XPost: sci.physics, sci.space.tech   
   From: bondage@frontiernet.net   
      
   Joe Strout wrote:   
      
   [snip]   
      
   > > All that needs to be done is to make the upwards push a greater   
   > > impulse than the downwards push - the rocket would essential jerk its   
   > > way upwards - after all there is no "conservation of displacement"   
   > > with such an inertial system.   
   >   
   > There is conservation of momentum, and you just proposed to violate it.   
   > This is a stiction (static friction) drive, and works only when in   
   > contact with some other body.  The movement comes from the difference   
   > between static and sliding friction.  And, BTW, if you want a drive that   
   > only works when in contact wiith a larger body, there are much better   
   > ones (the wheel comes to mind).   
   >   
   > Such a drive is utterly useless in space, however.  Jerk your rocket   
   > around all you want, it'll never make any net progress at all.   
   >   
   > Cheers,   
   > - Joe   
      
      
      One more reason for cheap access at least to LEO: Everyone who thinks   
   they've got a reactionless drive can take a prototype up there, put it   
   outside the ship, and then they can put up, or shut up.   
      
      (I know, there are cheaper ways of doing this [suspend it, and see if   
   you get a unidirectional deflection, instead of gyrating or oscillating   
   around the perpindicular], but my approach is instinctively unambiguous.   
   This, after all, is where the thing is supposed to work.)   
      
      It would be even more interesting, if the losers have to find their   
   own way back to the ground.....   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)