Teaching Power on Stalls

snOOp

snOOp

Well-Known Member
Hey guys I had a quick question for you. Ok so usually i tell my students during the power on stall to use rudder to control the roll of the aircraft and do not use ailerons. I tell them to make sure their wings are level but lately this has been failing me because I look at the turn coordinator and the ball is to the right. Now if there wings are level and the ball is to the right and they try to stay coordinated by pressing right rudder they will start turning. So my question is how do you guys teach it because my student's wing is dropping a lot and we don't seem to be turning. Any tips I am so frustrated that I am not able to get her to do this because of my instruction.

Also when the ball is to the right and they press the rudder they start turning to the right but while they are turning they are in coordinated flight. But obviously will lose that +-10 degrees. I was trained to never cross control stalls so that's the reason i don't want her to use ailerons to correct for the right turn. Right Rudder and Left aileron= cross control.

Any help greatly appreciated
 
This is common because people preach so much about how bad ailerons are that most assume you need to neutralize them as you are approaching the stall, then they use rudder which in turn makes them uncoordinated. The wing is dropping because you are uncoordinated. It is okay to use aileron prior to the stall. Use the rudder to level the wings once you are stalled and neutralize ailerons. With practice they will be able to tell if the aircraft is uncoordinated by looking outside and "feeling" the aircraft. Don't get them looking at the ball because they will fixate.
 
snOOp said:
my student's wing is dropping a lot and we don't seem to be turning. Any tips I am so frustrated that I am not able to get her to do this because of my instruction.
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So? If a wing drops, it's stalled, therefore apply stall recovery technique: 1) relax back pressure, 2) apply full power, and 3) roll wings level with coordinated controls.

I teach the setup just the way we fly in normal flight...wings level with the ailerons and ball in the center. With a slow, smooth increase in AoA, the aircraft will stall pretty much straight forward, but whether or not it does isn't a criterion for the maneuver.
 
snOOp said:
Hey guys I had a quick question for you. Ok so usually i tell my students during the power on stall to use rudder to control the roll of the aircraft and do not use ailerons. I tell them to make sure their wings are level but lately this has been failing me because I look at the turn coordinator and the ball is to the right. Now if there wings are level and the ball is to the right and they try to stay coordinated by pressing right rudder they will start turning. So my question is how do you guys teach it because my student's wing is dropping a lot and we don't seem to be turning. Any tips I am so frustrated that I am not able to get her to do this because of my instruction.

Also when the ball is to the right and they press the rudder they start turning to the right but while they are turning they are in coordinated flight. But obviously will lose that +-10 degrees. I was trained to never cross control stalls so that's the reason i don't want her to use ailerons to correct for the right turn. Right Rudder and Left aileron= cross control.

Any help greatly appreciated
Click to expand...

One of my students was having difficulty with this a little while ago. Turns out he was just improperly recovering from the stall. (When one of the wings dropped because he was uncoordinated, he wasn't reducing the angle of attack enough before trying to level the wings). Because of that, even when he tried to properly bring the wings level by use of rudder, it wouldn't be effective because the aircraft was still stalled. Once I emphasized reducing the angle of attack before trying to level the wings (should one of them drop due to being uncoordinated), the problem was eliminated.

1: Make sure you're properly coordinated at all times.
2: Should one of the wings drop, make sure the angle of attack is reduced enough before trying to bring the wings back to level.
3: Like others have stated, it's ok to use aileron before the stall to level the wings (like we do in normal flight).
 
snOOp said:
Hey guys I had a quick question for you. Ok so usually i tell my students during the power on stall to use rudder to control the roll of the aircraft and do not use ailerons. I tell them to make sure their wings are level but lately this has been failing me because I look at the turn coordinator and the ball is to the right. Now if there wings are level and the ball is to the right and they try to stay coordinated by pressing right rudder they will start turning. So my question is how do you guys teach it because my student's wing is dropping a lot and we don't seem to be turning. Any tips I am so frustrated that I am not able to get her to do this because of my instruction.

Also when the ball is to the right and they press the rudder they start turning to the right but while they are turning they are in coordinated flight. But obviously will lose that +-10 degrees. I was trained to never cross control stalls so that's the reason i don't want her to use ailerons to correct for the right turn. Right Rudder and Left aileron= cross control.

Any help greatly appreciated
Click to expand...

Ignore the Ball,
Keep your heading with rudder use, (no left or right nose movement looking outside)
keep wings level with aileron.
 
Why not just try it every which way?

How about a stall at full power? How about an accelerated stall?
 
Does this happen only in one aircraft? First thing that came to my mind is that the airframe could have been majorly repaired. Some aircraft just don't fly perfect after a good little crunch. I could be wrong but just a thought not knowing how drastic the problem is.
 
