Power-On Stalls

[oldxfr8dog]

Full power on stall in a AC560 is 29mph, would definitely be an E-Ticket ride doing one (an probably a one way ride).

I know you mean IAS, which at that pitch is unreliable, but do you mean full-power stalls are some kind of suicide ride in an 560?

 

[Metro752]

Should be able to do it just fine in a C152 at full power, as well as a 160HP or lesser C172.

 

[AC560]

I know you mean IAS, which at that pitch is unreliable, but do you mean full-power stalls are some kind of suicide ride in an 560?

You aren't going to get 29 mph at full power without a pitch way in excess of what would be safe (probably in excess of 60 degrees). You won't drop a wing when it breaks you will probably roll inverted. I also don't like the idea of being way below VMC in an 50 yr old airplane. If Bob Hoover was riding along maybe....

 

[svcta]

I'm one of the largest commander fans I know but those poor things are just getting tired. And cold-bent spars aren't standing the test of time. I'm wichoo on that one AC.

 

[AC560]

I'm one of the largest commander fans

probably the greatest light twin ever made.

 

[CFI2766]

One of the purposes of stall traing is to learn to hold a constantly straight heading throughout the entry and recovery of the stall - no matter where the ball is. Just like a landing. You keep the nose pointed straight down the center line with rudder and hold the wings level with the aileron. Period. You don't give a whit about the ball.

That's how you should stall.[/quote]


I just don't think this is the best logic. True enough, light GA planes used for training, and to some extent, a 182, are difficult to stall. That being said, a coordinated ball will ward off a lot of evil things.

 

[Joshrk22]

You think if you kept the ball centered and the wings level when you stalled the plane, it would still fly on the same heading...

 

[nosehair]

As to the power setting for a power-on stall, read the Airplane Flying Handbook. Not the PTS.

The AFH is the training handbook. When you teach the maneuvers required in 61.107 or 61.127 for pvt. and comm. certs.; when you make the endorsement that "you have trained and consider him/her proficient", you are saying you have trained in all the maneuvers indicated in the AFH, not just the "snapshot" maneuvers listed in the PTS, which are specifically designed to be standardized to be evaluated. But you, as instructor, and you as a student, should be covering, as a minimum, all the maneuver scenarios outlined in the AFH.

The AFH description of power-on stalls uses the terms "full power" and "take-off power", and "climb power".

Is there anyone out there that does not want to be proficient at being in full control authority if you happen to approach a full power stall during your take-off sequence?

The allowance to use only 65% during a checkride is for those high-power airplanes that might climb a couple thousand feet in a very steep pitch attitude which would be unsafe to climb through a large piece of sky with the nose way up.

You don't need to do that in most trainers, certainly not a 152.

And even in the high powered airplane, I am going to have the student do full power stalls for his/her own personal proficiency, and also do 65% power-on stalls for the checkride.

 

[AC560]

The allowance to use only 65% during a checkride is for those high-power airplanes that might climb a couple thousand feet in a very steep pitch attitude which would be unsafe to climb through a large piece of sky with the nose way up.

You could use 65% regardless of the airplane it is the minimum listed in the PTS. The high performance exception is for power less then 65%.

C. TASK: POWER-ON STALLS (ASEL and ASES)
NOTE: In some high performance airplanes, the power setting may have to be reduced below the practical test standards guideline power setting to prevent excessively high pitch attitudes (greater than 30° nose up).

REFERENCES: FAA-H-8083-3, AC 61-67; POH/AFM.

Objective. To determine that the applicant:
1. Exhibits knowledge of the elements related to power-on stalls.
2. Selects an entry altitude that allows the task to be completed no lower than 1,500 feet (460 meters) AGL.
3. Establishes the takeoff or departure configuration. Sets power to no less than 65 percent available power.

 

[nosehair]

C. TASK: POWER-ON STALLS (ASEL and ASES)
NOTE: In some high performance airplanes, the power setting may have to be reduced below the practical test standards guideline power setting to prevent excessively high pitch attitudes (greater than 30° nose up).

So, if you're using an airplane that you have to get the nose up above 30 degrees, then you can use less than 65% - ok, since most civilian proppeller airplanes, including what we call High Performance, and most HP airplanes are in the 200 plus area, 300hp at best, that little notation isn't even in our area of consideration.

REFERENCES: FAA-H-8083-3, AC 61-67; POH/AFM.

