We're ALL pilots!

[FastEddieB]

So, I will accept his modified statement that you won't stall if you stay coordinated AND don't exceed critical angle of attack.

Of course, the first part is unnecessary, right?

[drseti]

I guess I wasn't being clear, Eddie. If you go uncoordinated, that may result in lowering your critical angle of attack, even if you weren't aware (and didn't change your pitch angle or back-pressure at all). So, staying coordinated will keep the critical angle of attack where you think it is.

[CharlieTango]

Which gives the bigger safety margin for avoiding a stall/spin entry on the left base to final turn?

a) Coordinated turn
b) Slipped turn

[drseti]

CharlieTango, why do there have to be rhetorical questions?

[FastEddieB]

I guess I wasn't being clear, Eddie. If you go uncoordinated, that may result in lowering your critical angle of attack...

Maybe getting a bit pedantic here, but...

...is not the critical angle of attack an angle specific to any particular airfoil design?



So, a given airfoil will always stall at the same angle of attack*.

Now maybe it's accurate to say that the pitch angle of the plane at the stall may change for each wing in uncoordinated flight.

Is that more accurate?


*Understanding that various high lift devices in effect change the airfoil shape.

[drseti]

Maybe getting a bit pedantic here, but...

Who am I to quibble over pedantic?

maybe it's accurate to say that the pitch angle of the plane at the stall may change for each wing in uncoordinated flight.

Imagine an aircraft with two wings, each of the same airfoil (well, I hope so!), each attached to the same fuselage. In coordinated fight, no matter what you're doing, the two wings are each at the same angle of attack.

Now, go uncoordinated. The two wings (same airfoil, same airframe, remember) are now at different angles of attack. That's because, even if each is at the same pitch angle, the relative wind is different between the slower wing and the faster wing. And that's what makes a spin possible, should a stall occur.

Pedantic enough for you, Eddie?

[FastEddieB]

Imagine an aircraft with two wings, each of the same airfoil (well, I hope so!), each attached to the same fuselage. In coordinated fight, no matter what you're doing, the two wings are each at the same angle of attack.

Now, go uncoordinated. The two wings (same airfoil, same airframe, remember) are now at different angles of attack. That's because, even if each is at the same pitch angle, the relative wind is different between the slower wing and the faster wing. And that's what makes a spin possible, should a stall occur.

Pedantic enough for you, Eddie?

Yep!

That's what I thought you meant! Just wanted to clarify.

Also in play is the blanketing effect of the fuselage on the inside wing in a skid, leaving less effective lifting surface and disrupting the airflow.

But you knew that!

[drseti]

But you knew that!

And, if I didn't, I do now.

[3Dreaming]

Maybe getting a bit pedantic here, but...

Who am I to quibble over pedantic?

maybe it's accurate to say that the pitch angle of the plane at the stall may change for each wing in uncoordinated flight.

Imagine an aircraft with two wings, each of the same airfoil (well, I hope so!), each attached to the same fuselage. In coordinated fight, no matter what you're doing, the two wings are each at the same angle of attack.

Now, go uncoordinated. The two wings (same airfoil, same airframe, remember) are now at different angles of attack. That's because, even if each is at the same pitch angle, the relative wind is different between the slower wing and the faster wing. And that's what makes a spin possible, should a stall occur.

Pedantic enough for you, Eddie?

Wouldn't the speed effect on angle of attack while turning be the same whether coordinated or not, except while changing from coordinated to un-coordinated flight. While changing you are accelerating one wing and decelerating the other, after you are established wouldn't it be the same as turning coordinated. Except for the blanked portion of the wing on one side.

[FastEddieB]

...after you are established wouldn't it be the same as turning coordinated. Except for the blanked portion of the wing on one side.

Isn't the inside wing flying a slightly smaller radiused turn than is the outer?

If so, it must travel slightly slower.

Kind of like why a car needs a differential.

I think.

[MrMorden]

Coordination has NOTHING to due with a stall. If you remain below critical angle of attack, you will not stall. Full stop.

Well, sort of. Although his terminology is questionable, there's a kernel of truth to what CTLSi said this time around.

Consider that, if you're seriously uncoordinated, one wing may inadvertently exceed its critical angle of attack, even though you did nothing to overtly increase pitch angle. That's because the critical angle of attack is influenced by more than just pitch and airspeed. So, I will accept his modified statement that you won't stall if you stay coordinated AND don't exceed critical angle of attack.

True, but you are not talking about exceeding angle of attack in this case, but *perception* of whether you are exceeding angle of attack. Whether the wing stalls or not has nothing to do with whether you thought you were going to exceed critical AoA or not...only whether or not it happens.

It's kine of like saying you will not exceed the speed limit if you don't drive faster than the limit and you watch our for cops. The second is really irrelevant.

[3Dreaming]

...after you are established wouldn't it be the same as turning coordinated. Except for the blanked portion of the wing on one side.

Isn't the inside wing flying a slightly smaller radiused turn than is the outer?

If so, it must travel slightly slower.

Kind of like why a car needs a differential.

I think.

That was addressed in the first part of my post that you didn't quote, but maybe not so clearly.

Paul said, "Imagine an aircraft with two wings, each of the same airfoil (well, I hope so!), each attached to the same fuselage. In coordinated fight, no matter what you're doing, the two wings are each at the same angle of attack."

I think the angle of attack is different between wings while turning, because of what you describe above. I also think un-coordinated flight does not change angle of attack, except while levels of un-coordination are changing. For example in a established un-coordinated turn the angle of attack difference between wings is because of the turn and not the un-coordination.