Technique: telemetry and its analysis through the Hamilton example

The term telemetry refers to a system designed to perform measurements on a remote object, transmit them live via radio communication, and record them for later use. Also used in fields as diverse as aeronautics, meteorology, and the nuclear industry, telemetry is an integral part of the onboard electronics in Formula 1 single-seaters. It is therefore quite logical that it emerged with the advent of electronics in motorsport at the very beginning of the 1990s.

In practical terms, the racing cars are equipped with several hundred sensors (temperature, speed, pressure, frequency, etc.) connected by cables to the car’s electronic control unit, which, besides being able to display them on the steering wheel if needed, transmits them via radio link to a computer located in the pits, which receives and stores them. This way, engineers, whether on the pit wall or in the garage, can see in real time the evolution of the data measured by the sensors, and thus observe the driver’s actions and how the car reacts to them.

There was even a time when technology was so advanced that telemetry could be done in the other direction, known as bidirectional telemetry: data could be sent from the pit to the car, allowing engineers to modify the engine’s mapping without involving the driver. But those days are over since 2003, as the FIA legislated to ban data transmission from the pit to the car.

Since 2008, the electronic system of Formula 1 single-seaters has been common to all teams and is provided, after a tender by the FIA, by McLaren Electronic Systems. Consequently, the telemetry is also completely standard, with MES displaying in its catalogue all the necessary elements: sensors, wiring, control units, power supply systems, displays, transmission antennas, as well as all the software required for displaying data on a computer screen and for printing it on paper.

But McLaren did not suspect that one day, information from their system, particularly concerning one of the creations of the Woking team, would fall into the public domain. By posting a photograph of his telemetry on Twitter, Lewis Hamilton unleashed the wrath of McLaren, whose director Martin Whitmarsh had lamented an “error of judgment” by the English driver. The relational implications of such a maneuver, in the context of the possible departure of the Stevenage native to Mercedes, having already been widely discussed in its columns, Motorsinside.com invites you to take a look at the data thus made available to all.

At first glance, the document is divided into two parts. On the right is a large graph (a) displaying a set of curves that we will detail later. In this area, the data from two laps are actually overlaid, represented respectively by a blue line and a red line, where one can see a vertical marker (b). In the top left corner, a box (c) gathers a set of information taken at the moment highlighted by the marker (b). Thus, by reading the horizontal graduations «, at this point on the circuit, that is to say about 2200 meters after the starting line (which corresponds to a point near the end of the Kemmel straight), the speed of the car during the red lap was 291.6 km/h, and the engine speed was 16,268 RPM.

The different plots represent:

– 1 : la vitesse de la voiture ;

– 2 : le braquage des roues avant (la courbe monte lorsque les roues sont braquées vers la droite) ;

– 3 : l’écart entre le tour rouge et le tour bleu (la courbe descend quand le tour bleu est plus rapide que le tour rouge) ;

– 4 : le rapport de boîte engagé ;

– 5 : la pression sur les pédales d’accélérateur et de frein (superposés).

Of course, other information can be selected and analyzed. Examples include the use of KERS or DRS, engine power, tire pressure, centrifugal forces, suspension travel, or ground clearance. This data comes in various forms, allowing telemetry to be used in different ways. For instance, telemetry can enable a driver to observe their own actions (throttle, brake, steering, gearshift, KERS, DRS) to improve their driving, especially by comparing their own data with that of their teammate.

Teams also use telemetry to improve the settings of their car. While the graphs do not have the same impact as the driver’s feedback upon exiting the single-seater, they help highlight understeer or oversteer behavior, or even assess a car’s handling on curbs.

Finally, as we will see with the example we are studying, telemetry helps in the development of a car by allowing comparisons between different parts configurations. Thus, the purpose of the sheet tweeted by Lewis Hamilton is to compare the performance of the MP4-27 with and without the new rear wing brought by McLaren to Spa.

At first glance, a simple reading of plot 1 clearly highlights a lack of top speed. Since the scale of the plot is not clear, it is, however, difficult to quantify the differential between the red lap and the blue lap. Interestingly, the operation of the rear wing seems to activate at a certain speed, at which point the blue plot overtakes the red plot, which seems to plateau.

A second analysis also allows us to state that, contrary to the generally accepted idea in the F1 Circus, the two laps compared are not the Q3 laps of Lewis Hamilton and Jenson Button. Firstly, plot 3 shows that the final gap between the two times is less than 0.1 seconds (about 6 or 7 hundredths), in favor of the red lap, paradoxically the one that is by far the slowest in the straights. However, the gap in Q3 between the best laps of the McLaren drivers was 821 thousandths, and in favor of Jenson Button.

