Landing a 262

[Oldman731]

There is no debate about a stall! A stall is defined as when the wing stops producing lift!

This.

- oldman

[colmbo]

To be precise you have to mention AOA and airflow separation when talking about a stall. 

A wing on a parked airplane is not producing lift nor is it stalled.

[Oldman731]

To be precise you have to mention AOA and airflow separation when talking about a stall. 

A wing on a parked airplane is not producing lift nor is it stalled.

True, true.

- oldman (there's a wise guy in every crowd...)

[WaffenVW]

Total loss of lift in the graph is at 22 degrees. Stall is 18 degrees. Say you're flying at 18.1 degrees. Now you're stalled. Not a huge difference. You are past CLmax and still flying under control. You haven't dropped your nose or a wing. 19 degrees is just a matter of degree.

And we are talking WW2 fighters generally not that particular lift curve which simply illustrates my point.

I'm afraid not. Once your AoA is beyond critical the onset of stall is usually abrupt. This is because the loss of lift (even if it is minor at first) leads to an uncommanded increase in AoA (aircraft starts dropping). The increase in AoA worsens the stall and thus increase the AoA rapidly until the aircraft becomes uncontrollable. We're talking a fraction of a second to a couple of seconds depending on aircraft type, G-loading, attitude and other factors.

[FLS]

I think some of you are confusing the stall with the separation of airflow that occurs after the stall.  This supports my statement that the stall definition is debatable.    There are more than one accurate descriptions of a stall.

It's instructive to look at the lift curves for different wings and the obvious differences in post stall lift.

[Mongoose]

Wow, look what I started.

  Thanks you all for the input.  From a quick read of the first few posts, I quickly picked up that I was trying to land the jet the same way I would land my normal prop-driven plane, and not giving it nearly enough time to slow down.  I rarely take a 262 for a spin, but I will remember this next time.

[Zimme83]

I think some of you are confusing the stall with the separation of airflow that occurs after the stall.  This supports my statement that the stall definition is debatable.    There are more than one accurate descriptions of a stall.

It's instructive to look at the lift curves for different wings and the obvious differences in post stall lift.

In this case it is not debatable, as i said - You need a modern fighter jet to be able to fly and control a plane at an AoA beyond stall. A WW2 plane cannot do it even in theory.

[FLS]

In this case it is not debatable, as i said - You need a modern fighter jet to be able to fly and control a plane at an AoA beyond stall. A WW2 plane cannot do it even in theory.

So your theory is that you can't fly at 18.1 degrees AOA on the lift curve in the graph?

[Zimme83]

I dont have a theory, it is very simple. once the critical AoA is exceeded the wing will stall and the only thing you can do then is is to decrease AoA and restore the airflow over the wing. The exact critical angle differs from plane to plane and it is not so relevant here. When the wing stall it happen so fast that it is irrelevant if you can go 0.1 degree past critical AoA or not. Look at the first video i posted, it clearly shows that once the critical AoA is reached the airflow separates from the wing and the wing will no longer produce any lift.
There isnt any smooth "curve" like in the chart, its more like falling of a cliff.

[FLS]

I dont have a theory, it is very simple. once the critical AoA is exceeded the wing will stall and the only thing you can do then is is to decrease AoA and restore the airflow over the wing. The exact critical angle differs from plane to plane and it is not so relevant here. When the wing stall it happen so fast that it is irrelevant if you can go 0.1 degree past critical AoA or not. Look at the first video i posted, it clearly shows that once the critical AoA is reached the airflow separates from the wing and the wing will no longer produce any lift.
There isnt any smooth "curve" like in the chart, its more like falling of a cliff.

Perhaps your example doesn't represent the behavior of all wings.

The lift curve in the graph shows too much lift after the stall to indicate separation of flow.

[BaldEagl]

It's instructive to look at the lift curves for different wings and the obvious differences in post stall lift.

If a stall is defined as the point at which the wing no longer produces lift how can there be "post stall lift"?

[FLS]

If a stall is defined as the point at which the wing no longer produces lift how can there be "post stall lift"?

Because the stall AOA  is defined as the point of CLmax on the lift curve not as the loss of lift from air flow separation. What pilots casually refer to as a stall may be the nose or wing dropping after the stall AOA is passed. 

When the definition is "no longer able to maintain level flight" then it's more obvious that lift has simply decreased prior to the point of separation of airflow.

[Busher]

If a stall is defined as the point at which the wing no longer produces lift how can there be "post stall lift"?

Formal definition: A stall is a condition in aerodynamics and aviation wherein the angle of attack increases beyond a certain point such that the lift begins to decrease. The angle at which this occurs is called the critical angle of attack.

The stalled wing still produces lift.. just less lift than the weight of the aircraft.

Also, a given wing stalls at the same AoA regardless of airspeed.

[Busher]

That's a fine definition for a uniform wing section. What do you call it when the wing doesn't have the same AOA from root to tip?

Also most wings don't depart at Clmax, they lose lift as AOA increases but separation leading to departure occurs after that point which defines the stall.

FLS, with respect Sir, Angle of attack is an aerodynamic term that applies to an aircraft's flight condition. What you refer to in the reference "from root to tip" is actually "angle of incidence". AOI is adjusted to force sections of wings to stall at different times as angle of attack increases. I am sure you can visualize that if the tips of a swept wing jet were permitted to stall before the roots, the resulting change in center of pressure would cause a pitch up - making an already poor situation worse.

[FLS]

Thanks Busher I'm aware of your points. The conversation started with landing with flaps and as you know the flaps change the incidence of the inner wing relative to the outer wing. I was making a point about being stalled while maintaining control since the outer wing's incidence gives it a lower AOA compared to the inner wing for a given attitude. This was in contrast to the uniform wing section typically used to illustrate attached flow.