Note the reference to FAA-H-8083-3 which describes the use of full power for power on stalls.

Objective. To determine that the applicant:
1. Exhibits knowledge of the elements related to power-on stalls.

The knowledge of power on stalls is outlined in the above referenced handbook. This includes the knowledge of full-power on stalls. As a matter of fact, the AFH does not mention 65% power.

3. Establishes the takeoff or departure configuration. Sets power to no less than 65 percent available power.

OK. "Establishes takeoff or departure configuration".
Is that with less than take-off or departure power?

"Sets power to no less than 65%." Not to 65%. To not less than 65%.

Now, it is up to you, Mr. Instructor. Do you really think it is good for a pilot to not be trained in handling the equipment he is flying??

The PTS is not a training syllabus.

When you endorse a pilot applicant, your endorsement says you find that person competent - wait, here it is in the front of every PTS:

FLIGHT INSTRUCTOR RESPONSIBILITY

An appropriately rated flight instructor is responsible for training the pilot applicant to acceptable standards in all (bold in book, not mine) subject matter areas, procedures, and maneuvers included in the TASKs within each AREA OF OPERATION in the appropriate PTS.

ALL subject matter...with the references given for each task.

Your endorsement says you have done that and find him/her competent and proficient in all areas referenced for that task.

And, of course, the defining person is you, the CFI.

Are you really comfortable teaching only the rote minimums of the PTS, even if you are in the camp that says the minimums of the PTS are good enough?

 

[AC560]

The PTS is not a training syllabus.

I didn't say it was. You made the comment "The allowance to use only 65% during a checkride". Had you said training I wouldn't have commented.

From a training perspective you can see from my previous post that I don't dispute what you are saying "Probably true but the purpose is to handle departure stalls so unless you regularly plan on taking off at 65% or less power you might want to be able to cope. Amish gave some good advice on how to master the maneuver, try working through that in conjunction with your instructor. You will get more satisfaction and be a better pilot."

Peace out.

 

[nosehair]

You sure you want to stick to that?

Yeah...

I would actually contend that as one wing falls of, you should only counter that with yaw. By yawing the airplane in the direction you need to roll to bring the low wing up, you're restoring a little airspeed to that side, therefore balancing the stall out over the entire wing again. Theoretically, yaw could prevent a spin, whereas aileron will only aid one.

Yeah, that's what I said. No yaw = no spin. If yaw begins to occur, sufficient rudder to stop the yaw prevents the spin.

 

[svcta]

an issue of semantics, perhaps, but I don't believe that yawing motion actually causes a spin as a blanket statement. It WILL if you use ham-fisted rudder inputs. However, aileron will absolutely do it, especially in airplanes that aren't trainers. In some airplanes improper use of ailerons(as in any at all) will lead to control reversal, and aggravate a stalled situation very badly. I suggest you learn to do stalls without aileron....especially if you want to train beyond your training, as has been mentioned above.

 

[nosehair]

Nosehair,

Are you saying it's okay to cross the controls in the stall to keep it on heading? That's what I was doing and it worked fine. But everywhere I've read it says not to do that.

That's why I said I have never read about the "assymetrical thrust" in any flight training material I know of. I only figured it out because of experience.
So I try to pass it on.

It's the same theory that multi-engine pilots talk about when operating on one engine. If the thrust line is not in line with the airplane fusalage, that thrust provides a yawing motion which must be corrected with rudder, but the rudder horizontal lift makes the airplane slide sideways through the air and you bank slightly, 3-5 degrees to make the airplane fly straight through the air in the direction the nose is pointed, but the ball will be out about a half of a ball width.

We should apply that same technique to climbing in a single. The P-Factor in 100HP engine at normal climb speeds is almost not noticable, so the technique is missing, but when you get to 225HP or so, you really notice it.

The only time you should be concerned about "coordination" or keeping the ball centered is in a turn. That's right - in a turn.

When you make that base-to-final turn, (or any turn, really) you should be concerned that you have the correct bank angle for the rate of turn that you are inducing.

When you practice the turning stalls, the focus should shift from the heading to the ball.

When you are flaring for a landing, rotating for a take-off, or practicing a straight-ahead stall, which should simulate something like a landing or take-off, you aren't concerned with the ball, are you? I hope not. Those times are strictly rudder-controls-heading, and ailerons control bank, regardles of the ball. You land in a slight slip in a crosswind. You might make the entire approach in a slip correcting for crosswind, and the ball is hanging down in the inside of the slip.

