"Fully developed stalls"

[jpower]

Hi all,

I'm about to take my PPL checkride this Sunday the 22nd (I took my Sport a little less than a year ago), and I'm wondering how the examiners will be evaluating the fully developed stalls. I looked in the PTS and there's nothing more specific about what they want, and the Airplane Flying Handbook doesn't define a fully developed stall either. My instructor and I have of course stalled the airplane to the point where it breaks a million times, and I never thought to question whether that was the FAA's (or really, the DPE's) definition of a fully developed stall. I assume it is, because how more "developed" can you get than a break? A falling leaf? Unless there's something I'm missing.

Is that what they are going to want to see (recover at the break), or are they going to want a falling leaf? Or something in between?

Thanks!

 

[Velocity173]

I believe the newest PTS has you recovering from a "fully developed stall." DPEs can chime in but I think it's a change over the previous one? Either way I'm sure you won't have a problem recovering within the standard.

Good luck on your check ride. Little advice, don't do anything different than what you've been taught. I tried a technique once on a checkride that I had never done before and it ended poorly! Checkrides aren't the time to try something new.

 

[jpower]

I believe the newest PTS has you recovering from a "fully developed stall." DPEs can chime in but I think it's a change over the previous one? Either way I'm sure you won't have a problem recovering within the standard.

Yup, that's what I'm wondering about. What exactly constitues a "fully developed stall." I hadn't thought about it until today at work.

Good luck on your check ride. Little advice, don't do anything different than what you've been taught. I tried a technique once on a checkride that I had never done before and it ended poorly! Checkrides aren't the time to try something new.

Oh you bet. I've been through one already, so I know generally what to expect, and I'm not going to go off doing something I've never done before!

 

[TMetzinger]

Until a CFI who's recently had a pilot get evaluated against the new criteria can chime in, here's what I've HEARD at some recent FAASTeam CFI/DPE get-togethers.

Some students and CFIs and DPEs were prepping/passing candidates who were recovering from the stall in the incipient phase, where the buffet is occuring as the airflow begins to separate.

In places where the PTS calls for recovery at the first indication of an impending stall, I've known DPEs to pass folks who recovered at the stall warning, or when the controls got very mushy. From the standpoint of avoiding the stall, that's a good habit.

But the Private PTS wants you to STALL the airplane, and recover the airplane AFTER it stops flying. What I've heard is that the recovery shouldn't begin until the "break" occurs and your nose is below the horizon but the wing is still stalled, or, in the cases of aircraft that don't "break" cleanly (many LSAs come to mind), when you are descending in spite of pitch attitude and elevator position. The key point is that the airplane is no longer flying, it's (more or less) falling.

The recovery is unchanged. Reduce the angle of attack, add power, then as energy is recovered, increase the pitch attitude and recover to level flight.

I look forward to comments that are better informed than mine.

 

[poadeleted20]

My instructor and I have of course stalled the airplane to the point where it breaks a million times, and I never thought to question whether that was the FAA's (or really, the DPE's) definition of a fully developed stall.

Yes, that's it -- when the nose first pitches down on its own.

 

[poadeleted20]

But the Private PTS wants you to STALL the airplane, and recover the airplane AFTER it stops flying.

Correct.

What I've heard is that the recovery shouldn't begin until the "break" occurs and your nose is below the horizon

In some (many? most?) light trainers, the nose will never get below the horizon unless you let it slice laterally first -- and that's an incipient spin, not just a stall. You can hold the yoke all the way back to the stops, and the nose will just bob up and down between 5-10 nose up and 15 nose up or so. In that situation, you are bobbing in and out of the stall.

but the wing is still stalled, or, in the cases of aircraft that don't "break" cleanly (many LSAs come to mind), when you are descending in spite of pitch attitude and elevator position.

That's just being "behind the power curve," where drag is so great your flight path is negative despite the nose being above the horizon. You can get a real good sink rate like that without yet having stalled the plane.

What tells you the plane is really stalled is the nose pitches down (any amount, not necessarily all the way to/past the horizon) without you having moved the yoke forward. That's when you initiate the recovery.

 

[jpower]

Excellent. Thanks to everyone!

