Re: AAPTApparatus Competition [ A cart and a fan (not exactly physics of flight) ]

[brian whatcott <inet@INTELLISYS.NET>]

At 19:25 8/11/99 -0500, Mike Moloney wrote:
> I was in charge of the AAPT Apparatus Competition this year in San
> Antonio, and have put the entire competition on the web
...
> Two of the entries by Bill Franklin relate to the physics of air
> movement, and so have something (at least vaguely) with the physics
> of flight.
>
> .... When the air stream
> is directed toward this plate, the stream is deflected back away from
> the curved edge of the plate.  In this picture the air would
> 'rebound' to the right, and the cart would travel to the left.
> Reversing the direction of the plate reverses the motion of the cart.

*** Though Mike describes it in undramatic terms, I will add
that this is a practical example of a ship mounted fan, which by
blowing air into the 'sail' pushes the boat forwards. Delightful!

> Further down in the pictures you will find Bill's Magnus effect
> demonstrator, in which a rotating two-liter pop bottle on a cart
> shows this effect. [Point a fan at the rotating bottle, and the cart
> moves sideways, due to the Magnus effect.]
> ...
> Mike Moloney, Dept of Physics & Applied Optics, Rose-Hulman Institute
> of Technology

***In browsing the exhibits, I ran into this interesting text,
which I think originated with Bill Franklin:
==============================================================
While searching for a picture of Flettner’s ship, I found an
 excellent resource for the Magnus effect, as well as many other
topics related to lift and flight. It is a soon to be published
book, See How It Flies, (ISBN 7016405) by John Denker.
It will be available from McGraw Hill for about $35. It is
currently available on the internet at:

 http://www.monmouth.com/~jsd/fly/how/htm/title.html#mytoc

This is the address for the main menu; chapters can be accessed
from there.

===============================================================

***I was struck again by Denker's helpful text and illustrations.
 I was particularly pleased to see a representation of the airflow
over an inverted asymmetrical airfoil.

 (Color bars marking the time-tagged air flow over and under the
 foil showed cross-hatching, at least on my color monitor which
took something away from the stream line directionality however)

  The personality of the author was in no way obtrusive there.



brian whatcott <inet@intellisys.net>
Altus OK