There are plenty of airplanes, in my experience, that don't fly quite straight whether crunched or not. Out of trim, out of rig, fuel imbalances, loading imbalances... and don't forget that torque, P-factor, accelerated slipstream, and all your gyroscopics are not inducing stabilized and equal forces.

The simple answer is that, in my opinion (And bear in mind that you're reading the opinion of a barely-314-hour commercial pilot who's working on his CFI, though he does have about 40-hours upside down...), you shouldn't be staring at the ball. It's fine for maintaining coordinated flight in instrument conditions, and it can be useful for other things, too, but overall the airplane will tell you what its doing, whether through your butt, through the tracking of the nose, by dropping a wing.. and when that's occurring, it doesn't matter where that ball is going, because you have a much better answer right in front of you.

Or.. something. Like I said, I don't want to paint myself as an expert. Just giving you my viewpoint. :>

~Fox
 
Like others have mentioned, ignore the ball.

Find a nice puffy cumulus cloud one day and stare directly at it while pitching up. If the nose moves to the right.....too much right rudder, too much to the left, insufficient rudder.

In a nutshell use the cloud as your heading indicator.
 
I say you let them depart the aircraft......good way to see the real limits of their technique. Like has been said, each aircraft can be different, so learning to get a feel for what is happening and what the airplane is trying to tell you is key IMHO.
 
tgrayson said:
So? If a wing drops, it's stalled, therefore apply stall recovery technique: 1) relax back pressure, 2) apply full power, and 3) roll wings level with coordinated controls.

I teach the setup just the way we fly in normal flight...wings level with the ailerons and ball in the center. With a slow, smooth increase in AoA, the aircraft will stall pretty much straight forward, but whether or not it does isn't a criterion for the maneuver.
Click to expand...
:yeahthat:

"Stomping" on a rudder to raise a wing is a good way to induce a snap roll. Personally, after looking at the flight data, I think that is what happened in that Cirrus crash a little while ago. One of the pilots (maybe the CFI involved), panicked when a wing dropped, stomped on a rudder to raise the wing and induced a snap roll. I've had a client do something like this in a 152 and another in a 182 at altitude. Wing drops, they panic and stomp on rudder and away we go.
 
///AMG said:
I say you let them depart the aircraft......good way to see the real limits of their technique. Like has been said, each aircraft can be different, so learning to get a feel for what is happening and what the airplane is trying to tell you is key IMHO.
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+1

Blackhawk said:
"Stomping" on a rudder to raise a wing is a good way to induce a snap roll. Personally, after looking at the flight data, I think that is what happened in that Cirrus crash a little while ago. One of the pilots (maybe the CFI involved), panicked when a wing dropped, stomped on a rudder to raise the wing and induced a snap roll. I've had a client do something like this in a 152 and another in a 182 at altitude. Wing drops, they panic and stomp on rudder and away we go.
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Usually for a snap roll you need a pretty brisk accelerated stall as well enough entry energy to continue on the horizontal plane... never tried it in a Cessna while doing a power on stall - but it sounds pretty hard.
 
ryan1234 said:
+1



Usually for a snap roll you need a pretty brisk accelerated stall as well enough entry energy to continue on the horizontal plane... never tried it in a Cessna while doing a power on stall - but it sounds pretty hard.
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We are not talking about a competetion snap roll and I call it that for lack of a better term. If you look at what happened in the Cirrus accident it is essentially a snap roll into the ground. One wing dropped in an accelerated stall, one of the pilots tried to lift the wing with rudder and away it went into the ground:
http://www.youtube.com/watch?v=7nm_hoHhbFo
In both cases where I had pilots do this it was something similar. Somewhat accelerated power on stall (a turn that the pilot lets get oversteep), pilot panics during the stall as a wing drops and reverts to their training of trying to raise the wing with rudder... and away it goes.
 
Blackhawk,

I think it's important to emphasize that the critical input is the unloading of the wing at that point in an accelerated stall. As you know, the fundamental part of a snap roll is to keep the wings stalled--if you don't do that, as soon as you release it, you'll come out of the maneuver in some fashion that depends on how fast you're going and what the orientation of the snap is.

Here's the real problem--This really should be intuitive. A large part of me wishes that at least some aerobatics were still a requirement for primary training. I was talking to a young student a few weeks back in Dallas, and the subject of aerobatics came up. I mentioned that it's frustrating how many pilots 'grow up' only ever flying straight and level, and how many of those pilots learn only the elements needed to pass the tests, and bemoaning how many are, even as CFIs with hundreds of hours of dual given, terrified of actually performing stalls. As I came out of the briefing room (I was waiting to go practice CMEL maneuvers), I picked up one of the aviation rags on the table outside, and right there was an article about the 121 carriers' surprisingly poor Loss of Control inflight history.