But, look, this type of "crossed-controls" does not allow yaw. As long as you have rudder authority to hold the nose straight, you ain't gonna roll over into a spin.

Of course, you have to maintain rudder authority. If you run outta rudder as you stall, then you are gonna yaw, and maybe spin.

So, now when you do your practice turning stalls, the ball becomes the controlling factor of how much rudder to apply.

If you do a power-on stall in a 20 degree banked turn to the right, you will wind up with the controls severely crossed.

Start a 20 banked climbing turn, with the ball centered, then ease the nose up to about a 20 degree nose-up attitude and maintain this attitude while holding a constant bank angle and keeping the ball perfectly centered.

As the speed slows, the ball will try to slide down inside the turn and you will have to add right rudder which will cause the bank to try to increase, and you will have to add left aileron to keep a constant bank so that by the time you stall, you will have a good bit of right rudder and a very significant amout of left aileron. But the bank is constant and the ball is centered. When the stall occurs the airplane rolls left - towards level.

Of course, if you continue to hold that large aileron input, the airplane would roll past level into a spin/spiral to the left, but of course you would neutralize the ailerons as you roll level.

The point is: there are lots of times you will be "uncoordinated" :
1) crossed-controls to keep the ball centered in turns, and
2)having the ball out of center when in a straight ahead-wings-level situation.

 

[caliginousface]

You sure you want to stick to that? The only reason we use rudder to induce a spin is because it's the easiest way to do it. What you need is a stalled wing and one side more so than the other. By kicking the rudder(yawing the airplane) you accelerate one wing through the air and increase its airspeed while decreasing the other wings airspeed. Sort of like retreating blade stall in a helo.

If you utilize a little theory, you can see how having the ailerons in play in a stalled situation will increase one wing's angle of attack while reducing the other's, resulting in having one wing further stalled than the other. Especially as one wing begins to fall, you try to counter that with aileron and the stall on that wing is further developed. I would actually contend that as one wing falls of, you should only counter that with yaw. By yawing the airplane in the direction you need to roll to bring the low wing up, you're restoring a little airspeed to that side, therefore balancing the stall out over the entire wing again. Theoretically, yaw could prevent a spin, whereas aileron will only aid one.

Now again, in the trainers that we're talking about, we have to impart a yaw on the airplane(usually) to force it to spin(to accelerate one wing and decelerate the other). But this is NOT the case in every airplane.

So if the right wing is dropping during a power-on stall, I would need to reduce right rudder or use left rudder rather than correct the bank with aileron, then neutralize them, and reduce some of the rudder pressure?

Is that what you're saying?

 

[svcta]

You're asking for trouble by correcting roll with aileron exclusively when stalled. Trainers are, of course, very forgiving. But other planes may not be, and old habits die hard.

 

[caliginousface]

You're asking for trouble by correcting roll with aileron exclusively when stalled. Trainers are, of course, very forgiving. But other planes may not be, and old habits die hard.

I meant before the stall occurs, but yes I agree.

 

[MauleSkinner]

I meant before the stall occurs, but yes I agree.

Before the stall occurs, you should be using coordinated aileron and rudder for roll correction...keeping in mind that at the airspeeds involved, it could take a LOT of rudder to coordinate a little aileron.

Fly safe!

David

 

[Amish RakeFight]

For you practicing CFI's out there, I've got a good exercise that will keep your students from using that forbidden alieron.

Next time you go out to practice power-on's, demonstrate one where you maintain your heading solely by use of the aileron. Zero rudder input. Keep pitching up with full power and maintain heading with aileron input only. When that baby hits the stall, let'em see how bad an idea it is to use aileron. They'll be sure to be more assertive with rudder inputs in the future.

 

[VNugget]

For you practicing CFI's out there, I've got a good exercise that will keep your students from using that forbidden alieron.

Next time you go out to practice power-on's, demonstrate one where you maintain your heading solely by use of the aileron. Zero rudder input. Keep pitching up with full power and maintain heading with aileron input only. When that baby hits the stall, let'em see how bad an idea it is to use aileron. They'll be sure to be more assertive with rudder inputs in the future.

Funny. After reading most of this thread, that is exactly what I did with a student today, with good results*, and came here to post exactly what you did.

*By good results, I mean it did what I expected and went into a spin. Don't you hate when you tell the student to do something and such-and-such bad thing is gonna happen, and it doesn't happen? Argh!