On torsdag, okt 24, 2002, at 23:13 Europe/Amsterdam, Richard Vizins wrote:
Sverker: I actually thought you had me there for a while ;). But your idea about momentum to store the access energy is flawed. Remember that your cranks
Sorry, I used the wrong term, I should have written "inertia", not "momentum". My theory is sound, I think, see below.
The only thing that drives the bike is the power from the rider. This power the whole vehicle is simply the result of this power. All of the kinetic energy has come from the rider (if he wasn't starting down a hill). I think
I wouldn't deny that...
you were after the fact that the moment of inertia (tröghetsmomentet) of the vehicle is quite large compared to the forces we are talking about. This is
Yes, that's correct.
what I have been trying to say all along: the power in the spike is in part lost trying to accelerate a relatively heavy object (the vehicle). A
This is where I think you are lost. The energy, however, is not lost, it is stored as a minute increase of inertia (and thus speed) of bike + rider, and this extra inertia then drives the bike and rider over the dead spots. No need or use for additional springs in the system above those already there in the form of elastic materials of bike and rider's body.
The reason there is no perceived pulsation in speed is that the energy provided by the legs is small compared to the energy stored as inertia.
The benefits of a good circular pedalling technique, I say, is not smooth energy input per se, but better use of resouces, i.e. to spread the load on more muscle and to avoid having muscles work against oneother.
Sverker
-- Sverker Fridqvist, PhD Eindhoven University of Technology Faculty of Architecture * Design Systems Group http://www.ds.arch.tue.nl/General/Staff/sverker