bank angle impact on stall speeds

[RobertE]

A recent comment in a discussion concerning a probable recent stall/spin fatality on base to final made a recommendation that we all keep in mind the bank angle/stall speed chart in our POH.  That got me thinking about its application in a base turn to final scenario.

Am I mistaken, but don't those calcs assume level flight? If I'm prepared to lower the nose and lose a lot of altitude quickly - and, believe me, I'm not suggesting this during any landing approach - can't I adopt pretty much whatever bank angle I want without risking a stall?

[aerobat95]

It just depends....if you unload the wing then you can bank at whatever angle you want and you won't stall.  We show students in the T-6 UPT syllabus called a stability demonstration.  Basically we set the nose 60 degrees nose high and once we hit the stick shaker (approach to stall) we go idle and neutral.  I have seen airspeeds as low as 45 knots well below the straight and level stall speed, but because we not demanding anything out of the wing the wing is not in a stalled condition.  We are just above 0g's and in a decent.  So....if you don't demand anything out of the wing and you are in a 60 or greater degree angle of bank the plane will not stall, however once you add back pressure and demand to much out of the wing the the airplane will stall.  This is something that inexperienced pilots (students) don't seem to understand.  If you are slow and try to demand to much out of the wing it will stall.  I see it all the time at the top of loops.  You start a 4g pull up at 250kts, but once you go over the top you are only around 100kts and you cannot get 4gs out of the wing.  I also see it in the final turn in a overshoot situation....scarry as hell when the student see's the overshoot and increases bank angle and then attempts to pull.....

[jetdriven]

It's the g load effect on stall speed.   Bank angle is irrelevant, but "G" can be inferred from bank angle if coordinated level flight.  

[N9660M]

Quote: RobertE

...can't I adopt pretty much whatever bank angle I want without risking a stall?

[xftrplt]

Sorry, JC.

The above post was mine, not N9660M's.  (The gremlin strikes again.)

Quote: RobertE ...can't I adopt pretty much whatever bank angle I want without risking a stall? The short and absolute answer is yes.  (And any attitude you want, too.) At the airspeeds and altitudes we fly, the ONLY factor determining the wing stalling is AOA. I'd suggest a bit of self-study and recommend "Aerodynamics for Naval Aviators" as the best single volume on the subject.   http://www.amazon.com/Aerodynamics-Naval-Aviators-FAA-Handbooks/dp/156027140X

[smccray]

There was a really good thread on beechtalk that addresses these concepts.  It's worth reading: http://www.beechtalk.com/forums/viewtopic.php?f=7&t=61861&hilit=corner+speed

It's another one of those threads that makes my head hurt.