Use of rudder during stalls

bjm

bjm

New Member
I have had a couple students who were taught stalls elsewhere that used rudder to correct the turning tendency after breaking in a stall. I haven't done a lot of stalls in our Warrior yet, but the 150 we have and the 172's I trained in want to turn to the right after breaking. Anyway, I told them they should correct with aileron instead, otherwise you're flying uncoordinated on purpose, and while doing stalls, that just isn't smart. Anyone heard of this, or teach this technique of using rudder??
 
If one wing is dropping in the stall it tends to mean that the low wing is more stalled than the high wing - it's AoA is higher that the wing that is still flying a little, right? So, if you use aileron to try to correct the situation, what are you doing to the AoA of the low wing? Will it help?

If you neutralize the rudder completely in that configuration, I bet you'll find that you are =already= uncoordinated. With the low wing more stalled, that dip isn't as much turn as it is uncoordinated yaw - the final step before a spin.

The =real= answer is that at this point the wing should be lifted using coordinated rudder and aileron, but in most cases, "coordinated" will lead with the spin recovery rudder rather than the stall-on-that-side-aggravating aileron.
 
I don't neccessarily use rudder to correct for the turning in a stall. I use rudder before the aircraft stalls. Like mentioned in the previous post, the wing that stalls more drops. If this is the wing that is a little more stalled, wouldn't raising that wing put it at a higher angle of attack and further aggravate the stall?

My stall procedure calls for me to use just enough right rudder to correct for the left turning tendancy and after the aircraft stalls simply release the back pressure off the yoke and the right rudder pressure and the aircraft usually will break straight forward. If you hold the right rudder pressure to long, it usually causes the aircraft to break to the right.
 
That's all precicely right MidLife, (p.s., I checked out your website-- very nice!!) But I think if you tried to explain that to your average pre-solo student, you'd get the blank stare, nod with mouth agape, and they would carry on doing the exact same thing over and over again.

My personal teaching technique for power on stalls was all K.I.S.S. : set up your pitch attitute and hold it with smooth, continuous elevator travel, point the nose at a cloud, and keep it there with rudder. I don't mention aileron, because 9 out of 10 students are going to use aileron, instinctively, anyway, and the results are purt' near coordinated.

I suspect what the student in question is doing is ham-footing the rudder, causing pilot induced yaw-roll occillation after the break. This overcontrolling probably stems from stress, trying to aviod the 'dreaded spin' and can be abetted by doing a little spin recovery work. That's right-- spin the HELL out of them. Let them see what the plane does when it spins, and how easy it is to recover. Once they have a benchmark, it's much easier to judge how much rudder to use, as well a boosting confidence and having a hell of a good time!
 
I agree about the ham foot, Captn. One time a student put us into a spin when he set up great, kept nice and coordinated, and the sort of forgot to lessen the right rudder pressure when the stall broke.

But on the explanation, well, the post posed a situation in which the wing already dropped, and my explanation was meant for the CFI who asked the question, not his presolo student (although I have to say that my presolo students don't seem to have any trouble concept. I lead them with questions, and they usually explain it to me).

Thank you very much for the kind comment on my web site. Wish I had more time to keep it current.
 
I'm not a CFI yet but am in the process of becomming one, and it just so happens I gave a lesson today in ground school about stalls so I'm recenly read up on it. I'd have to say, never, ever, try to use ailerons to correct for the wing dip. As was said in another post above, the reason the wing dipped is becasue it was more stalled than the other. If we raise that wing, the AoA will increase and you'll make the situation even worse.

Now you were asking about purposfully uncoodinating while stalled, i.e. applying the rudder opposite the direction the wings are banked. Well what we need to remember is that the reason one wing dipped is because we were already uncoordinated, and the wing dip is essentially the edge of a spin. What we're trying to do is prevent a spin right? Well, what do we do to break a spin? Ailerons neutral, and rudder opposite the direction of the turn. So, we're essentially just going through the spin recovery before the spin starts.
 
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I'm not a CFI yet but am in the process of becomming one, and it just so happens I gave a lesson today in ground school about stalls so I'm recenly read up on it. I'd have to say, never, ever, try to use ailerons to correct for the wing dip. As was said in another post above, the reason the wing dipped is becasue it was more stalled than the other. If we raise that wing, the AoA will increase and you'll make the situation even worse.

Now you were asking about purposfully uncoodinating while stalled, i.e. applying the rudder opposite the direction the wings are banked. Well what we need to remember is that the reason one wing dipped is because we were already uncoordinated, and the wing dip is essentially the edge of a spin. What we're trying to do is prevent a spin right? Well, what do we do to break a spin? Ailerons neutral, and rudder opposite the direction of the turn. So, we're essentially just going through the spin recovery before the spin starts.

