Spinning Metal Sails Could Slash Fuel Consumption, Emissions On Cargo Ships (sciencemag.org) 170
sciencehabit shares a report from Science Magazine: U.K. soccer star David Beckham was known for "bending" his free kicks over walls of defenders and around sprawling goal tenders, thanks to a physical force called the Magnus effect. Now, the physics behind such curving kicks is set to be used to propel ocean ships more efficiently. Early next year, a tanker vessel owned by Maersk, the Danish transportation conglomerate, and a passenger ship owned by Viking Line will be outfitted with spinning cylinders on their decks. Mounted vertically and up to 10 stories tall, these "rotor sails" could slash fuel consumption up to 10%, saving transportation companies hundreds of thousands of dollars and cutting soot-causing carbon emissions by thousands of tons per trip.
Rotor sails rely on a bit of aerodynamics known as the Magnus effect. In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows. If the ball were not spinning, air would stream straight past it, creating a swirling wake that would stretch out directly behind the ball like the tail of a comet. The turning surface of a spinning ball, however, drags some air with it. The rotation deflects the wake so that it comes off the ball at an angle, closer to the side of the ball that's rotating into the oncoming air. Thanks to Isaac Newton's third law that every action must have an equal and opposite reaction, the deflected wake pushes the ball in the opposite direction, toward the side of the ball that's turning away from the oncoming air. Thus, the spinning ball gets a sideways shove.
Rotor sails rely on a bit of aerodynamics known as the Magnus effect. In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows. If the ball were not spinning, air would stream straight past it, creating a swirling wake that would stretch out directly behind the ball like the tail of a comet. The turning surface of a spinning ball, however, drags some air with it. The rotation deflects the wake so that it comes off the ball at an angle, closer to the side of the ball that's rotating into the oncoming air. Thanks to Isaac Newton's third law that every action must have an equal and opposite reaction, the deflected wake pushes the ball in the opposite direction, toward the side of the ball that's turning away from the oncoming air. Thus, the spinning ball gets a sideways shove.
Round and round... (Score:5, Funny)
Re: Round and round... (Score:3, Insightful)
Or they could just use old fashioned sails and cut fuel consomption by 100%.
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Re: Round and round... (Score:5, Informative)
They don't really use "oil" on cargo ships, its more like asphalt tar. Since the oceans don't have any governmental bodies setting emissions standards, shippers are free to use the nastiest, foulest leftovers of distillation in their power plants. That crap'll be on the market decades, if not centuries, after the last of the light sweet crude runs out.
You're not competing against expensive "clean" fuel here. You're competing against the cheapest crap that'll burn.
Re: Round and round... (Score:5, Informative)
Re: Round and round... (Score:5, Informative)
There's increasing talk of regulating the fuel. Ships are already required to burn cleaner fuel near coastlines in a lot of places and some have been caught not doing this. I wouldn't be surprised if the end result is a requirement that any ships going to or from a nation's ports or travelling through its territorial waters must only burn cleaner fuel, because that would be a lot easier to enforce. That gives a big incentive to switch to more efficient propulsion.
There have been a few designs in recent years for ships with electric drivetrains, large solar arrays and wind turbines, and backup diesel generators (or primary diesel generators that are only expected to provide 50-90% of the total power depending on conditions).
Re: Round and round... (Score:5, Informative)
There's increasing talk of regulating the fuel.
There's no "talk" on the fuel side of the regulation. There's actual action which refineries are already gearing up to support. One big one is by 2020 there needs to be a 3% reduction in sulfur in open oceans (down to 0.5%). The last change happened only in 2015 where controlled area sulfur was reduced by 0.9% down to 0.1%.
There is talk on the burning of it side though with the actual emissions not being regulated yet. It's much easier to regulate what goes in the tank than what comes out of the exhaust in the middle of the ocean.
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It's insane [industrytap.com]
Re: Round and round... (Score:4, Insightful)
Oil is not expensive enough. It's just a matter of time.
