Re: Airfoil lift, new article

[William Beaty <billb@ESKIMO.COM>]

On Thu, 14 Jan 1999, jlu wrote:

> Hi all-
>     Anderson came and gave a lunch seminar in the high energy physics
> division.  The upshot is that he thinks that downwash is a better prime
> cause than is the pressure distribution around an airfoil.  He did have
> pictures showing that airflow above and below the wing does not "join"
> at the trailing edge.

There is currently a discussion about this paper going on at
rec.aviation.piloting newsgroup.  The Anderson/Eberhardt paper about how
airplanes fly:

   http://www.aa.washington.edu/faculty/eberhardt/lift.htm

John Denker has posted a critique of their paper at:

   http://www.monmouth.com/~jsd/fly/lift.htm

I have a crude "thought experiment" explanation of flight here, see if
you can poke holes in my reasoning:

   http://www.amasci.com/wing/rotbal.html

The newsgroup discussion is typical: most of the people are totally
confident that an aircraft can remain suspended entirely because of a
pressure difference, and it need not obey F=MA, or change the momentum of
the air.  The way I see it, an aircraft flys ENTIRELY because it changes
the momentum of air: it pushes down on the air, and therefor the air
pushes up on the aircraft, THEN THE AIR MOVES DOWN.  The pressure
difference doesn't just sit there, instead it CAUSES the "downwash."

I don't know if PHYS-L people really would want to get involved with that
discussion, because we can talk forever and not convince anyone.  To
convince them, they must confront the fact that they've been visualizing
the physics of flight incorrectly, as well as angrily defending an
incorrect premise.  And these people are pilots!  It's far easier to
convince a non-expert that their pre-existing concepts are actually
misconceptions!  :)

The discussion thread can be viewed at Dejanews by pasting this huge
url into your browser (edit it to remove line breaks):

http://x10.dejanews.com/=dnt_test1/dnquery.xp?search=thread&svcclass=
dncurrent&threaded=1&ST=PS&CONTEXT=916331856.695009561&HIT_CONTEXT=
916331856.695009561&HIT_NUM=9&recnum=%3c76c4t8$sul$1@
eskinews.eskimo.com%3e%231/1

.. or go to www.dejanews.com and search for these keywords:

  ~g rec.aviation.piloting lifting force


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William J. Beaty                                  SCIENCE HOBBYIST website
billb@eskimo.com                                  http://www.amasci.com
EE/programmer/sci-exhibits          science projects, tesla, weird science
Seattle, WA   206-781-3320          freenrg-L taoshum-L vortex-L webhead-L