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Tim.Wright wrote:You have twitter? Ask Lewis, he should be able to give you the information you need.
Tim
=D>The hoosier R25B compound I have on my car has a coefficient of 1.5 on concrete. I am quite sure the F1 tires are at least in that range. I don't know what you're observing that's leading you to believe the cf is 1, but in all the slow "pure" mechanical corners on the grid, I see 2-2.2G or so.Stradivarius wrote:How can you be sure that the frictional coefficient is 1.7? I would then expect that we would not see accelerations much lower than 1.7 g, even in slow corners. Based on observation, I would think that the friction coefficient is close to 1, although it changes slightly depending on different factors, like the normal force the track surface and the tyre compound. Super soft should have the highest friction coefficient.Tommy Cookers wrote:surely the frictional coeff of the tyre is about 1.7 ?
most high speed circuits (incl Monza ?) have some fast corners that are now (with only 750 bhp in F1) power-limited ?
Nice of you to offer your driving wisdom to the f1 grid. The goal of the corner is to navigate it in the lowest possible ET, not necessarily the highest lateral G. In most corners the drivers will use some degree of trail braking, using the brake until the turn in point where the driver simultaneously begins to release the brake and begins to feed in steering input. The car is only in "pure" cornering for a brief moment until the driver reverses his steering input and feeds in the throttle. When you watch the G force trace from the on board camera, the driver is basically illustrating the traction circle.Stradivarius wrote:If you are braking all the time until you start accelerating again, your driving is not optimal, as you could have held a higher speed through the corner by lifting the brake earlier and accelerating later.
I still find it hard to explain how the sideways acceleration is smaller than 1 through any turn on any track, if the friction coefficient was significantly higher than 1, except of course, for the earlier mentioned camber of the track. However, I don't think there is any camber at turn 1 at Monza, so why is the "g-force" as they call it on f1.com only 0.73 g? By the way, g-force generally means total acceleration, not only centripetal component, isn't that so?
conceptually, the time spent at peak lateral g should (and does) tend to zero, followed by a phase prioritising acceleration ?Greg Locock wrote:" The goal of the corner is to navigate it in the lowest possible ET, not necessarily the highest lateral G"
Incidentally if you ever plot real racing data on a gg graph you'll see that even a good driver struggles to make it a circle rather than a diamond. bad drivers like me make it a cross.
Here's one of mine from an autocross course, it's from the entire run, not just a corner or segment.Greg Locock wrote: Incidentally if you ever plot real racing data on a gg graph you'll see that even a good driver struggles to make it a circle rather than a diamond. bad drivers like me make it a cross.
There wasn't much opportunity for heavy braking on the course we ran, so not much action on the top of the circle to fill in. Each of the actual braking zones had numerous bumps in them (car is massively underdamped and doesn't handle bumps well), making it not only hard to fully trail in, but also to hit peak deceleration (I didn't). The car is also front grip limited, and it doesn't stand up on the outside front tire during very heavy trail quite as well as other cars I've had. The overall circle isn't quite a circle. About 2G brake/turn w/ 1G of acceleration from a standstill to about .5G @50mphGreg Locock wrote:Nice data. why is the top pointy and the bottom so nice and round? double entendre's not meant. <later edit> well that was too good to delete, ok, the top is braking, so you can see that you are having trouble filling in the trail braking quadrant, so you've got the classic diamond shape braking (like most good drivers), but you are very confident when accelerating and cornering at the same time, so it is a nice circle, limited by the acceleration of your car. I'll see if I can find g-g diagrams that show incredible trail braking ability, aka ABS.
Tommy, comparison I did on f1 (very limited) and road tires (lots) indicated that the friction circle is elliptical, but a circle is not a bad approximation (to within 10%). max long mu/max lat mu is a very interesting tradeoff in wet and dry, I do not know how the big tire companies play with it and they don't seem inclined to explain.