Oil will be "expensive enough" when something comes along to replace it. We don't burn oil to be assholes to the environment, we burn it because it's the best we got right now. Wind power might replace it, but then so could nuclear power. It's not like nuclear propulsion is a new technology.
I know someone just fainted upon reading the idea of civilian shipping powered by nuclear reactors. We have a choice. We can burn oil, use nuclear power, or leave vital shipping to the whims of the weather. Nuclear powered shipping has been tried before and failed primarily on poor ship design and politics, not for any technical reasons. We've got better reactors now so it's not like they are going to melt down or something.
I've heard of proposals for a lead cooled reactor, where the reactor is surrounded by molten lead. It's probably heavy as fuck but it's in a ship, so no one cares. If there's a problem the reactor is shutdown and the lead solidifies, sealing everything inside. The lead is a neutron reflector, so if it leaks away the reactor cannot function. Probably not a good thing if your coolant leaks away but at that point the ship is likely taking on water, and water makes a good radiation shield. If a leak is detected then shut it down and dump water on it, that will solidify the lead and seal it up. There's other reactor types that could work, but lead cooled has been tried and shown to work. Nuclear powered ships can't be any worse than oil fired ships, can they?
Again it's oil, nuclear, or leaving vital shipping to the whims of the weather. There might be some future alternative but those are our choices right now.
Re: Round and round... (Score:5, Interesting)
You again with your half knowledge. Nuclear marine propulsion is so horribly expensive only a few navies can afford to operate that. There has been only handful of merchant ship with a nuclear reactor, and only two of them actually ever carried cargo. You see, marine reactor fuel is highly enriched, which is very expensive, and the reactor life span is ridiculously short compared to a marine diesel. After decomissioning the whole reactor together with the coolant loop have to be cut out and buried somewhere - recycling is not possible. The daily operating expenses for the Sevmorput is around 90k USD. A conventional freighter with a similar capacity has only a third of these daily costs and is permitted to any port.
Re: Round and round... (Score:4, Interesting)
Nuclear marine propulsion is so horribly expensive only a few navies can afford to operate that.
It is now. What happens to the price of nuclear propulsion when the oil runs out? People want their fresh bananas and coffee, and if it means using nuclear power then it's going to happen. Shipping by oil fired ships used to be real expensive at one time too. People figured out how to make it cheap. There's nothing that makes nuclear power inherently "horribly expensive". It's expensive now because there's probably only one or two such reactors built every year. If built one or two per month on an assembly line, like we do with jetliners, then they get cheaper. Not "cheap" because anything that size is expensive.
You see, marine reactor fuel is highly enriched, which is very expensive, and the reactor life span is ridiculously short compared to a marine diesel.
The US Navy uses highly enriched fuel in their reactors because they need to operate their reactors in ways that a civilian ship doesn't. Highly enriched fuel solves a lot of problems that a low enriched fuel doesn't have. One problem highly enriched fuel solves is the production of xenon if output power is increased quickly, which is easy to solve in a commercial shipping environment, just don't stomp on the accelerator. If some idiot does get a lead foot then they'll just have to sit still for a few hours for the xenon to decay away.
The daily operating expenses for the Sevmorput is around 90k USD. A conventional freighter with a similar capacity has only a third of these daily costs and is permitted to any port.
It costs only three times as much to operate? Well then, all we need to see for civilian marine nuclear propulsion to be viable is oil prices to triple. The problem on costs isn't nearly as bad as I thought. We'll see civilian nuclear powered container ships in no time then.
Oh, and being unable to put a nuclear powered ship in a port is real easy to solve if it's carrying coffee and iPhones. That's a political problem, and those can be solved in a single election.
Re: Round and round... (Score:5, Interesting)
It isn't. Even biodiesel and GTL is much cheaper than nuclear propulsion so if oil becomes too expensive, synthetic fuels and biofuels will be used. Nobody wants to pay for civilian nuclear marine propulsion except Russia, and they need it for the Arctic region.
They weren't. Just somewhat more complicated to build than steam turbine ships that used coal.
