cheapracer
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| posted on 21/4/09 at 05:18 PM |
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quote:
Originally posted by kb58
quote:
I've found saying something is often pointless even if well-intended. It often causes said dangerous person to get defensive, coming back with
an "oh yeah, I'll show you," reply, and crash their car anyway...
[Edited on 4/21/09 by kb58]
 Ain't that the truth.
Kurt I'm confused by your signature, is the mid engine book out or not? Or does that refer to Kimini?
It's coming....
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kb58
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| posted on 21/4/09 at 06:28 PM |
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That's the Kimini book. The new one is in the works along with the car.
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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cheapracer
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| posted on 22/4/09 at 05:29 AM |
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quote:
Originally posted by kb58
That's the Kimini book. The new one is in the works along with the car.
Thanks Mate and good luck with it.
It's coming....
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Sam_68
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| posted on 9/1/10 at 05:21 PM |
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quote:
Originally posted by Syd Bridge
Rollcentres of any type DON'T come into the design process of a road or race car. Anyone telling you that they do, and professing to be a
designer, is pulling your whatever.
Whilst I have some sympathy for Syd's position (in as much as the geometric roll axis is a myth), I can state absolutely and
categorically that the above statement is incorrect, false, untrue, erroneous, complete-and-utter-tosh, and bollocks.
Whilst (as Syd asserts) cars certainly do not roll about their geometric roll centres, the front and rear roll centres are an important factor in
dictating diagonal weight transfer via the sprung mass when cornering, which in turn has a major influence on understeer/oversteer balance.
The roll centre heights therefore have a major part to play in the basic handling balance of the car, and roll centre movement when
cornering can cause all sorts of nasty issues, since it will result in variations in diagonal weight transfer as the car negotiates the corner.
I know for a fact (having had detailed personal discussions with them), that a number of very emininent race car designers (including a couple
of ex-F1 Chief Designers and several designers of championship winning hillclimb single-seaters) pretty much start off their design from
geometric roll centre positions, whenever they're designing a car with significant suspension compliance (ie. everything apart from
wings-and-slicks circuit single-seaters), with the geometry focusing on minimising roll centre movement throughout the working range, and everything
else - spring rates, tyre widths, ARB rates etc. - developed from there.
In terms of the OP's original question, if you were thinking purely about cornering, you'd actually want the camber agin to be
arranged so that the outside (loaded) wheel progressively went into negative camber as it loads up in the corner, as most tyres generate most
girp with a surprising amount of negative camber, and you pretty much wouldn't care about what the inner wheel was doing, as it progressively
takes less and less of the load as cornering forces increase.
In reality, however, this approach would leave you with unacceptable camber change under pitch (dive and squat) or single-wheel bump, leading to a car
that was squirrelly under braking and had uncertain grip under hard acceleration.
Unless you have active suspension, all supension geometry is a compromise and unfortunately it's up to the individual suspension designer to
choose his own balance of priorities: there's no wrong and right, which is why the discussions frequently get so heated between people who think
that there is...
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