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Dear Sir/Madam,
Is there an empirical data available on what the loads (lbs or Newton) are on a typical splitter for an average passenger car at various speeds?....or is there an easy way to calculate/estimate the force for a given splitter size/area ?
Thanks in advance
kindest regards
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Group: Forum Members
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+x+xI'm not talking about Radicals or the likes, I'm talking about Time Attack cars. Take a look at any of the Pro or Pro Am cars competing at WTAC. These cars are all making more downforce than an F1 car, they're looking at numbers in excess of 3000kg of aero loading. Yes, in those classes the cars are a tube frame chassis with tunnels in the floor, so they are proper aero cars, but they are based on passenger cars. I was sort of more making the point about how open ended your question was - a splitter can quite literally make anywhere from no downforce at all to over 1000kg of downforce. Its simply impossible to estimate a value without knowing anything about the design or the car its going on. Yes, the total aero package needs to be designed so that it is properly balanced. You need a proper weight distribution including aero loading so that the centre of gravity is as close to the centre of the car as you can get it, but this often comes down to class rules and the actual base car you are starting out with. But with good design it is certainly possible to balance the aero loads and produce very high downforce. As for front airfoils, yes I have designed and built these, and yes they can be superior to a splitter. Again, take a look at any cars running at the pointy end of time attack, they will all have front wings (except the Lyfe GTR, but ccompare them to the competition and you can see they would gain a lot by having some better front aero). RP968 and the 1:1 R8 are probably the best examples of a full front airfoil rather than a splitter. Lots of the other cars will have a combination of splitter and front wings, and this is especially more common in the lower Open Class cars, as this category is still a stock chassis design with flat floors and tunnels prohibited. To throw you another design curve ball - attachment points should all be behind the bumper/air dam. Mounting solutions like splitter tie rods and cables are absolutely horrific when they are external and placed in the air flow. These create so much drag and destroy so much lift potential that you would be better off running a much smaller splitter design in order to do wothout them. Any aero car that has been properly designed will not have any mounting points in the air flow. So what sort of lateral acceleration can these Time Attack cars muster? I couldn’t find any data on that, but I suspect no where near an F1 car…or even a Radical ….i guess one of the limiting factors is the mass of the Time Car….. given that the friction forces (tyres/road surface) would need to overcome m.v^2/r….therefore the greater the mass m, the greater the counter force (grip needed) that needs to be generated to negotiate a bend Yeh you won't find that sort of data published, the teams will keep that information pretty close. I know the race engineer for the Tilton Evo, I'll see if I can get it out of him. However these cars are past the limits of the R-Compound control tyre, the Advan A050. Every year there is a tyre failure from aero loading. They could actually generate more downforce and more grip and go faster, but the current tyre regulations are what holds them back. Which for me is great, you play within the rules, but it makes it a little bit incomparable to most other racing series that run on full slicks. But even on R-Compound tyres, these are 1000kg/1500hp+ cars going full throttle (~300km/h) through Turn 1, which is just unheard of in any other racing category that Sydney Motorsport Park hosts. Even our pinnacle motorsport category here, the V8 Supercars, are completely blown out of the water and running 12 seconds a lap slower.
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