 

[iWantWings]

Hello jpower,

Am glad you asked the question because I was wondering the same thing as well. I don't have anything to add to the answers you already got, but would like to ask two questions related to aerodynamic stall:

Question 1: If a single engine airplane (like a C172) had a functional Angle of Attack indicator, would there ever be case wehre the wing's Critical AOA is exceeded and the definition of "fully developed stall" not be met?

In other words, in the example above, in a case of a "fully developed stall" would it always true that the wing's Critical Angle of Attack is always exceeded?

Question 2: I read that the requirement for a spin is for "one wing to be more stalled than the other". Does that mean that in a "fully developped stall" the wing's critical angle of attack can further be increased to a point where even less lift is provided by one of the wings in comparison with the other wing (and that would result in a spin in a direction of the wing that is stalled the most)?

(This is just an "academic" sort of question. The way I thought of it was that a fully developped stall is the instance where the lift developped by the wing is sharply reduced to the point where the aricraft's weight is no longer supported (In in practice, the nose would (hopefully) drop, depending on where the CG is))

Thanks!

Hi all,

I'm about to take my PPL checkride this Sunday the 22nd (I took my Sport a little less than a year ago), and I'm wondering how the examiners will be evaluating the fully developed stalls. I looked in the PTS and there's nothing more specific about what they want, and the Airplane Flying Handbook doesn't define a fully developed stall either. My instructor and I have of course stalled the airplane to the point where it breaks a million times, and I never thought to question whether that was the FAA's (or really, the DPE's) definition of a fully developed stall. I assume it is, because how more "developed" can you get than a break? A falling leaf? Unless there's something I'm missing.

Is that what they are going to want to see (recover at the break), or are they going to want a falling leaf? Or something in between?

Thanks!

 

[TMetzinger]

Correct.

In some (many? most?) light trainers, the nose will never get below the horizon unless you let it slice laterally first -- and that's an incipient spin, not just a stall. You can hold the yoke all the way back to the stops, and the nose will just bob up and down between 5-10 nose up and 15 nose up or so. In that situation, you are bobbing in and out of the stall.

That's just being "behind the power curve," where drag is so great your flight path is negative despite the nose being above the horizon. You can get a real good sink rate like that without yet having stalled the plane.

What tells you the plane is really stalled is the nose pitches down (any amount, not necessarily all the way to/past the horizon) without you having moved the yoke forward. That's when you initiate the recovery.

Thanks!

In the 172s, at least with two upfront, a full stall always seems to end up with me looking at the ground with the nose 5 degrees or so low. but that's at the Forward CG edge. It does come up if you leave it alone.

The Tecnam (Sierra I think) LSA "break/bob" is so gentle (and the one I flew had no stall warning horn), that it was a surprise, Idle power, nose still above the horizon bobbing maybe 3-5 degrees, and coming down at 1500 FPM.

 

[poadeleted20]

Question 1: If a single engine airplane (like a C172) had a functional Angle of Attack indicator, would there ever be case wehre the wing's Critical AOA is exceeded and the definition of "fully developed stall" not be met?

Keep in mind that the wings on a plane like a Cessna are tapered and twisted, and the airfoil isn't constant end to end. As a result, the stall doesn't occur at the same time at the tip as it does at the root. In fact, the wing is specifically designed this way so you maintain unstalled airflow over the outer portions for aileron control well after the inboard portion has stalled and the nose has dropped as a result.

That means there's no one point where the stall occurs, and it also means the AoA at one station of the wing isn't the same as the AoA farther inboard or outboard of that station. So-called "AoA gauges" aren't really measuring the angle of attack at every station from root to tip, but rather are measuring the angle of the relative to the longitudinal axis of the airplane. We treat this as though it were the angle of attack, but it's not.

That said, as long as configuration is constant, the stall will occur at the same pseudo-AoA every time. However, the pseudo-AoA for stall will change as you change configuration, most notably, by extending/retracting flaps. So, you won't see the same pseudo-AoA at stall with the flaps up, down, or somewhere in between. You should, however, see the same response from the aircraft at any given pseudo-AoA.

In other words, in the example above, in a case of "fully developed stall" would it always true that the wing's Critical Angle of Attack is always exceeded?

As noted above, the response we call a "fully developed stall" (pitch-down of the nose) occurs while much of the wing is not yet stalled. However, it should occur at the same pseudo-AoA (as indicated by your "AoA" gauge) every time in the same configuration.