There is a lot of things that makes nuclear power inherently horribly expensive. First, everything has to be radiation-hardened because neutron flux damages pretty much every material. Second, the manufacturing tolerances have to be much lower. Average manufacturing quality won't do because subsequent repair is difficult to impossible. Third, for marine propulsion the fuel has to be highly enriched. People have been trying for over 60 years to make marine nuclear propulsion cheaper. Didn't work out and never will. We'll have fusion power sooner than that.
Nope, the main reason why all marine reactors - and not just the US navy - use highly enriched fuel is the power density. Even the four merchant ships with nuclear propulsion I have mentioned previously used highly enriched fuel and so do all the Russian nuclear ice breakers. There is simply no room on a ship for a reactor that uses 2-4% enriched fuel - they would be seriously huge.
You seriously think that fuel is the only operational expense on a ship? It isn't, that's why you won't see nuclear powered container ships ever. The operating cost on Sevmorput is triple of the operating cost of a conventional freighter with a similar capacity, which is about the lower end as container ships go. Large container ships are still about half as expensive to operate as a nuclear power ship, but can easily carry 20x more stuff.
That ships already carried cargo - well, two of them did - and yet they weren't allowed to many ports. This cannot be solved in a single election because maritime law is involved, and that is international.
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All you have to say that civilian nuclear power shipping won't happen is either it costs too much or laws/politics/regulations won't allow it.
The problem with costs are solvable, if only because oil prices get high enough to make nuclear power viable. Saying that there is no room on a ship for a nuclear reactor is idiotic. There might not be enough room for a nuclear conversion but there will be enough room if designed with nuclear power from the start. Even then so what if they need highly enriched fuel
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Even without subsidies it will be cheaper than nuclear.
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EU has been overproducing food for quite a while. Many farmers get subsidies for not producing anything at all. It won't replace all crude, but it would easily be enough for marine propulsion if cars switch to electric. Matter of fact, it wouldn't even be biodiesel. Since marine engines use petrochemical waste as fuel and have to preheat it due to its viscosity, straight vegetable oil, even waste vegetable oil will be fine, no need for any transesterification. It would also burn much cleaner and it would al
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Again - its all lies and propaganda. It takes something like 2 barrels of crude (in fertiliser and farm machinery) for every barrel of Biodiesel produced.
That fact alone should make you think twice about what has been said.
And thats before you get into the fact that plants are not as efficient as solar cells in converting the suns energy into usable power.
Meanwhile, a safe betavoltaic/alphavoltatic battery, that could power an iPhone for 25 years uses about 1c of raw materials, that are abundant in every ho
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Nuclear marine propulsion is so horribly expensive
Not really. The NS Savannah [wikipedia.org] wasn't cost competitive with oil. But it was a demonstration project and was decommissioned two years before the Arab oil embargo. Had it hung on for another two years, it would have competed effectively on fuel costs*.
You see, marine reactor fuel is highly enriched
Not necessarily. The Savannah ran with commercial-grade (power plant) fuel.
*But not operating costs. Because it was designed before containerized cargo and automated loading became a thing, it's labor costs (loading/unloading) were still high.
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Ferries around here are beginning to look into batteries. The first is already being built, and It's expected that all short-range routes will have converted in the next couple of decades.
Container and cruise ships are a different game. I think they are going to need synthetic fuel for the foreseeable future.
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That's easily solvable, and has been for a long time. It's just we are not keen to actually take the required action.
Basically you revert to 19th century gun boat diplomacy. That is we sail some ships up to the Somali coast and just pound the coastline with you naval guns till they stop coming. Further any pirates seen actually on the ocean, you just mow them down with your miniguns, no questions asked.
I guarantee you that the Somali pirate problem will be solved very quickly if this is the approach taken.
