Apologies for not changing the title on my last post on this. <<The engine doesn't accelerate past v because the net forces all balance.>>
Okay, in an "ideal" drag=free system, thrust increases with centrifugal force as chamber pressure, etc., increase. The specific kinetic energy of the propellant in the inertial frame must increase as it flows to the tip engines, and this energy must be supplied by engine thrust, so I suppose (without doing the calculus--no time, sorry) that at some tip velocity, all the thrust of the tip engines is needed to bring the propellant up to that tip velocity. But there is no apparent reason for that tip velocity to equal the exhaust velocity "v", and I should think the ultimate tip velocity would be very much higher. The kinetic energy of the exhaust in the inertial frame should equal the chemical energy of the propellant-which, at a large distance, would be apparent as a positive radial velocity of propellant mass increments moving outward in spiral waves. This seems not that much different from what happens in a lawn sprinkler, except that some of the exhaust energy comes from chemical reactions rather than feed pressure. Globally (imagine an opaque Gaussian surface around the system with propellants going in and exhaust going out), it would be as if the same propellants were exhausted through a non-rotating engine with a radial nozzle. --Best, Gerald _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
