Practicality of ion propulsion? Answered
I've been trying to design a compact propulsion system and have considered ruling out liquid fuel chemical engines due to bulkiness (the fuels are surprisingly heavy, go figure). I've read about ion propulsion and its use in spacecraft because of its high efficiency, at least in a vacuum. However, in such cases the thrusters are rather large and provide a relatively small amount of thrust, usually less than one newton per tonne. Now I'm certainly no rocket scientist and know little about the efficiency of thrust, but to me that doesn't exactly seem remotely powerful, especially considering there are roughly 4.5 N to every pound.
Anyway, regardless of the exact fundamentals involved, I have a limited amount of space here so I'll keep it brief.
What I would like to know is if a small ion thruster could be made that can reasonably lift a ~40lb weight a few inches off the ground. I've seen compact ion thrusters built by amateurs, so I know they can be built in small sizes, but no clear demonstration of their power has been shown. I need to know if what I'm asking can be done, and if so, how.
And please, for the love of all that is holy, I want serious answers only.