Question 2: I read that the requirement for a spin is for "one wing to be more stalled than the other". Does that mean that in a "fully developped stall" the wing's critical angle of attack can further be increased where even less lift is provided by one of the wings in comparison with the other wing (and that would result in a spin in a direction of the wing that is stalled the most)?

Not exactly. A spin results when a yawing motion occurs while the wings are "stalled," although as noted below, the wing isn't entirely stalled, just that enough of the wing is stalled so the net pitch forces result in the nose dropping. When you add a yaw input to that condition, the airspeed over the outboard wing increases, and the airspeed over the inboard wing decreases, and that creates a rolling moment to add to the yawing moment, and the result is a spin entry.

 

[Seanaldinho]

Question 2: I read that the requirement for a spin is for "one wing to be more stalled than the other". Does that mean that in a "fully developped stall" the wing's critical angle of attack can further be increased to a point where even less lift is provided by one of the wings in comparison with the other wing (and that would result in a spin in a direction of the wing that is stalled the most)?
Thanks!

I was always told that a spin is stall with y'all (yaw). So technically if you keep the plane coordinated you will never spin.

 

[iWantWings]

Keep in mind that the wings on a plane like a Cessna are tapered and twisted, and the airfoil isn't constant end to end. As a result, the stall doesn't occur at the same time at the tip as it does at the root. In fact, the wing is specifically designed this way so you maintain unstalled airflow over the outer portions for aileron control well after the inboard portion has stalled and the nose has dropped as a result.

That means there's no one point where the stall occurs, and it also means the AoA at one station of the wing isn't the same as the AoA farther inboard or outboard of that station. So-called "AoA gauges" aren't really measuring the angle of attack at every station from root to tip, but rather are measuring the angle of the relative to the longitudinal axis of the airplane. We treat this as though it were the angle of attack, but it's not.

That said, as long as configuration is constant, the stall will occur at the same pseudo-AoA every time. However, the pseudo-AoA for stall will change as you change configuration, most notably, by extending/retracting flaps. So, you won't see the same pseudo-AoA at stall with the flaps up, down, or somewhere in between. You should, however, see the same response from the aircraft at any given pseudo-AoA.

As noted above, the response we call a "fully developed stall" (pitch-down of the nose) occurs while much of the wing is not yet stalled. However, it should occur at the same pseudo-AoA (as indicated by your "AoA" gauge) every time in the same configuration.

Not exactly. A spin results when a yawing motion occurs while the wings are "stalled," although as noted below, the wing isn't entirely stalled, just that enough of the wing is stalled so the net pitch forces result in the nose dropping. When you add a yaw input to that condition, the airspeed over the outboard wing increases, and the airspeed over the inboard wing decreases, and that creates a rolling moment to add to the yawing moment, and the result is a spin entry.

Thank you for answering both questions. Although I was aware of the wing having different regions whose airfoil varies, i didn't think that the AOA indicator does not represent an "average" AOA, but the AOA at whatever point it is installed (?).

I do have some more questions about how the use of flaps affect the chordline and AOA, but I'll ask try to answer them myself before asking.

And for the 2nd questions, as you well explained, i understand that the basic "requirement" for a spin is an uncoordinated stall; I, however, thaught that the uncoordinated stall is what caused one wing to be stalled more than the other, hence the bank and rotation - but now I know (I think i do anyways).

thanks again for the explanation, it helped me quite a bit!

 

[iWantWings]

I was always told that a spin is stall with y'all (yaw). So technically if you keep the plane coordinated you will never spin.

What you wrote is what was told/read as well, I just mistakenly thought that the uncoordinated stall is what caused one wing to be "more stalled" than another, and that is what led to the bank about the longitudinal axis and rotation about the y axis. But i was wrong.

 

[TMetzinger]

What you wrote is what was told/read as well, I just mistakenly thought that the uncoordinated stall is what caused one wing to be "more stalled" than another, and that is what led to the bank about the longitudinal axis and rotation about the y axis. But i was wrong.

Not completely wrong - one wing is generating more lift as a result of the yaw, and can be said to be less "stalled" than the other. What causes the roll is the lift difference, what causes the yaw is the lack of coordination.

