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Old 08-02-2012
eyytee eyytee is offline
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Re: speed vs wind

Quote:
Originally Posted by MikeWhy View Post
I remember reading about a windmill sort of contraption that used wind power to drive the wheels mechanically. I don't recall the details, but think this moment that its claim to fame was its ability to exceed windspeed directly upwind.
I guess you mean the Blackbird:
http://en.wikipedia.org/wiki/Blackbird_(land_yacht)

It went directly downwind at 2.8 x windspeed, and direclty upwind at 2.1 x windspeed:
DownindRecord


Quote:
Originally Posted by MikeWhy View Post
(In all cases, the apparent wind is the issue. Dead downwind, you can never exceed windspeed. Upwind, though, the v-squared relationship is beneficial, although aero drag also increases at that same rate.)
A conventional sail craft can neither go directly upwind (at any speed), nor directly downwind faster than wind. Using rotors, like the Blackbird, you can do both.

Last edited by eyytee; 08-02-2012 at 10:21 AM.
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