🚀 go-pugleaf

I do not have experience with the specific case that you mention, but I would
like to point out a few things you may wish to consider:

1) Your gyroscope will be 10 feet in diameter?  If it is not spiining in
a vacuum, you will find that due to the high velocity of the spinning rim,
a lot of air friction will be generated.  You probably won't store a full
"charge" more than a day.  And, of course, putting such a large gyro in
a vacuum is impractical.  I recall an article a few years ago in 
Scientific American about gyro powered cars, but those gyros were spinning
in a vacuum.

2) With all that weight on them, your thrust bearings will fail very soon.
You may wish to consider a more exotic oil-lubricated thrust bearing.
Look in some mechanical design journals.

3) Balancing a gyro automatically is a non-trivial task.  Have you thought
about the "simple mechanical device"? How does it work?

Eric