Airplane Pilot's As Physicists

wrote:
On Oct 10, 7:46 am, Dudley Henriques wrote:
Bertie the Bunyip wrote:
"CWatters" wrote in
:
"Mxsmanic" wrote in message
...
The essential feature of an airfoil is that it twists the flow of
air as
it
passes (or as the airfoil passes through still air, which is
equivalent,
and
that's how it works in airplanes). The air is accelerated downward,
and
this
engenders an equal and opposite force that is lift.
Nope. That wouldn't explain how wing sections for tailless planes
work. The sections for those curve up towards the trailing edge. The
leading edge produces lift but the trailing edge produces a _downward_
force to counter the pitching moment. Example section...
http://www.desktopaero.com/appliedae...mages/image13_
43.
gif
Good point.
The porblem with this guy is (and it's just one guy with a handful of
sockpuppets) is that he ses some discrepencies in how bernoulli is
explained and has concluded that it must be incorrect since there is
"disagreement amongst the experts"
A good analogy here would be the eeedjit creationists who grasp at the
straws presented by the minor scuffles occuring within the evolutionary
sciences.
Bertie
This is exactly how I see this as well. This character and his puppets
are playing out a conversation with themselves (one person) designed to
capitalize on the few simple misconceptions concerning Bernoulli that
are common knowledge among the professional aviation community and have
been "corrected" years ago.
Unfortunately for this forum, there are still a few old textbooks
hanging around out there reflecting these misconceptions. This, coupled
with the fact that there are individual pilots out here (from the GA
community mostly) who apparently lack the formal physics knowledge to
take on someone whose sole intent is to discredit them by cleverly using
the remaining confusion in the community concerning Bernoulli against them.
The REAL rub in this situation is that the idiot doing this, from what I
have seen in his posting, has very little knowledge HIMSELF about the
lift issue and is totally wrong in critical areas of his argument.
It's an unfortunate situation designed by a person who seems to pleasure
himself by what he's doing.
Personally I wouldn't give this idiot the time of day. His understanding
of Bernoulli is much worse than those with whom he has engaged. Those
who are on to him he avoids, only taking glancing shots at them knowing
he won't be answered directly.
It's a shame really....but what the hell, it's Usenet!!
:-)))

--
Dudley Henriques

I haven't minded taking the bait. The process has
pointed out many good websites we can use in instruction, and has
forced a review of some basic principles. Got to find the silver
lining, right?

Dan


A good visual tool I've used as an example through the years is a
cylinder. Stationary with no circulation on a cylinder in a freestream
you have a 0 AOA stagnation point leading and trailing edge with equal
streamlines. No Bernoulli; no Newton. no lift.
Now spin the cylinder (same as increasing AOA on an airfoil...simple
Magnus effect)and you lower both stagnation points front and back as
circulation becomes a factor. You now have Bernoulli top and bottom and
up wash and down wash created simultaneously on the cylinder; you also
now have lift!
An airfoil works the same way as it rotates through angle of attack.
Actually, a barn door will work the same way as well :-))

There are differences of course in how symmetrical and cambered airfoils
work as far as the center of pressure and moment arms work on the wings
vs angle of attack and zero lift but basically using a cylinder then
rotating it demonstrates simply that if lift is being created, both
Bernoulli and Newton are existing at the same time and either can be
used to explain how a net lift force is created.
The rest of it is all peripheral data and usually confuses both people
as well as the airport cat as they get lost in what causes what how what
causes lift.

--
Dudley Henriques