Power-On Stalls

[AC560]

Its been a while, but I believe the PTS allows for 65% or 75% of full power during the maneuver. This is as you stated, to prevent the nose from becoming abnormally high.

PTS is 65% but they now state "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)."

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

 

[Joshrk22]

When it says 65%, does it mean 65% of the maximum RPM? So on the 182 max RPM is 2,700. So I should do them around 1,800 RPM?

That means the rudder usage will be less and the wing shouldn't drop as much. So it's probably a lot easier to do it that way.

 

[AC560]

When it says 65%, does it mean 65% of the maximum RPM?

65% of available power.

So it's probably a lot easier to do it that way.

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.

 

[svcta]

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.

Yeah, but I'd venture to guess that stalling a 182 at takeoff power would be difficult, even intentionally.

To the original poster. Stick to the 65% for purposes of demonstration and practice. (Regarding that power setting: Consult the POH. With a constant speed prop your power setting will be a funtion of both MP and RPM, not just RPM.) You will at least develop an understanding of how to recognize what the airplane will do as it approaches a stall at a high power setting. That's the spirit of the thing. And as far as technique, there's been good advice so far. The best of which is to take your time. A 182 while, as said, having more power than a conventional trainer, also has more mass. Therefore you'll need to allow it to bleed off energy for a little longer as you slowly increase the pitch angle. Let it settle in as you enter the maneuver and you'll see more manageable pitch attitudes, too.

 

[AC560]

Yeah, but I'd venture to guess that stalling a 182 at takeoff power would be difficult, even intentionally.

And anyone who did probably wouldn't be smart enough to recover it in any case. I wasn't implying that the original poster should shove the power in and pull the nose up 90 degrees. My intent was more focus on some of the things Amish posted and at 65%+ power you are going to find it to be a non event.

 

[midlifeflyer]

Remember right rudder.

Also, per PTS I think you need a minimum of 65% power for the stall. I typically have my students do it around 2000 RPM in a C152 so we don't pitch up as much.

If you need to go less than full takeoff/departure power to induce a takeoff/departure stall in a 152 at a reasonable "too high" pitch, I think you're doing something wrong. Most common thing I see is entering the maneuver at too high an airspeed.

 

[nosehair]

Ahh, I love this one. Especially in a higher powered airplane where it is more pronounced.

The big common error, which is not taught or dicussed in most flight training material that I know of, is that you cannot "keep the ball centered" in a straight climb.

Because of "P-Factor", the propeller thrust moves to the right side of the prop, causing the nose to turn left.

Now, what follows may not be exactly aerodynamically correct, but the bottom line is, you cannot hold a constant heading with the wings level and the ball centered when you have P-Factor.

You push right rudder to hold a heading, but that adds drag to the right side and decreases lift so the right wing comes down, so you add left aileron to hold the wings level. This crosses the controls, but is not a cross-control situation that will result in a spin.

The necessary component to a spin is yaw.

The nose must be yawing, either too much or not enough rudder to keep the nose constantly straight. If the nose is pointed straight and not allowed to yaw, a spin will not result no matter how much the controls are crossed.

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.

 

[svcta]

If the nose is pointed straight and not allowed to yaw, a spin will not result no matter how much the controls are crossed.

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.

 

[Joshrk22]

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.

 

[MauleSkinner]

Technically, as Nosehair indicated, a power-on stall in a single-engine airplane is aerodynamically similar to an asymetric (engine out) stall on a twin. In other words, "ball in the center" doesn't have the airplane's flight path in line with its longitudinal axis. If you stall the airplane with wings level and ball centered, the right wing SHOULD drop.

The way to get the airplane to stall straight ahead is with a slight bank to the right (just like "into the good engine" on a twin) with the ball slightly out to the right.

Sparky Imeson explains it much more clearly than I do in "Taildragger Tactics", a book I recommend whether you fly taildraggers or not

Fly safe!

David