From: alcore@uurth.com   
   Copy: sci-space-tech@moderators.isc.org   
      
   On 20 Jan 2005, daniel.m.v@terra.es wrote:   
      
   [snip]   
   >When the stake stops forward wheel angular motion quantity transforms   
   >in a component of linear motion quantity and in another component of   
   >angular motion quantity. You can test this at home with the back wheel   
   >of you bicycle braking it when it is turning to the maximum speed you   
   >can give it.   
   >   
   >It is not the same to brake a wheel by one side than by the axis. In   
   >the last case there is a motion quantity transformation (angular ->   
   >angular + linear), in the first case there is not transformation   
   >(angular -> angular).   
   >   
   >I have been talking with people and we think that following this basic   
   >principle, propellantless propulsion systems can be built because   
   >angular motion quantity can be transformed in a component of linear   
   >motion quantity and in another component of angular motion quantity. If   
   >we isolate the linear motion component whe can build a propulsion   
   >device.   
   [snip]   
      
   Ummm... no.   
      
   In the movie you cited, what *really* happened was that when the front   
   wheel stopped spinning, it transferred all of it's angular momentum to the   
   bike... which forced the bike to put it's front wheel down... which   
   because it was locked and unable to spin, immediately acted as a brake   
   against the ground... which violently stopped the bike.  Unfortunately the   
   rider didn't stop all that fast... so he continued forward with a   
   share of the Bike's angular momentum and *all* of his own linear   
   momentum... until he too hit the ground.   
      
   As for your premise...   
      
   My 10 speed bicycle used caliper brakes mounted at the top of the wheel.   
   By your theory this should have interfered with stopping as the angular   
   momentum of my wheels got turned into forward momentum...  This was simply   
   *not* the case.   
      
   The bike and it's caliper brakes form a closed system.  While the calipers   
   were certainly subjected to a linear force vector in the forward   
   direction, they in turn were held in place by the stucture of the bike   
   (including the wheel axles... and wheels) pushing back with enough force   
   that they remain in place.   
      
   While it is certainly possible to project an object using a rotating drum   
   as a launcher, in this case, your "propellant" is the entire launcher   
   assembly... as your projectile flys away from it.   
      
   Gene Pharr   
   Slidell LA   
      
   --   
   Alcore Nilth - The Mad Alchemist of Gevbeck   
   alcore@uurth.com   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)