Thrusting or Sucking (where's Howard Stern when we need him.)

Alexander Georgas schreef:
There is plenty of good understanding that can be gained
by explanations that contain false premices. Should
we be as purist as this to reject even a cursory mention
of things that are not 100% accurate in the educational
process?
Being an aerospace student myself I`m probally a bit of a purist as
well. Nevertheless I think that the final goal of teaching aerodynamics
(anything actually) is understanding, not perfectionism.


In the same principle, when trying to explain the very
complex phenomenon of wing lift, do we go from stating
the Bernulli effect and Newton's 2nd law to diferential
equations of fluid dynamics -- or possibly stop there,
explaining that the actual phenomenon is too complex
for 'common people' to understand?
What`s wrong about only telling the short version of the theory,
without complicated stuff:
"An airfoil creates an flow which accelerates air downwards. This
results in a pressure (and shear) field on you`re wing which causes
both lift and drag. Nothing really complicated about that I guess, and
no problem with applying it to reality at all.


I would like to know what this forum thinks in terms
of this? In my experience, quite a few gliding instructors
are either very much missinformed about the aerodynamics
of lift (and keep on missinforming students), or offer
explanations that while accurate fail to answer a student's
question by advancing the understanding of what take
places. This is very discouraging for most people and
it is only the few who will then go back into the literature
and try to sort things out.
About a year ago I was having a discussion with a couple of gliding
instructors. None of them understood "anything" about aerodynamics and
I heard the weirdest theories. Nevertheless they seem to teach flying
quite well without any problems for their student. Not understanding
flow completely doesn`t seems to be such a problem in flying a glider.


The funny thing about this is that, while it is not
very important to know about aerodynamics to fly a
glider, all sorts of misinformation eventually trickles
into discussions and advice about such things as the
best bank to turn in, or when a stall occurs etc.

So what should we do about this?

Just skip the complicated theory?
Real world aerodynamics is extremely complicated with a lot of issues
(especially vortices) still beyond oure understanding. You can`t expect
every glider pilot to understand complex differential equations or the
navier-stokes equations.
Instead of putting a lot of effort in explaining lift we maybe should
concentrate a bit more in the relationship of weight, surface and so
on, which is very usefull in normal flight operations. The square and
squareroot equations seems to be complicated enough for most pilots.

Jarno Nieuwenhuize,
The Netherlands.