Why does an Airplane turn?

[duplicate2]

More follow-ups since we are all posting at the same time.

Is the heading of the airplane the most important idea in a turn? Are you not really trying to make your aircraft go (track) in a new direction? If you could have your aircraft move in a perfectly straight line while constantly spinning about its normal axis (constantly changing heading) would you consider that you have successfully accomplished a turn? I doubt it.

[duplicate2]

Let's try a different track against the "weathercocking":

Does everyone agree that in a banked condition the forces are:
-vertical component of lift equal and opposite to weight therefore balanced therefore aircraft is flying at a constant altitude
-thrust equal and opposite to drag therefore balanced therefore aircraft is not increasing or decreasing forward speed
-horizontal component of lift (centripetal force) unopposed and unbalanced (or if you like dream worlds/rotating reference frames, equal and opposite to centrifugal force therefore balanced)

Hopefully we all agree to this so far?

So, keeping in mind that the unopposed horizontal component of lift is parallel to the earth, what force is causing the aircraft to supposedly slip towards the low wing?

[Flying Low]

Flying Low: your analysis of the car example is just a beginning. Imagine the car did just that, how did it get to its new position, a diagonal path to the northwest, right? Now the rope (horizontal lift force) has to be 90deg to that diagonal path, so it's very slightly west-southwest. Assuming the amount of the two forces (thrust and rope) haven't changed, the new path will be more west than the last time. Now the rope has to be 90deg again to the new path and you keep doing this over and over again. The resulting overall path will be a poor approximation of a curve made up by straight lines. But this really all happens simultaneously so it is a real curve. (If you don't believe this, then try drawing it out.)

If you pull on the rope the resultant path will be the diagonal you talk about, however, for the force to be 90 degrees to diagonal the car/plane/whatever must turn around the normal axis. Lift acts perpendicular to the wing and the relative airflow, therefore, the horizontal component of lift causes the aircraft to slip to the side but not to turn. The car/plane/whatever is tracking diagonally but heading in the same direction so the horizontal component of lift is still acting 90 degrees to the longitudinal axis.


Centripetal force is the horizontal component of lift. This causes the aircraft to slip to the applicable side. Centrifugal force is not a balancing force but a result of the change of direction on already existing momentum.

[ahramin]

goldeneagle, well said. I thought my explanation was pretty good but after reading yours i see it is not. Mine still requires a fair bit of cogitation but after reading yours anyone should be able to figure it out.

I think i am done with this one.

[ZLIN 142C]

I think i am done with this one.

Yeah, I'd say you are.

Thanks, Ahramin, for reminding me why I don't spend much time on this forum anymore.

[duplicate2]

goldeneagle and ZLIN 142C:

Your explanations are well said and are attractive on the surface.

Only problem is, both the horizontal stabilizer downforce and the CofP are usually behind the CofG. A body that rotates will do so around it's CofG. Since both turning moments are aft of the CofG, they will work against each other (one will want to turn the nose left, one will want to turn the nose right). The resulting turning moment will be decided by which ever is stronger.

If you were to do the calculations, you would see that the moments are equal and opposite. Net result, no turning moment due to this effect.

[duplicate2]

Centripetal force is the horizontal component of lift. This causes the aircraft to slip to the applicable side.

Funny that you would call it centripetal force since that is the name for the force that causes rotational motion.

If that is the force causing the slip, the slip would have to be perfectly horizontal since there are no other net forces acting. The aircraft would just be sliding sideways in the direction of the low wing.

Let's just assume that's true. Rate of turn increases with AOB, right? If the aircraft only turned because of weathercocking, why would the rate of turn increase past 45deg AOB since less and less surface area of the vertical stabilizer would be "showing" to the relative airflow caused by the slip?

In a related question, how does a hanglider turn since it has no stabilizers or rudders?

[duplicate2]

Let's not forget that the car (if we're comparing to an aircraft) is also moving forward because its thrust is greater than its drag.

