November 1st, 2008 - Open Knowledge — LiveJournal
Nov. 1st, 2008
06:46 am - Self trimming wing sail
From the maker:
Since the invention of aircraft, a similarity has been noticed between the operation of sails on boats and the function of wings of aircraft. Sails on boats provide thrust in a horizontal direction derived from moving air, and wings on aircraft provide “lift” in a vertical direction to support a plane in the air, also from moving air (relative to the plane).
In order to fly, wings had to have a certain degree of efficiency, and some experimenters have realised now that aircraft-type wings could be used on a boat and would be more efficient than sails.
Having tested wings on boats in place of sails (“wingsails”) designers noticed another feature used on aircraft that would be useful to use in conjunction with wingsails – controlling the wingsail with another smaller surface mounted behind or in front of it (a “tail”).
There are many examples of tails used to control the direction of bodies both in the water and in the air, and aircraft use them to adjust, to a precise degree, the lift or (angle of attack) of their wings.
If a tail is used attached to a boats’ wingsail, it can adjust the wing perfectly to every small change of wing direction, in this way relieving the sailor of this task, which is mostly guesswork and at best very approximate, and it can perform that job much better than any sailor can do.
Such a wingsail/tail combination is referred to as a self-trimming wingsail.
Come join us for a leisurely stroll around Golden Gate park! We’ll be meeting at the entrance of the Conservatory of Flowers. See here for details:
After the hike, we’ll meet for lunch at the Beach Chalet restaurant:
If there’s a small amount of rain (drizzles), the hike will go as planned. In the event of large amounts of rain, we’ll skip the hike, and meet directly at the Beach Chalet for lunch at 12:30 p.m.
The Beach Chalet is located where Golden Gate Park meets the Pacific Ocean above the Park Visitor’s Center.
1000 Great Highway @ Ocean Beach
San Francisco, CA 94121
If you have any questions, give me a call 650 773 6419.
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