Skid Pad -- what was radius on 8/22 practice?

[Steve Glusman]

anyone know what the radius was set up as?????

[George Schilling]

anyone know what the radius was set up as?????

45'

[Mako Koiwai]

that's small ... usually skid pads are like 100' radius for steady state set-up. I believe that's what we had for the EVO Set-Up School

[Webster Jessup]

45' is tiny.

Like Mako said. 200' diameter skidpads are the norm.

There is enough room. The runways at El Toro are 250' wide edge of pavement.

[Mako Koiwai]

The AMCI skidpad is 200'

[Steve Ekstrand]

If the runways are 250' wide, we probably max out at about 170' diameter to maintain 25' safety margins on the outside of the imaginary course boundary.

90' diameter seems like something I'd inflict on the kid karters.

[Mako Koiwai]

El Toro:

[Steve Glusman]

could the Spitfire really pull 1.3 g's ?

Acceleration = V^2/R

I was doing 30 mph

30 mph *5280 ft/mile /3600 sec/Hr = 44 ft/sec

44 ft/sec ^2 / 45 ft /32.2 = 1.3 G's....

IU wasn't expecting that many g's.

[KJ Christopher]

could the Spitfire really pull 1.3 g's ?

Acceleration = V^2/R

I was doing 30 mph

30 mph *5280 ft/mile /3600 sec/Hr = 44 ft/sec

44 ft/sec ^2 / 45 ft /32.2 = 1.3 G's....

IU wasn't expecting that many g's.

Are you sure you were really hitting 30mph tight to the cones? I think I saw 33 on the RX8 speedo.

[KJ Christopher]

El Toro:

The photo is a little deceptive. If you look at the area of the runway were we had the skidpad (one up and way to the left), you can see how much of the edge is compromised by cracks and weeks. When George and I set it up, we started with 50' radius, but when we noticed how close the edges came to the junk, we switched to a 45' radius.

[Mako Koiwai]

Karen likes to use our smallish skid pad as part of an oval. She goes out ... and then flys up to the corner so that she has to brake, corner and exit ... out, slows to change direction and back the other direction.

When we did the Evo Set-Up school ... we first set-up so the car felt good on the skid pad. But at least my Suby was then WAY to loose in transition on the AX handling course. I think Barco said that with proper triple adjustable shocks one should be able to achieve proper steady state and transitional handling?

[Steve Ekstrand]

My understanding is that triples allow you to tune for surface irregularities (high speed bump) and car loading (low speed bump). I don't see how that gets you around the classic setup compromise?

[Mako Koiwai]

Yeah ... I never got that either. Jeff?

Blub blub blub, blub blub .... blub blub blub

[Marshall Grice]

could the Spitfire really pull 1.3 g's ?

Acceleration = V^2/R

I was doing 30 mph

30 mph *5280 ft/mile /3600 sec/Hr = 44 ft/sec

44 ft/sec ^2 / 45 ft /32.2 = 1.3 G's....

IU wasn't expecting that many g's.

1) the center of mass for your car was not going around a 45' radius arc on a 45' skidpad, and you probably weren't exactly on the inside edge of the cones. So i'd guess 48 or 49' is a better estimate of the radius.
2) you didn't go exactly 30mph around the entire circle, and in all likelihood after you take tire slip angles into effect you were probably going less then 30mph at all times (the speedo reads higher when the tires slip and you're trying to maintain the same speed).

i'd guess you have at least a .5g error margin.