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  • From: "WILLIAM JONES" <billj AT harborside.com>
  • To: <homestead AT lists.ibiblio.org>
  • Cc:
  • Subject: [Homestead] Wirtz Bike
  • Date: Sun, 17 Jun 2012 22:59:56 GMT

Our ultimate goal is to have a power-assisted bike that runs on compressed
air.  I call it the Wirtz bike.  Since a regular bike already has a set of
gears that keep the required torque within a certain range, it's best to
utilize the existing pedal assembly.  Simply attach a coil of hose on both
sides and half-fill each coil with water.  About 30 pounds of water shouldn't
weight things down too much.  Hey, it's not for racing.  Now, what happens
when compressed air is applied to the inner coil?  If they're wound in the
right direction, the water will push forward until a high torque is
developed.  Now, if we just continue injecting air, it will just bubble up in
the coils.  So we inject water for another half a cycle.  After that, water
will just flow over the top, so we inject air, and so forth.  I call the
device that alternates between air and water a Wirtz alternator.  It's
basically just a double-barrel air displacement pump that manages the
injection of air and water into both coils of hose.  The only remaining thing
that needs to happen is that air and water need to dump into a gravity-based
separator, so that air can just be released, and water can flow back into its
reservoir.
A magnet-based air displacement pump can be seen in the second attached pic
from my previous post.  This model used hollow iron floats (cans) to detect
when the chambers are full of water.  Since then I've concluded that it's far
easier to compare the weights of the two cylinders with a sort of balance. 
The hydraulic valve in the picture is connected up so that it changes to the
opposite state once one cylinder clearly outweighs the other, since that
means that one is full of air and the other is full of water.  Note that the
volume of each chamber is equal to about that of half a loop of hose.
Each side also requires not just one but two swivel valves, just like the one
used in an Archimedean screw.
Getting sleepy, so I'll write more later.
Bill



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