Coordinated turns and the little ball

How much of a movement in the little ball in the turn indicator
corresponds to something you can feel in a real aircraft? And how
much of a movement represents an error large enough to affect flight
safety or proper maneuvering?

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

Mxsmanic wrote:
How much of a movement in the little ball in the turn indicator
corresponds to something you can feel in a real aircraft? And how
much of a movement represents an error large enough to affect flight
safety or proper maneuvering?


The answer is that it depends. It is more important to keep the
plane coordinated at slower airspeeds and/or higher load factors.

It is also important on climbout (high angle of attack & large P
factor) because you want the best climb capability you can get
especially with underpowered aircraft. Needless to say it is well
to keep it coordinated in cruise as well since drag is greatly
incresed thus reducing cruise efficiency.

An experienced pilot can feel it when the aircraft is not
flying coordinated. If you were a passenger with a drink sitting
on a table in the back you would notice un-coordinated flight
because the liquid would not be level in the glass.

Recently, Mxsmanic posted:

How much of a movement in the little ball in the turn indicator
corresponds to something you can feel in a real aircraft? And how
much of a movement represents an error large enough to affect flight
safety or proper maneuvering?

All of this depends on what you're doing at the time. One can slip fairly
drastically -- with the ball pretty far off center -- without much of a
physical sensation. OTOH, one can pin the passenger against the wall with
the same amount of slip. How dangerous any of this is also depends on what
you're doing at the time. If you're careless and go into a stall, then
it's possible that you'll wind up in a spin, which if you're close to the
ground can kill you. The bottom line is that if the pilot is in control of
the aircraft, all of this can be quite safe and routine.

Neil

I'm a flight instructor so I can feel 1/4 of a ball out, but that's
what I'm trained to do. However, in your simulator, I would not worry
about it. You're not going to be able to reproduce the environment
similar to the aircraft without having rudders, etc. When I play MSFS I
set it to autocoordination.

-Robert, CFII

Mxsmanic wrote:
How much of a movement in the little ball in the turn indicator
corresponds to something you can feel in a real aircraft? And how
much of a movement represents an error large enough to affect flight
safety or proper maneuvering?

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

On Fri, 06 Oct 2006 15:04:36 GMT, "Neil Gould"
wrote:

Recently, Mxsmanic posted:

How much of a movement in the little ball in the turn indicator
corresponds to something you can feel in a real aircraft? And how
much of a movement represents an error large enough to affect flight
safety or proper maneuvering?

All of this depends on what you're doing at the time. One can slip fairly
drastically -- with the ball pretty far off center -- without much of a
physical sensation. OTOH, one can pin the passenger against the wall with
the same amount of slip. How dangerous any of this is also depends on what
you're doing at the time. If you're careless and go into a stall, then
it's possible that you'll wind up in a spin, which if you're close to the
ground can kill you. The bottom line is that if the pilot is in control of
the aircraft, all of this can be quite safe and routine.

Read Kershner on cross-control stalls on the base to final leg.

Even novice passengers can feel uncoordinated flight, but they won't
know why they feel queasy.

Don

"Mxsmanic" wrote in message
...

How much of a movement in the little ball in the turn indicator
corresponds to something you can feel in a real aircraft?

Pretty much everyone can sense large deflections -- they'll
feel as they're being pushed to one side of the plane. The
more experienced you are, the smaller movements you can
detect without looking.

And how
much of a movement represents an error large enough to affect flight
safety or proper maneuvering?

It is considered to be good style, and it is generally more
efficient, to maintain coordinated flight in most situations.
Better for passengers & easier not to spill your drink.
But in a slip -- used to deliberately increase air resistance
when you are too fast or too high, or to align the plane with
the runway in a crosswind landing -- the plane will be
uncoordinated on purpose; the ball on the inside of the turn
doesn't indicate "an error" at all, nor does it make the
flight any less safe.

A skid -- which doesn't have any purpose outside of
training AFAIK -- is more problematic. This tends to be a
issue on base-final turns when pilots are tempted to use
too much rudder to tighten up the turn if they've
underestimated wind drift or otherwise miscalculated. When
you are in a turn, the inside wing is always moving through
the air a bit slower than the outside wing and so is closer
to stalling. A skidding turn increases this airspeed difference,
and if you're too slow turning base to final, the danger is that
it'll make it more likely that the inside wing will stall and start
a spin. Just where the ball might be when this happens would
depend on your airspeed, so there's no simple "red line" beyond
which you can't push the ball if that's what you're looking for.

