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125cc Shifter Kart

Author Topic: 125cc Shifter Kart  (Read 5168 times)

Offline Seanus

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125cc Shifter Kart
« on: August 20, 2020, 10:25:17 AM »

 
« Last Edit: August 28, 2020, 08:15:18 PM by Seanus »
I always knew the Sun shone out of my arse. Sean's bum is an anagram of Sunbeams.

Offline Bacchulum

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Re: Shifter Kart
« Reply #1 on: August 20, 2020, 11:06:38 AM »
You'll have to wait until I finish work.

2+2=√16

Offline Bacchulum

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Re: Shifter Kart
« Reply #2 on: August 20, 2020, 05:41:44 PM »
Cheers Seanus! ;D ;D
That's the first time I've been able to (virtually) emulate my father and drive a shifter kart around Lakeside. 8)

There was nothing unexpected, handled like a kart, slid like a kart, generated grins like a kart. ;D ;D ;D
I haven't hit anything yet, so no test on the collider.

You don't happen to have a version of Surface Paradise International Raceway ('70s vintage) stashed away somewhere do you? ???

2+2=√16

Offline Seanus

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Re: Shifter Kart
« Reply #3 on: August 20, 2020, 11:21:14 PM »
Here's the SP on the Kart physics hack.

A kart has no suspension other than tyre and chassis flex, and a solid rear axle. To get that axle to turn some weight must be taken off one of the wheels to allow some slip in lieu of a differential.
With a lot of caster and extreme scrub radius, the front wheels, whilst steering, jack up the inside rear wheel to achieve this.
AC's suspension can be arranged to have almost zero movement using sod all travel and million tonne springs, but the jacking force seems to ignore this and moves the suspension up and down rather than the chassis.
The hack was to roll the suspension over 900  and arrange it to bind rather than move. The jacking force now not only lifts the chassis but through some programming quirk actually applies that force to the rear axle. Setting a large enough front spring rate ends up applying so much force to the rear axle that it comes off the ground! Despite what Newton has taught us about real world physics. (also demonstrating that AC has no gravity as such).
By tuning the caster angle and front spring rate I can dial in just enough jacking so that the Kart turns.
The apparent snap spins you'll find whilst driving these Karts is due to steering too much and lifting the entire rear end off the deck. Take that as a sign that you were going too fast for that corner, however you can also induce this over steer if you need to back it in.


Now using a less hacky hack.  :o :o :o
« Last Edit: May 05, 2021, 05:12:35 PM by Seanus »
I always knew the Sun shone out of my arse. Sean's bum is an anagram of Sunbeams.

Offline Bacchulum

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Re: Shifter Kart
« Reply #4 on: August 21, 2020, 07:17:37 AM »
I was inducing the oversteer in conjunction with a down shift into The Carousel and Eastern Loop, worked well. ;)

2+2=√16

Offline Seanus

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Re: 125cc Shifter Kart
« Reply #5 on: May 05, 2021, 05:04:32 PM »
Dawned on me that Karts have zero sprung mass, so I redid all three Karts I have done. Seemed to help. (but placebo may have reared its ugly head)
You can pick up all three from you know where.  :P
I always knew the Sun shone out of my arse. Sean's bum is an anagram of Sunbeams.

 

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