Mxsmanic wrote:


Coordinated turns maintain an acceleration vector parallel to the yaw axis.

Not true. In a normal coordinated turn (lets do 45 degrees of bank),
the acceleration vector points towards the inside of the turn. The
yaw axis itself is canted at a 45 degree angle.

It is impossible to do this in a 90-degree bank. There is always a vertical
component produced by gravity, and this means the acceleration vector can
never be completely horizontal, and yet it would have to be in a 90-degree
bank for a coordinated turn. The horizontal component would have to be of
infinite magnitude, which is not possible.

Sorry, that's untrue. The acceleration is always horizontal in a level
turn regardless of bank.

There
is nothing that prevents coordinated 90 degree banks. In most aircraft
however, you're not going to be able to sustain that.

You cannot achieve it in any aircraft, much less sustain it.

That would be news to a lot of acro pilots. The fallacy (in addition
to your other mistakes of physics and aerodynamics) is that the wings
are the only aerodynamic surface in play.