Spins- Normal and Accelerated

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sperdue

Filing Flight Plan
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Gunny Perdue
For those of ya'll interested in what happens at the stall end of the envelope check out this video of spins. The most common problem I've seen in instructing is folks adding aileron to pick up a wing during a slow flight/stall event.... you can see that aileron accelerates the spin (besides introducing adverse yaw and potentially inducing a spin). All stall recoveries are normal: Idle, Neutral, Aft- rudder opposite yaw, stick forward and recover from the dive.

gunny

http://youtu.be/p66Fz2uNGq4

By the way.... does anyone know how to embed a Youtube video here? thanks.
 
Nice video. I'd like to see something like this in a cessna.

Do as below. Remove the periods and only put the text after the youtube.com/ in between like shown below.

[...yt...]p66Fz2uNGq4[.../yt...]


result


 
Nice.

I did stall practice on Sunday, and I can see how it may be a first reaction to use aileron when you feel a wing dipping during a stall. Before any stalls, we did an exercise where my instructor put us in a moderate bank.. and then had me bring us back to level flight using only rudder. This showed me that I can be confident that the rudder will bring the wing back up (as long as the bank is not too steep).
 
N659HB said:
Were you on the verge of a flat spin at any time in the later examples?
Click to expand...

Not really such a thing as strict flat vs. non-flat spin. There are really varying degrees of flatness. On the spin where he applied right aileron and the nose rose a little, the nose would have risen a lot more if he had applied full power. That would have been a flat spin in that airplane. It's no big deal. Just another spin mode, and easily recoverable. That airplane will not go very flat unless you force it with power. And the nose will come back down when you pull power off.
 
N659HB said:
Were you on the verge of a flat spin at any time in the later examples?
Click to expand...

Good observation. The last two spins met the criteria of a Flat Spin. The last one was a true Flat Spin, I could have gotten the nose very near the horizon with full power, didn't want to do that (it adds quite an acceleration outward and I'm old and lazy... what I did was enough to show the effect).

gunny
 
N659HB said:
The last one looked pretty flat. How does one recover from a flat spin?
Click to expand...

Hope you're flying an airplane that WILL recover. :) If I was in a flat spin in a Mooney, I'd be looking for my chute. In aerobatic airplanes, it's a no brainer. Let's assume the flat spin is intentional in an airplane that has predictable spin recovery characteristics in all spin modes. In a flat spin, the rudder has very little ability to counter yaw when the relative airflow is nearly vertical to the belly of the airplane. For emergency recovery technique, you need to get the nose down so that you regain some airflow across the rudder. This involves pulling power off and applying opposite rudder, in-spin aileron, and moving the stick foward to a degree. Except for in-spin aileron, this is standard spin recovery. In most airplanes, flat spin recovery will take just a little longer than standard spin recovery.

In high-powered aerobatic airplanes with big rudders, you can stop a flat spin more quickly if you apply the same controls described above, but with power left wide open. If you watch most airshow pilots do flat spins, they typically leave full power on. But this is something few instructors will actually teach, since for safety reasons, emergency recovery techniques should be taught to newbies, since leaving power on can aggravate the spin if your inputs are not perfect. Power off is always the first step in emergency spin recovery. In fact, most aerobatic airplanes will recover a flat spin pretty quickly if you pull power and simply neutralize all controls.
 
N659HB said:
The last one looked pretty flat. How does one recover from a flat spin?
Click to expand...

Lo-

There are various versions of the same basic procedure.... the one we were taught in the USAF was:

First:
Idle - Pull the power to idle (this will kill most of the flat spin)
Neutral - Set the Ailerons to neutral (this kills the rest of the flat aspect)
Aft - Pull the stick all the way aft (this stabilizes the spin and exposes as much rudder as possible to the relative wind)

Then:
Rudder - Opposite Yaw (Spin right rudder left, look outside, this kills the yaw)
Pitch - Forward of neutral as yaw slows to break the stall
Neutral - Ailerons/ Rudder
Recover - From the dive

It is a relatively simple procedure, sounds complex.... and several folks teach mnemonics to help you remember.... I think its better to actually fly a few.

gunny

BTW- what Wifferdill says about power is true in high powered aerobatic airplanes. But I would never suggest that you use in-spin aileron.
YMMV
 
sperdue said:
But I would never suggest that you use in-spin aileron. YMMV
Click to expand...

In-spin aileron typically does help recover a flat spin more quickly, and that is commonly accepted. However, it should be noted that there is an important distinction to be made between emergency spin recovery technique, and active spin recovery technique. Active spin recovery assumes the pilot has the wherewithal to apply each control exactly as needed to effect the most efficient recovery. In-spin aileron does help with that in most airplanes.

However, if a flat spin is accidental, and you have lost control of the airplane, it's best to revert to an emergency spin recovery technique, which is designed to minimize the amount of situational awareness needed. These issues are typically related to spin training in the aerobatic commmunity, and this is widely accepted --- there are only two recognized emergency spin recovery techniques. 1) The hands off 'Beggs-Muller' method which involves pulling power off, applying opposite rudder and completely letting go of the stick, and 2) The neutral control method that involves pulling power off and visually neutralizing all controls. Whichever method you choose to revert to should be known to work for all spin modes in the aircraft type you are flying. All are a little different.

Emergency spin recovery is a very different concept from that of the aerobatic pilot doing deliberate, perfectly controlled spins, to known outcomes. I too, would not recommend in-spin aileron be used as part of an emergency recovery technique...just as I would also not recommend power be left on. But the skilled pilot can learn active techniques to extract more performance and precision from the airplane. Just be willing to pull an emergency technique out of the bag if necessary.
 
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How do u know if ur plane can do spins? I have a 48 stinson 108-3. Doesn't say much in the POH at all. Just says light acrobatics should b done in utility cat with no body in back seat. I dont know what they consider light acro. I have taken a full emergency maneuvers course & some acro. Probly done 50-60 spins. All in a decathlon tho
 
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