Debunking Lift Theories Still Taught

[completeaerogeek]

As I said, if you don't read what you are commenting on, you may be embarrassed. I have been teaching BSC CPL/ATPL Aerodynamics at University.

 

I teach cadets in my spare time as a way of contributing to the future of aviation. how about you?

 

Now if you have a specific fact to challenge please do so. Anything else is trolling...

 

 

[completeaerogeek]

I suppose you can't do much harm with cadets.

I am a waiting Mr Turbo? Anything? Anything at all????? Anything to contribute? Facts maybe? Well reasoned arguments? Or just galley chat...

 

I do enjoy a good discussion.

 

 

[bexrbetter]

Oh and I would be happy to know in which way I am unravelling. Any factual statements will do. I have all day...:)

In your aloofness you have failed to complete a critical strategy in a debate, know thy enemy.

 

Many of us here are aware of Head in the Clouds long distinguished flying history and plane design/building history and you are looking rather less than clever.

 

Theory is great and thanks goodness for Mathematicians and other scientists who have got us where we are today, but theory without knowledge of how to practically apply it is as useless as big tits on a Nun.

 

 

[Head in the clouds]

Here the aircraft is rolling and turning to the left. Ailerons

work opposite to each other to roll the aircraft. Rudder is

 

used to assist the turn and prevent skidding.

 

My friend-am I to assume that you have never heard of adverse yaw? ?

I'd rather not be called your friend if you don't mind, we've barely met.

 

Yes, I know adverse yaw very well, I thought you might like to explain how countering it with rudder assists the turn. If I was writing your course notes I'd have been more specific to aid understanding, and said it prevents adverse yaw caused by use of ailerons, or even that it assists rolling the aircraft, it certainly doesn't assist the turn.

 

How about the rest of your statement concerning using it to 'prevent skidding', would you care to have a go at expanding on that one?

 

I take it you're not a pilot/flyer yourself are you?

 

I am a waiting Mr Turbo? Anything? Anything at all????? Anything to contribute? Facts maybe? Well reasoned arguments? Or just galley chat...I have been teaching BSC CPL/ATPL Aerodynamics at University.

 

 

[completeaerogeek]

nQUOTE="bexrbetter, post: 447929, member: 8594"]In your aloofness you have failed to complete a critical strategy in a debate, know thy enemy.

 

Many of us here are aware of Head in the Clouds long distinguished flying history and plane design/building history and you are looking rather less than clever.

 

Theory is great and thanks goodness for Mathematicians and other scientists who have got us where we are today, but theory without knowledge of how to practically apply it is as useless as big tits on a Nun.

 

The problem here is that you are falling into a Logical Fallacy called authority by eminence. Reputation and experience mean nothing if you are factually incorrect.

 

The classic example of this is religion which is long on 'reputation and authority' but bankrupt on verifiable facts. Science always wins...

 

Forgive me if I don't bow down before factually incorrect statements.

 

The eminent A.A. Griffiths also told Whittle that his engine was impractical and would not be of use. OOPS...

 

The problem is that applying actions without understanding the principles at work is a recipe for disaster...

 

Happy to be corrected factually on anything I have said... My respects to 'Head in the Clouds' for his achievements but how many 20,000hour captains have driven perfectly serviceable aircraft into the ground because they would not listen to their crew stating obvious facts. Want me to list them???

 

I'm sorry but when it comes to Physics vs Reputation, I will take Physics every time...

 

 

[completeaerogeek]

I'd rather not be called your friend if you don't mind, we've barely met.Yes, I know adverse yaw very well, I thought you might like to explain how countering it with rudder assists the turn. If I was writing your course notes I'd have been more specific to aid understanding, and said it prevents adverse yaw caused by use of ailerons, or even that it assists rolling the aircraft, it certainly doesn't assist the turn.

 

I did in my last two posts. And by the way, it is the FAA talking in that quote not me. In any case those notes are VERY BASIC and designed to give basic principles only. The ones used in the lessons are much more detailed.

 

How about the rest of your statement concerning using it to 'prevent skidding', would you care to have a go at expanding on that one?

 

I take it you're not a pilot/flyer yourself are you?

 

You see this its the problem. I laid out my qualifications and experience clearly for an enquiry several posts back. I won't repeat it here.

 

Please read before you make unfounded assumptions. It just makes you look silly.

 

If you like go back to the first post in the thread an read what I actually posted to help young pilots. Then come back to me.

 

Now as to adverse yaw-the tendency for the wing on the outside of the turn to have increased induced drag and pull the nose towards the outside of the turn which is then balanced with rudder into the turn... Would you explain which part of this is incorrect?

[David Isaac]

I'd rather not be called your friend if you don't mind, we've barely met.Yes, I know adverse yaw very well, I thought you might like to explain how countering it with rudder assists the turn. If I was writing your course notes I'd have been more specific to aid understanding, and said it prevents adverse yaw caused by use of ailerons, or even that it assists rolling the aircraft, it certainly doesn't assist the turn.

