[Spaceships] Reactionless Drives, Pseudovelocity, and NOT breaking a setting (much)

[vicky_molokh]

Greetings, all!

It's not my first attempt, and not my first request for aid either. I think I learned some things from the previous attempts and previous advice, and perhaps I'll have better luck this time.

So, I want to a coherent stat-up of how reactionless drives (and, by necessity, pseudovelocity) work in a setting. I know they're TL^, and that means that the best I can hope for is to minimize the damage to the setting in the process. So far, setting-breaking consequences that I would like to avoid the most:

• Hypervelocity kinetic-kill applications. This pretty much necessitates invoking Pseudovelocity.
• Perpetual Motion Machines. This seems to mean, at a minimum, that changes in potential energy due to lifting off from a planet must come from actual, real energy of capacitors aboard the ship that power the reactionless engine and that whatever displacement-velocity that can be achieved in excess of the amount of energy pumped through KE=½×mv² has to be pseudovelocity.

Relativity is an acceptable casualty, and in fact an etheric/hyperdynamic cosmos with some sort of frame-dragging by highly-massive celestial bodies is a suitable outcome. I'm not quite sure how much trouble the setting gets into due to breaks in conservation of momentum (angular and/or linear), but I realise that this is hard to avoid if invoking PV.

The intended effectiveness range of the drives is roughly 1G of 'pseudo+real' acceleration at 1 Power Point of 'normal' work, though I'm guessing that there might be a need to make a drive consume more power while pulling out of a gravity well (as per the potential energy delta relative to the well . . . I think that should be affordable, but I'm not sure yet).

What other things need to be done and adjusted in order to make it a reasonably playable technology that doesn't break settings?

Thanks in advance!