I can't believe I said this. I must have been drunk. Assuming that the aircraft is not increasing or decreasing airspeed, then thrust is EQUAL to drag. Since there is no net forward force, you cannot do vector addition to come up with a resultant in the diagonal. Which means the whole explanation of the car analogy with the diagonal paths is completely flawed (my bad entirely) so let's drop it if that's alright.

So here's my final word. A body in motion that has a force applied in any direction other than parallel to that motion will begin to travel in a curved path. Flying Low is paritally right, the force must always be perpendicular to the instantaneous direction of travel, but only in the case of a perfectly circular orbit. If the force is not perfectly perpendicular to the direction of travel, the force can be subdivided into components with one component being perpendicular to the direction of travel. These are just truths about rotational motion and Newton's Laws. If you don't believe in them, you obviously don't believe that the earth revolves around the sun.

So here's my new explanation, and I should have just gone with looproll's final statement after all:
-Aircraft banks.
-Horizontal component of lift is directed towards low wing.
-Aircraft as a whole begins turn towards low wing, even if nose does not immediately. But in any case, a curved flight path has begun to occur.
-Shortly after the turn begins, the horizontal component of lift is no longer perfectly perpendicular to the instantaneous direction of travel. This can be due to adverse yaw causing the nose to be on the original heading or even turning in the opposite direction. But the horizontal component can be further subdivided into components, one of which is perpendicular to the direction of travel. Thus the curved motion continues, but around a new centre point (i.e. the curve will not be circular)
-The inherent yaw stability of the aircraft from the vertical stabilizer, the surface area of the side of the fuselage, etc plus some appropriate rudder use in the direction of turn cause the nose to "catch-up" to turn in progress, and cause it to become coordinated, i.e. have the nose always pointing in the instantaneous direction of travel.
-Now that the turn is coordinated, the horizontal component of lift is once again perpendicular to the direction of travel as the turn continues, so the flight path would now be a circle around a single point.
-In pefect world with a perfect pilot (probably taught by Cat), this would all occur simultaneously.

So, the essence of my argument is that the turn (curved flight path) will occur without the "weather-cocking". Once the turn is in progress, the "weather-cocking" will help coordinate the turn.

Here's a good link to describe all of this. This guy is even wordier than me if you can believe it:
http://www.aeroexperiments.org/causeturn.shtml

And now, like ahramin, I am done. Thanks for a great discussion.

[2R]

Ask the right question and get the right answer.
Ask the wrong question and be forever perplexed and cursed.
The question should be HOW not why .Why would imply the aircraft had inteligence and was capable of decisions as to why.The airplane turns because the pilot controls it to do so . How it turns is easy.

[Cat Driver]

" How it turns is easy."

Seems that some here do not agree with that.

If you read to much of this stuff you might get paranoid about trying to turn an airplane.

God forbid we get into how a helicopter turns, Avcanada would have to buy more bandwidth to cover the hand wringing.

[GA MX Trainer Dude]

WOW - is this ever a funny thread!!!!

Airplanes turn and can be turned by a variety of ways.

1. Skidding turns using the rudder only - aircraft purely in Yaw. Not a usual way as it produces usually undesirable side effects. This is how a boat turns using a rudder only.

2. Asymmetric thrust. On a twin engine aircraft one engine producing more power than the other. A good example is a Twin Otter on floats - no water rudders, yet this aircraft can be maneuvered using differential power. A multi-engine aircraft with a feathered prop will turn towards the dead engine.

3. Asymmetric drag. Hang a canoe on one side of a single Otter and it will turn towards the higher drag produced. Asymmetric drag reduction is the reason for the invention of differential ailerons. The downward moving aileron produces more drag than the same displacement upwards. Simple solution is to produce more upward motion than downward motion with control input rotation. Anything that produces differential drag will turn the aircraft - one of the reasons we have rudder trim. Again a multi-engine aircraft with one engine feathered will turn towards the dead engine.

