Dave Ewing
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How are drums and discs different initially?
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
Ah, this is something I haven't included yet... Is this due to compliance in
the bushings and arms? That test machine doesn't look cheap...
>"Brake bias" (as we use it) is the ratio of either wheel torques or, better
I've read a bit on the proportioning valves, but never heard of ride-height
sensitive valves... Interesting. Are they used independantly at each wheel
usually, so brake bias changes at each wheel seperately as a function of
roll/pitch/wheel travel?
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
Or just bending at the attachment points to the chassis...
Used, iirc, on the rear of pick-up trucks to nearly shut off the rear
brakes when the truck is UN-loaded -- prevent rear lock-up. Just
a simple link between the valve and the axle senses the distance from
axle to chassis and varies the rear brake proportion.
Hmm.... I wonder if Ruud's Racer will do finite element analysis anytime
soon and allow us to build our own frames, specify materials, etc... :-)
Intersting though, I'll read up on that in your book. Thanks.
Oh, ok. Clever device..
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
<URL: http://www.tentenths.co.uk/http://www.tentenths.co.uk/ >
-Jari
Please remove SPAMLESS before replying via email. Thank you.
--
( Y ) : ``I'm not blipping the throttle.
()~*~() : It's... traction control :)
(_)-(_) . --Greger Huttu
Heh, that's at the end of the tasklist, right before 'build a car for
real and just race that'. Much easier. ;-)
Ruud van Gaal
Free car sim : http://www.marketgraph.nl/gallery/racer/
Pencil art : http://www.marketgraph.nl/gallery/
Hehe. But would the physics be as good? What about low speed instability?
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
Hm, probably the physics in the sim would be better. ;-)
Still, I was amazed to notice that my real car could stand still will
sideways on a small slope! Now if only I could figure that out?! ;-)
Ruud van Gaal
Free car sim : http://www.marketgraph.nl/gallery/racer/
Pencil art : http://www.marketgraph.nl/gallery/
The pads on discs sit much closer, so are likely to pick up
first. Drum brake shoes sit a little further away on fairly
heavy return springs, but given a leading-trailing arrangement
it's possible that they'll bite slightly more when the shoes
eventually touch (the leading shoe has a somewhat positive
'self-servo' effect; discs have a slightly negative value).
IIRC it was suggested on my degree course that we use a
threshold pressure for the drums and a percentage efficiency
for the discs when calculating brake split (especially at
low pressures), though just how close that is to the actual
characteristics I don't know.
Jonny
Thanks, Jonny.. I might have more questions for you on this later.
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
My little car sim screenshots:
http://performancesimulations.com/scnshot4.htm
