removing grip

Bob Evans · Joined: 03 Aug 2001 Posts: 65

Dave,
I'd prefer to use the example of whirling a rock around on the end of a string.
Centrifugal is the force the rock puts on the string (outward), centripetal is the force the string puts on the rock (inward).

On ride height, while my personal experience (albeit, no big league experience) with ride height tends to agree with you (Dave E.), I also see what Mark (Dis. Jr) is getting at.
If the rear ride height was too low and the kart didn't want to go to the apex on turn-in, then raising the rear ride height could easily help the kart on turn-in.
IMO, this would be more an example of "freeing" up the kart than loosening it.
But that's a whole 'nother can of worms.

[ December 04, 2001: Message edited by: Bob Evans ]

Dave Embry · Posted: Tue Dec 04, 2001 2:11 pm Post subject: removing grip

quote:
Originally posted by Mike Goebel:
Unfortunately there is no such thing as centrifugal force or centripetal force. Those are both accelerations. The force occurs when the acceleration is applied to the mass. There is no force trying to pull you out in a turn. You are applying a force on the kart by Turing the steering wheel to make it go around the turn. The kart wants to go straight.

Mike G.

aha.....so if the string were attached to the bullet where the......nah...just kidding!!

Bob Evans · Joined: 03 Aug 2001 Posts: 65

quote:
Originally posted by Mike Goebel:
Unfortunately there is no such thing as centrifugal force or centripetal force. Those are both accelerations.

Mike G.

LOL-- Don't quite know how to begin to respond to that.

Since the object (kart, rock, whatever) is, by definition, revolving around a center in order to generate the force, I'm thinking it does exist- In fact, it can be measured.

Mike Goebel · Posted: Tue Dec 04, 2001 11:46 pm Post subject: removing grip

Unfortunately there is no such thing as centrifugal force or centripetal force. Those are both accelerations. The force occurs when the acceleration is applied to the mass. There is no force trying to pull you out in a turn. You are applying a force on the kart by Turing the steering wheel to make it go around the turn. The kart wants to go straight.

Mike G.

John Learmonth · Posted: Wed Dec 05, 2001 2:57 am Post subject: removing grip

quote:
Originally posted by Dave Embry:

dadgum.....give an old man who has no memory left a break huh! Just call me Archie Bunker!

Can't get me upset today though....#1 son won his first SKUSA Regional race yesterday! Go Team Interkart!

Dave, no hard time intended!

Tell Austin from me "well done mate!". Of course the result might not have been the same without the ZTB (couldn't resist!).

PS You do have the decal prominently displayed on the kart don't you?!

Dave Embry · Posted: Wed Dec 05, 2001 5:17 am Post subject: removing grip

quote:
Originally posted by John Learmonth:
[QB]

Tell Austin from me "well done mate!". Of course the result might not have been the same without the ZTB (couldn't resist!).

QB]

I'll tell him...and thanks! Your ZTB really is a huge asset as was much of our "in-depth" discussions over the past year regarding chassis dynamics.

We trimmed OVER 1.1 seconds off our lap times over the course of this past race weekend doing nothing more than chassis adjustments. It still amazes me that this portion of the forum ("Chassis's and Handling") isn't the most commonly used one since it's the area that's going to make you faster....hands down! (of course many people don't want to "share" their knowledge publicly with their "competitors")

Of course you sometimes get a little dizzy!! (..."going in circles"?....)

Dave Embry · Posted: Wed Dec 05, 2001 5:33 am Post subject: removing grip

quote:
Originally posted by Bob Evans:

Dave,
I'd prefer to use the example of whirling a rock around on the end of a string.
Centrifugal is the force the rock puts on the string (outward), centripetal is the force the string puts on the rock (inward).

That makes sense! So the kart's wt. trying to continue in the same direction ....would be the rock ....and the tires contact patches would be the string. If you further break down the wt. of the kart into the more firmly attached wt. such as the wt. of the chassis, fuel, motor, etc. and the less firmly (but highest % of wt.) attached wt. of the drivers body, then the "seat" might also be "the string" as the moving drivers body pressing into the side of the driver.

