how critical is passive stability?

How much energy would be expended by a rotating
cylinder, with R= 2500 M, L= 5000 M? As I recall, the
rotational Velocity would be around 60 km/hour.

With energy input to two counter rotating
cylinders,refreshing the rotational V would be a
simple matter requiring both cylinders to be
synchronous. The air drag would be necessary to mix
the air in the passive containment vessal and prevent
accumulation of CO2 and other inert gases. Drag then
becomes just another energy investment, like fans in
free fall, to maintain dynamic atmospheric mixing,
necessary if we're to grow plants on the inside wall
of the passive cylinder. I just like the idea of using
all available space for SOMETHING, from as simple as
an air containment vessal to as complex as a micro G
shirt sleeve manufacturing environment to air
purification via plants growing in that free fall
area.

I really need more input than the statement "a
significant" problem. HOW significant IS significant?
How much energy cost are we talking about? The point
is, there doesn't seem to be any reason other than the
drag mentioned for not using a pressurized passive
shield vessal. It could solve a great many other
problems, from the use of non-rotating end caps, to
structural support of the active cylinder, to air
storage, to air refreshment with green growy things,
to micro g manufacturing,,,how do all those uses
balance out against the energy investment to overcome
drag?

Gary 7