DUNLOP RACING TYRES
last year’s season,’ says Meenan. ‘We did other tests with the cars that went on to win Sebring. We had one of the best performing cars at that race in the GT class.’
Rapid prototyping allows Dunlop to change the profile of the build machine segments in hours rather than days
A BIT OF EVERYTHING Dunlop went back there this year because the old airfield that is Sebring is one of the tracks where they see both the smoothest and the bumpiest surfaces, as well as fast and slow corners and some high-speed sections. It’s hard on cars – Audi goes there for weeks, just to do endurance testing on the chassis – and on tyres, too. Also the weather can be unpredictable there, so it has a bit of everything. ‘We think Sebring is the best all-round circuit for testing,’ says Meenan. ‘In Europe, you have to go southern Spain or Portugal to get anything close. Estoril, Jerez or Portimao at
Meenan. ‘Our biggest challenge is trying to optimise performance for a specific car. From previous tests we would decide on the area that we would like to explore from a car performance point of view, improve the front or balance the rear etc. We would have a weight distribution or stiffness balance that we would want to target, so we would take a few options [different tyres] in that area to test. Baseline is another variable term. When describing a test, baseline is a term that describes a tyre that is a known quantity. This is one that has a given construction and compound that the team and driver know well and know how it reacts with the car. In a given test, the tyre variants will be compared and contrasted to the baseline tyre. In the test shown here, the baseline would generally be in the middle,
“the percentage difference we
see with the FEA simulation we also see on the track“
testing time (in the off season) can be wet or foggy, whereas Florida is bound to give you dry days. We went to Sebring with all our development partners to prepare for ELMS (European Le Mans Series) and WEC (World Endurance Series, the new name for the ILMC).’ ‘We use some element of
CATIA - SIMULIA Model showing a loaded cambered cross section
The Dunlop monsoon tyre can give up to 50 per cent water clearance.
CAD to design the tyres,’ says Meenan. ‘We would start off with a construction we may already have, make some modifications and put it through Abaqus. We compare different designs this way. And from that we can get the delta stiffness – the difference between the tyres. Because our process is so well honed, the percentage difference we see with the FEA simulation we also see on the track.’ It’s difficult to get absolute
correlation with track testing because there are so many variables that you can’t control absolutely. ‘Things like the actual construction and lay up, the way the tyres shape in the mould, the way the tyre fits on the rim are more predictable than how it performs with the car,’ explains
with two softer and two harder compounds either side. After a test, the baseline is usually the optimum compound combination for the car and the circuit, and this is the combination that goes into the race set up process where dampers, aero and suspension geometry are adjusted. ‘We have a lot of on-board
data logging, with a number of accelerometers and slip angle sensors. We work very closely with the race engineers and the drivers to get an understanding of how the tyres are performing,’ says Meenan. ‘We have a long relationship with a number of drivers so we can trust their feedback. ‘The driver would go out with a baseline tyre and we generally tell him it’s a baseline (a tyre that he knows well). We give him as long as he wants to understand how the car is reacting on the baseline set and then we go into a test programme where we have five test tyres,’ continues Meenan. ‘The baseline could be in the middle or at the start of the sequence. We sometimes
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