The FIA introduced the plank, which runs from the rear to the front wheels underneath the cars. The FIA initiated it to reduce the under-body aerodynamics and prevent the F1 cars from bottoming out on straight roads.
Interestingly, the plank is made of a wooden material called Jabroc instead of carbon fibre or any other specialized material. Resin and veneer are used on each layer while building this plank.
Therefore, the sparks that you see come from embedded titanium skid blocks on the plank. These blocks prevent and control the damaging of the plank. They protrude out of the plank at about 3mm. You can see a shower of sparks once the skid block hits the ground when the car bottoms out.
Bottoming out is the lowest point, after which the car again begins to gain height. When a car bottoms out, its underbody hits the track's surface.
Photo Credit: f1chronicle.com
Interestingly, the sparks that come from beneath the car intend to prevent the car from damage rather than damage it. The skid block is governed and measured by the F1 rules, and the skid blocks help reduce the damage to the plank.
The plank ensures that the teams are racing correctly and preventing "ground effect" aerodynamics, which tends to suck the car to the ground. Excessive damage to the plank results in disqualification, and Jarno Trulli fell victim to this rule in the 2001 US Grand Prix.
Photo Credit: f1chronicle.com
The F1 cars are pushed downwards into the tracks due to the aerodynamics that creates downforce. F1 cars race at a specific height, and the cars are designed to push them downwards when air flows over them, creating downforce.
This generally happens on the straight stretches as the speed is high, and aerodynamics plays its role effectively on these stretches. Furthermore, the aerodynamics increase with increasing speed and helps the cars to turn quickly on the corners, which reduces the lap time.
There is almost no lateral movement on straight stretches, while side-to-side movement is allowed in corners. In more straightforward terms, which means that the car's aerodynamics forces the car to go downwards, which lowers its height. In turn, the car is more likely to contact the ground resulting in sparks flying out of the bottom plank.
You will generally see sparks on kerbs that are slightly more in height or when the race starts as the fuel is the maximum at this point, and the cars weigh more initially with the fuel.
Photo Credit: www.roadandtrack.com
