car, would allow a 3% shift in the weight distribution - forward for stability under braking, somewhere in the middle for cornering and rearwards for traction. Still apparently legal under the regulations, though possibly falling foul of health and safety legislation, it is one of the few remaining methods of dynamically tuning the handling characteristics and must be in the minds of designers, if not yet built.
A lot of people will be watching the new Ford V-10, both in the Sauber and also in the Stewart, when it appears in testing later in the year. With the first non-V-8 Formula 1 engine to emerge from Cosworth, Sauber and their two drivers will be trying very hard to gain the maximum credibility for all concerned, in order to ensure their futures. It must have occurred to Ford that a competitive Sauber-Ford, in 1996 and 1997, would provide an excellent benchmark by which to judge the progress of their BIG gamble with the Stewarts. Everyone involved has a great deal to prove.
Suspension design will continue down the route started in 1994, of de-coupling the stiffness and damping characteristics at each end of the car, by fitting three dampers as well as separate heave and roll springs. Those teams that have the resources to analyse and model the systems in detail and to systematically track test all the combinations until they have a full understanding, will benefit most from the relatively subtle advantages. The same holds true for damper development, though we shall not see or know what is being changed inside those complicated little cylinders.
Another part of the car that keeps it's secrets well is the differential. A level of electronic control is permitted, provided that it no more than emulates a purely mechanical, fixed characteristic differential. In practice this means that the only parameters that are permitted as controlling inputs are: input torque, differential rear wheel torque, and differential rear wheel speed - definitely not the mean rear wheel speed. It is known that most of the top teams are working on systems to provide both flexibility of set-up (changing a differential takes a good hour) and to provide the driver with a means of manually selecting the characteristics.
The torque split in any differential is a function of the internal friction. The various forms of limited-slip differentials set out to generate internal friction - either mechanical or viscous - with a usually non-linear characteristic that is a function of one or more of the permitted parameters. Using electro-hydraulic control of clutch plates, to vary the friction across the differential, opens up the potential of much more complex characteristics, greater precision and infinite variability. If it's not here already, it's definitely coming.
There is a trend, again among the top teams, towards networking the various computers on the car. Instead of one or two central computers, for engine and chassis, and heavy wiring looms snaking around the car connecting them to the multitude of switches, sensors, actuators and displays, the computing power is distributed to where it is needed, and one or more data buses (lightweight pairs of wires) link them, carrying suitably addressed data and commands. A typical example of the benefits of this approach is the steering wheel. Equipped with a dozen or more switches and lights, there just is not enough room in the column, for a plug with sufficient number of connections, that permits quick-release of the steering wheel. Put a microprocessor on the wheel and suddenly only 4 wires are needed for data and power.
Anyone who has managed a PC Network will understand the level of sophistication in hardware and software needed to develop such a system reliably. What they may not understand is either the level of co-operation required between engine supplier and chassis manufacturer, nor the size of headache for the FIA's software checker.
A vintage year for Formula 1 technology spotters? I doubt it. The most interesting things will be going on out of sight, deep in engines, differentials, dampers and black boxes. I would like to be surprised by a whole new direction or some clever system that releases a quantum step forward in performance that had not been exploited before; but I'm not going to hold my breath.