end of thread: physics, non-physics, and airplanes

[John Denker <jsd@MONMOUTH.COM>]

At 09:09 AM 8/23/99 -0500, Richard Tarara wrote:
>  As stated, much of the debate being carried out on the list
> IS based on the referenced papers

Yes, thank you for noticing.

> (although John has also made reference to
> private communications).

I cited the dates of certain private communications in order to refute the
accusation that I had gone "behind [the authors'] backs" i.e. not given
them a fair chance to respond to my critique of their errors.

The *ideas* in those private communications have been fully aired in this
forum and in the URLs that have been cited.

There is a very special reason why I did not quote those communications
verbatim, which I will be happy to share with anyone who asks offline.

> I'm sure there are many of us who would
> like to know a bit more here, but don't want to slosh through all the gory
> details (over which the two sides disagree anyway).

Understood.

> I guess my point is
> that if this fight is to be carried out on the Phys-L list, the participants
> should keep in mind that their audience IS the WHOLE LIST and not just each
> other.

Understood.

>  When talking about a particular point they should copy the
> appropriate passage from their web pages (when possible--figures being an
> exception) so that the rest of us do not need to search through these long
> papers to find the information being debated.

I've tried to do this, with the special exception noted above.  To the
extent that I haven't done this perfectly, I apologize.

> When the debates get bogged
> down in name calling -- one person is working behind the back of the others
> or someone is being intellectually dishonest, etc.-- then this needs to be
> off the list, as do (disingenuous) apologies for some obscure personal
> offense.

I would be *delighted* if this whole degrading spectacle could have been
conducted off the list.  Let me say that I didn't want it on the list, for
all the reasons Mr. Tarara cites.  Indeed, back in January 1999, after
exchanging many thousands of words of private email with me, one of the
participants repeatedly implored me and dared me to share this discussion
with this list.  I replied on Sun, 31 Jan 1999 09:05:26 -0500, saying:
> Well, most of my friends are embarrassed when they make a mistake.  They
> *really* hate screwing up in public, and they find it painful to back down
> in public.  Therefore (applying the golden rule) I try to avoid telling
> people "you screwed up" in public.  If this discussion *had* been on the
> list, I would have tried to take it off-line, so as to reduce the chance of
> hurt feelings.

So here is where I will leave things:
  *) The authors of the "scoop model" claim that it presents "true
physics".  Alas, when applied to any single airplane, it is not true
physics.  It is not science at all, for the reasons I posted earlier (Mon,
23 Aug 1999 08:55:25 -0400).  In Fermi's words, it is "not even wrong".  It
purports to calculate two quantities (lift and induced drag) but does so by
the use of two fudge factors (the size of the scoop and the percentage of
the true airspeed that is converted to downwash velocity).  The two
calculated quantities are not predictions but postdictions.
  *) When applied to more complex situations, such as formation flight, the
scoop model can be coerced into making predictions.  In such cases, it
makes grossly wrong predictions.
  *) The paper in question also makes categorical statements about the
effect of upwash on lift and drag, and the effect of ground effect on
upwash.  These statements are grossly inconsistent with well-established
experimental, analytical, and simulational results.
  *) I stand by the correctness of my on-line book
        http://www.monmouth.com/~jsd/how/
and recommend it as suitable for student pilots, flight instructors, and
anyone else who is interested in airplanes.
  *) I stand by the correctness and fairness of
        http://www.monmouth.com/~jsd/fly/lift.htm

I have nothing more to say.  I will leave the last word to others.