There is a path that, if followed by a vehicle, produces a
loop at exactly 1G. It can be visualized as a combination
of a path that accelerates downward to produce 0 G and a
path that makes a perfect circle at exactly 1 G in the 0 G
background field.

This is true as far as it goes. However, in order to do this in still
air, using wings, the aircraft has to assume certain attitudes that
preclude the 1G from being pointed in the same direction relative to the
cabin throughout the maneuver. To illustrate, consider the aircraft at
the bottom of a loop done in this manner, after completion. It would be
essentially horizontal (since it's the bottom of the loop and the
centripetal forces are pushing outward (downward w.r.t the cabin).
However, it is descending at whatever rate a freefall would be after
however long it takes to complete the maneuver. I bet that's pretty
fast - probably much faster than the forward speed of the airplane.

Consider the relative wind against the wings - I bet you'd see much more
than a 1G load on them were they to actually get into this configuration.

Now, it would work if the surrounding air were also freefalling.
However, the circumstance that would lead to freefalling air with an
airplane inside of it is not a circumstance in which I want to be the
pilot.

Jose
r.a.student snipped - I don't follow that group
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