Well I'm just an old bloke that loves flying thingies and has been flying them since age 16 and it is the elevator that causes the aircraft to turn, the elevator is the principal control for turns.

 

 

[completeaerogeek]

Yes but that can be a bit confusing for a new pilot can't it? Elevator up and down and all that?

 

Of course you are correct once the turn has been initiated by rolling but the elevator cannot initiate a turn... Unless you are in a 90 degree bank already!

 

 

[completeaerogeek]

Yes but that can be a bit confusing for a new pilot can't it? Elevator up and down and all that?Of course you are correct once the turn has been initiated by rolling but the elevator cannot initiate a turn... Unless you are in a 90 degree bank already!

 

Well I'm just an old bloke that loves flying thingies and has been flying them since age 16 and it is the elevator that causes the aircraft to turn, the elevator is the principal control for turns.

In any case the point of my posts was to make young pilots aware that the way many people are taught that lift works is rubbish. As in my first post on page 1.

 

It amazes me that these myths are still around...

 

Have a nice day...

 

 

[David Isaac]

Yes but that can be a bit confusing for a new pilot can't it? Elevator up and down and all that?

Not really, I believe it should be taught from the beginning and it can be easily shown by holding a model in your hand and explaining the interactions between the control surfaces. There are also some great videos in a Decathalon (cant remember who produced them) that show the principle very clearly.

I think these basic principles should be taught correctly from the beginning, particularly the controls and effects in turns and the dangers of unbalanced turns, maybe we would kill less if it were better understood.

 

 

[Gnarly Gnu]

Hello CAG welcome & I'm sure you are very knowledgeable with that background and will be a valuable contributor here. But HIC is also extraordinarily knowledgeable in aviation matters and indeed I think he makes a very valid point so can I respectfully suggest perhaps best not to start off by bagging out others straight off?

 

Science always wins...

I really like science too but I have to say this statement is somewhat naive. Which science always wins? The science taught 100 years ago, 50 years ago or today's version? Much of science is flux, it's always subject to change by superior understanding eg you started off pointing out the error of applying Bernoulli's principle to the wing, we now know better so I'm pretty sure you would agree with me. There are also several historical instances where religion (which tends not to change) had certain physical principles correct before scientists finally figured it out. We shouldn't be too proud to acknowledge facts like this, true science is about being sceptical not dogmatic.

 

 

[David Isaac]

In any case the point of my posts was to make young pilots aware that the way many people are taught that lift works is rubbish. As in my first post on page 1.It amazes me that these myths are still around...

I agree, I got what you were trying to get across and yes it is amazing how these myths survive. But I am sure you would know that it is possible to say that pigs can fly and eventually have a whole bunch of corporate tossers believe you in the right (wrong) circles. History is full of industry myths blindly followed by loyal minions who dare not question the establishment.

 

 

[completeaerogeek]

Hello CAG welcome & I'm sure you are very knowledgeable with that background and will be a valuable contributor here. But HIC is also extraordinarily knowledgeable in aviation matters and indeed I think he makes a very valid point so can I respectfully suggest perhaps best not to start off by bagging out others straight off?I really like science too but I have to say this statement is somewhat naive. Which science always wins? The science taught 100 years ago, 50 years ago or today's version? Much of science is flux, it's always subject to change by superior understanding eg you started off pointing out the error of applying Bernoulli's principle to the wing, we now know better. There are also several historical instances where religion (which tends not to change) had certainly physical principles correct before scientists finally figured it out. We shouldn't be too proud to acknowledge facts like this, true science is about being sceptical not dogmatic.

______________________

Hi Gnarly, thanks for your feedback but if you go back to my first post, and read on, I have been fairly very restrained with people making incorrect statements and misquoting me snidely. You may also better understand my comments in context.

 

When someone says that pitch changes do not affect AOA I have to wonder if they should be near an aeroplane.

 

All I am trying to do is to help young pilots understand that what they most likely have been taught is rubbish.

 

It was not my intention to insult anyone and I did pass my respects to HIC but his facts were simply incorrect.

 

Should I ignore that because he is an experience flyer? I very much admire anyone with lots of experience. Pilots and anyone in aviation should be expanding their knowledge and challenging their assumptions. It is critical.

 

Actions by the most experience and venerated pilot of the two crews involved at Teneriffe were the primary cause of the worst accident in aviation history...

 

Confirmation bias is deadly. I love this business that is why I am trying to clear up these myths...

 

Aerodynamicists have never promoted these silly explanation mainly because they are so easily disprovable.. They have been cobbled together by people who don't understand how thing work. And I have to respectfully disagree with you. Science is not in 'flux'. Science moves ahead because of investigation, logic and challenge by peer review.

 

It is only by this process that we have moved from caves to the moon. Challenging established thought is the very basis of science (and in this respect, the antithesis of religion) but to do so, you have to be able to prove what you assert because everyone else will be climbing over you to prove you wrong. That's how scientists make their careers.

