Why do F1 cars not have an automatic transmission

This is how a Formula 1 transmission works

How does a Formula 1 engine work? How much better are Formula 1 brakes than normal brakes? Why are the tires so crucial? For everyone who wants to understand the extreme technology in Formula 1 in more detail, mySPOX user Manül - a highly valued expert for technical questions in the community - explains exciting details in his technology column on SPOX that make a Formula 1 racing car one Making a miracle of engineering. Part 2: The drive with clutch, gearbox and differential.

Dear SPOX readers,

Several times I have received inquiries from the community as to whether I could explain Formula 1 technology in more detail, or have been asked to write something about one or the other technical topic. I am very proud to be able to present you a whole technology series together with the SPOX editorial team and to be offered a corresponding platform for it.

So that you can perhaps follow the races with a different focus and get to know Formula 1 from its interesting side, I'll give you a little insight into the uniqueness of the technology in the next few weeks. Then the hasty screams for certain rule changes may disappear.

Comments like "test drives are not about anything" or "wow, team XY is far behind" will perhaps be reconsidered by one or the other after reading my texts. On closer inspection, one can gain insights into each individual round about the problems, developments and advantages of the individual teams. Test drives and training are worth more than any race, no matter how many points you score.

So, over the next few weeks, I wish you a lot of fun with my attempt to increase the excitement and interest in Formula 1. If the content is unclear, please do not hesitate to use the comment function and ask.

In the first part of the series I already explained the engine to you. The second part is about the drive. That means: clutch, gearbox and differential.

The drive

The heart of every Formula 1 racing car is the engine. That should have been the minimal knowledge from the last episode. But what use is the drive energy of the engine if it is not brought onto the road? So let's leave this rhetoric and just get to the point:

Like pretty much every normal road car, F-1 vehicles also have a clutch, gearbox and differential to transmit power from the engine to the tires. Although at first glance there are practically no functional differences to a road car in this area, pretty much everyone can guess that the drivetrain in an F-1 racer differs significantly. Let's now take a look at the various components together:

VIDEO: This is how a clutch works

The clutch: The clutch is the direct connection between the engine and the transmission. The demands on this part are particularly high. On the one hand because of the high working temperatures of over 500 degrees Celsius, on the other hand because of the low weight of just over a kilogram.

The two manufacturers AP racing and Sachs produce the multi-plate clutches from carbon for the teams. The advantages of woven carbon fibers are high frictional resistance and high temperature stability. Compared to other materials, carbon coverings can withstand three times more pressure (6 N / mm²). The multiple layers ensure that the forces are evenly distributed over several levels and do not heat up quite as much.

A modern F-1 clutch is as compact as nowhere else. This specimen from the 2008 season is just under 10 centimeters in diameter (see illustration).

Another difference to the road variant is the clutch process itself. The pilots only have the accelerator and brake pedals in the cockpit. The gear changes take place semi-automatically using paddle shifters behind the steering wheel. The coupling process is automatically controlled by the software when the rockers are operated. Since 2007 there have been no more interruptions in tractive power during upshifts. Two gears are engaged in the transmission for a short time (one hundredth) at the same time (when the rocker is pressed). The individual gear wheels have a torsional backlash to the shaft and can therefore only be disengaged when the next higher gear has already been engaged.

VIDEO: This is how a transmission works

The transmission: F-1 transmissions are sequential, which means that only directly adjacent gears can be shifted (i.e. 1-2-3-4-5-6-7 or 7-6-5-4-3-2 -1). So if a particularly clever pilot comes up with the idea of ​​downshifting particularly quickly, the gearbox flies around his ears.

In contrast to the clutch, most teams build the gearboxes themselves or in cooperation with specialized companies (e.g. X-trac). All F-1 teams now drive with seven gears plus reverse and neutral. Titanium-magnesium combinations are used as the material due to their extreme stability. Because, as mentioned in the last episode (engine), the rear suspension is mounted on the transmission unit, which consequently has to bear the entire weight.

The translation (i.e. the coordination of the gears with each other) is different depending on the route. The first gear is tuned so that it offers the best acceleration from the slowest corner of the respective route; the seventh gear is set so that the speed limit is just reached at the end of the fastest passage. This coordination work is usually done in the factory before the race weekends with the help of data from the preseason and computer simulations. Fine adjustments are only necessary depending on the wind strength / direction.

All driver helmets for the 2010 season

The differential: The differential in a road car normally regulates the steady rotational speed of opposing wheels when cornering, for example. One speaks here of an open differential. Racing cars - F-1 bolides more than in any other racing series worldwide -, on the other hand, usually work with so-called limited-slip differentials.

The traction when accelerating out of a curve is optimized by tire rotation speeds of different speeds. The differential regulates cornering by means of various preloads and, for example, prevents the wheel on the inside of the curve from spinning too quickly due to less friction (e.g. when there is air level) without reducing the engine speed.

The differential is locked via an electro-hydraulic servo valve; also known as Moog-Valve (principle of negative feedback; see also Control Theory). So much for a deterrent! Here you can see the general functionality of a differential.

The energy via the drive train is transferred to the drive axle (in Formula 1 only the rear axle) to different degrees. The wheel on the outside of the curve has to cover more distance than the wheel on the inside of the curve and should therefore turn faster.

The difference between the two rotational speeds is regulated via the differential. The excess energy of the wheel with less slip is redistributed to the wheel with more grip.

The adjustment of the limited slip differential is an elementary part of the adjustment of the car to one's own driving style. The higher the locking effect, i.e. the preload, the more torque the differential can distribute to the wheel on the outside of the curve when accelerating out, which results in an oversteering yaw moment; the lower the preload, the more likely the vehicle is to understeer.

However, not only the yaw rate (angular speed of a vehicle around the vertical axis), but also tire abrasion, traction and coordination with the braking balance are important for the adjustment. The setting of the differential may no longer be changed from the beginning of qualifying, so it must also be selected with consideration of different handling characteristics under changing weather and refueling weight.

Due to the extended wheelbase of the 2010 racing cars, the range of the tuning options is limited a little. The narrower front tires also provoke a more nervous rear, which is why the more sensitive coordination of this component is of particular importance. Did you know, by the way, that Nico Rosberg invested a whole morning focusing on this aspect during the test in Jerez?

The next episode also deals with adhesion and handling properties. Subject: the tires

Profiles of all drivers and teams