4. Vectored thrust. Good example of vectored thrust aircraft is the Harrier, or if you want something simple - the outboard engine on a boat - pointing the propeller in a different direction will cause a turning moment. Same idea as the tail rotor on a helicopter or landing a twin with only one thrust reverser deploying. “P” Factor is another example of vectored thrust - the swirling movement of the propeller slipstream strikes the tail and causes a turning moment.

5. Coordinated banked turns. This is a bit harder to explain but not that hard. If we take the bank to the extreme of 90 degrees in an aircraft capable of level flight we will se that the controls assume different functions. The rudder will become the elevator and is now used to control the pitch. The elevators are now used to cause the aircraft to turn. At lesser degrees of bank the elevators and rudder are doing a lesser degree than in knife edge flight. A coordinated rate of turn at 15 degrees of bank will require a specific airspeed and once entered the rate must be maintained by keeping the 15 degrees of bank using the ailerons, using the rudder to control the pitch - ie nose up slightly to use some vectored thrust from the propeller or jet blast to maintain the same altitude, and using the elevator to pull the aircraft around the circumference of the turn.

This will be a state of equilibrium - where the thrust component is equal to drag - if not the aircraft will slow down or speed up - the lift component from the wings, airframe, and the thrust component from the propeller or jet blast is equal to the weight of the aircraft - if not the aircraft will climb or descend, and finally since all turns have a circumference the centrifugal force must be equal to the centripetal force or the aircraft will not track in a circle.

Another way to visualize it is by the dynamics of a loop - which is a vertical 360 degree turn. It is accomplished solely by use of the elevator, the rudder and ailerons being used to keep the aircraft in plane. Just like the 90 degree bank!!

One of the most interesting things to do in the simulator is to fly the aircraft with a locked or inoperative control and see what you can do to direct the aircraft. A wonderful example of this concept is the Sioux City DC10 accident. #2 engine grenades - takes out all 3 hydraulic systems that just happen to be concentrated in the tail. No hydraulics mean there are no flight controls. The crew enlisted the help of a deadheading pilot who was in the back of the aircraft and came forward to help. Since the #2 engine power lever was jammed from the engine destruction he knelt between the seats and used one hand for each remaining power lever. They flew the aircraft on differential power without the use of the flight controls. After it was all over they tried to duplicate the feat in the simulator with some high time pilots and couldn’t - guess the sim wasn’t quite true to the aircraft performance.

Now Wasn’t that easy?

[GA MX Trainer Dude]

Weathercocking

Weathercocking only happens when an object - boat, airplane, or rooster windvane is attached to the surface of the earth.

An aircraft will weathercock and align with the wind only on the ground. In flight the aircraft will align with the relative airflow.

Definition
The 'weathercocking' refers to the action of an aircraft, moving on the ground, attempting to swing into wind. It is brought about by the pressure of the wind on the rear keel surfaces, fin and rudder causing the aeroplane to pivot about one or both of its main wheels. It is usually more apparent in tailwheel aircraft because of the longer moment arm between the fin and the main wheels: although if a nosewheel aircraft is 'wheelbarrowing' with much of the weight on the nose wheel, then there will be a very long moment arm between the nose wheel pivot point and the fin.

Most unpowered boats will end up beam-to in waves. If it weathercocks badly, you'll point up wind, if you leecock badly, you'll point downwind.

[Cat Driver]

GA-MX :

While you are on a roll here can you jump in and write a good description of how to judge height when landing?

That way I may get off the hook for explaining how I do it.

[GA MX Trainer Dude]

This is for CatDriver and anyone else who has an interest in teaching.

Here are the Laws of Learning before Transport got them!!!!

It's pretty long but is worth the read if you are new to the game.

By the way Cat I only know 2 guys in the industry that were named MOOSE - one was at Transport and I have forgotten his name and the other one was Moose Murdock.


The Laws of Learning

Back in the early part of the previous century - (about 1920) the laws of learning were developed. They have been modified over the years but for most purposes are still valid.

A quick internet search will bring them up but since we are all lazy ( sorry I mean we want non-frustrating learning) I will post them here for us all.




