Angle of attack in a climbing turn

[gaamin]

Heh

[Class 1 Instructor]

Well I think we have put the climbing turns thing to bed, so at the risk of really stirring the pot how about an area that I still find I struggle with despite teaching flying for almost 25 years. That is how to explain how a wing creates lift to a ab initio student in a understandable and factually correct 60 seconds or less blurb ?

[Cat Driver]

It is simply amazing how idiotic this forum can get when people get bored.

If only this forum could produce some useable ideas that would improve the flight training industry, like teaching how to fly, instead of overkill on theory that adds SFA to the ability to handle an airplane.

[Cat Driver]

Well I think we have put the climbing turns thing to bed,

Not yet, I am waiting for one of these experts to bring this lesson to the same level as teaching navigation....drift lines.

Seems that without drift lines the students will wander off forever into oblivion if they get off their track line on a map.

If they get off the angle of attack line they will lose lift and crash back onto the earth...

...so we have to wait for the drift lines to be added to those graphs.

By the way in a few months I will have been flying for sixty years and never ever, even once drew drift lines on a map...so how come you people teach them?

[floatplanepilot]

"Beware the lessons of a fighter pilot who would rather fly a slide rule than kick your ass!" — Commander Ron 'Mugs' McKeown, USN

[Class 1 Instructor]

If only this forum could produce some useable ideas that would improve the flight training industry.

Well despite the fact that I have been teaching flying for many years I am still always on the lookout for better ways to teach something. So how about throwing out some of those "useable" ideas you think are missing ?

[Class 1 Instructor]

Not yet, I am waiting for one of these experts to bring this lesson to the same level as teaching navigation....drift lines.

It is also one of my pet peeves. Unfortunately you have to have drift lines on your chart in order to pass the flight test. Since TC seems to be in no hurry to move flight training into the 21'st century I have to continue teach this silliness, but I also make sure that my students also get a lesson in how "real world" flight planning works and effective use of a GPS.

[photofly]

Wow, I am trying to think of a word to describe your attitude......it is difficult because if I used the words I would like to my post would be removed by the moderators, but the word sanctimonious comes to mind.

Reading this thread has not been of any useful value to me period.....then again maybe I shouldn't have all the pilot licenses I hold.

I'll take "sanctimonious". I've heard worse.

What kind of threads do you approve of?

[Cat Driver]

Well despite the fact that I have been teaching flying for many years I am still always on the lookout for better ways to teach something. So how about throwing out some of those "useable" ideas you think are missing ?

I used to write useful flight training ideas on this forum as well as Pprune, you can use the search function if you are really interested.

I sold my flight school in 1992 because I found it to be just to difficult to run due to the stone age mentality of the TCCA flight training department, my school was both fixed and rotary wing training with a AMO.

Bottom line for me was I could make way more money teaching outside of the FTU sector of aviation.

I have the fourth edition of the flight training manual here in my library.

Reading the advice regarding performing a wheel landing I note there is a bit of advice about how to perform one that I find a bit unorthodox if not down right wrong if you want to land without bouncing back into the air.

Have they changed that part yet?

[dr.aero]

Well I think we have put the climbing turns thing to bed, so at the risk of really stirring the pot how about an area that I still find I struggle with despite teaching flying for almost 25 years. That is how to explain how a wing creates lift to a ab initio student in a understandable and factually correct 60 seconds or less blurb ?

First question: why do you want to be able to explain how lift is created by a wing in 60 seconds? Do you intend to expand on that 60 second explanation or is that explanation supposed to be the entire subject of lift? It won't take you 25 years to come up with a 60 second introduction to lift but if you're trying to explain lift in 60 seconds, then I'm not surprised you haven't come up with a way to do that!

It's like explaining the orbital mechanics of launching a rocket to the moon - you can explain that a rocket is shot off the earth towards the moon and then orbits it. But if you say that you're going to explain the "orbital mechanics" of it... that will take you one heck of a while to do so! So, you can explain that lift is what makes the airplane fly and thrust moves it forward and drag slows it down and weight pulls it down... but if you want to explain 'how' lift is created by the interaction of air with an airfoil, you will need a lot longer than 60 seconds!

I'm going to assume that you actually mean to explain lift in 60 seconds.

I find that this is where the misconceptions get generated - I can certainly tell you that there was no aerodynamic engineer that came up with the misconceptions that abound in the flight training world these days! There are a few reasons, I believe, that it's very hard to find such a thing. First thing being that you've put a time restriction on your explanation - that immediately tells me that you're focusing on the wrong thing. What you should be focusing on is finding a factually correct way of explaining it and then ensuring that you present those facts in an understandable way.

The second thing that makes this difficult is that everyone has a different background and, as a result, have a different level of understanding of a particular subject. You may find an accurate, clear, and concise way to explain lift to John Q but then when you present that to someone else you will be very disappointed because they can't understand your explanation.

Back to the initial question: are you intending to give a 60 second intro or a 60 second explanation of how air interacts with an airfoil, creating lift?

[dr.aero]

Photofly...

Not sure if you saw my last post to you.

Would you be able to show me the post on December 7 that answered your initial question you asked at the beginning of this thread?

