Re: Geared unicycles? Old hat
On Tue, 25 Oct 2005 02:34:37 -0500, john_childs wrote:
> - Greater powertrain system efficiency
>I don’t know what they’re comparing the efficiency to. They may be
>comparing it to an automatic automobile transmission
Indeed! Note how they say powertrain SYSTEM efficiency. That is not
the drive alone, but includes also an engine. E.g. a combustion engine
that is only optimally efficient at a particular rpm. With a CVT the
engine may be kept at optimum efficiency, compensating for greater
losses in the CVT. Still, the NuVinci may ‘eat’ more power than a
conventional gear box, automatic or not.
Does the human muscular system also have optimal efficiency at a
particular rpm (cadence)? Even if this is so, I wouldn’t like it if
the NuVinci would eat a substantial amount of the power I provide.
I would like to know a typical number (percentage? absolute?
combination?) for the power loss in the NuVince drive. It may be
telling that such a number is lacking on the site.
(I wrote a much more thought-out reply but my PC crashed before I had
posted it. Indeed, it crashed when I went to unicyclist.com but I
guess that’s rather coincidental.)
Klaas Bil - Newsgroup Addict
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