What to learn from a temperature camera?

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Since the introduction of Formula One's new thermal camera images, there has been talk about the relevancy of the images, leaving apart the obvious coolness that is associated with it. It is for sure that such imaging will help people understand the complex nature of Formula One, and increase the technical interest in the sport.

Before going into what we've been seeing, one needs to take into account that the images are not meant to give away technical details that other teams could use. Instead, their calibration is not made public, making it unclear when an area is considered hot enough by the camera to be visualised as blue, purple, red, yellow or white. It is even possible that this calibration is not linear either, making it even less useful from a technical perspective. Nonetheless, the new images are worth a look, as they do certainly show a few things that were known before, but not actually visible.

At the Italian Grand Prix in Monza, FOM repeatedly showed images of the front wheels on Paul Di Resta's car. There it was clear that the sidewalls are considerably cooler than the thread, while the car's negative camber setting - a common feature in racecar setup - made sure the inside of the front tyres take the main load when the car is running in a straight line. When cornering, it is obvious how this camber setting works, as the roll of the car offsets this camber on the the outer front tyre - the one that takes the biggest load - making its thread heat up evenly across the entire width.

Now at the Singapore Grand Prix, Felipe Massa's Ferrari featured a rearward looking camera, showing how the rear tyres heat up and cool down during the course of a lap. That image showed that the rear tyres are heating up mostly during acceleration, and to a little less extent under braking. This is of course easily explained by the weight transfer of the car, as under braking, the weight shifts forward, hence also why the brake balance is set up so that more brake pressure is applied to the front wheels.

In addition, it's also clear that there is less or no camber on the rear wheels, as they have to work at their best on a straight line as well. Any minor camber angle however is easily offset by the downforce on the rear wheels, pushing the entire thread onto the tarmac under acceleration.

One final, and perhaps the most interesting observation we can make, is how the inner wall of the rear tyre is heating up. It is clear that this is mostly due to the Coanda exhausts that direct the hot stream of exhaust gases down onto the car's floor, passing alongside the tyre. This considerably heats up the rear tyres and has been a particular problem for some teams to keep under control. Mercedes AMG for instance reverted to their traditional exhaust during 2012 after finding out that their tried Coanda exhaust layout worsened rear tyre wear.

In the below clip, you will also clearly see how the tyre wall is hotter when the car is accelerating hard - due to the high RPM of the engine and hence the more powerful exhaust stream. Also look at the behaviour under braking, where downshifts are followed by a short increase in rear tyre wall temperature, again due to the increase of engine revolutions. All this of course is influenced by engine mappings, but as most teams now have a good understanding of the tyres, it's unlikely anyone is using less afterburn than possible to preserve the tyres.


Note that the only time the sidewalls of the front tyres were seen coloured, and thus relatively warm, was when cars left the pits, hence with the tyres still warmed up by the blankets.




Comments

By maranello55 on 22-09-2013 at 17:31

Leave the technical to the technicians. I tuned in to watch some racing. Havent been getting much nowadays!


By juniormoose on 22-09-2013 at 19:48

Any reason why this clip has been flipped horizontally? It's Singapore alright, but at the start of the clip the last and first corner are left, not right-handers...


By zenji on 23-09-2013 at 01:44

I reckon it's cool in small doses.


By Kiril Varbanov on 23-09-2013 at 14:48

BTW, I have asked the officials what the colors mean, and as soon we get an answer we shall update the article. I hope we will get an answer.


By Steven on 23-09-2013 at 20:44

@juniermoose : likely to avoid copyright infringements. I've seen it used before, as FOM usually takes down every unauthorised F1 clip published on youtube.


By Shrieker on 27-09-2013 at 04:42

I heard some guys are inserting black lines on the top and bottom of the frame to avoid copyright stuff. Anyway, great article; very well written and insightful ! + Props ;)


By SystemsWiz on 11-10-2013 at 21:14

Colormaps without legends are very useful. They look cool, but you don't have know what temperature range you're looking at.


By SystemsWiz on 11-10-2013 at 21:15

*aren't


By n_anirudh on 14-10-2013 at 02:35

Lots to be learnt from these. For starters, we can pick a point in the image (break up the video) which is on the tire and monitor the variation over the lap. we can calibrate the variation with regards to the track temperature/ body temperature of surrounding people..Compare the soft and hard compounds.Lots to gain from these images :)


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