The red lap is also not Lewis Hamilton’s fastest lap in Q3: just look at a comparison between the best Q3 laps of Jenson Button and Lewis Hamilton to hear that the engine speed at the end of the straight for Lewis Hamilton is close to 18,000 RPM, at which Jenson Button is stuck at the top of 7th gear. This does not align with the 16,268 RPM indicated on the marker: it is therefore difficult to clearly know which laps are actually being compared.

After reviewing all the times recorded by McLaren on the Saturday of the Belgian Grand Prix – with Friday taking place under rain and the document being sent on Sunday morning – several significant laps completed by the English team’s drivers are separated by a margin ranging from 51 to 99 thousandths. Therefore, it is not possible to determine the actual origin of the two laps being compared: while it seems certain that Lewis Hamilton is the driver of the red lap, lacking in straight-line speed, it is impossible to know whether he or Jenson Button was at the wheel during the blue lap, and in which session (Free Practice 3 or Qualifying) each was completed: the direct comparison could therefore be purely futile if the laps were recorded in different sessions, and thus in incomparable conditions.

Obviously, the engineers at McLaren, besides knowing which laps are involved, have additional data that can allow them, if needed, to correct any potential differences in conditions between these two timings. In any case, for the purpose of the current demonstration, we will assume that these two laps were completed under comparable conditions—aside from the rear wing, which is the very subject of the comparison.

As indicated in writing to the left of the frame reserved for graphs, in the only full load leading from the Source to Combes, the red lap loses a lot of time compared to the blue lap. It seems, however, that given the graduations (e), the gap is slightly overestimated: at the start of the decrease in gap », the red lap is ahead by one-tenth over the blue lap, but at the end of the straight line (g), the gap is 4 tenths in favor of the red lap, which is more of a deficit closer to half a second than the indicated 6 tenths. The same approximation is found on the right in the full load leading to Blanchimont and then to the Bus Stop: the gap is measurable at about 35 hundredths rather than the indicated half-second.

The author of the handwritten notes also omits the fact that despite losing nearly 9 tenths during the long full-throttle sections, the driver of the red lap makes up for the delay through braking, cornering, and re-acceleration, allowing them to finish sector 2 with a 2-tenth advantage over the blue lap. In the end, they even lead at the finish line: the additional downforce from the old wing enabled the driver to brake later, enter turns more aggressively, and accelerate earlier and more decisively than with a wing that generates less downforce.

It is therefore surprising that Lewis Hamilton wanted to highlight the deficit of the old rear wing with this document, especially since this analysis, although brief and carried out by someone outside the team, shows that the advantages of the new wing in sectors 1 and 3 are offset in sector 2. Some might even think that this telemetry sheet is the reason behind Lewis Hamilton and the McLaren number 4 team’s decision not to use the new wing for qualifying and the race, and that attributing the lack of performance in qualifying solely to the absence of the wing is somewhat simplistic.

Moreover, the video mentioned above is very clear: while the wing undoubtedly played a role in the 4-tenths gap recorded in the first sector during Q3, it should also be noted that Lewis Hamilton made a braking error at La Source. By locking his front wheel, the Briton missed the apex and accelerated later, a speed deficit that inexorably accumulated over the 1700 meters separating La Source from Les Combes. In sector 2, however, Lewis Hamilton fails to gain the upper hand over Jenson Button despite the additional downforce, due to a car that seems slightly oversteering. In sector 3, the gap widens again while Lewis Hamilton’s corner exit is clean this time, a disparity that can thus be entirely credited to Jenson Button’s wing.

We can therefore consider that with a slight adjustment to his front wing (a few clicks less), Lewis Hamilton would have found himself with a car that was slightly faster on the straight and better balanced in the corners, making it much more capable of competing with Jenson Button’s. Of course, the chances of the 2008 World Champion were not the best without the wing installed on Jenson Button’s car, but the telemetry and video show that the entire 8-tenths gap between the two McLarens at the end of qualifying was surely not solely attributable to the wing.

Here, in any case, is what can be gleaned from the scant information in this image. It goes without saying that with a higher quality and higher definition photo, this analysis could have been more detailed. But it represents only a very small part of what the kilometers of data collected by the teams can teach them. So much data means that telemetry, with its multiple uses, is crucial in modern Formula 1.