Thorndike:
The Laws of Learning (About 1920)

A behavioral learning theory based on connectionism that studied increasing a behavior with the use of rewards, punishment, and practice. Three major laws in the theory include:

The Law of Effect

strength of connection is dependent on what follows

"Of several responses made to the same situation those which are accompanied or closely followed by satisfaction to the animal will, other things being equal, be more firmly connected with the situation, so that, when it recurs, they will be more likely to recur; those which are accompanied or closely followed by discomfort to the animal will, other things being equal, have their connections to the situation weakened, so that, when it recurs, they will be less likely to occur. The greater the satisfaction or discomfort, the greater the strengthening or weakening of the bond."

The Law of Exercise

practice strengthens the connection, disuse weakens it

The Law of Readiness

if physically ready, the connection is satisfying for the organism



An Updated Version

The Laws of Learning
Effective learning experiences have several things in common - whether we are learning to drive a car, repair a motor, or read a simple sentence. As tutors, you'll need to be aware of these things and how you can use them to design successful lessons.

The Law of Doing
Students don't learn as the result of what tutors do, but as a result of what tutors get them to do. This basic principle is equally important for students and tutors to understand. The student who expects to learn by simply sitting back and listening is likely to be disappointed. The tutor, on the other hand, who relies solely on the "I'll lecture, you listen" type of teaching is not likely to see much learning taking place.

Why is this? Learning is change - behavioural change in an individual. Behavioural changes don't truly become part of a person, until he has reinforced them through use. For example, a student can memorize the operation of a piece of equipment, or a new word for his vocabulary. But he doesn't actually "learn" those things until he practises operating the equipment or using the new word. The student, in short, must be involved in the process of learning.

The Law of Effect
People tend to accept and repeat those responses which are pleasant and satisfying and to avoid those which are annoying. If an adult finds that he is learning to read and enjoying the process as well, he will tend to keep returning to class. In short, "nothing succeeds like success". Students should experience personal satisfaction from each learning activity and should achieve some success in each class period

The Law of Exercise
The more often an act is repeated, the faster the habit is established. Practice makes perfect - if the practice is of the right kind. Practicing the wrong thing will become a habit too - one which is hard to break.

The Law of Primacy
First impressions are the most lasting. This means that those first lessons are all- important. The tutor should arouse interest and provide subject matter which meets the student's immediate needs.


Another set of Laws

Lowthert's Laws of Learning
ã William H. Lowthert, 1991
http://www.alwaysimproving.com

Law of Readiness. People learn more easily if they have a desire to learn. Conversely, people learn with difficulty if they are not interested in learning the topic.

Law of Effect. People learn more quickly those things that give them satisfaction. This could be called the "Law of FUN."

Law of Relaxation. People learn best and remember longest when they are relaxed. Reducing stress increases learning and retention.

Law of Exercise. The more often an act is repeated or information reviewed, the more quickly and more permanently it will become a habit or an easily remembered piece of information.

Law of Disuse. A skill not practiced or information not reviewed will become difficult to perform or remember.

Law of Intensity. A vivid, exciting, enthusiastic, enjoyable learning experience is more likely to be remembered than a boring, unpleasant one.

Law of Size. Learning should be in units that are small enough to be absorbed readily, but large enough to be interesting.

Law of Involvement. People learn by doing. Learners must be actively involved in learning.

About Bill Lowthert
email to Bill Lowthert at BillisImproving@aol.com
http://www.alwaysimproving.com/

This document is free for you to print, download or make posters. Permission is granted for reproduction of copies for reference use. Reference credit is expected. The title, copyright statement, and internet address must be included on all reproductions.



And Finally

Laws of Learning:
14 Important Principles Every Trainer Should Know


Adults Only
These laws are particularly relevant to adult learners.


Law of previous experience : New learning should be linked to (and build upon) the experiences of the learner.

Check the entry level of the participants. Remind yourself that adults bring a variety of rich experiences to the training session. Design activities to ensure easy adjustments to fit different entry levels and to incorporate relevant experiences.

Law of relevance: Effective learning is relevant to the learner’s life and work.

