Friction Circle (or why am I slower than I should be)

[jeffw]

I've been doing some analysis of my Brands Sprint runs to see why I was 6 secs slower than the 280bhp Westfield with the sequential box and big, very soft tyres (bitter me !!!!)

So there is a concept of the 'friction circle' which is the maximum grip available from the tyres in acceleration, braking and turning. In the case of R888s it is around 1.2-1.3G maximum load. So if you think of a circle at 1.3 G you'll get the idea.

So this is my flying lap through Paddock Hill Bend on my fastest run.



As you can see I am not braking hard enough (no where near 1.3G) but the most telling part is the lack of trail braking to the apex which you can see as the dip upwards as the car turns into the corner. This effectively means I am leaving significant levels of performance un-tapped and losing around 1 sec in that one corner. By trail braking I can gain speed on the straight, brake later and then start to come off the brakes so as to maintain the friction circle all the way to the Apex, balancing braking and lateral G.

So looks like the old dog needs to learn some new tricks

[David]

Jeff

All true -- but it's supposed to be fun, don't you know. If it's any consolation to you the Westy which made you bitter was 2nd FTD at Thoresby Park on Sunday (beating all but one single-seaters, and all but one slick-shod cars). So you were playing with some quite big boys at Brands.

Must get some logging installed on the Westy

All best

David



P.S. What is it about 08:22? You've posted at exactly that time these last two days!

[jeffw]

Fluke I think.

[jeffw]

I am certainly becoming more interested in the logging side David, gives me something to look at over the winter as the engine gets rebuilt

I've got some SG compound R888s so I expect heavy rain for the last two sprints I'm entered in

[David]

so I expect heavy rain for the last two sprints I'm entered in

Jeff, you redefine the "Eeyore Tendency"

[jeffw]

lol

[dopdog]

What i did not understand any of that apart from the braking bit can you let me know when you have finished the drawing as it looks like you have just started

[jeffw]

This is what it is meant to look like if you where close to realising the friction circle

[jeffw]

And this is the guy who won the class.

http://www.youtube.com/watch?v=TY-QE_VlFTA

[David]

Pete's got perfect gearing for Brands. Shift light in sixth along the main straight, but not on the rev-limiter