 

I don't want to start a religious argument -my point was about empirical evidence. However - as an analogy it is pertinent: Which principles were figured out by the religious (supernatural) aspect of religion (unquestioning faith) as opposed to religious scholars who were practical scientists.? Perhaps we should ask Keppler and Gallileo... :)

 

And to be fair which science is in flux? Science (certainly the physical sciences) are long established. Newton wrote Pricipia in the 1600s and we still send satellites into space using his formulas. Nothing has changed unless you get into the weird world of Quantum Mechanics

 

I don't mind where evidence comes from and you can believe whatever you like but don't confuse scientific facts with unsupported assertions. They are very different.

 

My analogy was talking to the fact that even our institutions (CASA) are teaching that a wing is a venturi. It boggles the mind...

 

 

[completeaerogeek]

Not really, I believe it should be taught from the beginning and it can be easily shown by holding a model in your hand and explaining the interactions between the control surfaces. There are also some great videos in a Decathalon (cant remember who produced them) that show the principle very clearly.I think these basic principles should be taught correctly from the beginning, particularly the controls and effects in turns and the dangers of unbalanced turns, maybe we would kill less if it were better understood.

You bet. That is kind of my whole mission here. How in the world did the guts on AF447 not notice that there was too much blue and not enough brown on all 5 ADIs?

 

Why did the pilot of the Colgan Air Dash 8 (and the PF of AF447) pull back on the stick when he got a stall warning?

 

Boggles the mind...

 

 

[completeaerogeek]

If you want to discuss another dangerous idea, how about Power + Attitude = Control? Ask the Asiana 214 crew how well that worked for them or the AF 447 guys (oh you can't)

 

 

[turboplanner]

This has been most illuminating. You should also try http://www.pprune.org/pacific-general-aviation-questions-91/ They have more guys up in the theory world who could be interested in what you have to say.

 

 

[M61A1]

Your NASA link in the first post is only debunking the "equal transit" portion of the theory, and says that many aspects of the Bernoulli's theory are correct in relation to lift production. It was my understanding that making lift was a bit more complex than "it's ALL this, or it's ALL that", and that both the low pressure on top and the reactive force from deflection, create lift.

 

 

[David Isaac]

and circulating currents.

 

 

[dazza 38]

I have read all of this and I had to learn the theory of flight of both fixed wing and rotary wing when I was a airframe fitter in the RAAF. It was all rivetting stuff but it really isnt that important IMO when flying. All I need to know is when I pull back on the stick to houses get smaller until I reach a certain point and then the houses get bigger again. Simple.

 

 

[geoffreywh]

Dr Mr Completeaerogee, Please don't stop posting, I'm certain there are other principals that you can shoot down. I have been vindicated in what I have thought for many years....This all both entertaining and instructive, no matter what detractors say....By the way , Do you know Richard Dawkins, from your posts you may well be family?

 

 

[Gnarly Gnu]

By the way , Do you know Richard Dawkins, from your posts you may well be family?

Ha ha, he certainly isn't Dr John Lennox at any rate!

 

 

[bexrbetter]

I'm sorry but when it comes to Physics vs Reputation, I will take Physics every time...

While physics can not be changed or argued with, supporting a view of a singular action without introducing surrounding and greatly influencing actions that make the total sum, is a somewhat faulty course to follow and doomed to less than optimal results.

 

HIC doesn't have a "reputation", he has a factual and substantial resume and if you said 'X' airfoil will suit 'Y' application because your computer says so and HIC says; "No it won't" because he has found that including 'G' and 'P' factors make 'X' less than optimal, but he has found that 'K' airfoil is suitable under those conditions, I will most likely take his advice over yours. Nothing to do with the "HIC Church", just lots of hands on experience offering real world results.

 

Vans still chooses a NACA230** series airfoil, not because it's technically the best airfoil for their planes, it's not, but because it's the most consistent performing airfoil when it gets rain, bugs and crap all over it - real World factors right there.

 

 

[jwn57030]

As an engineer learning to fly I have run into the same kind of issues in ground school. The instructors have no real background in physics. They just know what they were told when they got their certificate or degree in aviation. I have had to more than once correct what they said and sometimes hold my tongue. Its not really their fault as its what they were taught, but the text book makers and people in charge definitely need to do a better job. One of my biggest concerns with ground school is that seems to be more about teaching you to pass the test instead of having an in depth understanding of topics.

 

 

[frank marriott]

Without buying into the physics or the argument generally............(I find the discussion interesting actually)..........

 

Just how detailed a "pilot" needs to know the physics is debatable (and I accept in RAA there are builders & designers which is a different subject)

 

the dumbing down of the CPL syllabus in the 'eighties' to one 3 hour multi guess exam from 6 three hour written exams caused a lot of comment but did not have the disastrous effect on safety as predicted by many.

 

Although a better understanding in how the physics actually work is indeed no load to carry, just how detailed it is necessary to be a "pilot" seems to vary in opinions - I believe the CPL exam has changed again from the one exam?.?

 

 

[completeaerogeek]

This has been most illuminating. You should also try http://www.pprune.org/pacific-general-aviation-questions-91/ They have more guys up in the theory world who could be interested in what you have to say.

Thank you I will.