Rounds and rounds (Score:2)
You're sure that isn't the sort of thing that would cause more problems than it solves? We're not exactly ten for ten on those kind of violent interventions. Probably the cost of a bullet is pretty close to the cost of a meal in those parts, without considering the money spent to put a warship and trained soldiers there to fire said bullets. It's also possible that some of these people might shoot back. I'm not saying that your plan is bad, but I think you should maybe revisit the idea that shooting people
Re: Round and round... (Score:5, Informative)
It's going to be different from how you expect. I did the numbers once, and it came out something like less fuel is expended shipping white goods from the China shore to the UK shore than is spent delivering the white goods from the warehouse to your home. It was a factor of 3 IIRC. In other words, the delivery infrastructure will move to all electric long before we stop shipping things by sea in oil fuelled ships.
Those things are outrageously efficient. Even the engines themselves reach raw efficiencies of over 50%. By comparison the best full sized utility scale combined cycle plants manage 60 and normal coal fired powerstations are around 40 or so. And then they go slowly. And carry crazy huge amounts.
Re: Round and round... (Score:5, Informative)
There has long been talk of building modern windjammers, but it never happens.
There are reasons it doesn't happen, such as:
1. Bridges
2. Container cranes
3. Fixed port schedules
Kite sails avoid these problems, catch faster wind at higher altitude, and have the further advantage of already being commercially deployed [wikipedia.org].
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There has long been talk of building modern windjammers, but it never happens.
There are reasons it doesn't happen, such as:
1. Bridges
2. Container cranes
3. Fixed port schedules
1. Most trading ports can be accessed without passing under bridges. Some ports up river used to involve a bridge (eg Bristol, London) but such bridges were made very high to allow sailing ships to pass. But then the ports generally moved down-river to nearer the sea (eg Avonmouth, Tilbury), for reasons of depth.
2. Easily soluble. Not every ship carries containers anyway, some carry bulk.
3. What has that got to do with it? No modern sailing ship would wait for the right wind to enter or leave port - they w
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The fastest China Clippers had limited cargo capacity and could average a bit better than 15 knots if the winds stayed favorable. Modern container ships mostly travel at 18-24 knots without needing luck with the wind. And they can operate on something resembling a schedule.
OTOH, with a robot crew, maybe it doesn't matter all that much if your (non-perishable) cargo takes a long time to wend its way from Shanghai to London.
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A quick google search shows many of these
Your link does not work, but yes rotor ships have been tried before. The Barbara of 1927 was probably the best known.
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Otherwise known as ... (Score:3)
..."English," in tennis and pool.
Re: Otherwise known as ... (Score:3)
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..."English," in tennis and pool.
But that's just not cricket!
Table Tennis players know about this. (Score:2)
Modern table tennis bats can impart a large amount of spin to the ball, causing it to drop quickly or float, depending on the direction of imparted spin.
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of all the sports that employ this, why reference table tennis? :)
baseball => curve ball
tennis => drop shot
i'm sure there are other examples, but TT is pretty niche (though fun)
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of all the sports that employ this, why reference table tennis? :)
baseball => curve ball tennis => drop shot i'm sure there are other examples, but TT is pretty niche (though fun)
Perhaps because the effect is so dramatically noticeable in table tennis. Somewhat less so in tennis, and much less so in baseball.
The purpose of the spin in the tennis drop shot isn't to generate a Magnus effect, which actually holds the ball aloft longer. The backwards spin on the ball is used to decrease the bounce forward and may even cause the ball to bounce backwards after hitting the ground. The Magnus effect is used in tennis in the serve and forehand topspin.
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Great (Score:2)
Re:Great (Score:5, Informative)
Well if you read the article (ridiculous, I know)...
Rotor sails are generally effective if the wind is moving faster than 18 kilometers per hour—roughly 10 knots—and is blowing across the ship’s bow at an angle of at least 20. Ships often encounter such conditions on northern Pacific and northern Atlantic shipping routes
Power generation? (Score:2)
Seems like a rotor sail could drive a generator collinear with the axis of rotation no matter what direction the wind comes from, then apply it directly to propulsion using electric drive.
Worst case, the wind comes from the front, but instead of just being a counter-force, it contributes to forward motion to some degree.
And of course, if there are lossy angles, you pull them down.
Just speculating.
