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Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 4:27 pm
by Steve Glusman
anyone know what the radius was set up as?????
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 4:29 pm
by George Schilling
Steve Glusman wrote:anyone know what the radius was set up as?????
45'
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 5:06 pm
by 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
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 5:50 pm
by 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.
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 5:52 pm
by Mako Koiwai
The AMCI skidpad is 200'
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 5:55 pm
by 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.
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 6:50 pm
by Mako Koiwai
El Toro:
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 9:01 pm
by 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.
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 10:43 pm
by KJ Christopher
Steve Glusman wrote: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.
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 10:50 pm
by KJ Christopher
Mako Koiwai wrote: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.
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sat Aug 29, 2009 11:02 pm
by 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?
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sun Aug 30, 2009 3:46 am
by 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?
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sun Aug 30, 2009 7:38 am
by Mako Koiwai
Yeah ... I never got that either. Jeff?
Blub blub blub, blub blub .... blub blub blub
Re: Skid Pad -- what was radius on 8/22 practice?
Posted: Sun Aug 30, 2009 12:03 pm
by Marshall Grice
Steve Glusman wrote: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.