I find it amusing that you refuse to acknowledge my post where I explained and answered your question! The only post on this thread to do so.

I will drop the subject if you still choose not to reply though.

[photofly]

Sorry, driving up to the cottage now. Harder to post.

Your diagram was the one I wanted, thanks, but three weeks late. The helpful post was the on the first page linking to the other thread. I think the diagram was on there too. I should have used the search feature before posting.

[dr.aero]

Photofly...

I'm exceedingly sorry for being three weeks late on your deadline. You are a very tough person to satisfy!

[photofly]

Photofly...

I'm exceedingly sorry for being three weeks late on your deadline. You are a very tough person to satisfy!

Lol! No problem. I've enjoyed talking about AoA, learned a lot. Not just from thinking about what you and others have said but also from reading outside avcanada, thinking things through, and writing. It's all good.

[Class 1 Instructor]

but if you want to explain 'how' lift is created by the interaction of air with an airfoil, you will need a lot longer than 60 seconds!


Back to the initial question: are you intending to give a 60 second intro or a 60 second explanation of how air interacts with an airfoil, creating lift?

When in the initial stages of flight training everything is new to the student. It is therefore easy to over complicate a subject which in the end just confuses the student. However there are aspects of "lift" that have immediate practical application to flight training. Concepts like the existence of a relative low pressure area on the top of a wing, the fact that a wing generates wing tip vortices and that the air is bent downward as it comes off the trailing edge of the wing and msot importantly that lift is proportional to AOA.

Since how a complete and accurate explanation of how wing actually creates lift is quite complicated and way beyond the scope of initial flight training, the problem of how to introduce the topic in a quick and meaningful way that supports the early in the air lessons in a practical way, has at least for me been a subject of much thought.

The default seems to be to use the hoary old "the air over the top of the wing goes faster then the air over the bottom" line, which is shamefully repeated in the first chapter of the FTM. Then trot out the old air bouncing off the bottom of the wing is deflected downward explanation and quickly move on before the student can ask any questions

Long complicated descriptions are easy; distilling a complicated process into a quick and simple explanation is really hard. I have a set of PGI's refined over 25 years which I think are pretty good, but I freely admit the weakest area is still that initial explanation of how a wing lifts, hence my request for some ideas on how to do it better in the context of a lesson plan 2 level PGI.

[photofly]

lift is proportional to AOA.

of course that's only true for definitions of AoA of which dr.aero disapproves.

[gaamin]

That is how to explain how a wing creates lift to a ab initio student in a understandable and factually correct 60 seconds or less blurb ?

To show that the extrados can produce lift, hold the "leading edge" of a sheet of paper as if it were horizontal, blow over it, it raises : lift is created.

I generally do not explain the "why", except if a curious pilot asks for it.
To do it in 60 seconds I would assume the curious pilot has a decent background in physics.
- an approximation : air is not compressed
- section is reduced by airfoil, so the mass of air needs to travel faster
- travelling faster means kinetic energy is increased
- total energy remains constant, so potential energy is decreased : lesser pressure on the extrados

[dr.aero]

Class 1...

the problem of how to introduce the topic in a quick and meaningful way that supports the early in the air lessons in a practical way

How does knowing that air is turned downward, and the existence of a low pressure on top of the wing help with a student learning how to use ailerons, rudder and elevator to turn the airplane? I taught my nephew how to turn a plane in flight and didn't mention a word about aerodynamics. I could have continued teaching him different maneuvers in flight without mentioning aerodynamics.

Don't get me wrong, I fully support that a student needs to understand aerodynamics! But your argument doesn't seem to support itself, IMO.

Long complicated descriptions are easy

Yes, that's how we get misconceptions about aerodynamics!

Long, complicated, descriptions that are correct are NOT easy.

initial explanation of how a wing lifts, hence my request for some ideas on how to do it better in the context of a lesson plan 2 level PGI.

I think I've found out what's going on here! Why are you trying to teach the theory of flight in a PGI? That's not standard practice. Ground school is where the student is supposed to learn about the theory of flight. The PGI should be a refresher for the student of the points, they should have learned in ground school, that are applicable to the operation of the airplane in flight. There is absolutely no way you're going to explain lift in 60 seconds!

[dr.aero]

lift is proportional to AOA.

of course that's only true for definitions of AoA of which dr.aero disapproves.

This shows you still have absolutely no idea what I'm talking about!

Lift most definitely is proportional to AoA... up to the critical AoA.

[photofly]

lift is proportional to AOA.

of course that's only true for definitions of AoA of which dr.aero disapproves.

This shows you still have absolutely no idea what I'm talking about!

Lift most definitely is proportional to AoA... up to the critical AoA.

I think you're mixing up "proportional to" and "a linear function of". A linear function is a straight line, but doesn't have to go through (0,0) on a graph.

To have a proportional relationship the graph of CL vs. AoA would have to pass through the origin.

You've spent the last ten pages trying to persuades that the graph of CL vs AoA doesn't go through the origin. If it doesn't go through the origin, it's not a proportional relationship.

