Landing a 262

[hitech]

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.

FLS: Your confusing your self my mixing terms. Per any flap configuration there is only 1 stall AOA.  That angle is when the entire wing starts producing less lift with more AOA. You can absolutely maintain level flight with some parts of the wing stall, (normally it will  be the wing roots) but the WING has  not yet stalled because more AOA can still generate more lift.


AS to the 262 the key is slowing down before you try to begin you pattern and glide slope. Nose up first, flaps down, then descend also works instead of a break turn. But if you are trying to descend with out first having the flaps down, it is almost impossible to slow down.


Also this is a much more typical lift curve then show previously in this thread. Most airfoils do not drop off sharply. And many start to increase again with higher AOA.

See this document for very High AOA lift curve.




See this document for very high AOA lco's
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090001311.pdf

HiTech

[FLS]

Thanks Hitech. I know that any aircraft, even an inverted gull wing F4U with flaps down, has a 0 lift AOA and a stall AOA regardless of what happens with parts of the wing. I was trying to explain that you can fly beyond the critical AOA and the stall point is not the departure point. I would have been better off pointing out the video did not identify the critical AOA and referred to the total loss of lift as the stall.

I still think "stall" is not specific enough in general usage to avoid confusion but I could have explained myself better.

Thanks for the graph.

This reminds me of a lift discussion with stoney.   

[Zimme83]

But still, for conventional aircrafts flying with a stalled wing is in reality impossible due to loss of control (no airflow over ailerons) and the huge drag created at such high AoA. None of the planes in the game have the engine power to overcome the drag.

Flying with a stalled wing requires a very powerful jet and also a system like thrust vectoring or canards to maintain control.

I dontīt know why we discussing this in a thread about landing a 262, if you stall a 262 on final or try to fly the approach in a stall you will crash.

[FLS]

We're trying to tell you that your concept of "stall" is incorrect.  You are in a stall condition when the AOA increases beyond the critical AOA, this happens before the airflow is disrupted and you lose all lift. The stall is not a sudden event, you can fly stalled, you just can't maintain level flight.

If you need help reading the chart let me know.

[WaffenVW]

This thread is just sad.

[EskimoJoe]

I found it rather interesting.

Sent from my SM-G900T using Tapatalk

[Someguy63]

lol

[colmbo]

if you stall a 262 on final or try to fly the approach in a stall you will crash.

….you can fly stalled, you just can't maintain level flight.

In game or real-life?

Buffet is the vibration felt from airflow turbulence caused by the separation of flow over the wing.  Separation of the airflow is the stall.

I've attached a link to an AH vid of a flight in a 262 where for very nearly the entire flight I am in buffet--- climb, downwind and landing --- if I correctly understand the AH stall modeling being in buffet means at least part of the wing is stalled. Flight done with full fuel.

Get the vid here

[FLS]

Correct. In game if any part of either wing is stalled you get stall buffet. 

You're over 1g so that's an accelerated stall. Instead of losing altitude you're degrading the turn rate.

Btw you can turn the ack off if you put the drones in field guns.

[earl1937]

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.

Hold on a sec sir! Angle of attack is the angle at which the airflow flows over the wing! Angle of incidence is the angle where the wing is attached to the fuselage, relative to the center line from tail to nose! Neither has anything to do with the other! Wing wash out or in is when the engineer's "twisted" the wing tip up or down, to make the whole wing stall together, so as to promote a more docile stall condition! Of course in later years, with the advent of "slats", a slower stall speed was reached in the interest of safety! Of course all of these statements are referring to a straight and level flight path!
Now, lets take the same aircraft, doesn't matter which one, and put it into a 60 degree bank angle! Which wing will stall first and where does the stall begin and end on the wing? and when the stall occurs, which way does the aircraft react? 

[FLS]

Earl, Busher was responding to me talking about how the incidence in the inner wing effectively changes when the flaps are deployed. As you know this lets the outer wing with the ailerons meet the air at a different angle than the inner wing so you have more control when flying past the critical AOA.

This is obvious in AH if you fly with the stall buffet with and without flaps.

[Wolfala]

Here you go.

[pembquist]

The semantics of this thread are killing me.

[Busher]

Hold on a sec sir! Angle of attack is the angle at which the airflow flows over the wing! Angle of incidence is the angle where the wing is attached to the fuselage, relative to the center line from tail to nose! Neither has anything to do with the other! Wing wash out or in is when the engineer's "twisted" the wing tip up or down, to make the whole wing stall together, so as to promote a more docile stall condition! Of course in later years, with the advent of "slats", a slower stall speed was reached in the interest of safety! Of course all of these statements are referring to a straight and level flight path!
Now, lets take the same aircraft, doesn't matter which one, and put it into a 60 degree bank angle! Which wing will stall first and where does the stall begin and end on the wing? and when the stall occurs, which way does the aircraft react?

I think you might have simplified AOI - the actual aerodynamic definition is:

the angle between the chord of the wing and the longitudinal axis of the fuselage

As to your comment "to make the entire wing stall together", I must respectfully correct.

Aircraft with a swept wing suffer from a particular form of stalling behaviour at low speed. At high speed the airflow over the wing tends to progress directly along the chord, but as the speed is reduced a sideways component due to the angle of the leading edge has time to build up. Airflow at the root is affected only by the angle of the wing, but at a point further along the span, the airflow is affected both by the angle as well as any sideways component of the airflow from the air closer to the root. This results in a pattern of airflow that is progressively "sideways" as one moves toward the wingtip.

As it is only the airflow along the chord that contributes to lift, this means that the wing begins to develop less lift at the tip than the root. in extreme cases, this can lead to the wingtip entering stall long before the wing as a whole. In this case the average lift of the wing as a whole moves forward; the inboard sections are continuing to generate lift and are generally in front of the center of gravity (CoG), while the tips are no longer contributing and are behind the CoG. This produces a strong nose-up pitch in the aircraft, which can lead to more of the wing stalling, the lift moving further forward, and so forth. This chain reaction is considered very dangerous and was known as the pitch-up.

[Oldman731]

You are in a stall condition when the AOA increases beyond the critical AOA, this happens before the airflow is disrupted and you lose all lift.

I don't think this is true.  By definition, if you exceed critical AofA, you're in a stall and you've lost virtually all lift.

- oldman