Ron Natalie writes:

And you profess to know everything even though you fly nothing.

I have never claimed to know everything. I don't need to fly to know things.

Of course you'll have a terrible time convincing people of that.

Not if they understand the theory, which many pilots do not.

All coordinated flight involves is that the tail of the aircraft follow
the front in the flight path (this is confusing to most people primarily
because of the FAA's stupid pseudo-physics definition of it).

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

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.

--
Transpose mxsmanic and gmail to reach me by e-mail.