Axel

First please realize that the brother Wright had to reinvent
aerodymanics whent hey found out the all the material that they had
collected was junk. (Mr. langley didn't like them very much.) They
were also the first people to build and used a wind tunnel (they built
three in total) to any advantage.

The "sail as a foil" convention can not really be tied down easily, but
the oldest paper in my library is from the mid-teens and contains some
things that are now known to be in error. A book that I have was
written in the mid-twenties and it is hard to tell the difference
between the going to weather part of this book and my newer ones.

From the things that I was taught by much older people about a half a
century ago, the understanding of the function both square and
fore-and-aft rigged sails is not recent, but the language to describe it
is (realiviely).

Matt Colie
Lifelong Waterman, Licensed Mariner and Perpetual Sailor

Axel Boldt wrote:
Thanks a lot for the illuminating answers. I read somewhere that the
"sail-as-airfoil" trick is a rather recent one, and that formerly
people would just let the wind push them around. Is that true, and if
yes, how recent is the invention?

Thanks,
Axel