02-07-2012, 10:58 PM
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#11 (permalink)
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A Legend in his Own Mind
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I built a (soft water) sail boat that went just under three times windspeed, called the Windrocket. Ice boats and land yachts can do about 8 times wind speed. I doubt that the A2 creates enough lift vectored in the right direction to gain enough range to make up for the weight of the hoop and the unfavorable aerodynamics on bad points of sail. But the first one would definitely work as a land yacht.
On almost all of these craft that go faster than the wind, the true wind must come from roughly abeam to go fastest. (This puts the apparent wind well forward of abeam.) The machine that Niky showed, however, actually goes faster than the wind when going directly downwind. My boat would do better than windspeed down wind (as will an iceboat) on a velocity-made-good basis. (I'd sail 45 degrees off the wind for a while, tack and sail to the other side of straight downwind. I'd travel 1.414 times as far as straight downwind, but would go double windspeed over the water.) The downwind sailer in Niky's pic doesn't need to tack. Not all that fast on other points of sail, but a neat trick.
I've toyed with the idea of making a practical landsailer that would run on north south tracks in the midwest. It could haul freight from Chicago to New Orleans.
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02-08-2012, 12:59 PM
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#12 (permalink)
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Master EcoModder
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An Amick-like design could certainly work for me, since I live on the east side of the Sierra Nevada. A lot of travel is north-south, and we get frequent strong winds down out of the mountains, which Mark Twain described thus:
Quote:
But, seriously, a Washoe wind is by no means a trifling matter. It blows flimsy houses down, lifts shingle roofs occasionally, rolls up tin ones like sheet music, now and then blows a stage-coach over and spills the passengers; and tradition says the reason there are so many bald people there is, that the wind blows the hair off their heads while they are looking skyward after their hats. Carson streets seldom look inactive on summer afternoons, because there are so many citizens skipping around their escaping hats, like chambermaids trying to head off a spider.
The "Washoe Zephyr" (Washoe is a pet nickname for Nevada) is a peculiarly Scriptural wind, in that no man knoweth "whence it cometh." That is to say, where it originates. It comes right over the mountains from the West, but when one crosses the ridge he does not find any of it on the other side! It probably is manufactured on the mountaintop for the occasion, and starts from there. It is a pretty regular wind, in the summer-time. Its office-hours are from two in the afternoon till two the next morning; and anybody venturing abroad during those twelve hours needs to allow for the wind or he will bring up a mile or two to leeward of the point he is aiming at. And yet the first complaint a Washoe visitor to San Francisco makes, is that the sea-winds blow so, there! There is a good deal of human nature in that.
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02-08-2012, 02:33 PM
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#13 (permalink)
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A Legend in his Own Mind
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Great quote -- that man could certainly write well.
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02-26-2012, 01:13 AM
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#14 (permalink)
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EcoModding Lurker
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cool cars
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02-26-2012, 09:11 AM
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#15 (permalink)
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Gen II Prianista
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A fanciful and impractical play thing.
There is a long history of wind powered vehicles that are justifiably lost
in the dustbin of history.
Perhaps the most telling image is this one, now more than 370 years old:
Flora’s Wagon of Fools, (Hendrick Pot, 1640.)
A viciously satirical allegory for the 1630s Dutch Tulip Bubble, which is to say
foolishness run amok.
Last edited by Rokeby; 02-26-2012 at 09:37 AM..
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02-26-2012, 02:55 PM
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#16 (permalink)
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...beats walking...
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...likewise, we haven't seen another wind-sail boat like Jacques Cousteau's CALYPSO have we?
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02-26-2012, 05:40 PM
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#17 (permalink)
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Gen II Prianista
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Do you mean the Alcyone?
Alcyone with modified Magnus effect "lift" generators.
Picture from here, which has a pretty good write up.
You'll find that the Costeau arrangement is frequently called "turbosails."
Here's a description of how the "turbosail" works.
Last edited by Rokeby; 02-26-2012 at 05:49 PM..
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02-26-2012, 06:13 PM
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#18 (permalink)
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...beats walking...
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...that's the one I couldn't remember, Thanks!
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02-27-2012, 03:56 PM
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#19 (permalink)
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A Legend in his Own Mind
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Quote:
Originally Posted by Old Tele man
...likewise, we haven't seen another wind-sail boat like Jacques Cousteau's CALYPSO have we?
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I'm guessing by wind-sail you mean wing-sail? There have been quite a few wing-sail boats (also called rigid airfoil boats, etc). My Windrocket was one.
The Windjet page on softwater boats shows a few others.
One that had a little commercial success was the Planesail:
I built an RC version (about 3' tall) of a boat vaguely like the Planesail, and had intended to commercialize it after commercializing the Windrocket. Like the Planesail, its wing was self-trimming (whereas the Windrocket was manually trimmed... and sailed much like other fast sailboats -- just faster and with more of a Jeckyl/Hyde personality.) In mine, the self-trimming was strictly aerodynamic, so that as you steered the boat under the wing, the wing would maintain a set angle of attack with the wind. The RC boat could be quickly stopped or reversed, both of which are very hard to do with a soft-sail boat. The Planesail added a layer of automatic control to the aerodynamic control, so that, for example, as wind sped picked up , the angle of attack would be reduced automatically to prevent capsize, etc.
Where rigid wings are indespensible is in very fast sailboats. In slow boats (most typical cruisers and racers) that cannot sail at multiples of windspeed, it is easy enough to get any desired amount of lift (used as thrust in a sailboat, because the "wing" is on end) just by making the sail big. But in very fast boats, the limiting factor becomes the ratio lift over drag... and it is there that a rigid wing has a large advantage. In the Little Americas cup, if has been decades since a soft sail boat was competitive.
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02-27-2012, 05:35 PM
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#20 (permalink)
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Corporate imperialist
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Quote:
Originally Posted by ConnClark
I would also move that this is some what a viable technology and it doesn't belong in the Unicorn Corral.
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I agree.
It works far better than HHO or browns gas and is proven technology, just not widely used on land.
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