Re: sailing upwind?

[Hugh Haskell <hhaskell@MINDSPRING.COM>]

> On Thu, 30 Dec 1999, P. O. Johnson wrote:
>
>  > Experimentally confirmed? I thought that was true only in cartoons.
>
> Not at all; you just have to have a sail that manages not merely to
> *stop* the air blown at it by the fan, but to "turn it around and send off
> in the other direction.  One that should do this quite nicely might look
> like this:
>
>             -
>               \
>                |
> air   -->     /
> from  -->  --      <- sail
> fan   -->     \
>                |
>               /
>             -
>
> The same effect *can* be accomplished by simply turning the fan around and
> losing the sail, but doing it this way is perhaps a better illustration of
> the power of momentum conservation as an analysis tool.
>
> John Mallinckrodt      mailto:ajm@csupomona.edu
> Cal Poly Pomona          http://www.csupomona.edu/~ajm

This shouldn't be too surprising. It is exactly how thrust reversers
on jet engines work.

Hugh


Hugh Haskell
<mailto://hhaskell@mindspring.com>

Let's face it. People use a Mac because they want to, Windows because they
have to..
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