Originally Posted by IO540
All the stuff about Bernoulli, the Coanda effect etc etc etc can be derived from Newtonian mechanics. If you apply NM to each particle, you will derive all the other (more convenient, in their intended applications) principles. So, why not simply teach NM and how to apply it to each particle, using finite element simulation on a computer? All the other stuff is irrelevant. Einstein would probably have a similar view, incidentally
Most explanations of Bernoulli will agree with you. But have you seen the MATH!
I'm sure you can work most things out from first principles but as you correctly point out, we don't have 747s plummeting from the sky due to the pilot's insufficient technical knowledge. God forbid we should require them to do a finite element analysis on the back of fag packet during their Landing Checks, because they'd probably fly into a mountain in the meantime!
In my search for "the truth", this is not what I'm advocating at all.
The "watered down" version of Bernoulli's theorems which we get taught as pilots, provides us with a reasonably simple set of equations from which we can derive answers for ourselves which are
approximately correct and which give us a
reasonable model about the conditions which enable us to fly. From this we can also get an appreciation of why we Stall, Load Factors, the markings on an Air Speed Indicator etc etc. All good stuff for a Pilot to know. He doesn't have to be an aerodynamicist to understand the basic Lift Equation.
I don't have a problem with any of that.
What I DO have a problem with is questions such as this:
Q 87, H912 CFI
Why does increasing speed also increase lift?
A) The increased velocity of the relative wind overcomes the increased drag;
B) The increased impact of the relative wind on an airfoil's lower surface creates a greater amount of air being deflected downward;
C) The increased speed of the air passing over an airfoil's upper surface increases the pressure, thus creating a greater pressure differential between the upper and lower surface.
FAA Answer (according to Gleim) = B
This completely skews the "Newtonian" origins of Bernoulli's theorem, to imply that it is merely the action of the wind whacking into the underside of the wing which causes the plane to fly. This is inexcusable IMHO.
It's really just "Chinese Whispers" isn't it? You start off with a set of equations (Bernoulli's), simplify them for "Pilot Consumption", and then Misquote and Misapply them. It reduces the theory of aerodynamics to "Chants and Incantations" which would adequately describe the flight of a witch's broomstick.
I see little point in teaching the theory at all if it's not going to generate a reasonably correct model in the Student's mind about what's going on - and as I've said to a number of previous correspondents, an inaccurate model is harder to learn than a correct one, because when the model ceases to make accurate predictions - the student cannot work out the correct answer. He has to Learn the Answer, rather than rely on his knowlege.
The same applies to the irritating "Word Play" which appears a lot in JAA Exams. I agree with you whole heartedly for the same reason.