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Gilligan wrote:
The USS Constitution demonstrated that in light air, the speed of the ship could be increased by spraying water on the sails. Documented he http://www.history.navy.mil/photos/e...a/const-es.htm Sure. Well known and oft-practiced trick for getting a bit of speed out of natural fabric sails. I don't know when it was first used, possibly back when they started weaving cloth strong enough that sails no longer needed leather reinforcing strips (the Viking Age tape-drive laminate). Think of this. The sail has the most power delivered to it when the residual wind velocity is zero after interacting with the sail. I think that's a mistaken assumption. The sail has the most power delivered to it when it is developing max differential pressure theoretically possible for it's density & initial velocity. The maximum pressure differential occurs for any given windspeed when the airspeed on the low pressure side of the sail is zero. No, the maximum differential pressure possible is when the LP side is a vacuum. Velocity can produce pressures lower than ambient; air that is sitting still cannot. .... If the velocity on the "low pressure side" equals the velocity on the high pressure side there is no lift. C'mon, you're not thinking in vectors! What if that velocity is equal to, or faster, than on the HP side and in a different direction? DSK |
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