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The wind doesn't make the rotor sail spin more. In fact, thanks to the faster airflow and friction, it'll probably slow it down. All the spin comes from an electric motor, so it would be more efficient to just connect the electric motor directly to your generator. Then I guess you could supply the motor's electricity from the generator.
Hmm, there ought to be a law against that...
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Not what I was thinking, then. This is. [thegreenage.co.uk]
Wind comes from any angle, it turns the shaft. The shaft turns a generator or alternator, and the resulting power gets fed to the screw(s.)
A ship's mass gives a wind turbine a relatively fixed reference. So as long as there's wind, there's power generation.
The process I describe turns wind energy in any direction into motive power in the desired direction.
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This is exactly how that land sail vehicle "going downwind faster than the wind" works. It takes the angular for used in tacking and puts it to work as angular blades on a windmill, then attaches it to the wheels.
The question here is how large must the sails (or bladez) be to get a noticable input of energy at that cargo ship scale, and how durable are they for long term use.
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I'm not sure what you're saying, but in a sailboat sailing into the wind works because the sails, when filled with air, make good airfoils.
Not happening. (Score:2, Interesting)
saving transportation companies hundreds of thousands of dollars and cutting soot-causing carbon emissions by thousands of tons per trip.
Ha! The engines are already terribly inefficient and they could easily be optimized a little and do both of these things. So why not do it? Simple, it has to always work because time is money. Besides, we would all be better off if we connected all six continent with a single intercontinental railroad. Not only would things arrive faster, it would be better for the environment.
Re:Not happening. (Score:5, Informative)
Ha! The engines are already terribly inefficient and they could easily be optimized a little and do both of these things.
Well, no. The most efficient internal combustion engines on the planet are in container ships. They are ultra-large, ultra-low RPM diesels, and they can reach around 50% efficiency.
Re:Not happening. (Score:4, Informative)
What are they made of,
Steel.
as materials normally limit efficiency of the Otto cycle to 35%.
They're supercharged two stroke diesels, not otto cycle engines.
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My last encounter with a supercharger was the Aston Martin I followed from Uttoxeter to the M1 on Sunday.
Could tell it was about to accelerate a third of a second before it did because of that beautiful sound. Couldn't keep up with it when it did that, but kept catching up again when it hit the next traffic.
Damn thing nearly made me crash, I was keeping pace with it around and coming off the roundabout at the end of the A50 and found out my car doesn't hold the road at those speeds. I blame the rain making
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Think we can shoehorn it into a mustang?
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Ah, I see. You had me going for a bit. I thought you were serious about thinking of something that no one else thought of in 150 years of burning oil to transport goods. That's cute. Though in the future you should end your post with [/sarcasm] so people don't think you've gone insane or something.
Popular Science mag back in the 60s? (Score:2)
I seem to recall reading about this as a kid back in the 60s in Popular Science. It was supposed to make shipping freight cheaper. But for some reason it never caught on. Is this round 2, fifty years later?
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I seem to recall reading about this as a kid back in the 60s in Popular Science. It was supposed to make shipping freight cheaper. But for some reason it never caught on. Is this round 2, fifty years later?
According to the article the reason why it didn't catch on was the cost of running the engine to turn the sail. Modern material science allows them to be built out of lighter materials like carbon fiber, etc. They say that it takes about one-third the power to turn it, making it more efficient and the economics more viable.
That being said, it still needs a steady 20+ knot wind blowing perpendicular to the line of travel so it wouldn't be useful for all shipping lanes, limiting it's current application. Pe
Re:Popular Science mag back in the 60s? (Score:4, Informative)
That being said, it still needs a steady 20+ knot wind blowing perpendicular to the line of travel....
That statement contradicts the article:
"Rotor sails are generally effective if the wind is moving faster than 18 kilometers per hour—roughly 10 knots—and is blowing across the ship’s bow at an angle of at least 20. Ships often encounter such conditions on northern Pacific and northern Atlantic shipping routes..."
Re: Popular Science mag back in the 60s? (Score:2)
To be fair, effective and âoemore total efficiencyâ are not the same.
