What causes an airplane to stall?

[Contact Flying]

You know you are a good instructor if other instructors are stealing your stuff. I got this question/answer drill from Robert Reser, in his book, How To Fly Airplanes. In the US, all pilots are indoctrinated to answer, "It exceeds the critical angle of attack. Bob points out that is when it stalls not what makes it stall. The design of the airplane is to fly. It cannot stall itself. It cannot even create load factor. Only the pilot can cause an airplane to stall by pulling back on the stick.

 

 

[Pearo]

I think that quote should go to the Author of Stick and Rudder.

 

 

[bexrbetter]

How about if it just goes too darn slow as well.

 

 

[Kamloops]

He loaded the moose he shot on his hunting trip to far aft ☺

 

 

[Kamloops]

For those unable to grasp my bad humor.....that was a joke....although could be correct to under certain circumstances.

 

 

[Contact Flying]

Astute observation, whatever the source. I like a good quote, even if it has been passed around. You'alls Winston Churchill stole a good quote from time to time. Great leader, and teacher, anyway.

 

Wolfgange said, "airspeed is altitude and altitude is airspeed." I usedthat as the basis of my explanation of what I call the energy management, no load factor, turn. Later I read, "Boyd, the Fighter Pilot who Changed the Art of War and learned that "Forty Second Boyd" had done the math and called it "Energy Maneuverability." Boyd had no use for credit. The first thing he asked anybody who wanted to work for him was, "Do you want to be, or do." Like him, I have no use for those who choose the former. You can't have it both ways.

 

 

[aro]

Wolfgange said, "airspeed is altitude and altitude is airspeed." I used that as the basis of my explanation of what I call the energy management, no load factor, turn.

Except that a "no load factor" turn is physically impossible. You must have a load factor to change direction - basic physics. Having read your description, you are just changing the direction of the added load factor from horizontal to vertical. It's more of a minimum radius turn than no load factor.

 

Having read a few of your posts I'm guessing you may have learned to fly helicopters before fixed wing? A lot of what you post sounds like it might work in helicopters, but is not optimum in fixed wing e.g. rudder turns at low level.

 

 

[Contact Flying]

aro,

 

No, I started at age nine in my Dad's pardner's C-180. I was too short to reach the pedals or see over the panel. Press Maxwell, the golf architect, had flown B-24s out of N. Africa and Italy during WWII. He taught me instrument and by the time I soloed at age 16 I was a pretty good instrument pilot.

 

I grew up building golf courses before going into the Army in 1969. By the time I finished Officer Rotary Wing Aviation Course, I had come to the realization that there are more similarities in the control of various machines, both land and air, than differences. Since 1974 I have taught flying, both military and civilian, with that in mind.

 

The airplane is designed so that it cannot create the load factor that pilots cause when they pull the stick back in a level turn. If the pilot does not pull back but rather allows the nose to go down as it was designed to do in a turn, there is no load factor. The wings level load factor caused when the pilot pulls up from cruise to start the energy management turn is not as dangerous as that caused in a steep, level turn. The wings level load factor caused when the pilot pulls up after the turn is completed is not as dangerous as that caused in a steep, level turn.

 

I appreciate the criticism. We all need to justify what we teach.

 

Contact

 

 

[aro]

Despite your experience, a lot of your terminology seems confused.

 

If the pilot does not pull back but rather allows the nose to go down as it was designed to do in a turn, there is no load factor.

If you allow the nose to go down in a turn, the result is a spiral dive and the load factor does increase dramatically. The AOA stays approximately the same if the pilot doesn't pull back, but the load factor changes.

 

The wings level load factor caused when the pilot pulls up from cruise to start the energy management turn is not as dangerous as that caused in a steep, level turn.

Perhaps, but after the pullup while you are trading airspeed for altitude you will be at less than 1G (a reduced load factor). The danger, which has killed many people, is that you end up at an airspeed too low for 1G flight and the aircraft stalls as you try to complete the turn.

 

 

[aro]

By the time I finished Officer Rotary Wing Aviation Course, I had come to the realization that there are more similarities in the control of various machines, both land and air, than differences.

I don't think that fixed wing is as similar to rotary wing as you believe. In a helicopter the rotor disk is symmetrical in all directions, so it flies the same whichever direction the fuselage is pointing. That is not the same as fixed wing. Also helicopters are naturally less sensitive to loss of airspeed - as evidenced by the fact they can hover.

 

 

[facthunter]

The fact the pilot stalls the aeroplane has been discussed at length on this forum . It's either tail heavy or the elevator is too effective. Nev

 

 

[Contact Flying]

Nev,

 

I missed something. Pilots stall perfectly loaded airplanes all the time. Right. Take the pilot out and the airplane will not stall. It may hit the ground in a turn or in a dive regaining trimmed airspeed, but it will not stall and fall.