Quite a few texts refer to one wing being "more" or "less" stalled than the other in spin entry, including the Airplane Flying Handbook on page 4-12, which states:
"The autorotation results from an unequal angle of attack on the airplane's wings. The rising wing has a decreasing angle of attack, where the relative lift increases and the drag decreases. In effect, this wing is less stalled."

 

[Jaybird180]

And for the 2nd questions, as you well explained, i understand that the basic "requirement" for a spin is an uncoordinated stall; I, however, thaught that the uncoordinated stall is what caused one wing to be stalled more than the other, hence the bank and rotation - but now I know (I think i do anyways).

This statement aroused a purely academic question for me:

Is it possible that prop wash can account for some of the lift difference Tim mentioned in the above post?

 

[poadeleted20]

Is it possible that prop wash can account for some of the lift difference Tim mentioned in the above post?

Depends on the aircraft's design. In your C-172, the wing is pretty much up out of the propwash.

 

[DouglasBader]

The gist of what they're after here is to differentiate between an approach to stall recovery, and a demonstration of an actual aerodynamic stall.

Previously, one recovered at the first sign of the stall; stall warning, stall break, stick shaker, stick pusher, etc. Whatever that particular aircraft exhibited as the initial sign of a stall; the game plan was stall awareness.

The crash of the Colgan flight at Buffalo revealed some poor response to a stall, as well as the industry standard. The feeling was that it's not just a problem endemic to airline training, but basic flight training as well.

The FAA has waffled on this sort of thing before, introducing spin training, then taking it away, then introducing it again. Presently only CFI applicants must have spin training, but that hasn't always been so.

Likewise, where stall awareness has been the watchword for some time now, the FAA also wants to see you actually stall the airplane. "Fully developed stall" is somewhat of a misnomer, and is very unwise in some airframes (don't go doing that in t-tail swept wing jets, for example), but shouldn't present a problem in most all light airplanes used for training and checking.

Use your normal entry and recovery procedures, and you'll be fine.

 

[gismo]

I was always told that a spin is stall with y'all (yaw). So technically if you keep the plane coordinated you will never spin.

You don't even have to keep it coordinated as long as you have enough rudder authority to keep it from turning and things don't happen so fast you can't/don't apply adequate rudder pressure. If the longitudinal axis is kept pointing in the same direction an airplane cannot spin.

 

[Seanaldinho]

You don't even have to keep it coordinated as long as you have enough rudder authority to keep it from turning and things don't happen so fast you can't/don't apply adequate rudder pressure. If the longitudinal axis is kept pointing in the same direction an airplane cannot spin.

That makes sense having never done one my "expertise" is limited.

 

[bflynn]

Yup, that's what I'm wondering about. What exactly constitues a "fully developed stall."

Your stomach goes "wheee".

Seriously, hold the nose up until it all falls on it's own. Then recover.

Remember in power on stalls, you have to release the heavy rudder input at stall.

 

[RoscoeT]

Remember in power on stalls, you have to release the heavy rudder input at stall.

What does that mean? Never heard that. But sounds a bit like some sort of "cookbook" technique for simply controlling yaw and keeping the wings level with the rudder during a stall. When I say "cookbook", I mean a rote sequence that does not foster understanding and feel of the airplane. There's a lot of rote teaching/learning in flight training...too much, IMO. Forget which rudder you're pushing...just keep the wings level. And it's generally not a simple "release" or "push" of rudder, but more of a quick dance on both rudders, similar to handling a tailwheel airplane on the ground.

 

[bflynn]

If the longitudinal axis is kept pointing in the same direction an airplane cannot spin.

A forward slip to stall? The airplane points the same direction the whole way, but it is an uncordinated maneuver.

 

[bflynn]

What does that mean? Never heard that. But sounds a bit like some sort of "cookbook" technique for simply controlling yaw and keeping the wings level with the rudder during a stall. When I say "cookbook", I mean a rote sequence that does not foster understanding and feel of the airplane. There's a lot of rote teaching/learning in flight training...too much, IMO. Forget which rudder you're pushing...just keep the wings level. And it's generally not a simple "release" or "push" of rudder, but more of a quick dance on both rudders, similar to handling a tailwheel airplane on the ground.

