On Feb 7, 2:47 pm, Mxsmanic wrote:
I'm still in a bit of a quandry as to how to learn to make coordinated turns
in a PC simulator that does not include a motion platform.

I've turned on the visual alignment indicator that MSFS provides, which is a
red "V" that sits squarely ahead in the visual field, effectively bolted to
the airframe. I've been trying to turn such that this V always moves along
the horizon at a constant speed for a given bank angle. Logically, a specific
bank angle in a coordinated turn will always produce a heading change at the
same speed. If the speed at which the horizon is moving varies, the turn is
not coordinated.

Nope, that's not true. It may be true on a windless day in absolutely
level
flight with no changes in pitch, altitude, or airspeed, but it's not
true
in a real plane.

In coordinated flight, the tangent of the bank angle is the ratio
of the horizontal component of lift to the vertical component of
lift.
The horizontal component of lift is what produces centripetal
acceleration, and thus turning.

But if you change total lift, you change both components of lift
simultaneously without changing bank angle.

Try this. Set up a 30 degree bank angle, keeping things coordinated,
and then pull back on the stick sharply. Your turn rate will
increase as your lift increases. Push forward on the stick and your
turn rate will decrease as your lift decreases.

I know, you're going to say "but I just have to maintain level
flight during the turn!" True enough, but now your head
has to be down in the cockpit watching the altimeter and VSI,
which is a very indirect way of getting the information that you
would have gotten from looking at the ball (or still more
directly by feeling the seat of your pants in a real plane).

Furthermore, as already pointed out, the centripetal acceleration
is related to the turn rate by an equation that includes airspeed.
If your airspeed changes during the turn, your turn rate will
change. And your airspeed WILL change.

When you set up the bank, you must increase total
lift in order to maintain the vertical component of lift, and
thus maintain altitude. You increase total lift by increasing
angle of attack. This increased angle of attack increases
drag. Absent a corresponding change in power setting,
this causes a drop in airspeed. The drop in airspeed
causes a further requirement to increase pitch in
order to maintain altitude, causing more drag,
etc. Most small planes don't have enough power to
maintain cruise airspeed if the pilot attempts to
maintain altitude while steeply banked. Even in a
plane with plenty of power in reserve, it's not easy
to precisely judge exactly how much additional
power must be applied to keep airspeed exactly
constant through the turn -- typically, the
pilot doesn't worry about such things for small
turns, and keeps the throttle at its cruise setting.

Also, it seems that in a coordinated, level turn, this V should stay at the
same distance above the horizon throughout the turn.

No. As stated before, you've got to increase angle of attack to
maintain lift. And as your airspeed drops, you keep having
to further pitch up.