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www.engineeringnews.co.nz 9 suspension geometry are adjusted.) “We have a lot on-board data-logging with lots 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 put them in, in illogical places so that the driver doesn’t know which is the baseline tyre. If he’s good he can usually figure it out.” “We give rating sheets after each run and he rates the tyres on the warmup, consistency, balance front to rear, then we have a section that relates to low and high speed cornering performance,” continues Meenan. “He rates each section describing whether the car is neutral or has understeer or oversteer. He will generally get understeer and oversteer at some point. You would be surprised how consistent this procedure is.” “If we have a baseline and we want to go stiffer, we go where we think we need to be in two steps and then go one step further just to see where the edge is and how much is too much,” says Meenan. “Once we’ve found a baseline front we will use it and try some rear options to find a better balance and then we would tend to home in on a best front with the best rear. It’s A, B, A testing but it works. We go through this procedure pre-season with development partners and it puts us in a good place to go to the first race. We might try some compound options as well in this test programme.” “Once we have found a promising tyre combination on lap time performance and driver feedback we get an afternoon’s worth of set-up work in, to help the teams optimise the set-up,” says Meenan. “Teams will work with dampers, aero and kinematics to get the optimum from the tyre combination. The driver would also work on his driving style for a specific set. Once we decided on a conclusive baseline option, we test that on a vehicle kinematics rig and get some force and moment data back and put that into the car FEA simulation.” “We use an external company that does a lot of work for us and other developers in these race series,” says Meenan. “They have a rolling road that generates force and moment data for a variety of slip angles, inclinations and loading. In this way we get more data about the performance of the car tyre and driver combination, so that we can ‘calibrate’ our simulation and predict more accurately how it will perform at different tracks and in different conditions.” “We generate slip ratio curves which allows teams to set the differentials and traction control settings and to understand the maximum slip that the tyre will stand before traction control needs to operate,” says Meenan. “The kind of testing we do is much more rigorous than people generally believe is necessary for a tyre manufacturer. Our objective is to understand as much as we can and to gather as much data as we can, to feedback into our computer systems in order to produce much more accurate simulations next time around.”


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