How do pilots know the plane is going to stall?

[colmbo]

Sound? Please explain.
Wing does not produce any sounds and aren't you wearing a headset anyways?

You're kidding aren't you?  In light aircraft the sound of the air moving around the airplane is quite noticeable and a good indication of speed.

FYI, a noise canceling headset makes it easier to hear the "little things" in the airplane.

[MachFly]

You're kidding aren't you?  In light aircraft the sound of the air moving around the airplane is quite noticeable and a good indication of speed.

FYI, a noise canceling headset makes it easier to hear the "little things" in the airplane.

No I can't hear it. I do remember hearing the wind on some older airframes but that's only above 150kts.
Will try to pay more attention to it on the next flight but I don't expect to be able to hear it.

Yeah I heard that about noise cancelling headset, never used one thought.

[titanic3]

Thanks for all the replies guys. Learn something new everyday. 

[SouthLanda]

Hi Machfly and Hitech,
Respectfully, not disagreeing with your experiences, I accept that my experiences are not extensive, and if I have the wrong idea, then no worries.

But may I ask this question?

Can anyone tell me the up angle of the elevator of the P51D at the point of stall for 1G, 2G. 6G stalls? Is it the same or virtually the same?

If we look at the stall speed of a P51D:
Stall speed = Vs  x square root of G 
Using the following.. 1 G  say 113 MPH IAS at 9500lb, 2 G its 160 MPH, 6 G its 276 MPH

So I guess my question is, what is the up elevator angle of the P51D at 113 MPH, 160 MPH and 276 MPH IAS?

I tested it offline with the external view as best I could, taking screenshots and it looks like the elevator has pretty much the same upward deflection angle for each stall, regardless of the speed. (Tested P51D and Spit14)

[MachFly]

Just to make sure that I understood you right, your asking for the elevator position at constant G, constant airspeed, and constant weight.

Given that those 3 things are constant the elevator position will still be different because of CG. So for example if your flying with the stick a bit forward of neutral and as your burning fuel the CG moves forward you will eventually need to move the stick back a little therefore moving your elevators down. I don't know how much their going to move because I just never tested this and this would be different on every airplane.
Note that this is not the case in aircraft with fly-by-wire controls.


This is what would be the cause of difference in CG:

Forward:
Longer T/O roll
Longer Landing distance
Harder to rotate
Slower cruise TAS
Higher fuel burn rate
More stable
Less maneuverable
Easier to stall
Easier to recover (from a stall)

Aft:
Shorter T/O roll
Shorter Landing distance
Easier to rotate & flare
Higher cruise TAS
Lower fuel burn rate
Less stable
More maneuverable
Harder to stall
Harder to recover (from a stall)

Think of stall as the AoA of the wing and elevators and CG are the things that let you change that. Also the wing cares only about two things; dynamic pressure and AoA.

[FLS]

Southlanda in Aces High the stick position for a specific AOA depends on the trim setting. In a real aircraft the trim would hold the stick in position but in flight sims with spring centered sticks the trim changes the control deflection position of the centered stick. This allows the same AOA with different stick positions.

[VonMessa]

Anyone want to try building/installing this and tell me how well it works?     

[B4Buster]

In the Beechcraft I fly, the stall horn comes on well before the buffeting. For the sake of me getting a good feel for the airplane, my instructor would have me fly the buffet and change heading every so often. Good learning experience.

[B4Buster]

Anyone want to try building/installing this and tell me how well it works?     

(Image removed from quote.)

You don't need one of those for your light single

[VonMessa]

You don't need one of those for your light single

What single?

[B4Buster]

You're kidding aren't you?  In light aircraft the sound of the air moving around the airplane is quite noticeable and a good indication of speed.

FYI, a noise canceling headset makes it easier to hear the "little things" in the airplane.

I'm willing to bet MachFly notices the sound but doesn't even realize it. Even as a strictly VFR guy, I certainly use the sound of the plane passing through the air to give me a feel for my airspeed. I enjoy looking out the window and not at my instruments constantly.

[B4Buster]

What single?

the single engine plane you are constructing.

[VonMessa]

the single engine plane you are constructing.

Thought you meant single-seater

[pembquist]

Can anyone tell me the up angle of the elevator of the P51D at the point of stall for 1G, 2G. 6G stalls? Is it the same or virtually the same?

If we look at the stall speed of a P51D:
Stall speed = Vs  x square root of G 
Using the following.. 1 G  say 113 MPH IAS at 9500lb, 2 G its 160 MPH, 6 G its 276 MPH

I tested it offline with the external view as best I could, taking screenshots and it looks like the elevator has pretty much the same upward deflection angle for each stall, regardless of the speed. (Tested P51D and Spit14)

I'm thinking if you want to test in the virtual world you should have combat trim off and measure the stick deflection directly.

[BravoT]

Sound? Please explain.
Wing does not produce any sounds and aren't you wearing a headset anyways?

I believe he means wind noise past the airframe, engine noise, etc.  You can hear a lot despite the headset.

As part of my instrument training my instructor had me close my eyes and try to maintain straight and level.  I almost immediately knew I was in a dive because of the increase in wind noise past the airframe.