On 07/08/14 14:41, Troy Prideaux wrote:
No, Jake there is a limit with the reactionless drive, exactly as there's a limit with rocket engines. The limit is *energy*. A rocket engine is propelled by *energy* and guess what, a reactionless drive device is also propelled by *energy* and both are limited by the onboard supply unless you transfer energy to the devices from external sources. But more importantly, the claim here is of a violation of the conservation of *energy*. Nothing to do with mass limitations or mass transfer. If that was critical, you could effectively replace the reactionless drive device with an electrical motor propelled device with the assumption of frictionless movement along a surface for the thought experiment to arrive at the same conclusion. Troy
Lets see if my physics works for this one.(Keeping in mind that I have no particular bias against this drive (I want it to work) and I feel that if the argument being made is true, it means that any reaction-less drive is impossible (IE photon thrust should not work))
work = force * distance power = work / timeAssuming the thruster takes a constant power input and produces a constant output force regardless of its speed.
The thought experiment I propose is to put the thruster on an arm connected to a generator so as the thruster thrusts the arm spins the generator.
The power from the generator is going to be speed * force (In the real world speed = volts, torque = amps)As RPM of the motor goes up the power the generator makes will increase for the same constant torque value.
At some point the power generated will exceed that required to run the generator and presto you have a perpetual motion machine.
My argument against this is that photon thrust works, if you replace "magic drive" with a torch then at some point you get perpetual motion without magic.
(I know that at 300MW for 1 newton of thrust you probably run into something like the thing must be spinning at light speed to work *but*
http://en.wikipedia.org/wiki/Laser_propulsion#Photonic_Laser_Thruster_.28PLT.29 claims thrust in the order of millinewtons at presumably sane beam powers)