There's nothing rote about it. It's a step in a power on stall. I had a discussion with a CFI about two weeks ago on the topic because I was dropping the right wing in a power on stall and I couldn't put my finger on why. If you learned spins in a very forgiving airplane, you might not have seen these. Or you might have automatically been doing this.

Think of it like this - you're doing a power on stall, you're at a really high AOA and high power....you need hard right rudder to fly coordinated. But as soon as you stall, you're not under power any more, so the rudder is no longer needed.

For me, it was keeping the rudder in that was causing the wing to drop as the start of a spin.

 

[poadeleted20]

Remember in power on stalls, you have to release the heavy rudder input at stall.

Only if you want to enter a spin. While you lose some P-factor during the recovery as you lower AoA, you don't want to simply release the rudder. The engine is putting out just as much power, so torque and spiraling slip-stream are unchanged. Just continue to make whatever rudder inputs are necessary to keep the nose from yawing either way and you'll be fine.

 

[poadeleted20]

Think of it like this - you're doing a power on stall, you're at a really high AOA and high power....you need hard right rudder to fly coordinated.

Correct.

But as soon as you stall, you're not under power any more, so the rudder is no longer needed.

Stalling the wing does not stop the engine -- it's still putting out just as much power as it was when you stalled the wing.

For me, it was keeping the rudder in that was causing the wing to drop as the start of a spin.

It sounds like you're using some sort of canned rudder input rather than using the rudder in response to yaw deviations. You need to work more on using rudder to keep the nose from yawing rather than relying on some set amount of rudder for some particular situation.

 

[bflynn]

I don't think either of you are understanding what I'm describing. Perhaps thats because I'm not describing it well.

You don't need right rudder at full throttle in level flight..yet, you still have slipstream, engine torque and gyroscopic precession in play. So the fact that these things are also in play during a power on stall cannot be not a significant contributing factor.

The reason is p-factor, aka asymmetric blade effect. That is the primary reason hard right rudder is needed with a high AOA. When the stall breaks, the nose drops and p-factor is reduced. The same rudder input that made you coordinated with a high AOA/high p-factor makes you uncoordinated when the stall occurs and p-factor is reduced.

Does that explain it better?

I'll admit this is all theoretical to me right now - due to weather and work schedule, I haven't been able to fly since talking this out on the ground. But it makes sense to me and I can feel how it works for my situation. If you're unconsciously doing this because you're just a superior natural pilot, then this probably sounds like I'm crazy...thats OK, you might be right.

All I'm suggesting - if, as has been happenning with me, your right wing drops in a power on stall, remember what I've been saying and see if letting off the rudder input because of the reduced p-factor works.

 

[RoscoeT]

I don't think either of you are understanding what I'm describing. Perhaps thats because I'm not describing it well.

You don't need right rudder at full throttle in level flight..yet, you still have slipstream, engine torque and gyroscopic precession in play. So the fact that these things are also in play during a power on stall cannot be not a significant contributing factor.

The reason is p-factor, aka asymmetric blade effect. That is the primary reason hard right rudder is needed with a high AOA. When the stall breaks, the nose drops and p-factor is reduced. The same rudder input that made you coordinated with a high AOA/high p-factor makes you uncoordinated when the stall occurs and p-factor is reduced.

Does that explain it better?

I'll admit this is all theoretical to me right now - due to weather and work schedule, I haven't been able to fly since talking this out on the ground. But it makes sense to me and I can feel how it works for my situation. If you're unconsciously doing this because you're just a superior natural pilot, then this probably sounds like I'm crazy...thats OK, you might be right.

All I'm suggesting - if, as has been happenning with me, your right wing drops in a power on stall, remember what I've been saying and see if letting off the rudder input because of the reduced p-factor works.

I understand the cause and effect that you feel is taking place, and that a reduction in p-factor would occur during the nose drop of a power-on stall, but I don't think this effect is generally as pronounced as you describe it to be. I just don't think it's good to teach control inputs in the rote or "canned" (Ron's apt word) sequence that you describe. I have done power-on stalls in lots of airplanes from low power/performing trainers and antique classics to high powered aerobatic airplanes, and never noticed that right rudder needs to be significantly reduced (if at all) during a power on stall. If it is, you might be holding too much to begin with. Furthermore, like I've already described, I'm simply looking out the window and applying inputs as needed to make the airplane do what I want.