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I seem to recall reading about this as a kid back in the 60s in Popular Science. It was supposed to make shipping freight cheaper. But for some reason it never caught on. Is this round 2, fifty years later?
And I recall reading it in the 80s in Popular Science. I'm sure we'll be reading about it in another 20 years.
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I seem to recall reading about this as a kid back in the 60s in Popular Science. It was supposed to make shipping freight cheaper. But for some reason it never caught on. Is this round 2, fifty years later?
I seem to recall reading about this as a kid back in the 60s in Popular Science. It was supposed to make shipping freight cheaper. But for some reason it never caught on. Is this round 2, fifty years later?
I've read of this before, I gave it some 20 years ago. 60's sounds reasonable as it's such a simple a techonolgy. Popular Science does have a tendency of covering an new produce (what's new) that never makes it to the market/masses.
right up there (Score:2, Insightful)
Rotor ships are right up there with Sterling engines, fuel cells, and a lot of other "great ideas" that turn out not to be so great in practice. When a fairly simple technology like this hasn't caught on for over a century, there's probably a good reason for it. My guess is in the case of rotor ships, it's higher purchase price, higher maintenance costs, higher weight, higher center of gravity, vulnerability to high winds, and insufficient savings under real weather conditions.
Re:right up there (Score:4, Informative)
Or you could actually read the article and see that it's because better materials, higher cost of fuel, and greater pressure on emissions are starting to make it an attractive proposition.
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I read the article. Unlike you, who seems to uncritically swallow every b.s. the press presents you with, I actually thought about it too.
Maintenance (Score:5, Interesting)
It's the same problem the NS Savannah [wikipedia.org] encountered. Making it nuclear power dropped its fuel costs to near zero. But the increased labor required to operate and maintain the nuclear reactor ended up making it more expensive than a cargo ship powered with fuel oil.
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Surely they can figure out a way to have the bearings and such not exposed to salt water spray. Not to say they'll be zero maintenance, but that just seems like a solvable problem.
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When a fairly simple technology like this hasn't caught on for over a century, there's probably a good reason for it.
Just like fuel injection....
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You don't see the difference between big, showy perpetually "almost ready" technologies like rotor sails, and invisible internal improvements like fuel injection? Seriously?
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Mechanical fuel injection 'caught on' during WWII. For aircraft, basically as soon as it was feasible. EFI caught on as soon as it was feasible, for racing. 10 years later for emission control.
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Mechanical fuel injection 'caught on' during WWII. For aircraft, basically as soon as it was feasible. EFI caught on as soon as it was feasible, for racing. 10 years later for emission control.
And other technology that hasn't caught on for decades may also catch on once they become feasible too.
To counter the GP's claim, just because something didn't catch on first time it was invented doesn't prevent it from catching on at some later stage when other external factors change.
If there's a good reason why this won't work I'm happy to hear it, but saying it can't work purely because it was tried once ages ago and failed is a bit short sighted.
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If you RTFGP, you'll see that materials are only one of many problems with rotor sails.
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When a fairly simple technology like this hasn't caught on for over a century, there's probably a good reason for it.
Yes because we know everything right off the bat. There certainly hasn't been any advances in transport that has gained wide spread adoption over half a century after the discovery of the mode of transport. /Sarcasm
For a practical example see Winglets. Invented in 1897, patented for aircraft use in 1930, didn't even get considered for passenger aircraft until the late 80s, and now because of the large fuel savings and stability you get for this over 100 year old invention you won't find a passenger aircraft
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There are actually surprisingly many aircraft without winglets. For example neither of the two latest Russian airliners have winglets, even though USSR has been one of the early adopters. SAS still has a lot of their B737 flying with clean wings, B777 and B787 don't have winglets (they have raked wingtips instead). Clean wings have their benefits, so winglets are always a trade-off.
Interesting footnote - Artillery (Score:3)
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And with a decent scope and light coming from the proper direction you can see it happen to a 22 bullet in flight. Just like artillery but on a smaller scale.