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Very good!
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You'll be ready for the CFI!
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What's said above is it... No need for me to re-type anything.

This is how I incorporate one of my first aerodynamics lessons with the students... And before our first stall flight, I have them walk me through the explaination above. Covers the stalls and the Spin Awareness discussion.
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Thanks for the replies. If I really would have analyzed what was happening more in depth, hopefully I would have come up with the same explainations as you have given. I've been doing some reading on the topic and talking to some other CFI's around here, and I want to offer the points of emphasis as I've picked up.

(1)Remain coordinated and there's nothing to worry about as the nose will break straight ahead.

(2)Use of rudder to counter spin and level wings is correct, as long as the wing(s) are stalled.

(3)Use of coordinated rudder and aileron throughout stall and recovery should prevent turning.

(4)Stall recovery per the POH does say to use aileron to level, but this must be done after the wings are producing lift once again. (which is not mentioned in the POH).

So there is what I've found. Does this sound about right? Reflecting on your answers and what happened with the one student who surprised/spooked me in recovering his stall, I do think he held his right rudder too long then "hammed" it the other way to correct. Thanks again for the insights.
 
Just like it was mentioned previously, I always teach my students to use the rudder along with some coordinated aileron to correct during stalls.

One thing you have to remember is that during a power-on or power-off stall, just like in slow flight, there is a minimal amount of airflow over your control surfaces, such as the aileron. You will notice that the ailerons are not very effective due to this reduced airflow, which in turn, reduces their effectiveness.

A lot of student pilots will instinctively try to correct a wing low by pure aileron. I found that an effective teaching tool is to first show during slow flight how much "play" you have with the yoke due to the slow airflow over the control surfaces and then to correlate that into what is happening during a stall in respect to your ailerons. The other thing I allow the student to do is to stall the aircraft and try to correct it by purely aileron--which rarely works (just make sure you are at a safe altitude if they put it into a spin).

Good luck!
 
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The other thing I allow the student to do is to stall the aircraft and try to correct it by purely aileron--which rarely works (just make sure you are at a safe altitude if they put it into a spin).

Good luck!

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And also let them watch the aircraft whip into the direction of aileron input (assuming they have a lot of input in) as the airflow begins again over the wings.
 
The CFI to be said it best. Slow flight with turns incorporated will show the student the effectiveness of ailerons. If the airplane is coordinated during the break, the "yaw" will be minimal. This turning you will see is yawing. Rudder is the key, airlerons will increase AoA and therefore, the spin will occur.

By the way, the AoA will increase on which wing, or which direction does an aileron have to travel to stall that wing more and go into a spin.? Is it up of down?
 
The down aileron will produce more lift than the up aileron--therefore creating a larger AOA for the increased lift.

Think of it like a banked turn, when you make a turn, to say the left, which aileron is moving up and which aileron is moving down? The left aileron is up, and the right aileron is down. The right wing is now producing more lift, which banks the plane to the left.

Good luck!
 
Interesting subject...
the reason why one wing dropped is due to uncoordinated flight at the first place. Raising the dropped wing will not increase its angle of attack, at the contrary it will lower it, since it re-directs the relative airflow, also increasing its speed.
As CaptainJim was saying, during a stall, use the rudders to maintain the wings level (at slow speed).
Use of the ailerons to raise the wing will only aggravate the situation on this part of the wing, since the down aileron increases the overall curvature of the wing, the aoa is greater.
But who knows, it depends on the day, the turbulence, a lot of factors can affect this.
 
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Interesting subject...
the reason why one wing dropped is due to uncoordinated flight at the first place. Raising the dropped wing will not increase its angle of attack, at the contrary it will lower it, since it re-directs the relative airflow, also increasing its speed.
As CaptainJim was saying, during a stall, use the rudders to maintain the wings level (at slow speed).
Use of the ailerons to raise the wing will only aggravate the situation on this part of the wing, since the down aileron increases the overall curvature of the wing, the aoa is greater.
But who knows, it depends on the day, the turbulence, a lot of factors can affect this.

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It's difficult to pigeon-hole what the ailerons specifically do and what the rudder is meant to do. Basically they work together to achieve co-ordinated turns. I know of a DE who maintains that the aircraft is turned with the rudder and the ailerons are used to coordinate the turn!
 
You are right, they work together to give a coordinated turn; but I think they do have a specific role each.
I was trying to explain the way I teach stall and stall recovery; when a wing drops during a stall, the proper recovery is to use the rudder, and not the ailerons (for obvious aerodynamic reasons).
As the DE says, you can turn the airplane using the rudders only, just as well as using the ailerons only... it won't be pretty, but you'll get what you want, the plane will bank, and turn in the end.
 
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