On Oct 16, 10:20 am, "Androcles" wrote:
"Le Chaud Lapin" wrote in oglegroups.com...
: On Oct 16, 3:47 am, "Androcles" wrote:
: "Le Chaud Lapin" wrote in
glegroups.com...
: : On Oct 15, 7:54 pm, "Androcles" wrote:
: : "Le Chaud Lapin" wrote in
: ooglegroups.com...
: : : On Oct 15, 6:42 pm, "Gatt" wrote:
: : : "Le Chaud Lapin" wrote in
: : oglegroups.com...
: : :
: : : I read last night in another piloting book, again, that the
common
: : belief
: : : about the dynamics of airfoils is wrong,
: : :
: : : Yeah? Which one?
: : :
: : : I'd have to go back to bookstore to find the name.
: :
: : AHAHAHAHAHAHA!
: : Or back to sleep to dream again...
: :
: : Barry Schiff, in "The Proficient Pilot", "An AOPA Book", writes on
: : page 2:
: :
: : "There is, for example, this amusing fable: "Air flowing above the
: : wing has a greater distance to travel (because of camber) than air
: : flowing beneath the wing. Therefore, air above the wing must travel
: : faster so as to arrive at the wing's trailing edge at the same time as
: : air flowing underneath. This is pure nonsense."
:
: Since it is true Schiff must be a raving lunatic. Maybe you don't
: understand that travelling the greater path in the same time involves
: a greater speed.
:
: Perhaps you could explain in detail what you mean by this last
: statement. I am sure that there are plenty of people here would would
: like, for once, that a pilot explains what s/he means by this.

Really?
Ok, for plenty of cretins such as yourself...

Travelling 70 miles (distance) in one hour (duration of time)
is a speed of 70 mph by definition.
100 miles (the greater distance) in the same time (1 hour)
is 100 mph.
100 mph is faster than 70 mph.
People unaware of this simple fact are prone to getting
speeding tickets and losing their license.
Aircraft pilots are even more aware of it than motorists,
using their stop watches to compute distance.

In this video the air moves MUCH faster over the top of the wing
than it does over the bottom:
http://www.youtube.com/watch?v=KCcZyW-6-5o

I just looked at this video.

What you wrote and what this video demonstrates are two entirely
different things. There is no reason to say that the air moving above
the wing must meet beneath the wing.

I keep hearing people say,

"The air moves faster, therefore Bernoulli's Principle must be
invoked."

The thesis of what I have been saying all along can be seeing in an
inversion of this sentence.

"It is Bernoulli's principle that causes the air to flow faster."

In particular, it is the pressure gradient that causes the air in the
contstriction to flow faster. This same pressure gradient exists
above a wing in an air craft, and it has nothing to do with the
distance traveled. The camber of the wing is carefully designed my
airfcraft manufacturers to incudes, as much as possible, this pressure
gradient, at a particular speed, but *with* the conflicting
requirement that resulting drag must be reduced. This is why I said
earlier that pressure at the front of the wing is not necessarily bad.
It is desirable, but it also causes some laminar drag. Intuitively,
one can see what the edge must not be made sharp - doing that would
elimate the very pressure that is need to bring about the pressure
gradient.

Now you can go back to sleep and dream of Barry Schiff and
his "nonsense".

-Le Chaud Lapin-