Tech Analysis: Why the tyre blanket ban for 2015 is unrealistic
Tyre blankets have been in F1 for decades and their purpose is very simple – to pre-heat the tyre to a suitable temperature so that they maximise the car’s performance. They enable drivers to take less life out of their rubber to get them into the correct operating window and allow close combat racing and fast flying laps right from when they exit the pitbox.
As pressure increases with temperature, getting heat into the tyre has an effect on the car’s ride height and mechanical grip: these both drastically affect cornering ability. Changing the ride height is done in millimeters, such is the sensitivity of the car’s underfloor aerodynamics, so if the pressure in the tyre isn’t up to where it should be the driver is going to have a real problem.
Despite the huge forces that the driver puts through each tyre when driving at full speed, you often hear them complaining about tyre temperatures. Tyre blankets do a good job at warming the surface (contact patch) temperature, but the core temperature is raised due to the loading of the tyre at high speed. The core properties are primarily responsible for the car’s handling, but the blankets hugely help the driver to get the core temperatures up sooner.
All of these statements underpin the fact that banning tyre blankets from next year onwards is probably a bit unrealistic, which also raises the question as to whether banning them in the future at all is really possible. In 2012 the FIA proposed this action to be put in place for 2013 but this fell through, so why should it be any different this time?
Transporting the blankets (and all of the other equipment such as the racks, wiring and monitors) around the world is extremely expensive, as the complete kit weighs a lot. Banning them is a quick way of cost cutting but perhaps the FIA are missing the point.
Pirelli have recently announced that they are not in favour of the ban due to safety implications and they are spot on. Rolling out of the pits on cold rubber will make the cars extremely difficult to drive and will take the best part of four to five laps to come up to optimum temperature and pressure without hurting the life of the tyre too much.
A problem could also arise with teams trying to raise the temperatures too quickly and Pirelli are aware of this. Paul Hembery, Pirelli’s motorsport director, has stated that the biggest challenge of producing a tyre that will not rely on blankets is preventing them from “becoming a balloon”. The ballooning effect is a real danger if the tyres are not designed correctly.
Pirelli also set a minimum tyre pressure to prevent teams from running the risk of inducing a high speed blowout, which is more than necessary given how fragile the sidewalls are of late. Using tyre blankets, the teams can predict how the pressures will come up as the driver circulates the track to ensure that this minimum target is met. Without the blankets there is no way of judging how quickly the target will be met, or if it will be met at all.
Pirelli can design and test as many tyres as they want (the first batch was brought to the second Bahrain test session in February, and a further developed set will be tested next week after the Bahrain GP) but there are too many variables, even from car to car, to make any solid calculations that can improve the tyre that is designed around the exclusion of blankets. From a technical perspective, designing the car around warming up the tyres rather than optimising it around an already known concept would be a nightmare, too, as this would then impact on how the car uses the tyres over the stint.
So, for now at least, it’s probably best to keep the round bits of rubber tucked up during the race weekend.
Images courtesy of Octane Photographic.
William Tyson - a Mechanical Engineering student at Swansea University - has been writing about the technical side of Formula 1 since February 2013. After joining the Richland F1 team for 2014 he has continued to establish himself as a more rounded technical analyst whilst maintaining a healthy following on his blog.