I dunno.

~Fox
 
The ball will not be centered during a power on straight-ahead stall in a single-engine airplane. Mostly due to torque - the 4 left turning tendencies become much more exaggerated as the angle of attack approaches stall angles, most predominately the P-Factor. As the airplane approches stall angle, the thrust from the prop moves to the right side of the propeller disk, so that a wings level and nose straight configuration produces an uncentered ball. This is normal. You cannot have a high angle of attack and high power and a wings level/nose straight ahead with a centered ball.

Being "coordinated" does not mean having the ailerons and rudder in the same direction - all the time. If you do a power-on climbing turn stall to the right, while holding a constant 20* bank, you will see that you need more and more right rudder, and more and more left aileron to keep the ball centered.

In turns, especially stalling turns, the point is to keep the ball centered, and that may (will) mean crossing the controls.

In straight ahead stalls, the point is to maintain a constant heading, and wings level, and that may (will) mean crossing the controls, as well as not having the ball centered - as long as you are keeping a constant straight ahead heading, and not wallowing +/- 10*, but holding a constant heading and the wings are level during the stall, you don't care where the ball is, the airplane will be in your command and control as it stalls and you push the nose down as you keep it straight forward with rudder and the wings level with aileron.

Teaching to pick up a wing with rudder only is only a technique to stop you from initially using aileron to control yaw. Once you learn to instinctively respond to yaw with rudder, by picking up a wing with it, then you should start using the ailerons as they are intended, by flying through the stall with rudder response to yaw, and aileron response to roll, (independently) and feeling pitch control with elevator and throttle.
 
nosehair said:
You cannot have a high angle of attack and high power and a wings level/nose straight ahead with a centered ball.
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Uh, yes you can. There is this device attached to the airplane called a 'rudder', which neutralizes the yaw associated with the left turning tendencies.
 
Blackhawk said:
In both cases where I had pilots do this it was something similar. Somewhat accelerated power on stall (a turn that the pilot lets get oversteep), pilot panics during the stall as a wing drops and reverts to their training of trying to raise the wing with rudder... and away it goes.
Click to expand...

The snap roll really requires two very specific inputs at nearly perfect timing with a reserve amount of energy to have the needed control effectiveness. Acrofox has a point where the correct input in any case is to ease up on the accelerated stall and unload the airplane...never really understood how people manage to do something like that unintentionally... usually you can really feel the airplane (a light recip) talking to you in an accelerated stall... telling you to ease up the pull.

But - as far as teaching power on stalls go... 'falling leafs' work pretty well in showing what happens when you mash on a rudder to try to 'raise' the wing...even in a Pitts, I don't think I've been able to snap roll it without having a decent amout of airspeed and pulling up (or down) hard.. Also another big thing is the effect of gyroscopic precession when doing accelerated stalls... or anytime pulling up or pushing down.
 
tgrayson said:
Uh, yes you can. There is this device attached to the airplane called a 'rudder', which neutralizes the yaw associated with the left turning tendencies.
Click to expand...
Neutralizes? ...well, what I'm trying to describe is the same aerodynamic effect as a light twin operating on one engine. The yaw caused by the asymmetrical thrust is off-set with rudder which creates an aerodynamic lift vector in the opposite direction of the applied rudder. This causes the airplane to slip through the air in that direction causing a non centered ball if you keep the wings level.

This phenomena also occurs in a single engine in a high power high AoA, although not nearly as noticable as a twin, and not hardly noticable at all in small engines, unless you demand and execute a stall with absolutely zero deviation from heading or bank. The ball will not stay centered.
 
This causes the airplane to slip through the air in that direction causing a non centered ball if you keep the wings level...This causes the airplane to slip through the air in that direction causing a non centered ball if you keep the wings level.
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I agree that the aerodynamic effect is identical to the ME scenario, but this will not cause an off-center ball. Only accelerations cause the ball to be out-of-center, not steady motion. The ball is off-center in a ME aircraft because it's banked during single-engine flight, which is why the ball can be used as a bank indicator. The bank causes a component of gravity to act along the lateral axis, pulling the ball away from center line.

The ball is only an indicator of side slip when that side slip causes a lateral acceleration. In a ME aircraft, if you don't bank into the good engine, the aircraft will be in a steady sideslip towards the dead engine, and yet the ball will be centered, at least once the aircraft reaches its equilibrium sideslip velocity.

The ball doesn't directly measure slip, only a yaw string can do that, which is why I always have one attached during ME training.
 
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