>-----Original Message-----
>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] 
>Sent: 21 September 2006 13:18
>To: piclist@mit.edu
>Subject: Re: [EE]: Reactionless Drive
>
>
>Michael Rigby-Jones wrote:
>
>> Only if you let go the stone, whereupon it's potential energy is 
>> converted into kinetic energy.  If you put the stone on a shelf it 
>> would stay there, and you don't have to provide power to a shelf do 
>> you?
>
>But you have to provide force. Movement is not only about 
>energy, it is primarily about (resulting) force. 

Work = Force x Distance

Remove either force or distance and work = 0.  There is no primary dependance on either force or motion.



>He is only considering the forces generated by the reflections
>on the end pieces. That's fine as long as the waveguides are 
>cylindrical, because then the forces generated by the reflections
>on the sides cancel themselves out. But with a cone-shaped 
>waveguide, the reflections on the side walls have a resulting 
>force towards the smaller end, which possibly cancels out the
>difference between the forces generated by the reflections at
>the end pieces. 

>I haven't made the calculations to show how much force this 
>reflection on the cone shaped side walls generates and whether 
>it matches the difference in force generated at the end pieces, 
>but neither has he in his paper. Which seems strange. To me, it 
>may be that there is a net difference, but it at least would have
>to be considered -- and in any case it would reduce the effect.

I agree that this is a possible explanation.  The first thing I thought was if the net thrust is produced by the difference in area between the ends of the conical cylinder, then why not reduce the shape to a pure cone?  Perhaps this would not produce a resonant cavity with high enough Q?

Regards

Mike

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