The BritishV8 Pub

"Skid Pad"

I'm pretty sure Carl Floyd was first to suggest setting up a skid pad and measuring lateral-g performance for our cars. My elaborations on that idea (below) are mainly intended to increase participation and "fun-factor".

Compared to an autocross, I think a skid pad event might have the following advantages:
1) novelty (i.e. we haven't done it before)
2) relatively easy to set up
3) provides a tangible and somewhat transferable measurement of each car's cornering potential.

To elaborate on that last point... this is like dyno testing for engines. Just as one dyno gives different results from another, all skid pads aren't equal. However, with big disclaimers, the G numbers we generate will give us something to compare to car and tire test results we see in magazines. Does the lightest car win? The lowest car? The widest car? The car with the stickiest tires? Will any of us pull more than one lateral G?

I don't know if any of you are familiar with "Formula SAE" (aka "Formula Student") . It's an annual international competition for teams of college students in which they design and RACE very quick little open-wheel 600cc motorcycle-engined cars. They have a nifty way of measuring the cornering capability of participating cars. It's described in their rules... specifically "Part D, Article 6" (pages 87-90) of their rules, which you'll find here: students.sae.org/competitions/formulaseries/rules/2009fsaerules.pdf

(Note: we could simplify the test procedure a lot. We might also need to adjust the cornering radius.)

What's needed?
1) a level, paved area approximately half the size of a football field
2) timing equipment
3) a way to mark the circles (chalk, flour, lime, or paint... and/or ~40 small traffic cones)

The time required for each run is short. If we run this event well, each car can be tested multiple times. For those with adjustable sway bars or adjustable shock absorbers this could be VERY interesting. With more runs, we'll get a better feel for how much tire pressure matters. What happens if I swap tires with my buddy? Just how much better is a Holley than an Edelbrock on turns? Etc. On the other hand, we might possibly get more drivers involved.

Twenty-one years ago, I drove a Formula SAE car in the skid pad event. On the skid pad, there's no question of braking, "hitting a corner's apex", or driving the "right line". Probably no one will shift gears. However, I testify that it's still quite fun and challenging! Drivers are rewarded for being "smooth" and for driving tight, constant radius turns. (Practice is a big advantage.) It's a hoot!


Okay... give us YOUR thoughts!



Edited 1 time(s). Last edit at 07/21/2010 01:21PM by Moderator.

I think the paved area you need is much smaller. A 75 ft square with adequate runoff would be enough room. You can go clockwise or anti-clockwise on the same circle. Payne Engineering in Hurricane, W.Va. has a paved donut across their "Gartersnake" backyard road course about that size which they use for that purpose.

One caution for anyone wanting to run the skidpad. Either put extra oil in your engine, hook up an accu-sump, or take other measures to ensure you do not starve the engine of oil. At near 1G half the oil will be in the outside valve cover.

JB

Perhaps I should have pointed out two key features of the Formula SAE procedure:

1) It uses a figure-8 pattern.
2) Each car runs just twice around a clockwise circle, then immediately turns left and runs twice around a counterclockwise circle.

Does two quick loops provide enough time for oil starvation before the test is over, and the next car is flagged onto the course? A figure-8 course may also be more entertaining than a single donut, from both the perspective of driver or spectator.