 

Jim

 

 

[facthunter]

My point was UNLESS loaded tail heavy or too much elevator applied the plane WON'T stall. ALL in the control of the pilot. Same as yours , but expressed somewhat differently. A tail heavy plane will stall with the stick full forward with tailplane stalling first, and not much you an do about it subsequently. Nev

 

 

[Contact Flying]

aro,

 

The spiral you are talking about is the "graveyard spiral." The load factor occurs when the pilot attempts to pull up while still in the turn. We must level the wing first and then pull up wings level. Also this prevents putting a wing into a wire or terrain trying to get the turn in late going into a paddock while crop dusting. And yes, we do energy management turns very low to the ground hundreds of times a day while spraying. Level, high load factor, turns will kill us in low level work We need manage the energy available, power perhaps being the least important.

 

After the wings level pull up to start the energy management turn, we bank keeping the load at 1g and allow the nose to go down as it wishes. We don't push it down with the wing still level. If you are worried about rapid unloading or anything strange going on with your airplane, turn loose. They really know quite a bit about flying on their own.

 

Thanks for your comment/critique. We instructors need justify what we teach.

 

Contact

 

 

[Contact Flying]

Nev,

 

Got it. I've got to teach you hillbilly or you've got to teach me Aussie.

 

Jim

 

 

[djpacro]

strine

 

 

[facthunter]

I know when I'm beat. Stone the crows and stiffen the jewy lizards. Fair dinkum, that would be just too hard. Nev

 

 

[Contact Flying]

Plum nelly ain't got that one figured out yet.

 

 

[IBob]

Beached as, bro....

 

 

[Ultralights]

What causes an aircraft to stall? .......... I do.

 

 

[Kamloops]

I am just adding this and then walking away.

 

I strongly feel that stalls are no big deal if a pilot is trained to recognize that is what is happening. ....and to automatically drop the nose.

 

Problem is many don't practice stalls often enough...or train to drop the nose instantly.

 

In fact many go oh crap i am sinking and pull back even harder.

 

Aggravating it can be that sometimes they will also spin when stalled....and few spin train either.

 

I practice stalls frequently.

 

And by frequently i don't mean a couple times per year....i mean frequently.

 

Stalled my seneca probably over 60 times so far in 2015.

 

Power off, cruise, fire walled, level. banked both left and right. ....loaded lightly and at gross. Many airliners crash because pilots don't train enough. ...and heck they even have stick shakers.....how poorly are you trained to even ignore a stick shaker and see a descent rate, so you pull back even harder.

 

Morons like that after they crash and kill many, still get their memory to their loved ones kept all pretty and intact by the report calling it an accident.....i say let it be more honest and say Due to his negligence and stupidity he reacted 100 % incorrect and killed many....the pilot was a menace who never should have been allowed to fly anything more than a kite on a breezy day with his kids.

 

End of rant.

 

 

[Kamloops]

This is just 1 of many....but illistrates my point.

 

These morons were so clueless that not 1 of the 3 could recognize a simple stall....and didn't have the brains to even hear and comprehend the stall warning horn going off for a long time. It shouldn't take you even a full second to hear the stall horn and be reacting to it.

 

I doubt these 3 combined have the brains to deal with most any situation.

 

But because they could tie a Windsor knot to wear a tie with their uniform some idiot hired them.

 

I personally would not trust them to even latch my door, or check the oil levels in my engines.

 

But miraculously they were given an airliner to practice trying to fly on.

 

There are hundreds of crash reports similar to this.

 

The common area is lack of training and lack of brains to understand a very basic and simple concept.

 

Stalls are no big deal. ..drop the nose and add power if not already at full power.

 

Spin training is mandatory in Canada....in some places it isn't.

 

And to that I ask why the heck not?????

 

If you don't train for it....if it happens chances are high you are not going to recover from it.

 

Spins are just simply fun to practice.

 

Heck I enjoy them.

 

Sure nothing to be scared of.

 

 

[facthunter]

It's a natural instinct to pull back on the stick in response to the nose dropping. Also to use aileron to pick up a dropped wing. Exactly what you don't want to do if you want to survive. The best way to increase the wings angle of attack is with the elevators. (But we all know, this don't we?).

 

The airliner thing is a bit complex. You can get a bit confused by the logic of some of the flight management programmes, if you aren't solid on basics. If you have an upset at cruise level you are probably going to lose 10,000 feet or more before recovery. Plenty of airline pilots have never done a spin recovery in the normal sense. There aren't many basic trainers that permit them, since the mid 60's.Nev

 

 

[djpacro]

i would never train to drop the nose instantly

 

 

[Aldo]

i would never train to drop the nose instantly

Why not only way to break the stall is get the nose down.

Aldo