stalling speed

Bank angle increases load factor when you roll beyond 30 degrees when you attempt to maintain altitude by increasing back pressure to compensate for the loss in VCL, load factor will increase causing the stall speed to increase by the square root of the load factor multiplied by Vs.
 
meritflyer said:
Bank angle increases load factor when you roll beyond 30 degrees. When you attempt to maintain altitude by increasing back pressure to compensate for the loss in VCL, load factor will increase causing the stall speed to increase by the square root of the load factor multiplied by Vs.
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Foxcow's statement is correct. "Bank angle does not necessarily mean an increase in load factor." (emphasis added)

Your statement is correct also, except for the first sentence. Now if you had said "Bank angle increases load factor when you roll beyond 30 degrees while maintaining altitude." I would agree with you.

Subtle difference, but important.

:)
 
I immagine air density would be a factor. Also, unless you are comparing two identical aircraft, wing design (planform, surface area, aspect ratio, camber, etc.) would be a factor.

I'm not sure power would be a factor though. Because the actual stall speed would be the same, however the pitch that would yield that airpseed would differ.
 
Indicated stall speed will not change with an increase/decrease in air density and/or temperature. The true airspeed will however.
 
flyguy said:
I'm not sure power would be a factor though. Because the actual stall speed would be the same, however the pitch that would yield that airpseed would differ.
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A stall will always occur when the critical angle of attack (CLMAX) is exceeded.

The airspeed at which the wing stalls in not a constant though, it various based on airplane configuration (flaps/gear), aircraft weight, CG location (Fwd CG increases stall speed), modifications to the airfoil (ice/frost),turbulence and load factor are all factors that affect the stalling speed (not the CLMAX).

If an airplanes airspeed is too slow, the required angle of attack to maintain lift may be exceeded, causing a stall. As aircraft weight increases, a higher angle of attack is needed to maintain the same airspeed because some of the lift is now required to support the increased weight. This increases the airplanes stalling speed.

An increase in load factor, also increases stalling speed with the relationship that stall speed increases in proportion to the square root of the load factor. For example is your aircraft has a Vs of 50kts, your airplane will stall at 70kts with a load factor of 2 G's (typical for a 60 degree banked turn).

How you figure that out is you take the square root of the load factor (2) and you get 1.41. Multiply that by your Vs and you get 70kts.

I suggest the Jeppesen series of text books, they present the material very well.
 
Airdale said:
All turn should be level though, at least at 60 degrees of bank. :)
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Well, the last "steep" turn that I did for real (not for a check ride in other words) was on a circle to land approach in my previous job, and keeping it level might not have been the smartest move. Kinda crappy visibility (maybe 1-2 miles), circling fairly low (maybe 500' agl) due to ceilings, in a twin Cessna, and I've got the speed fairly low also because I want to stay in tight on the field so I don't lose sight. On the turn to final I needed to bank it a little extra steep (I didn't look, but I'd guess 45-55 degrees), but I made sure to ease off the back pressure and let it lose some altitude in the turn so as not to increase the load factor (and indicated stall speed!). You can feel in the seat of your pants whether you are adding any g-load or not. Gotta be real careful with those kind of maneauvers 'cause they can bite you, but that is the kind of situation when a non-level steep turn may be desirable.

I flew boxes rather seldom, since most of our 135 work was pax, but I'd bet the real freight guys could talk about close-in maneuvering with some more authority than I.

I'm really not trying to argue with you or tell you you're wrong, I just like putting another viewpoint out on the table for discussion.

:)
 
Airdale said:
A stall will always occur when the critical angle of attack (CLMAX) is exceeded.

The airspeed at which the wing stalls in not a constant though, it various based on airplane configuration (flaps/gear), aircraft weight, CG location (Fwd CG increases stall speed), modifications to the airfoil (ice/frost),turbulence and load factor are all factors that affect the stalling speed (not the CLMAX).

If an airplanes airspeed is too slow, the required angle of attack to maintain lift may be exceeded, causing a stall. As aircraft weight increases, a higher angle of attack is needed to maintain the same airspeed because some of the lift is now required to support the increased weight. This increases the airplanes stalling speed.

An increase in load factor, also increases stalling speed with the relationship that stall speed increases in proportion to the square root of the load factor. For example is your aircraft has a Vs of 50kts, your airplane will stall at 70kts with a load factor of 2 G's (typical for a 60 degree banked turn).

How you figure that out is you take the square root of the load factor (2) and you get 1.41. Multiply that by your Vs and you get 70kts.

I suggest the Jeppesen series of text books, they present the material very well.
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I agree with everything you said. But still don't see how power would affect the stall speed.
 
flyguy said:
I agree with everything you said. But still don't see how power would affect the stall speed.
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Because at high pitch angles and high power settings, engine thrust is actually helping to support the aircraft. While I don't know of any piloted recip airplanes that can do this, it is possible for some model airplanes to pull up into a vertical climb and hover at zero airspeed.

On a twin, high power settings can also delay the onset of a stall because of the induced airflow over the wings.
 
I don't know about about a internal recip but I know the Turbine Oracle Raven was (before it was destroyed) one of the only prop driven aircraft with a positive thrust to weight ratios. It holds a time to climb record to 10,000ft for prop driven aircraft.
 
flyguy said:
I agree with everything you said. But still don't see how power would affect the stall speed.
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Power doesn't affect stall speed. The airplane always stalls when it exceeds the critical angle of attack. You can exceed this at any power setting. Maybe you're confusing slow flight. " Any airspeed at which an increase in angle of attack, load factor or reduction in power will induce an immediate stall." When flying in slow flight, if you maintain constant back pressure and suddenly reduce power, you stall. Not directly because of power, but because with the reduction in power, the angle of attack will slightly increase with constant back pressure, thus exceeding CLMAX.

Slow flight and power also deal with the region of reversed command. Where you are on the backside of the power/drag curve and more power is required to go slower. This merely has to do with so much induced drag due to the high angle of attack that in order for the airplane to operate at such a slow airspeed and high angle of attack, you need more power.

To demonstrate that power doesn't affect stalling speed, take a 172 to up to about 4,000AGL, set the power to idle. Just pitch up until it stalls (power off stall). Let it recover then do a power off steep turn at 60' bank while trying to maintain altitude, you will accelerate the stall and probably stall somewhere in the ball park of 60kts. You can also initiate a descent at about 500'FPM power off, and abruptly pitch up (without exceeding airframe limitations) and you'll see an accelerated stall. Of course do this with an instructor. :)
 
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