is there yaw in a balanced turn?

[aerdna]

A question that one would think should have an easy answer has split opinions like never before.

In a rate 1 balanced turn, is there any yaw and if there isn't what would be a turn indicator actually detecting?

Someone said 'it depends on how you define yaw' ...

Anybody whants to try and give a definitive answer?
ciao
A

[PIGDOG]

Hmmm, I've had discussions with other people about this before. My interpretation is this:

The ailerons roll the aircraft. Once rolling begins (ignoring adverse yaw) the aircraft begins slowly to yaw. Yaw doesn't mean rudder input. It means any rotation about the vertical axis which changes your heading.

So, in my opinion, yes there is yaw in any turn. But I could be wrong.

[Capt Pit Bull]

the yaw/slip thread (http://www.pprune.org/forums/showthread.php?s=&threadid=143853)

CPB

[NWSRG]

Not sure about this, but here goes...

Yaw is rotation about the vertical axis of the aircraft, with respect to the front to rear centreline of the aircraft.

In a balanced turn, that centreline is itself gently 'swinging' though the angle of the turn. However, the aircraft should not rotate about it's vertical axis within that movement...therefore no yaw.

Imagine the aircraft as being at the end of a piece of string, and being pulled around by centripetal force...this is a balanced turn, and the aircraft should always point in a direction at 90 degrees to the string...so no yaw.

...preparing to be shot down...:p

[PIGDOG]

not trying to shoot you down NWSRG...

Yaw = rotation about the VERTICAL axis
Isn't vertical a constant 90 degrees upright from the horizontal?

Pilot training 101: effects of control, primary and secondary

... ailerons: primary = roll
secondary = yaw

Again, I'm not trying to contradict anyone, just explaining my understanding of it (until someone explains it better to me).

The pig

[jb5000]

Evening,

But is that secondary 'yaw' effect what is removed by using co-ordinated controls?

So *if* the turn was completely balanced, personally I don't think that there would be any yaw.

However my flying experience extends to 5 or 6 solos in air cadet gliders, if anyone is more informed than me please do jump in!

Ah one other thought... If we are considering the vertical axis to constantly remain 'vertical', would you consider a turn where there is 90 degrees of bank (unlikely, I know!) to be yawing the aircraft?

All the best,

James

[BOAC]

Pigdog Yaw = rotation about the VERTICAL axis - you need to add 'of the aircraft' - not in relation to earth. At 90 degrees of bank, rudder still 'yaws' the aircraft.

As to whether there is yaw in a balanced turn...............................

[Vee One...Rotate]

The thing to remember is that the reference frame we consider is important. We need to look at the problem from the reference frame of the aircraft to get any meaningful answers.

When this is done, and bearing in mind that yaw is lateral movement about the longitudinal axis of the aircraft, it can be seen that, in a perfectly balanced turn, any resultant yawing effect from aileron input, will, by definition of the balanced turn, be negated by rudder input. That is, no yawing will be occurring as it has been cancelled out by pilot input.

That is my understanding.

V1R :ok:

[aerdna]

I believe we should differrentiate between skidding/slipping and yawing.

We use rudder in a turn to YAW the a/c in order to prevent it from skidding or slipping, i/e to keep it in balance. That has nothing to do with the fact that the a/c is actually yawing constantly in a turn and i believe that is proved by the turn indicator.
Such instrument is ment to detect yaw, with a gyro mounted with its axis parallel to the longitudinal axis of the plane.
It would not react to any roll or pitch, only to yaw.
Anytime it is telling us we are turning, what actually means is that it is sensing yaw... or not?