For a good visual example... (Score:2)
For a good visual example, watch the Veritasium video on the Magnus effect [youtube.com]. Not only does it explain the effect using a spinning basketball dropped off a dam, but it also has pictures of what these ships will look like with rotor sails.
+1 Informative (Score:2)
This is a 1920's invention (Score:3)
Holy crap! They discovered the curve ball! (Score:2)
Spinning Metal Sails (Score:3)
Of topic but... "Spinning Metal Sails": I was looking for a name for my Styx cover band.
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Works for me.
This is very interesting. (Score:2)
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That - just as the idea of using this effect as sails - isn't a new idea. It have been tried. The result: how do the wings of current airplanes look like?
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So, yes, the general aerodynamics of this is not much different than that of traditional wings, just the method of creating circulation.
This again? (Score:2)
The idea isn't new, the incredible claims aren't new and actually testing it isn't new either. What have changed since last time this was attempted and failed?
The Tail of a Comet (Score:2)
The wake behind a ball is NOT like the tail of a comet - the tail of a comet points (approximately*) away from the sun, not opposite to the direction of motion.
Comet tails are not caused by some kind of drag - the comet moves in a vacuum in (almost**) geodesic motion around the host star.
* Yes, there are actually two tails, dust and gas, directly not exactly away from the sun. The point is really that comet tails do not follow comets around the sun.
** M_comet/M_sun is normally pretty small, etc.
I thought there were large practical hurdles... (Score:2)
IIRC; There were some major mechanical engineering problems to be solved before the concept could be scaled up to the size needed for commercial shipping.
1) Freakin' huge tubes, essentially only mounted at one end meant doing some serious engineering on the drive motors, bearings and so on, so as to not snap off in bad weather. On
Its called a "curveball" (Score:2)
In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows....
This has to be the most Slashdot way ever to explain something that everyone who has ever played a sport ever [wikipedia.org] needs no explanation for.
Try not to maim yourself walking from your desk to bathroom today.
Re:More like odd shaped aerial propellers than sai (Score:5, Interesting)
What you want is mostly in the article.
“Our largest rotor sails can provide forward thrust equivalent of up to 3 megawatts of main-engine power while drawing less than 90 kilowatts of electricity,” Riski says.
The Emma Maersk, a recently launched cargo ship, boasts 111 MW of propulsion. It's likely that these rotary sails are indeed more efficient than an underwater propeller but unable to deliver the same power as an underwater propeller without covering the deck in rotary sails. Having a few to lower fuel costs of the less efficient underwater propeller is simply economical. If it's actually economical, you'll see it on more and more ships just like those little winglets on airplanes.
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Kites sure seem to have more potential with significantly lower capital expense and proportional benefits. (5-10% reduction in fuel consumption)
https://en.wikipedia.org/wiki/... [wikipedia.org] Ironically, check out the "see also" section...
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How tough would they be? Rotors could last many years.
And kites can crash in spite of best efforts. They would need some kind of recovery yardarm. This assumes crashing doesn't rip it off the ship or destroy it.
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Well of course they are. If they provide 3 MW but only need 90 kW input, most of the energy is clearly coming from somewhere else i.e. the wind.
The problem with these sails is that they can only produce thrust at right angles to the direction of the wind and, of course, there has to be wind. This is the main reason why you need engines too.
One million dollars! (Score:2)
This is like Dr. Evil who held the world hostage to his Evil scheme, that is, until he was paid . . . one . . . million . . . dollars! Number Two had to take him aside to explain that a person having been in frozen suspension since the 60's might not be aware that one million dollars is not really all that much money taking inflation into account.
So this device cuts "soot causing carbon emissions" by "thousands of tons", "slashing fuel consumption by 10%"?
Such suggests that the emissions are in the t
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If you think it's insignificant, I'm sure we can somehow arrange to have a few thousand tonnes of it dumped in your yard.
But it would not all be in his yard. A few thousand tonnes of anything, even stuff with "green" labels on it, in someone's yard would do them no good. Straw man.
