Quote:
Originally Posted by Don Rotolo
Nice drawings. We are investigating if car-type steering will have any advantages with our chassis this year.
Several threads (and my own tests) have shown that the 2:1 ratio of transverse to lateral friction is a myth, reality shows it to be about 6:5.
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the 2:1 ration i am referring to is static vs dynamic friction coefficients. a simple test would be to fix 3 wheels leaning towards each other like a tripod. then incline the field material and measure the angle they start sliding at. while they are sliding, decrease the angle until they stop and measure that angle. the ratio of the sine of the angles should approximately match the ratio of the coefficient of frictions static vs dynamic. it will also be your increase in acceleration if you can prevent your wheels from sliding either laterally or transversely.
static friction is intermolecular bonding between 2 stationary surfaces (even if one is rolling). dynamic friction is trying make those bonds while the surfaces are sliding plus includes momentum. they should be very different.
that being said, the ratio is much closer with some materials and especially at low friction so your testing may be correct. thanks for posting that.