Turns at high AoA

[Garfly]

 

The following article and videos are related in that they cross reference each other.

It's an old topic but, for me, always worth revisiting, until the message sinks in (maybe only possible with aerobatic training).

 

 

Anyway, when Jari Halttunen (in his video, below) insists that  "Rolling Pull is Forbitten" 

he gets closer (with his Finnglish twist) to the truth than even he imagines. 

And it makes for a memorable take-away.  😉

If all I remember from his film is that phrase, along with "Plane is unloaded until rolled upright"

I'll feel I've learnt something useful; maybe vital.

 

His video also points us to the following article by Dave Hirschman

(as well as to "Stall/Spin Awareness" by Rich Stowell.) 

 

 

THE 'PANIC PULL'    By Dave Hirschman

(Excerpt)

Attitude isn't everything   

   ....   the nose of the biplane pointed straight down ... determined to make the loop round, however, I kept pulling until, finally, the airflow separated, the wings stalled, and the airplane snapped 90 degrees to the right. The instant I relaxed the back-pressure, the airflow reattached and I emerged from the botched maneuver.

 

I had heard and read during private pilot training that a wing could stall at "any airspeed and any attitude." But it hadn't occurred to me that an airplane pointed straight down at full power could exceed its critical AOA and stall. Finally, the light came on and I was able to grasp a concept that I had never fully understood or appreciated:

 

An airplane's attitude and its AOA really are completely unrelated.

 

An F–22 Raptor can climb vertically and accelerate straight up at a very low AOA, while an Extra 300 can snap roll with its nose pointed at the ground and a very high AOA.

 

 ... But that's how pilots learn, and for most of us, it takes real-world events for theoretical concepts to jell.

Of course, you don't need unusual-attitude training to understand AOA. Just realize that, in normal flight, pulling on the stick or yoke increases AOA—and when you reach the critical angle, the way to recover is to reduce the AOA regardless of the airplane's attitude.  In most of life, attitude is everything. With AOA, however, attitude means nothing. 

 

Full article:  https://www.aopa.org/news-and-media/all-news/2011/june/01/technique-the-panic-pull

 

YouTube upload by:

Jari Halttunen 

Skid Stall

Scenario:  Final turn goes over centreline "overshoots" • Pilot tries to increase turn rate by using rudder • Using rudder leads to Skid Stall

Recovery: Unload (Reduce AoA) • Power manage (idle) • Rudder neutral • Roll upright (plane is still unloaded 0.5G to 0G) • Pull up gently

 

Common errors:  See Panic Pull http://www.aopa.org/members/files/pil...

 

 

 

 

 

 

YouTube upload by:

 

AGL Simulations

A skid stall demonstration of a very light jet in a left turn.

Notice the rudder offset to the left causing slipping to the right and dropping of the left wing in the stall.

Quick unloading of the stick prevents the aircraft from entering into a spin.   

A similar maneuver is performed in an Extra 300 in this video by Jari Halttunen: https://www.youtube.com/watch?v=RlvPw...

 

 

Keeping track of the stick and rudder positions (lower right) illustrates the recovery method discussed by Jari.

 

And these are some instructive screen-shots referencing the AoA indicator (upper right).

 

𝛂 = 0º

 

𝛂 = 12º

 

𝛂 = 3.8º

 

 

 

Edited March 8, 2021 by Garfly

[Jase T]

Roll to the nearest horizon then pull!

[Garfly]

31 minutes ago, Jase T said:

Roll to the nearest horizon then pull!

Also memorable!  (Short and to-the-point  ;- )

[Garfly]