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Re: What chassis are you running ?
Posted by 'davidmc' on 29 Mar 2011 @ 12:42

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davidmcJoined: April 2003
Total Posts: 2
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I have no problem with being accused of being boring. I can't think of anybody more boring than someone who does not think critically for themselves (sheep I call them and they account for the bulk of the population)

1) Wrong. Sit on the dummy grid and steer the kart. The outside front lifts. now tip the kart from the rear bumper. The inside rear lifts. Now continue doing this and the chassis flexes at the outside front around the waist. Now imagine returning the steering to dead ahead with the load still applied to the three points of contact (OF, IF, OR). The inside rear then remains off the ground because of the "set" the kart has taken.

2) See above. It doesn't return to sitting flat (for which I read IR loaded again) until load comes off the outside front.

3) Agreed, the kart isn't biased by steering input (it has none afterall). However, until load comes off the outside front, the chassis remains flexed and the inside rear lightened. Altering stiffnesses changes the share of load each tyre takes. Altering track width and centre of gravity alters how much overall load transfer occurs.

4) Read again. There is not a huge angle of lift. The amount of inside rear lift due to steering angle is directly proportional to caster angle. Sit on the dummy grid, go to full lock and lift the kart at the inside of the rear bumper. This is the total amount of lift and it's usually only 1-2 inches. You see higher degrees of lift because the chassis flexes at the OF and around the waist. By allowing the rear axle and associated assemblies to flex also, you can maintain the contact patch of the rear tyre. A larger affect would be fitting a front torsion bar for instance (which is why axle changes are fine tuning tools, it's a slight change that is significant at the limits) which would reduce flex around the waist.

Secondly, I'm not talking about the axles harmonics. If you've studied simple harmonic motion, circular motion and spring mass systems you'll have learnt that they're analogous. Get a pendulum, an old record turntable with a marker at one point) and a sprung mass. Set each in motion and, if you have selected the parts carfeully, the frequency and amplitude of the pendulum will match the frequency and amplitude of the sprung mass and frequency and amplitude when projected onto a linear plane of the point on the turntable. Add a damper to these systems and fix their frequency and you'll alter the amplitude of each.

5) Not sure where 5 went :-).

6) Thirdly, steel is a good conductor of heat and cools quite easily. However, if you could measure the temperature around the bearing area directly after cornering you would see an increase in temperature.

Also, it's not a damper in the traditional sense, in the same way that a spring is not a damper. But, like manufactured springs (i.e., not ideal) they do have a damping component. It is this I believe is altered across the various axles.

I'd love to build a Simulink model and show what I'm trying to say but I don't have time. Maybe a basic excel spreadsheet could do the same?

Message Thread:

Hard or soft axle? by 'SteveAW' (28 Mar 2011 @ 18:06)

What chassis are you running ? by 'ScoobyScene' (28 Mar 2011 @ 18:23)

Re: What chassis are you running ? by 'SteveAW' (28 Mar 2011 @ 18:33)

Re: What chassis are you running ? by 'MikeMcMahon' (28 Mar 2011 @ 23:11)

Re: What chassis are you running ? by 'itpro' (28 Mar 2011 @ 23:35)

Re: What chassis are you running ? by 'davidmc' (29 Mar 2011 @ 0:06)

Re: What chassis are you running ? by 'itpro' (29 Mar 2011 @ 0:29)

Re: What chassis are you running ? by 'davidmc' (29 Mar 2011 @ 8:39)

Re: What chassis are you running ? by 'itpro' (29 Mar 2011 @ 10:19)

Re: What chassis are you running ? by 'davidmc' (29 Mar 2011 @ 11:06)

Re: What chassis are you running ? by 'itpro' (29 Mar 2011 @ 11:54)

Re: What chassis are you running ? by 'davidmc' << You are here!

Re: What chassis are you running ? by 'Rafe005' (29 Mar 2011 @ 7:55)

Re: What chassis are you running ? by 'NJB' (29 Mar 2011 @ 9:34)

Re: What chassis are you running ? by 'SteveAW' (29 Mar 2011 @ 10:05)

Re: What chassis are you running ? by 'davidmc' (29 Mar 2011 @ 10:14)

Re: What chassis are you running ? by 'chriskasch' (29 Mar 2011 @ 10:21)

Re: What chassis are you running ? by 'itpro' (29 Mar 2011 @ 10:35)

Re: What chassis are you running ? by 'BanzaiBoy' (29 Mar 2011 @ 11:00)

Re: What chassis are you running ? by 'davidmc' (29 Mar 2011 @ 11:18)

