tgrayson
New Member
Excellent insight, and I think you're correct. Unstable is a good description of both shallow and steep turns.
Overbanking v. Adverse Yaw
- Thread starter meritflyer
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Excellent insight, and I think you're correct. Unstable is a good description of both shallow and steep turns.
meritflyer
Well-Known Member
Sorry, I am jumpstarting an old thread and prolly going to bring up something already discussed but I just read a chapter about adverse yaw and here is what it had to say (in a nutshell).
Explanation:
The fact that the outside wing (aileron down) in a turn produces a higher resultant velocity, has a greater camber and therefore produces a higher amount of lift (along with drag as a bi-product of lift), contributes only a small portion to adverse yaw...
The main contributing factor deals with the relative wind, angle of attack, and the lift vectors produced as a result of their position in a turn. Assuming a turn to the right, starting with the inside wing (right), the relative wind strikes the inside wing at a smaller angle and therefore produces a smaller AoA. Secondly, the relative wind is now coming from "below" the wing as a result of the downward moment of the wing. Because lift always acts perpindicular to the relative wind, the lift vector must lean somewhat forward, which pulls the descending wing forward.
The raised wing (left), has the relative wind contacting the wing from the upper surface of the wing which produces a greater AoA and creates a retarding lift vector.
... When rolling into a turn, therefore, it is the force of lift that pulls forward on the low wing and retars the high wing, resulting in adverse yaw.
Okay, so there is the condensed version. Thought it was a little more detailed than the PHAK.
Explanation:
The fact that the outside wing (aileron down) in a turn produces a higher resultant velocity, has a greater camber and therefore produces a higher amount of lift (along with drag as a bi-product of lift), contributes only a small portion to adverse yaw...
The main contributing factor deals with the relative wind, angle of attack, and the lift vectors produced as a result of their position in a turn. Assuming a turn to the right, starting with the inside wing (right), the relative wind strikes the inside wing at a smaller angle and therefore produces a smaller AoA. Secondly, the relative wind is now coming from "below" the wing as a result of the downward moment of the wing. Because lift always acts perpindicular to the relative wind, the lift vector must lean somewhat forward, which pulls the descending wing forward.
The raised wing (left), has the relative wind contacting the wing from the upper surface of the wing which produces a greater AoA and creates a retarding lift vector.
... When rolling into a turn, therefore, it is the force of lift that pulls forward on the low wing and retars the high wing, resulting in adverse yaw.
Okay, so there is the condensed version. Thought it was a little more detailed than the PHAK.
tgrayson
New Member
What it says is more or less true, but note a couple of things:
1) The rolling velocity does produce part of the adverse yaw, but it only does so while rolling.
2) The degree of the adverse yaw due to this effect depends on your roll rate.
3) The deflected aileron still produces part of the adverse yaw; how much depends on the above factors and the aileron configuration itself.
4) I mentioned this in my second post on this thread.