Rotating Sails Help to Revive Wind-Powered Shipping
The interesting thing about the Magnus effect is that the lift goes up with the second power of the radius of the rotor, so twice as large gets you four times as much lift. The largest Magnus effect vehicle I know of was a huge sphere with the crew cabin hanging below it from the axle. The whole sphere was the lifting body.
The old OMNI magazine had an article wherein they calculated that you could put Magnus effect rotors on a bus and it would fly at (speeds as low as) 35mph.
I've had plans for years now to build large flying buildings (if I can get my act together I might eventually do it) using geodesic cellular kites and the Magnus effect. (Look up Alexander Bell's kites, and Bucky Fuller's "Cloud Nine" aerial city concept.)
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http://www.rexresearch.com/flettner/flettner.htm
http://www.rexresearch.com/skybow/mueller.htm
http://www.rexresearch.com/aero/1aero.htm#thompson
http://www.rexresearch.com/aero/1aero.htm#flettner
And I found some images but not the name of the upside-down-hair-band-sphere design on this blog post: https://steemit.com/airship/@everittdmickey/magnus-effect-ai...
MS Viking Grace has rotor sail. Fuel savings are 300 tons per year from the sail. It also uses LNG fuel. In best conditions the sail can provide 20% fuel savings. In reality much less than that, but it's a small sail compared to the size of the ship. Viking Grace is a cruiseferry, so even in full capacity it's almost empty compared to a cargo ship.
Maersk Pelican (tanker): 8.2% fuel saving during the first year of operation.
M/V Estraden (ro-ro cargo): 6.1% fuel saving.
From Wikipedia [1]:
> A rotor ship is a type of ship designed to use the Magnus effect for propulsion. The ship is propelled, at least in part, by large powered vertical rotors, sometimes known as rotor sails. German engineer Anton Flettner was the first to build a ship that attempted to tap this force for propulsion, and ships using his type of rotor are sometimes known as Flettner ships.
Container ships reduce the superstructure to enable loading but these rotor sails could possibly be used on oil tankers and bulk carriers. We don’t hear about autonomous water vessels very often, perhaps a Flettner water drone is possible.
Aren't kite systems much more efficient and lighter and cheaper?
https://www.researchgate.net/figure/A-ship-sailing-with-the-...
Very little discussion here or in the article on why use these in favor of traditional sails. Looking at America’s Cup, the trend one would expect would be foils supplemented by motor and more traditional sails. I’m sure these are easier to deploy, but consider that an America’s cup boat can do 40 knots in a 12 knot breeze. Sure that’s without cargo and on a highly optimized design with hard working crew, but it does prove the remarkable efficiency of a traditional wing.
I've already bought some chocolate that was transported by cargo sailboat Avontuur, a 100-year-old 2-master schooner.
Here's some information in English :
https://www.zotter.at/en/about-zotter/projects/translate-to-...
https://timbercoast.com/en/ship/
and in German:
https://www.zotter.at/das-ist-zotter/kakao-setzt-segel
https://timbercoast.com/de/schiff/
PS: The chocolate was delicious! It's also a fantastic gift for sailors
Oh, Flettner rotors again. Those keep coming around. Jacques Costeau used to have a rotor ship, the Alcyone.[1] It wasn't really worth the trouble. "In fact, we were motoring most of the time" - Alcyone's captain.
[1] https://sea-to-summit.net/the-flettner-rotor-makes-a-comebac...
Slightly related: wind powered car that goes faster than the wind
This looks similar to something Jacques Cousteau implemented. On his ship the Alcyone.
RC Plane leveraging Magnus effect
I remember seeing this on the cover of Popular Science in 80s (maybe early 90s). A ship with a large cylinder used for propulsion from wind energy.
edit: I found the issue https://www.google.ca/search?sa=X&sxsrf=ALeKk01n7hvalLGEwW3e...
Perhaps also of interest: E-Ship 1 https://en.wikipedia.org/wiki/E-Ship_1
In service since 2010!
Would like to see more about what's going on below the waterline. The challenge with any form of wind power is that the propulsion doesn't typically point forward - it's at an angle with a forward component. So on a sailboat you need a long keel (or centerboard/daggerboard) to translate the lateral propulsion into forward movement. That constricts the vessel from operating in shallow waters and causes the vessel to lean due to the opposing force under the waterline.
Some questions after spending 10 minutes studying this:
1. These ships all seem to have two towers. Why not more? Can't they be closer for some science reason?
2. This works by spinning the towers using a motor. How do the propulsion gains compare to using the same motor power on a propeller?
There's a great Veritasium video explaining the Magnus effect and the Flettner rotor here:
https://www.youtube.com/watch?v=2OSrvzNW9FE
The Norsepower company (which installs Flettner rotors on ships) also has a short video explaining the effect here https://www.youtube.com/watch?v=FUCShEXkpL8
Super interesting - is a perfectly smooth cylinder most desirable? or should it be a little rough in order to better tug on the air as it spins?
I'm just thinking out loud. Some things don't need fast shipping. Instead it needs a steady and even supply. And if a ship doesn't use any fuel, it could even serves as a kind of movable storage house. Thus I'm really looking forward for the developement of autonomous sailing ships. I really believe there's a market for them, or at least a niche within shipping.
I just wonder if massive sails that double as solar panels, and additional fold-out solar arrays, would be superior overall and lighter.
But any short-term "jury rig" is valuable.
And if we get enough cheap excess green energy, carbon-neutral artificial fuels might be superior too.
Related to this, a french startup is trying to build fleet of autonomous ships to harvest energy from ocean. They make use of flettner rotors also.
There were some planes that used this concept, but they were never commercially successful (partly because if they lose power they cannot glide to a landing like a normal plane can). I think it was used in some bomb designs as well.
Thankful. The few times I’ve been on a ferry or cruise ship I’ve been appalled enough at the amount of pollution to not do it again.
Are there any other technologies like solar, wind, or gulp nuclear, that are becoming economical?
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Off topic, but would a practical plan be to build a solar powered ship, with a large, miles-long towed solar panel array?
So how well does these sails point into wind and how do control lift angle?
Naive question: is solar + battery feasible for shipping?
No picture or video ?
This comes around every so often, with the same claim, then disappears.
Not gonna happen as long as those china ships belch diesel fumes underwater so we don't see them. They're killing the oceans.
Wow ... this comes up a couple of times a decade. It's like the Simpsons 'We'll build a monorail'. It's right up there with the Solar Sail scam.