"Roger Long" skrev i en meddelelse
...
OK, I admit to some shooting from the hip on the
freewheeling prop business. Let's see if I can make a
substantial contribution to the subject.

First of all, you have to recognize that a propeller,
airplane or boat, is just a wing going around in a circle.
The relationships are a little harder to understand
because the mental model you try to make in your head has
to spin around. If you break it down into short strips at
fixed distances from the shaft centerline however, it is
fairly easy to understand.

If you would first like a non-technical explanation of
wings, I can recommend some articles published in Avweb,
the major aviation E-zine, by a frequent contributor to
this and aviation newsgroups. These articles created a
firestorm of controversy among uninformed pilots but,
except for some minor errors, have never been seriously
questioned by an aerodynamics professional. One even uses
them in his college introduction to aerodynamics. Many of
the concepts apply to sails so may be of interest to this
group. For example, you can find out why sails do not
stall dramatically as do airplane wings.

You can find these articles he

http://home.maine.rr.com/rlma/Articles.htm

SNIP
--

Roger Long


Thank you for most interesting input Roger ... It seems to
be right, that "all complex problems has at least one simple
solution . . . . that does not work".

Unfortunately, I do not get a response, when I try to use
the above link ... Is it closed for Danes?

best regards

--
Flemming Torp