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["WILLIAM JONES" <billj AT harborside.com>]

I've pretty well decided to use cut-up tires as waterwheel paddles.  The same 
goes for float protectors for the solar heat engine, in a larger model.
Last I mused on the subject, I wondered whether a waterwheel could use both 
the Pelton momentum principle, and also have the water ride downhill.
I set up an equation for the total power.  At this point there were two 
unknowns, the desired turning speed, and the vertical distance that water
flows through the pipe before striking the waterwheel.  Using calculus, I 
differentiated the power expression with respect to both of these variables,
and set both derivatives equal to zero.  Surprising to me, I was able to 
solve this system of non-linear equations fairly easily.  Even more 
surprising 
was the result.  The interpretation seemed to be to allow the water to fall 
the entire available distance.  In other words, forget about the "Ferris 
wheel"
and let the water develop the maximum speed possible before entering a Pelton 
wheel.  It's no wonder they're popular.
That being said, I can't use a Pelton wheel at all.  The momentum effect can 
only be the icing on the cake.  Why?  To produce a constant torque,
necessary to operate a coil pump all year round, both the volume and velocity 
of the water have to be constant.  I need quite the opposite, since the
creek slows quite a bit in summer.  The one nice thing about the "Ferris 
wheel" is that it will always produce the same torque, no matter what rate the
water trickles in.
And they require no skill to make.