Yes, p-factor is reduced, but there is still a very strong left yawing force at work that IMO is stronger than p-factor - slipstream. This does not get reduced during the power-on stall process. And there are two more forces that attempt to yaw the airplane left and drop the left wing at the stall - torque and gyroscopics. As the nose pitches down, propellor gyroscopics will tend to yaw the airplane left. And propellor torque will apply a left rolling force. These last two forces are not going to be very noticeable in your typical trainer, but they are more pronounced in airplanes with much greater power-to-weight ratios than you may have experience with.

Do what works for you in what you are currently flying, but I think you'll find that different airplanes behave differently, and "canned" techniques will not serve you well when moving between different aircraft types.

 

[Jaybird180]

I understand the cause and effect that you feel is taking place, and that a reduction in p-factor would occur during the nose drop of a power-on stall, but I don't think this effect is generally as pronounced as you describe it to be. I just don't think it's good to teach control inputs in the rote or "canned" (Ron's apt word) sequence that you describe. I have done power-on stalls in lots of airplanes from low power/performing trainers and antique classics to high powered aerobatic airplanes, and never noticed that right rudder needs to be significantly reduced (if at all) during a power on stall. If it is, you might be holding too much to begin with. Furthermore, like I've already described, I'm simply looking out the window and applying inputs as needed to make the airplane do what I want.

Yes, p-factor is reduced, but there is still a very strong left yawing force at work that IMO is stronger than p-factor - slipstream. This does not get reduced during the power-on stall process. And there are two more forces that attempt to yaw the airplane left and drop the left wing at the stall - torque and gyroscopics. As the nose pitches down, propellor gyroscopics will tend to yaw the airplane left. And propellor torque will apply a left rolling force. These last two forces are not going to be very noticeable in your typical trainer, but they are more pronounced in airplanes with much greater power-to-weight ratios than you may have experience with.

Do what works for you in what you are currently flying, but I think you'll find that different airplanes behave differently, and "canned" techniques will not serve you well when moving between different aircraft types.

Been awhile since I've flown it, but I recall doing a pronounced rudder dance in power on stalls in the DA-40. IIRC it wanted to dip a wing (don't recall which) then fishtail.....or maybe it was my abrupt footwork

 

[poadeleted20]

Been awhile since I've flown it, but I recall doing a pronounced rudder dance in power on stalls in the DA-40. IIRC it wanted to dip a wing (don't recall which) then fishtail.

It doesn't matter which -- you just do whatever dance is needed to keep the nose from yawing.

....or maybe it was my abrupt footwork

Most folks tend to overcontrol a bit when first learning this -- just a matter of practice to get it right.

 

[bflynn]

but I don't think this effect is generally as pronounced as you describe it to be.QUOTE]

Well...it's strong enough to make the right wing drop and the plan yaw 50-90 degrees when the stall happens. So it isn't about what I think, it's about what actually has happened. I'm quite sure that if I had left the rudder input in and didn't reduce power, I would have been over into the spin.

And you keep talking about ""canned" techniques, but that isn't what's going on. It's about balance and you DO have to let the rudder input off when you stall.

 

[DouglasBader]

And you keep talking about ""canned" techniques, but that isn't what's going on. It's about balance and you DO have to let the rudder input off when you stall.

No, you really don't.

As you fly out of the stall you need to reduce rudder pressure, as less rudder is required as you increase speed.

In the stall, you need whatever rudder is required to keep the airplane flying straight ("coordinated"), and if you don't make a power reduction, that's not going to change appreciably from before, or after the stall.

 

[poadeleted20]

but I don't think this effect is generally as pronounced as you describe it to be.

Well...it's strong enough to make the right wing drop and the plan yaw 50-90 degrees when the stall happens.

If the plane is yawing that much at the power-on stall, you've got to be yawing already, i.e., too much rudder going in. The change in P-factor just isn't that large.

So it isn't about what I think, it's about what actually has happened. I'm quite sure that if I had left the rudder input in and didn't reduce power, I would have been over into the spin.

Reducing power will make the plane yaw even harder to the right, and you don't reduce power in a power-on stall recovery, anyway.

