Directly UPWIND faster than the wind

Llyricist

I see that the term has changed from "Advance Ratio", which also refers to something else related to props, to vehicle speed ratio. Fair enough :)

spork

Quote by Llyricist

I see that the term has changed from "Advance Ratio", which also refers to something else related to props, to vehicle speed ratio. Fair enough :)

Yes, JB and I initially did refer to it as "advance ratio". I think this would be the ideal term if not for the fact that it's too easily confused with the advance ratio of a propeller.

rcgldr

Quote by CWatters

There is an easy way to understand the feasibility of the upwind cart.. That's to understand that individual blades of the prop do not move directly upwind. They are "tacking" in 3D.

Although propellers and turbines are more efficient than other aerodynamic devices, tacking isn't required for directly downwind or upwind vehicles. It could be possible to make a vehicle using a paddle wheel like setup or a treadmill with collapsable sails (no taching involved),, and although it wouldn't be as efficient, in principle it could work.

spork

A.T.

NALSA confirmed 2.1 windspeed, directly upwind:
http://www.nalsa.org/

They are at it again! A new record has been set, this time sailing dead upwind...that's right, directly into the wind (not tacking). The NALSA Board of Directors has ratified the following two records achieved by Rick Cavallaro on New Jerusalem Airport near Tracy California on June 16, 2012, with the wind turbine driven sailing craft, Blackbird. Mr. Cavallaro achieved a maximum boat speed to wind speed ratio of 2.1:1 while sailing directly into the wind and a maximum speed in a wind turbine driven sailing craft of 22.9 mph on a different run.

r-j

This should be on television!

A.T.

Quote by r-j

This should be on television!

The downwind part was on Discovery:

The upwind record was mentionend briefly on CCN:

They tried to get on Mythbusters, but there is not enough fire and explosions in it.

r-j

I know somebody in SF that would so fund a documentary on this, do they have a media contract yet?

spork

Quote by r-j

I know somebody in SF that would so fund a documentary on this, do they have a media contract yet?

We'd be happy to have someone do a documentary on the project.

Quote by A.T.

They tried to get on Mythbusters, but there is not enough fire and explosions in it.

Just a slight correction... We tried like crazy to get Mythbusters to take on the myth that you can't make a wind powered vehicle go downwind faster than the wind. We never entertained ideas of getting our ugly mugs on Mythbusters. We finally gave up on the idea that they'd do it, so we built one ourselves.

rcgldr

I recall that CNN clip. They mentioned 2x faster than wind, but failed to mention it was upwind.

spork

Quote by rcgldr

I recall that CNN clip. They mentioned 2x faster than wind, but failed to mention it was upwind.

Yup. The whole idea that we built a wind powered cart that could simply go faster than the wind makes it sound even more pointless than it was.

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Llyricist	Directly UPWIND faster than the wind I see that the term has changed from "Advance Ratio", which also refers to something else related to props, to vehicle speed ratio. Fair enough :)

rcgldr Recognitions: Homework Help	I recall that CNN clip. They mentioned 2x faster than wind, but failed to mention it was upwind.

spork	Attached Thumbnails