CL is a linear function of AoA, up to the critical angle of attack, but the only way you can say CL is proportional to AoA is to adopt a definition of AoA based on using the imstantaneous zero-lift line as the reference ("zero") angle.

[dr.aero]

That is how to explain how a wing creates lift to a ab initio student in a understandable and factually correct 60 seconds or less blurb ?

To show that the extrados can produce lift, hold the "leading edge" of a sheet of paper as if it were horizontal, blow over it, it raises : lift is created.

I generally do not explain the "why", except if a curious pilot asks for it.
To do it in 60 seconds I would assume the curious pilot has a decent background in physics.
- an approximation : air is not compressed
- section is reduced by airfoil, so the mass of air needs to travel faster
- travelling faster means kinetic energy is increased
- total energy remains constant, so potential energy is decreased : lesser pressure on the extrados

Try using logic. For this, your student obviously needs to have some level of education - which leads to the question I brought up before about what sort of intelligence and aptitude is the minimum to be a pilot. But lets forget about that for now!

I find it amusing and sad that instructors use explanations that, to them, might make sense yet they leave so much unanswered - the student obviously doesn't understand (the instructor would figure that out if they'd ask the student a question) and the instructor knowingly moves on. I've seen it myself sitting in the back of a classroom! You may as well just not say anything to the student if you're not prepared to explain it clearly so they understand. In this respect I'm talking about an incompetent instructor with a student who was more than capable of understanding the basic physics principles.

The worst combination is an incompetent instructor who doesn't understand what they're talking about and a student who doesn't understand basic physics. Sadly, this combination abounds in the flight training schools across Canada.

Back to the topic: if you're an instructor I'm sure you'd be familiar with TKT (threshold knowledge test). That doesn't just mean you ask the student questions about what you covered in the last lesson! That means you also determine the student's level of understanding so that you can present the current lesson's material in an effective way for that student. If you don't realize that your student doesn't have a basic understanding of physics then you'll be wasting both your's and your student's time if you don't first cover that. Of course, most flight instructors (not all) don't care if their student actually has a good understanding of the subject matter so they couldn't care less about this matter.

Determine where your student's level of knowledge is and then build on that. There isn't a perfect 60 second blurb that will explain it for every student! Every student is different. That needs to be taken into consideration. What happened to being a good teacher?!

[dr.aero]

Photofly...

I think you're mixing up "proportional" and "a linear function of". A linear function is a straight line, but doesn't have to go through (0,0) on a graph.

To have a proportional relationship the graph of CL vs. AoA would have to pass through the origin.

You've spent the last ten pages trying to persuades that the graph of CL vs AoA doesn't go through the origin. If it doesn't go through the origin, it's not a proportional relationship.

CL is a linear function of AoA, up to the critical angle of attack, but the only way you can say CL is proportional to AoA is to adopt a definition of AoA based on using the imstantaneous zero-lift line as the reference ("zero") angle.

Here is an explanation of what proportional means: http://en.wikipedia.org/wiki/Proportion ... thematics)

Cl is proportional to AoA up to the critical AoA, at which point, Cl becomes inversely proportional to AoA.

The line does NOT have to pass through the origin to have a proportional relationship! You have no clue about what you're talking about.

I have NOT spent the last ten pages trying to show that the Cl line doesn't go through the origin. It depends how you define things (geometric or absolute) and if it's a symmetrical or asymmetrical airfoil - that will tell you if it will pass through the origin or not!

I'm not insulting you but it's clear your level of math education is quite low. Please stop wasting my time.

[dr.aero]

Photofly...

To further prove you wrong: http://i.imgur.com/iUkuc.png

I'll quote the important part -- "If two factors are proportional, it means that if one factor increases, so does the other."

[Cat Driver]

Try using logic. For this, your student obviously needs to have some level of education - which leads to the question I brought up before about what sort of intelligence and aptitude is the minimum to be a pilot.

You are suggesting there should be a minimum level of education / intelligence / aptitude, test before one can get a PPL? or for that matter any pilot license?

If so what would you want as the minimum?

[dr.aero]

Try using logic. For this, your student obviously needs to have some level of education - which leads to the question I brought up before about what sort of intelligence and aptitude is the minimum to be a pilot.

You are suggesting there should be a minimum level of education / intelligence / aptitude, test before one can get a PPL? or for that matter any pilot license?

If so what would you want as the minimum?

I really don't know. First I need to convince people that we need to have some sort of test prior to, IMO, starting training. Once that happens, then we can discuss what the test should include.

Universities have entrance exams, 911-operators need to pass an aptitude test as well as other tests (I know, I've done them), and more and more companies are contracting outside agencies to do their hiring and the hiring process involves aptitude testing. Why can you get a pilots license without passing an aptitude test? Why is a pilot allowed to fly people commercially for money when they've failed their flight test 3 times?

Frankly, taking an exact copy of the 911-operator aptitude test that I took awhile ago would be a damn good start! The nice thing about aptitude tests is that you won't figure out what answer you got wrong and you can make it so they aren't multiple choice - that way the aptitude test would remain relevant for a bit longer than the other TC multiple choice exams that get distributed across AvCanada.