All in all, I think you have some fundamental issues here with regard to the use of power in recovering from a power-on stall, the effects of power on yaw, and the correct technique for positioning the rudder. It's too hard to teach things like that over the internet (I'd have to fly with you to do that), but you really need to sit down with your instructor and discuss this thoroughly, and then explore it thoroughly in the airplane. Otherwise, you are going to get seriously hurt some day (not to mention having trouble passing a PP-Airplane practical test).

 

[RoscoeT]

I was thinking about it a little more and I'm not sure P-factor changes very much at the onset of, and during the stall. P-factor is a function of AoA, not attitude. So just because the airplane drops its nose a little (attitude change, not AoA change) as the airplane stalls, does not necessarily mean P-factor is reduced. You are entering a full stall, and the AoA (P-factor) will not diminish until you unload the elevator and break the stall. If anything, AoA will slightly increase as the nose drops...IMO. Of course, common sense dictates that once you have unloaded the elevator, you have re-attached airflow over the wings, the airplane is beginning to fly again, and you may need to reduce the amount of your rudder inputs. But at the onset of, and during the stall, I'm not sure you can make any generalizations on rudder inputs needed other than do what you need to do. Bflynn, that is the exception we took with your statement - your implication that how you handle the rudder (and the reasons for it) during power-on stalls (either correctly or incorrectly) applies to airplanes in the general sense. It does not.

 

[Jaybird180]

It doesn't matter which -- you just do whatever dance is needed to keep the nose from yawing.
Most folks tend to overcontrol a bit when first learning this -- just a matter of practice to get it right.

It was significant to me because the behavior was consistent. But I really didn't do enough of them to begin to learn to anticipate it. At the time, I was thinking bad habit (?).

http://www.pilotsofamerica.com/forum/showpost.php?p=732673&postcount=40

 

[dtuuri]

...because I was dropping the right wing in a power on stall and I couldn't put my finger on why.

...you're at a really high AOA and high power....you need hard right rudder to fly coordinated.

For me, it was keeping the rudder in that was causing the wing to drop as the start of a spin.

I'm siding completely with RoscoeT with these additional comments. Even if your plane is rigged correctly, a wings-level straight ahead 'coordinated' stall will produce a side-slip due to the asymetrical disk loading on the propeller. Ask any multiengine pilot. So, the trailing wing (right) will stall first. Try using less right rudder throughout, not only after the break. Oh, and keep your heels on the floor! And eyes on the horizon.

dtuuri

 

[poadeleted20]

And eyes on the horizon.

"...and i'll always come back, come back, baby, to you." Thank you, KT Oslin.

 

[Traveler0471]

What's old is new again. It's gone full circle and will most likely continue to do so. At least as far as stalls training requirements go. That’s where the glider world has the power side beat. They have always required full stalls and spin recovery be part of their basis pilot training. Perhaps someday we power guys will get it right.

 

[flyingron]

What tells you the plane is really stalled is the nose pitches down (any amount, not necessarily all the way to/past the horizon) without you having moved the yoke forward. That's when you initiate the recovery.

I've flown planes (tomahawk) where you can pretty much hold the nose in the same attitude throughout the stall. You're just falling with roughly the same attitude. If you are holding the elevator full back, then yes, the nose has to come down a bit at the stall but if you reach the stall before you reach full aft travel, you may not drop the nose at all.

 

[poadeleted20]

I've flown planes (tomahawk) where you can pretty much hold the nose in the same attitude throughout the stall. You're just falling with roughly the same attitude. If you are holding the elevator full back, then yes, the nose has to come down a bit at the stall but if you reach the stall before you reach full aft travel, you may not drop the nose at all.

You may think you've stalled, but without the pitch-down, it really hasn't -- just settled on the back side of the power curve where you're sinking like a rock but the wing is still unstalled. In some planes, the pitch-down may not be large, and the wing may unstall somewhat when it does, resulting in that bobbing motion, but without that response, it hasn't stalled.

 

[flyingron]

Sorry Ron, the power curve has squat to do with this. The pitch down occurs because the lift has decreased past what the elevator down force is countering. A pitch down only necessarily occurs at the point of the stall in a steady state, if you are increasing the aft stick, there's not necessarily a pitch down. The main wing doesn't completely stop flying at the stall point, the AOA to lift relationship just reverses.