In article <%[email protected]
>, [email protected]
> Doug Taylor writes:
> > Okay, pundits, what's the verdict?
> To bad these products never show a velocity profile for these solutions to non existent problems.
> If they did, you could see that this is nothing more than a complex way of converting the output
> of a round chainwheel to that of an elliptical one, using additional levers, bearings, and links.
> The claim of inefficiency with conventional cranks assumes that all development of piston engines,
> be they steam, diesel or gasoline powered, was amiss and that the correct solution for converting
> linear motion to circular motion will be found on bicycles. Investigating the definition of
> efficiency makes the concept fall apart because inefficiency means that energy is lost to heat
> somewhere in the power cycle. This is not so. Motion over the top and bottom of crank revolution
> requires no work and therefore, no power.
> Just as with IC engines, all available gas pressure on the piston is expanded and that work
> propels the crankshaft, regardless of geometric considerations of leverage and speed during the
> cycle. The same is true on a bicycle which approximates the working of a piston engine admirably.
> There is no inefficiency in pedaling that can be altered by invoking more muscles or operating at
> irregular velocity.
> I find amazing how these gimmicks keep arising and how seriously they are taken even though they
> are as much like perpetual motion machines as they can get, producing energy where the is none.
Jobst, many IC engines use offset small-end wrist pins to change the power stroke characteristics of
I see where you're going with this, and remain agnostic myself on the merits of rotor cranks,
Biopace, etc. But I think these offset cranks are in use in a good many applications where there is
a desire to make the power and return strokes asymmetrical.
Ryan Cousineau, [email protected] http://www.sfu.ca/~rcousine
President, Fabrizio Mazzoleni Fan Club