Overbanking Tendencies

[uwochris]

Hey guys,

Is there an easy way to try to explain why the a/c has an overbanking tendency in a climbing turn and why it does not have one in a level or a descending turn? I am working on my instructor rating now and I want to try to use an explanation that is accurate, but also easy to understand and demonstrate.

I find the explanation that "the outer wing travels faster and has a higher AOA" is a little difficult to get the student to visualize and understand it properly. This is how it was explained to me, and I never really did understand it all to well.

Specifically, I cannot try to provide an explanation to the following questions:

1) In a level turn, both wings should be at the same AOA, but the outer wing still travels faster. Why is there no overbanking tendency then in a level turn?

2) In a descending turn, the inner wing is supposedly at a higher AOA, while the outer one travels faster. There is no overbanking tendency because these effects are offset; however, if the inner wing is now at a higher AOA, should not that wing have more drag, and shouldn't there be a yawing tendency towards the inside of the turn? (i.e. aileron drag occurs because one wing is at a higher AOA than the other... in this case, the inner wing is at a higher AOA... shouldn't the aileron drag be higher on the inner wing then?)

Well, that's all for now. Thanks in advance!

Chris.

 

[Sc00ter]

I've had a couple of beers but I think you will find the answer in dihedral.

Good luck,

scoot

 

[mar]

Rotational aerodynamics...

...is for helicopters.

Next thing you know you'll want to learn about Settling with Power and Dynamic Rollover...

I think you pretty much have all the pieces: outside wing, AoA, dihedral, etc.

Sounds like the only other thing you need is a model to help the student visualize the manuever before you demonstrate it in the airplane.

One additional thing I liked to point out was the slightly crossed controls when in a steep turn.

Of course most pilots do this subconsciously but I thought by pointing it out it helped to underline the basic principles previously discussed.

Good luck.

 

[greyhound]

overbanking tendencies..

In a shallow banked level turn: Dihedral prevents overbanking. Dihedral effect is still greater than the amount of extra lift produced by outside wing even though it travels slightly faster through air. (Positive Static stability)

In a medium banked level turn: Outside wing travels faster producing more lift but it is only just enough that the dihedral effect and extra lift produced become equal.
So no over banking tendency exists.(Neutral static stability)

In a steep banked turn: Again outside wing travels faster producing more lift than inside wing but at a greater value than the dihedral affect, so overbanking will occur.(Negative static stability)