Compared with a full sailing ship, which would not need to be that much different in outline from a rotor ship (in fact it would be simpler), and would save far more, a 10% saving looks rather underwhelming.
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Another good read is How to Avoid Huge Ships [amazon.com] by John W. Trimmer.
Re:The history of container ships... (Score:5, Funny)
I've heard that the United States Navy has just put in a special expedited order for 50,000 copies of this book.
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Last I heard the ship carrying the books hit an iceberg, is taking on water, with a fire on board, and was surrounded by sharks. No word yet if the sharks had fricken lasers on their heads.
The US Coast Guard, US Army and US Air Force were sending aircraft to the area to assist in fighting the fire and treat the injured. They had to turn back because they hit A Flock of Seagulls. Not birds, the 1980s rock band. The band's record label and agent were not available for comment. The B-52's also had to turn
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"Why wait for shipping? Start listening today!"
Re:The history of container ships... (Score:5, Funny)
Personally, I enjoyed this review:
I wish I'd read this highly informative title in the late 90s. My husband and I both suffer from PTHSCD (post-traumatic huge ship collision disorder) which we acquired while piloting our own huge ship. I remember it like it was yesterday -- we were carrying over 3 million gallons of blue paint to Morocco when, wouldn't you know it, we collided with our competitors. They had about 4 million gallons of red-brown on board, and before we knew it, we were all marooned.
This one was also quite a helpful review:
When on my jet ski in the Chesapeake bay this summer I was confronted by a huge ship moving up the channel. You can imagine my horror when I realized I had only 1 hour and 45 minutes or so before the lumbering behemoth was sure to pass through my area. With no place to hide and only a water jet propelled small craft beneath me for transport, I quickly withdrew my Kindle Fire from the storage compartment beneath my seat and preceded to read the book How To Avoid Huge Ships. One hour later and with only 45 minutes to spare, I implemented the expert advice provided by the author and turned my jet ski in the opposite direction of the huge ship to avoid certain disaster.
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Those were good. This one hits the Trifecta:
"Last month when I was on a fishing trip I noticed that there was a huge ship on the horizon coming my way. Needless to say I was terrified. luckily I was adequately equipped with How to Avoid Huge Ships by John W. Trimmer, and the AutoExec Wheelmate Steering Wheel Attachable Work Surface Tray. Acting quickly I threw my Hutzler 571 Banana Slicer off of my AutoExec Wheelmate Steering Wheel Attachable Work Surface Tray, sending perfectly sliced discs of banana every
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You seem to be confusing football, you know, the sport in which the foot is used to move a ball around a field, and what the Americans erroneously call football, even though in it mostly hands are used to carry an object which is not a ball but a spheroid prolate, meaning the more apt name for the sport would be 'handegg'.
I've nothing against american football, in fact I even prefer watching it to actual football, as an ice hockey man football is way too sl
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You seem to be confusing football, you know, the sport in which the foot is used to move a ball around a field, and what the Americans erroneously call football, even though in it mostly hands are used to carry an object which is not a ball but a spheroid prolate, meaning the more apt name for the sport would be 'handegg'.
Its called football because its played on foot as opposed to on horseback like polo. Both soccer and football started in the 19th century before any of our other modern sports existed (except track, boxing and wrestling). There is some variant on football in many cultures around the world. The medieval Italian one is my favorite. Think UFC fighting plus american football played on something the size of a basketball court with the goal being to throw a round ball into a square tent. It was called Calcio
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Just for clarity, handegg is football - the Rugby variant.
as an ice hockey man
Is that even a sport?
cricket, which has absolutely nothing to do with grasshoppers but seems to be an excuse to gather in a field to drink tea.
Coincidence, but I'm typing this during the Tea break in today's Test match at Lords :)
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Solar forcing isn't the primary nor secondary influence in climate so IFF you didn't explain that clearly then you should simply been fired. If you didn't they were idiot assholes.
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That I may be - but I'm not wrong. That's what matters.
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Same would go for rotor ships.