Re: What chassis are you running ? by 'QuickOldTimer' (29 Mar 2011 @ 13:10)

Rafe by 'itpro' (29 Mar 2011 @ 10:28)

Re: Rafe by 'davidmc' (29 Mar 2011 @ 11:14)

Re: Rafe by 'itpro' (29 Mar 2011 @ 12:22)

Re: Rafe by 'PaulMRotax' (29 Mar 2011 @ 12:53)

Re: Rafe by 'davidmc' (29 Mar 2011 @ 13:04)

Re: Rafe by 'PaulMRotax' (29 Mar 2011 @ 13:25)

Re: Rafe by 'davidmc' (29 Mar 2011 @ 13:38)

Re: Rafe by 'PaulMRotax' (29 Mar 2011 @ 13:44)

Re: Rafe by 'davidmc' (29 Mar 2011 @ 13:54)

Re: Rafe by 'davidmc' (29 Mar 2011 @ 12:56)

Re: Rafe by 'itpro' (29 Mar 2011 @ 13:14)

Re: Rafe by 'davidmc' (29 Mar 2011 @ 13:32)

Re: Rafe by 'itpro' (29 Mar 2011 @ 14:20)

continued.... by 'itpro' (29 Mar 2011 @ 14:24)

Re: continued.... by 'itpro' (29 Mar 2011 @ 14:41)

Re: Grip continued.... by 'John' (29 Mar 2011 @ 14:59)

Re: Grip continued.... by 'itpro' (29 Mar 2011 @ 16:13)

data! by 'BanzaiBoy' (29 Mar 2011 @ 18:40)

Re: Grip continued.... by 'John' (29 Mar 2011 @ 18:46)

Re: Grip continued.... by 'Traxtar' (29 Mar 2011 @ 18:48)

Re: Grip continued.... by 'John' (29 Mar 2011 @ 22:28)

Re: Grip continued.... by 'itpro' (30 Mar 2011 @ 10:28)

Re: Grip continued.... by 'John' (30 Mar 2011 @ 12:07)

Re: Grip continued.... by 'davidmc' (30 Mar 2011 @ 12:15)

Re: Ian ----- Grip continued.... by 'John' (30 Mar 2011 @ 15:35)

Re: Ian ----- Grip continued.... by 'Bod' (30 Mar 2011 @ 15:40)

Re: Ian ----- Grip continued.... by 'DavidMH' (31 Mar 2011 @ 13:30)

Re: Grip continued.... by 'itpro' (31 Mar 2011 @ 2:38)

Re: Grip continued.... by 'itpro' (30 Mar 2011 @ 15:44)

Re: Grip continued.... by 'John' (30 Mar 2011 @ 16:15)

Re: Grip continued.... by 'itpro' (30 Mar 2011 @ 17:34)

Re: Grip continued.... by 'John' (30 Mar 2011 @ 22:03)

Re: Grip continued.... by 'QuickOldTimer' (30 Mar 2011 @ 22:22)

Re: Grip continued.... by 'John' (30 Mar 2011 @ 23:33)

Re: Grip continued.... by 'QuickOldTimer' (30 Mar 2011 @ 23:55)

John... by 'itpro' (31 Mar 2011 @ 2:22)

Re: Ian... by 'John' (31 Mar 2011 @ 5:31)

Re: John... by 'itpro' (31 Mar 2011 @ 11:11)

Re: Ian... by 'John' (01 Apr 2011 @ 0:32)

Re: John... by 'itpro' (01 Apr 2011 @ 1:19)

Re: continued.... by 'PaulMRotax' (29 Mar 2011 @ 15:42)

So what about tyre graining? by 'SteveAW' (29 Mar 2011 @ 17:48)

Re: So what about tyre graining? by 'itpro' (29 Mar 2011 @ 18:21)

Re: So what about tyre graining? by 'PaulMRotax' (29 Mar 2011 @ 18:22)

Hopping by 'NJB' (29 Mar 2011 @ 18:48)

NJB by 'Traxtar' (29 Mar 2011 @ 19:14)

Re: Hopping by 'Inter61' (29 Mar 2011 @ 19:17)

Re: Hopping....PFI by 'NJB' (30 Mar 2011 @ 11:49)

Re: Hopping....PFI by 'davidmc' (30 Mar 2011 @ 12:27)

Re: Hopping....PFI by 'itpro' (31 Mar 2011 @ 2:32)

Re: Hopping....PFI by 'NJB' (31 Mar 2011 @ 15:54)

Re: Hopping....PFI by 'itpro' (31 Mar 2011 @ 17:18)

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