rotation and translation
oh what a fabulous day for riding a bicycle. or anything outside, i guess. i only got to ride in this morning, with a perfectly matched set of wet/dry bulb temperatures: 51 °F and 51 °F. but this is not the sort of 100% humidity that persons ordinarily complain about (those persons who ordinarily complain about the weather, that is, instead of doing something about it). no sir, this is not that sort of humidity. in fact it is now 68 °F, with a dew point of 46 °F. and high pressure and lots of sun and just oh boy what am i doing inside? working, that's right, calculating recurrence intervals of flooding on the saginaw, looking for seasonality in the downstream stage at the bay, looking for other trends and figuring out what periods we should model, some floods and some not so floods. but i should be doing this after dark; now, at this time, i should be outside.
i have mentioned before that almost perfect moment at the beginning of the day, rolling along and hearing the almost perfect silence of my commuter bicycle. well, a little less perfect on mornings when i ride with the younger son up to school, but this morning about as close to perfect as one could expect, having spent some time last night cleaning the chain and the cog and chainring, and then tightening it up just so and then applying the triflow, and wiping the excess, and then this morning the glistening chain and the perfectly smooth and silent rotation of the chainring and cog and the wheels, and the perfectly smooth and silent translation of the chain, the top moving forward and the bottom moving backward, relative to the frame of the rider that is, the bottom actually moving forward as
omega1*r1*(rw/r2 - 1)
where:
omega1 = angular velocity of chainring (--)
r1 = radius of chainring (L)
rw = radius of wheel (L)
r2 = radius of cog (L)
but i digress. all i really want to get underneath me is that perfect smooth silence again, even if i have to battle a hundred white men in a hundred gmc envoys along the way. so here's hoping...
--->puff-a-diddle
i have mentioned before that almost perfect moment at the beginning of the day, rolling along and hearing the almost perfect silence of my commuter bicycle. well, a little less perfect on mornings when i ride with the younger son up to school, but this morning about as close to perfect as one could expect, having spent some time last night cleaning the chain and the cog and chainring, and then tightening it up just so and then applying the triflow, and wiping the excess, and then this morning the glistening chain and the perfectly smooth and silent rotation of the chainring and cog and the wheels, and the perfectly smooth and silent translation of the chain, the top moving forward and the bottom moving backward, relative to the frame of the rider that is, the bottom actually moving forward as
omega1*r1*(rw/r2 - 1)
where:
omega1 = angular velocity of chainring (--)
r1 = radius of chainring (L)
rw = radius of wheel (L)
r2 = radius of cog (L)
but i digress. all i really want to get underneath me is that perfect smooth silence again, even if i have to battle a hundred white men in a hundred gmc envoys along the way. so here's hoping...
--->puff-a-diddle
posted by cicadashell at
5:50 PM
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