Use simulations and role plays to increase the link between the learning situation and the real world. After a training activity, debrief the participants and discuss strategies for applying what they learned in the game to their real-world context.

Law of self-direction. Most adults are self-directed learners.

Don't force everyone to participate in every activity. Identify training objectives and let participants select among different resources and activities to learn at their own pace and according to their personal preferences. Involve participants in setting training goals and selecting appropriate types of learning activities.

Law of expectations. Learners' reaction to a training session is shaped by their expectations related to the content area, training format, fellow participants, and the trainer.

Some learners are anxious about mathematical concepts and skills. Encourage them with intriguing puzzles and short-cut techniques. Other learners feel uncomfortable about making fools of themselves in public while playing games. Establish ground rules that reward risk-taking among participants. Demonstrate non-judgmental behavior by applauding participants for their effort.

Law of self image. Adult learners have definite notions about what type of learners they are. These notions interfere with or enhance their learning.

Reassure participants about their ability to learn new concepts and skills. Motivate them to attempt challenging tasks. Ensure frequent and early successes by making initial tasks simple and by progressing in small steps. However, avoid patronizing participants with simple, trivial tasks. Incorporate learning tasks at different levels of difficulty in your activities.

Law of multiple criteria. Adult learners use a variety of standards to judge their learning experiences and accomplishments.

Encourage participants to choose personal standards and scoring systems. Provide different ways to "win" in your activities. In simulations and role-plays, keep scores related to different criteria. During debriefing, discuss alternative criteria for measuring participants' performance.

Law of alignment. Adult learners require the training objectives, content, activities, and assessment techniques to be aligned to each other.

Create a training situation that closely resembles the job situation. Teach and test for the same content, using similar strategies. Make sure that the scoring system used in your training activities rewards the mastery of the training objectives.

General Public
These laws apply to all human beings, from infancy to old age.

Law of active learning: Active responding produces more effective learning than passive listening or reading.

Intersperse lectures and reading assignments with active-learning episodes such as quizzes and puzzles. Provide participants with ample opportunities to respond by asking questions, encouraging them to ask questions, answering their questions, and questioning their answers.

Law of practice and feedback: Learners cannot master skills without repeated practice and relevant feedback.

Don’t confuse understanding a procedure with ability to perform it. Invest ample time in conducting activities that provide repeated practice and feedback. Make sure that the training activities incorporate immediate and useful feedback from peers and experts. Use rating scales, checklists, and other devices to ensure that the feedback is objective and useful.

Law of individual differences: Different people learn in different ways.

Use training activities that accommodate a variety of learning styles. Make sure that participants can respond by writing, speaking, drawing, or acting out. Encourage and permit participants to learn individually, in pairs, and in teams.

Law of learning domains. Different types of learning require different types of strategies.

Learn to recognize different types of training content and objectives. Don't use the same type of activity to teach different types of training. Use suitable designs to help participants achieve different training objectives related to concepts, procedures, and principles.

Law of response level. Learners master skills and knowledge at the level at which they are required to respond during the learning process.

If your training activity requires participants to merely talk about a procedure, don't assume that they will be able to apply it in their workplace. If you want participants to solve workplace problems, the learning activity should require them to solve problems. Avoid trivial, closed questions with rote-memory answers in your training games. Challenge participants with authentic that require innovative solutions.

All Creatures Great and Small
These laws apply to all animals, include white mice, pigeons, dolphins, and people.

Law of reinforcement: Participants learn to repeat behaviors that are rewarded.

Make sure that training activities provide several opportunities for earning rewards. Require participants to make frequent decisions and responses. During the initial stages of training, reward even partially-correct answers.

Law of emotional learning: Events that are accompanied by intense emotions result in long-lasting learning.

Use training games, simulations, and role plays that add emotional element to learning. Make sure that emotions don’t become too intense and interfere with learning. Make sure that participants don’t learn dysfunctional behaviors because of intense emotions. Debrief participants after emotional activities to reflect on their feelings and learn from their reactions.