Of course this could go on and one since the wt. of the kart isn't a single "fixed" wt. like the rock is. IE. the driver's body presses against the seat...the seat presses again the seat mounts/struts which presses against the chassis rails which press against the.....etc...etc...etc.. I guess that's where chassis dynamics and voodoo chassis tuning comes in. How do you control those "forces" acting upon all those parts as the wt. heads towards those contact patches!!

Mike Goebel · Posted: Wed Dec 05, 2001 5:55 am Post subject: removing grip

quote:
Originally posted by Bob Evans:

LOL-- Don't quite know how to begin to respond to that.
Since the object (kart, rock, whatever) is, by definition, revolving around a center in order to generate the force, I'm thinking it does exist- In fact, it can be measured.

Go read a physics book. You got it backwards.

Mike G.

Christopher Livengood · Joined: 28 Nov 2001 Posts: 119

A while back someone said that there was no such thing as centrifugal force or centripetal force. Mike i beleive it was you. And you beleived this cause you said they were accelerations. And that they had nothing to do with turning because of that. Well in someways your right and in others your wrong. Yes, they both are accelrations. But, when you turn the steering wheel it is a lateral acceleration that ocours. At the point of going straight forward there is no lateral acceleration but as soon as turn it acours it is there.
Now one of the latest posts by Dave is on the right track. He kinda hints and if you think into this further. Every flexing item on the kart is lost weight transfer in to a wheel. So now the more weight transfer as in adding seat struts would do give you more traction. So back to the title of this post "Removing Grip". To remove grip you are going to want to use a soft seat. TIllet makes a good one. Soft axle short hubs. A soft alloy rim, soft or no seat struts. Lower the CG of the kart and driver. Buy a Odenthal 5 degree motor mount. Remove the rear torsion bar and fourth rail if you have one. Basicly soften any thing that transfers weight untill you get that thing loosened up. If you try the things i said and they dont work your seat probably needs a major move.

jconard · Joined: 06 Aug 2001 Posts: 158

It is accurate to refer to centifugal and centripetal as measures of acceleration.

When combined with mass a measurable force can be measured that is a result of accelerating mass. Purely definitiional, but the formulas bear that out. Kinda of like g-force is called force but we are really measuring acceleration. That's why we lable it in g's. Gravity by the way is measured in terms of acceleration 10 meters/second/second. When you create lateral acceleration of two times that of gravity you are accelerating everything on the kart at 20 meters per second per second (not a typo means starts at a rate of 20m/s and picks up 20 m/s in speed for every second the acceleration continues.)

Each piece on the kart will experience different levels of strain dependant purely on their mass. That is why force is calculated as a result of acceleration. It is a combination of acceleration and the mass of the object being accelerated. Sadly the response box does not offer resolution for vector diagrams.

Gary Lawson · Joined: 21 Aug 2001 Posts: 547

Dave,
I have tested that theory and you are correct it doesn't change the weight. I thought that it would but it doesn't. It will change the handling, but it won't tell you on the scales.

Bob Evans · Joined: 03 Aug 2001 Posts: 65

LOL, No, I don't think I do.

Dave Embry · Posted: Thu Dec 06, 2001 2:03 pm Post subject: removing grip

quote:
Originally posted by Gary Lawson:
Dave,
I have tested that theory and you are correct it doesn't change the weight. I thought that it would but it doesn't. It will change the handling, but it won't tell you on the scales.

Right....I'm sure it does actually change the wt distribution front to back but it must be too small of a change to really register on our scales with the small amount we are raising/lowering the chassis with spindle spacers or axles. If we were to REALLY raise it up, I'm sure there would then be enough of a wt. change to make a big enough difference to be noticeable.

Mark Dismore Jr · Advertiser Joined: 21 Jul 2001 Posts: 1099

quote:
Originally posted by Dave Embry:

Of course you sometimes get a little dizzy!! (..."going in circles"?....)

Was that a crack at me?

Dave Embry · Posted: Thu Dec 06, 2001 5:32 pm Post subject: removing grip

quote:
Originally posted by Mark Dismore Jr:

Was that a crack at me?

haha!!!! Absolutely not!!

Say, how's your Dad. Has he gotten anything lined up for next year yet? Someone said the other day they thought he might be retiring.