"AC" wrote in message ...
The answer to your question, is yes. Sails are made from dacron for ease of
handling & shortening, and cost. Many examples of rigid-wing vessels exist,
I suggest doing a search on that. They often use fairings at the leading
edge, or movable trailing edges to fine tune the foil.

An aircraft can fly inverted, because its angle-of-attack changes to suit
the correspondingly lower efficiency of the foil in this position. As others
have noted, acrobatic craft often employ nearly symmetrical foils for this
reason. A normally profiled foil will fly inverted, but inefficiently, and
at a much lower VMG due to the increased drag from the higher angle of
attack.

The profile of the wing only handles the Drag, not Lift.

Angle of attack handles Lift (see the Cl/Alfa diagram)!

Try some "Bernoulli experiments for kids",and you will reach a better
understanding.


Bernoulli experiments are all due to other physical effects like
boundary layer (asymmetric) separation, entrainment of air, Coanda
effect etc.

The thought that " a change in air velocity will change the pressure"
is not real, only mathematic relations.


Jan-Olov Newborg