[GA MX Trainer Dude]

Just a quick and dirty explanation for things that cause aileron reversals.

Aircraft rolls or turns the opposite way to control wheel input.

There are several causes for this to occur.

1. Excessive drag from the downward aileron. Like Cat describes, the PBY will turn opposite with heavy aileron displacements. There are some corrective methods used to control this problem. The most common method is to use differential ailerons where the upgoing aileron travels a greater distance than the downgoing aileron.

2. Another cause is wing warping. The Wright brothers and others used wing warping instead of aileron to control roll. It is very effective and powerful but does not lend itself well to our present method of normal aircraft construction.

It is however a serious problem with high speed aircraft with long flexible wings. What happens is simple - at high speeds a roll is initiated, the aileron moves down and changes the camber of the wing, but also produces a twisting moment into the wing that tends to bend the wing back to a streamlined position. This effectively changes the incidence to a lesser degree - ie warps the wing - and the net result is to decrease the lift rather than increase the lift which allows the aircraft to roll in the opposite direction. This is cured by using inboard ailerons or spoilers that are in structure sufficiently robust to withstand the loads without deforming.

3. A third cause is control reversal as the aircraft goes transonic. This condition is complicated aerodynamically and is one of the reasons aircraft stay out of the transonic region for extended flight. Supersonic aircraft pass through it on the way to high speed flight and subsonic aircraft stay below it.

4. Crossed controls. I would be remiss if I did not address cross controls. IT HAPPENS and way too often. Many aircraft are not Murphy-proof when it comes to connecting the controls. Independent inspections are regulated but due to the human factors in maintenance and flight crews, aircraft still crash because of it. Always check for proper travel and direction of travel before flying the aircraft.

Fly safe guys!!

[Cat Driver]

GA MX :

Did you ever fly with Moose Murdock?

He taught me to fly both the PBY and the DC3 at Austin Airways, and I started working with him when he started Avalon Aviation...

..Moose could sure drive an airplane..

The only thing I know about the Moose that worked for TC was he came up with some ideas about the laws of learning that only he and TC understood.

Anyhow I have enjoyed your putting the how an airplane turns subject to bed.

Can I hire you to write for me?

Cat

[looproll]

...and now it's time to close-up the laptop and smash it with a large hammer.

[GA MX Trainer Dude]

YA I worked for Mudrock 1976 to about 79

Ended up in Chile and Norway as well as all over Canada - including Newfie with VIG

I think that Moose in his prime could fly the PBY better than most people could walk!!

We should start a thread on Moose stories - I have a few that are absolutely hilarious.

The funny thing about me is that I have about 3000 hrs of "flying" but have never bothered to take lessons and get a licence. It's not that I don't like to fly it was that with the sole income that came from fixing I never had any spare cash to go and get it. I will probably never even get a private unless I somehow win the lottery. I still enjoy sitting up front and herding the airplane but would never think about telling someone else how to fly - I can explain a lot of things because I used to teach basic training for AME's at BCIT - I have over 15 years and 16,000 hours of face to face time in the classroom and on the shop floor. I left basically when CAMC dictated the curriculum be the same accross Canada and what I saw was that everyone was finally on a level playing field - all mediocre.

PM me and we must get together one day.

PBYs I remember working on:

CRR, GLX, IZZ, VIG, HHR, PIU, HNF, HNH, NJE, and SAT


BTW - determining how high the aircraft is above the ground is such a concern in big aircraft that they actually have a seat/eye alignment system installed so the the pilot will always be in the same place every flight. I guess it helps with the visual reference. For me I learned to land in the single otter in the arctic - no TC guys up there in the winter - and as I remember it was all what you do with your periferal vision. The guy who was teaching me made me fly over the frozen lakes for miles and miles to get the aircraft attitude burned into my brain. from there it was a relatively painless transition to flying just above the stall for miles accros the lake - burning in the nose up almost stall configuration and again his focus was on what I was seeing with periferal vision - old Otter had zero visability at that attitude unless you wanted to see sky. Once he had that part of the training done and it was intense to fly that low he had me play gently with the throttle to get the feel of power changes, from there to touch and gos and then full stops. If I close my eyes I can still see in my minds eye what is happening in the aircraft. I never touched a nosewheel aircraft for almost a year of flying. That year was filled with 185s. Beavers, Single Otters, DC3s, and the old Bristol Frightener.

