With current World Champion Lewis Hamilton’s stuttering race starts coming into question of late, and changes in place for the season ahead, tech specialist Craig Scarborough writes exclusively for Mobil 1 The Grid to explain the mechanics behind starting an F1 car in 2016.
There is a critical moment for every driver in a Grand Prix weekend – the start of a race. Success or disaster in this moment will change the race result for the driver and the team. And since warm-up-lap driver radio and automated clutch adjustment were banned last year, the drivers are having to manage the start process much more independently this season.
In short, they’re very much on their own, which invites a degree of jeopardy at the start. A driver’s training and skill has subsequently become much more important when the lights go out. So how, then, do the drivers get the car off the line? And what is it exactly that goes wrong, as has been the case for Lewis Hamilton, amongst others, this year?
At a basic level, making a launch in an F1 car is much like that in a road car which uses a manual gearbox. The driver needs to balance the revs and the clutch, phasing the pedals to get just the right engine torque at the point when the clutch is released, before progressing the two as the car starts to accelerate.
Of course, we know from our driving lessons that too little throttle pedal will stall the car, and too much will send the tyres spinning. Getting the balance right sees the car fire off the line, with just a tiny fraction of tyre slip providing the quickest getaway. In a heavy and underpowered road car, this balance can be found quite easily, even when trying to beat another car off the lights. However, when it comes to powerful and erratic race cars, the process needs to be far better controlled for the optimum start.
If we look back to before the ‘90s, starts were fully manual, with the driver getting a feel for a heavy clutch and throttle pedal. As such, fraught nerves were the major variable. As we moved into the 1990s active era, the launch became automated, with drivers simply needing to release a paddle or button to set the car off for a fully-managed active launch process. The only variable here was the actual difference between the car’s engine power and traction, as the start itself was optimal for that car. Thus, we had a lot of very equal starts up and down the grid.
Moving into the 21st century, active launch control was banned and drivers reverted back to manual clutch and pedal control, but the teams were not going to lose the ability to stage the start to maximise speed off the line. This led to the recent era of passive, but carefully managed starts.
In this development, the driver would be talked through the start process – from leaving the pits, to the point before the lights go out. Key amongst this was preparing the clutch. F1 cars use tiny 97mm diameter clutches with carbon fibre plates, which vary in bite as they heat up. Given that a car’s bite point moves with both heat and wear, finding the clutch bite point was key to this process.
Just as is the case with a road car, in F1 the bite point is – of course – what you feel as the clutch pedal is lifted and the engine revs drop to allow the car to want to move. Every boy racer has sat at a traffic light with the clutch at bite point, waiting to beat everyone else away from the green light.
Nonetheless, as F1 progressed into the new millennium, this process soon became automated, so that it was done using electronic control systems. The ‘Bite Point Find’ (BPF) button on the steering wheel would put the clutch through an automated process on the parade lap, which moved the clutch to feel the bite point. With this recorded, the driver would then make clutch adjustments on the steering wheel dial, on advice from the pits. This would map the clutch paddles on the steering wheel to the actual bite point.
At the start of a race, the driver would then set the engine at a pre-set RPM from the throttle pedal, before pulling in both clutch paddles and selecting first gear. In the moments before lights out, each clutch paddle would be released to above half travel – meaning the clutch paddles would often align with the gear shift paddles, giving the driver a sense of the correct paddle position.
At the moment of lights out, the first clutch paddle would be released, leaving the driver to then control the car on the throttle for any wheel spin. At this point, the clutch would be only half engaged, to prevent too much power getting to the road. Then, once the tyres are gripping and the revs are rising, the second paddle would be fully released to pass full engine power to the wheels.
With this process, starts were once again largely consistent and any potential win or loss at the start was negated.
Nowadays, both the ‘Bite Point Find’ and the double clutch paddle start process are banned. Drivers have to get a feel for the clutch bite point and react to it accordingly, rather than just adjust the paddle settings. Equally, the two stage start with the clutch paddles has to be done with one clutch paddle being released part way, then fully released through the start process.
Clearly, this reintroduced jeopardy into a race start and, as demonstrated many times this year, has led to cars jumping up the order, as well as dropping down, at the start.
During winter testing, and often in Friday free practice, drivers rehearse starts to get a feel for the clutch and tyre grip.
Complicating this current, far more manual, process is the engine reacting to a fixed throttle position for a long period. F1 engines are designed to be run under load, not revving in neutral for long periods. In such conditions, the multitude of engine parameters change – things get hot, pressures rise or fall and the sensors tell the ECU what’s going on. It can be the case that the ECU gets confused and the RPM resulting from the fixed throttle position starts to vary. Of course, with varying RPM the driver gets different torque available. So, should the engine speed rise or dip as the start happens, variability will occur, generally either in the form of bogging down or spinning the wheels.
The result is that the pressure on the driver to control an already very difficult machine is ever harder this year.
For 2017, there is some respite for the driver. The radio and clutch controls will remain in place, but a new input to the ECU may allow drivers to be more consistent. As the regulations dictate, the throttle pedal doesn’t need to be a simple means to open the throttles on the engine. Rather, they regard it as the driver’s request for torque; a subtly different interpretation. However, even with the complex sensors on the cars, the ECU never really knows what torque the engine is producing. Simply, the maps within the software suggest that, for a given set of parameters, the torque requested from the pedal should be produced. Thus, any variability may mean the throttle pedal isn’t getting the torque it’s requested.
At the start of a race, that means the engine may have too much or too little torque for an ideal launch.
For a few years, F1 cars have had a torque sensor fitted to the shaft between engine and gearbox. Up until now, this sensor was used for FIA monitoring purposes but, for 2017, teams will be able to use this sensor as an input to the ECU. Therefore, the driver will be able to request a set throttle pedal position and, rather than the engine’s response being a prediction of the torque delivered, it can actually adjust itself and deliver the demanded torque. This takes the torque variable out of the start, which should make for far more consistent starts.
So, from a year of quite influential start performances, 2017 – with its very different cars – should again return to the racing after Lap 1 to decide a race. Yet, with clutch and grip levels still variable, drivers cannot become complacent, as the race will still have the potential to be won or lost at the start.