Originally Posted by
jgray
All the text books I read tell me that the predominant secondary effect of roll is yaw IN THE SAME DIRECTION OF BANK. They mention adverse yaw as an initial secondary effect, but emphasise that the adverse yaw is nowhere near as strong as the tendency to slip then yaw towards the lower wing.
My question is this: In every aircraft I have flown, the need to hold same side rudder to combat adverse yaw is obvious and very noticeable, yet I have never needed OPPOSITE rudder whilst turning. If the slip then yaw issue was so prevalent, wouldn't we all need to be turning with opposite rudder held on all the time?
Thanks in advance to any aerodynamics afficionados..
I believe that the books are referring to sort of a "bigger picture" than just the adverse yaw.
Step back a couple of steps and look at what an airplane does in a turn.
It yaws. A lot.
Take a plane on a heading of north. Roll right, and hold the turn till your heading is 090, During the course of that turn, your plane yawed (rotated around it's vertical axis) 90 degrees.
That 90 degrees of yaw is waaaay more significant than the +/- 5 degrees of adverse yaw that you may or may not get, depending one the aircraft model.
Even if you had 5 degrees of uncorrected adverse yaw, your airplane would still have yawed 85 degrees.
I believe that is what the text books are referring to as the predominant secondary effect.