"T o d d P a t t i s t" wrote in message
...
I'm a flight instructor, too, and I don't think I can detect
steady 1/4 ball out, but I *can* detect when we're
coordinated and the student suddenly uses inappropriate
rudder, either too much or too little. It's much easier to
detect changes than to detect where the ball is. [...]

It's almost as if your body is especially good at detecting acceleration or
something.

You're right. The best yaw indicator in the airplane is the nose of the
airplane. Instructors should be able to pick up the slightest amount of
uncoordination simply by watching the nose. Its also a good idea to wean the
student off the ball and onto the nose as soon as possible. I'll go so far
as to say that it was my common practice to do this on the first flight.
In my opinion, much too much attention is placed on the ball as a
coordination verification tool, and much too little attention paid to the
nose of the airplane by a great many CFI's.
Its a choice I know, but I've been teaching this way for a very long time,
and have found it the optimum method for teaching coordination to a new
student.
I will also say that in flying advanced acro, I don't even look at a ball.
At low altitudes in demonstration work, you don't have the time or the
luxury of referencing the ball. You reference the nose of the airplane. Its
the best "ball" you'll ever have.
Dudley Henriques

"T o d d P a t t i s t" wrote in message
...
"Robert M. Gary" wrote:

I'm a flight instructor so I can feel 1/4 of a ball out,

I'm a flight instructor, too, and I don't think I can detect
steady 1/4 ball out, but I *can* detect when we're
coordinated and the student suddenly uses inappropriate
rudder, either too much or too little. It's much easier to
detect changes than to detect where the ball is. When the
student is steady, your butt is sitting steady on the seat.
As soon as the amount of coordination or uncoordination
changes, the pressures change and you can feel it. The
change in pressure on my butt is what signals me to look at
the ball (or yawstring in the case of a glider) to see how
far it's going to move. Often I feel that signal before it
has changed much at all.
--
Rule books are paper - they will not cushion a sudden meeting of stone and
metal.

- Ernest K. Gann, 'Fate is the Hunter.'

ktbr writes:

The answer is that it depends. It is more important to keep the
plane coordinated at slower airspeeds and/or higher load factors.

Is it possible to spot an uncoordinated turn visually, just by
watching how things move out the window, or is it only perceptible
through the movement of the aircraft?

I'm trying to figure out how hard I should try to keep the ball
centered. In the sim I can't feel any movement, so I don't know how
tightly I have to control the turn (based on what the ball says).

It is also important on climbout (high angle of attack & large P
factor) because you want the best climb capability you can get
especially with underpowered aircraft. Needless to say it is well
to keep it coordinated in cruise as well since drag is greatly
incresed thus reducing cruise efficiency.

I note that rudder can keep the turn coordinated, but changes in pitch
seem to be able to do it, too. Pulling back on the stick in a turn
not only maintains altitude, but it also seems to coordinate the turn
to some degree.

An experienced pilot can feel it when the aircraft is not
flying coordinated. If you were a passenger with a drink sitting
on a table in the back you would notice un-coordinated flight
because the liquid would not be level in the glass.

I've seen videos of pilots rolling an aircraft while pouring drinks.
I haven't tried that in the sim.

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

Neil Gould writes:

All of this depends on what you're doing at the time. One can slip fairly
drastically -- with the ball pretty far off center -- without much of a
physical sensation. OTOH, one can pin the passenger against the wall with
the same amount of slip.

What distinguishes the two types of slip?

How dangerous any of this is also depends on what
you're doing at the time. If you're careless and go into a stall, then
it's possible that you'll wind up in a spin, which if you're close to the
ground can kill you. The bottom line is that if the pilot is in control of
the aircraft, all of this can be quite safe and routine.

The rudder is controlled in my sim by twisting the stick (not very
realistic, but inexpensive), and it's difficult to keep the ball
centered that way. I'm slowly getting better at it, though.

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