Ya gotta love them old days - TC was very different - they would actually help you if you had a problem. Now if you have a problem it's off to enforcement.

TTFN

[Cat Driver]

Yes, we must get together.

We are always looking for wrench pullers that know the old stuff are you interested in some interesting fixing on rich peoples toys?

Ever wrenched a Super Connie?

We have one to get airworthy this spring in sunny California so you won't have to freeze your nuts off.

And the Cats are getting to be rich mens collector items.

Talk to you tomorrow.

Cat

[Cat Driver]

Double post

Cat

[ZLIN 142C]

I really hate to keep beating this poor dead horse, so allow me a few last thoughts and I'll shut up.

Duplicate2: That site you linked to is very interesting, and gave me quite a bit of food for thought. I'm going to take the liberty of briefly paraphrasing some of the author's main thoughts. Essentially, the banked wing creates an unbalanced lateral force, causing the aircraft to move to one side. The inherent yaw stability (rudder) causes the aircraft to continually align it's longitudinal axis with the relative wind, which is continually changing as the aircraft's direction changes. That is what the author said (in quite a bit more detail!) and essentially what you wrote. And that's more or less what I meant by the term "weathercocking" (or as the author put it, the "weathervane effect"). I don't think we necessarily disagree at all.

So let me ask this: why does the rudder want to align the fuselage with the relative wind? I'm going to venture an idea. Think of the rudder as an airfoil (which it is) and assume that the aircraft is banked left. The relative wind is now coming from the front and left, and is creating a posititve AOA on the rudder, which in turn generates lift in the horizontal right direction until such time as its AOA returns to zero, which will happen only when it and the fuselage are aligned with the relative wind. As long as the wing is banked, the relative wind will continue to change and the tail will continue to follow it. The wing leads; the tail follows.

You brought up the point that rate of turn increases with angle of bank. Of course, the wing's horizontal component of lift is now much greater, so it more aggressively accelerates toward the centre of the turn. Beyond 45 degrees or so of bank, the surface presented to the relative wind is mostly the elevator. It fulfils the same function in a steep turn as the rudder does in a shallow one. Compounding this effect is that the elevator is already generating lift in the opposite direction to that of the wing. In a steep bank the relative wind greatly increases its AOA (relative to the wing's AOA, it's negative) and thus it's tendency to return to a state of equilibrium - zero AOA - aligned with the relative wind.

This is a horribly simplified thesis, and ignores a lot of additional factors at work in a turn. The physics of a "simple" banked turn are anything but. In fact, a case can be made for the idea that the engine and prop "pull" the aircraft through the turn. (The "engine" in the case of a glider is gravity. I'm not going to get into this particular can of worms.)

I think much disagreement on this topic arises from semantics. There are many different ways to look at the same phenomenon. Look at the term "weathercocking" for example. A dozen different people have used the term here and they probably have a dozen different ideas as to what that term means. Nobody has clearly defined the terms or the frame of reference. So while I talk about the angle-of-attack of the rudder and/or elevator increasing due to the relative wind and thus generating lift, someone else might just say the relative wind "blows the tail around" and mean pretty much the same thing.

This has been a great thread. If we could all agree on everything, would aviation be any fun at all? Not as much, I'll bet.

Cheers!

[PC12's are better]

With response to GA MX Trainer Dude, I beg to differ about the laws of learning as per GD of PFC

Fear
The fear of the instructor when you get the answer wrong,

Ridicule
The ridicule of your peers when the instructor makes an ass of you,

Scarcasm
The scarcasm from both if the previous 2 don't work.

I must say that there are a lot of people around here with too much time on their hands who feel that they have to make responses to postings at 2AM. come on guys, get a life.

Cheers