The Unforgiving (née Impossible) Turn.

[facthunter]

This is a straw argument. A plane is flown on attitude basically by reference to either the real horizon or the artificial one.  If you notice from a performance instrument you are say climbing , you look at the attitude and adjust it and WAIT to confirm the new attitude is the desired one. I'm keeping it simple deliberately. In your early S & L lessons the attitude changes as your speed changes and again you hold the level. constant for the purpose of the exercise. Instrument flying was known as "attitude instrument  Flying".  When you are stabilised, you then adjust the trim to ease the control forces. To do this accurately takes a bit of concentration but becomes second nature later. Some pilots develop the poor technique of flying on trim. which should be discouraged. Nev

Edited August 31, 2022 by facthunter

[Roundsounds]

1 hour ago, APenNameAndThatA said:

Power + attitude = performance isn’t actually true. Power + attitude + time + equilibrium = performance would be more accurate. 

 

If you are taking off and the engine stops, and you adopt the site picture for a Vy 45 degree banked turn, you could easily stall and spin. That is because there is every chance you will be going way less than Vy! 

Still hung on IAS? Exceeding the critical angle of attack causes the stall and uncoordinated flight at the stall causes the spin. There’s a lot going on for the typical PPL holder following an EFATO, which is why it’s often best to not turn back.

[Blueadventures]

54 minutes ago, APenNameAndThatA said:

Was the lag because the ASI took time to catch up ot because the airplane took time to accelerate. My guess is the latter, but I wasn’t there. 

It was explained to me as being due to the cross flow of air on the pitot tube resulted in a slight reduction of indicated air speed usually about 2 knots and as maintaining accurate speed and see in reduce in a glider can only point nose down a little and this resulted in then being 3 or 4 knots over speed and a chat from the instructor about chasing what you see on the dial not maintaining accurate speed.  Years ago now.

[Old Koreelah]

42 minutes ago, Blueadventures said:

It was explained to me as being due to the cross flow of air on the pitot tube resulted in a slight reduction of indicated air speed usually about 2 knots…

For a long time (until the mechanism broke) I had my pitot articulated to the airflow, which should have given accurate readings. I’ve toyed with the idea of installing a Reserve Lift Inducator (or AoA meter) but presumably they must be calibrated to flap position.

A simple stall horn is attractive, but it also would need to refer to what the flaps are doing. If you’ve forgotten to hang out the flaps, will the horn sound in time to save you?

 

Perhaps a more reliable stall warning is based not on AoA, but how much of the airflow over the wing is becoming turbulent.

 

[APenNameAndThatA]

1 hour ago, Roundsounds said:

Still hung on IAS? Exceeding the critical angle of attack causes the stall and uncoordinated flight at the stall causes the spin. There’s a lot going on for the typical PPL holder following an EFATO, which is why it’s often best to not turn back.

 The post you quoted did not mention IAS. 

Edited August 31, 2022 by APenNameAndThatA

[facthunter]

The vane type stall warning A la Cessna works clean or with full flap. Good enough to be a reliable reference. Get it to "beep" just as the wheels touch was the aim.. Audio doesn't need you to look. If it's continuous, you are slow. If it's intermittent you are close to slow, and if it's not beeping you don't really know..  Nev

[Roundsounds]

21 hours ago, APenNameAndThatA said:

 The post you quoted did not mention IAS. 

You were concerned about speed being less than Vy, that’d be an IAS?

Stalling has nothing to do with IAS, angle of attack dictates when a wing will stall.

[tcsmith]

Hi Aro,

 

Thanx for your response. The purpose of turn back exercise in Gliders is handling rope breaks on takeoff. Assuming a 30 to 1 Glide performance for an IS-28 , the instructor in the back will yell out rope break, the trainee will expect something to happen, and initiate a 30+ deg bank to the left. Provided response is timely, the glider will be pointed back to the strip quite quickly. Maintaining 50Kt in the turn from a 65Kt tow, this works. Traffic is held on the ground, and the site is chosen for a safety margin. I have done this as part of yearly checks on various occasions.  Again, dont try this with a Powered  Aircraft.....  Terry

[APenNameAndThatA]

1 hour ago, Roundsounds said:

You were concerned about speed being less than Vy, that’d be an IAS?

Stalling has nothing to do with IAS, angle of attack dictates when a wing will stall.

Okay, we’ve put the issue of lag to one side. It is true that stalling is determined by AOA. But it is obviously incorrect to say that airspeed has *nothing* to do with stalling. That’s how come aircraft have a published stall speed. Yes, you can stall at any speed (unless the plane breaks first) but Im pretty sure you’d agree that the lower the airspeed the more likely a stall?. I was obviously addressing the issue of AOA by referring to the sight picture, the pitch of the aircraft. 

 

Anyway, is there anything that I’ve said that is incorrect? 

[APenNameAndThatA]

The back and forth might be hiding an important question, IMHO. If you have an engine failure on takeoff or accidentally find yourself stalling turning final, do you a) adopt a glide attitude or b) quickly get the nose at least 10 degrees below the horizon? I favour the latter, big time, but Ive got a massive 212 hrs. 

[facthunter]

At that stage, put your head between your legs and kiss your Axs goodbye is considered appropriate, Ha Ha, but control is essential to any good outcome. Unloading the wing will do that but what height you have will restrict  the likelihood of a good outcome, when you're stalled. Most pilots need say 250 feet without using power to recover.  Nev

[Yenn]

It all depends upon the plane, but whatever happens it is most likely better to be recovering from a stall when you crash, than fully stalled.

[onetrack]

 

Quote

If you have an engine failure on takeoff or accidentally find yourself stalling turning final, do you a) adopt a glide attitude or b) quickly get the nose at least 10 degrees below the horizon? I favour the latter, big time, but Ive got a massive 212 hrs

A stall at low altitude is a recipe for a fatal accident. Watch any video of an aircraft stall at low altitude, they rarely recover to make a satisfactory landing. Why is 500 feet the legislated MSA?

 

Edited September 3, 2022 by onetrack

[facthunter]

It's also the standard height to commence final, though in certain conditions U/L's are far more flexible than that. The turn onto  final historically is a known high risk situation especially if the  base leg has a downwind.  Nev

[Thruster88]

On 01/09/2022 at 7:46 PM, Roundsounds said:

You were concerned about speed being less than Vy, that’d be an IAS?

Stalling has nothing to do with IAS, angle of attack dictates when a wing will stall.

We all know that stalls occur when the critical angle of attack is exceeded. For pilots not involved in aerobatic manoeuvring stalling has every thing to do with airspeed I would suggest.

 

Whether that is straight and level or a 60° banked turn, fly the appropriate airspeed and all will be good.

 

The other thing is many, most? recreational aircraft have no angle of attack stall warning devices. Only 1/4 of my aircraft have this feature.   

[facthunter]

it's a good start but you need to anticipate a power increase or a height loss where you are   asking the wing to do more work. Then we have the low level optical illusions (so called) but we don't teach low level flying for the U/Ls. . Learn to fly figure 8's accurately. There should be no such thing as an unintended stall. Nev

[pmccarthy]

Reno race pilot died yesterday. Engine failure, and stall spin trying the impossible turn. A most experienced pilot.

[Flying Binghi]

On 02/09/2022 at 10:11 PM, APenNameAndThatA said:

The back and forth might be hiding an important question, IMHO. If you have an engine failure on takeoff or accidentally find yourself stalling turning final, do you a) adopt a glide attitude or b) quickly get the nose at least 10 degrees below the horizon? I favour the latter, big time, but Ive got a massive 212 hrs. 

Go find an aerobatics flight school and do a few hours. Many questions answered..🙂

 

 

 

 

.

[APenNameAndThatA]

7 hours ago, Flying Binghi said:

Go find an aerobatics flight school and do a few hours. Many questions answered..🙂

 

 

 

 

.

I have done a few hours aerobatics. 

[Garfly]

9 hours ago, Flying Binghi said:

Go find an aerobatics flight school and do a few hours. Many questions answered..🙂

 

PenName's already known around here for keenly seeking answers through further training:

 

 

 

[Yenn]

If you are doing your finals turn at less than 500', there is a good chance that you are going to be influenced by the ground and if you are going downwind will get a false sense of speed. You will not be wanting to look at the ASI, because the ground is near, so there will be a tendency to pull back to slow down,  resulting in the stall.

[skippydiesel]

1 hour ago, Yenn said:

If you are doing your finals turn at less than 500', there is a good chance that you are going to be influenced by the ground and if you are going downwind will get a false sense of speed. You will not be wanting to look at the ASI, because the ground is near, so there will be a tendency to pull back to slow down,  resulting in the stall.

Moral of your story is; Practice down wind landings. Believe me, very different sensations/perceptions, to an into wind.

[Bruce Tuncks]

I agree skippy. Practice does not have to make perfect to be worthwhile. And I would add also practice EFATO stuff at a safe height. I personally reckon that a fast response enables the difference between the starting speed and the stalling speed to be used to avoid as much height loss.

[Bruce Tuncks]

One day, I watched an exemplary EFATO where the pilot did a lazy 90 degree turn to safely put down in a paddock out front of my hangar. I got there first to congratulate him, but he ( correctly) reckoned he would be in trouble with the club. The EFATO was caused by the loss of fiberglass from a Jabiru prop. It was so out-of-balance that the pilot shut down the engine before it shook off the plane.

The loss of glass from the prop was caused by the removal of the protective tape by our then maintenance guy.

[facthunter]

The "fast" response has to be the CORRECT one though.. The Instinctive one may be the wrong one. Training and the correct mental preparation on each occasion will help that to happen.

  We both posted at the same time. Your mate did the right thing  Nev

Edited September 5, 2022 by facthunter