[HN Gopher] Cycloidal marine propellers: Efficient thrust in any...
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Cycloidal marine propellers: Efficient thrust in any direction
Author : Zobat
Score : 78 points
Date : 2024-04-15 15:38 UTC (7 hours ago)
(HTM) web link (newatlas.com)
(TXT) w3m dump (newatlas.com)
| kayodelycaon wrote:
| This isn't exactly a new concept:
| https://en.wikipedia.org/wiki/Voith_Schneider_Propeller
|
| Tugboats use them.
| Cieric wrote:
| That appears to have already been mentioned in the article
| itself. Reading over it it seems that the improvement here is
| fully independent control of all the blades. From what I can
| see in diagrams of the Voith Schneider Propeller it seems to be
| a single linkage to all the blades that cause them to all be at
| the same angle depending on their current position in the
| rotation.
|
| If I'm getting this all wrong please someone correct me, I am
| interested in learning what the differences are.
| dylan604 wrote:
| > That appears to have already been mentioned in the article
| itself.
|
| I like how you let it go that it was the opening sentence.
| TeMPOraL wrote:
| There rarely is any useful information in opening sentence
| or paragraph of a typical article, so as with banner
| blindness, it's excusable to read the article and still
| miss it.
| kayodelycaon wrote:
| Yeah. That's an oops on my part. The "first paragraph"
| isn't part of the article text. It's styled as a quote,
| summary, or caption. Safari's reader view displays it as
| such. (Gray sub-heading) I tend to skip those because
| they are often misleading.
| all2 wrote:
| The linkage system in helicopters was called a "swash plate",
| a rather ingenious method of controlling pitch of rotating
| elements.
| agos wrote:
| individual blade control seems like a pretty big difference
| wtallis wrote:
| It's a big difference in implementation, but I'm not seeing
| where they state whether it achieves any significant
| improvement in performance over existing cyclorotor designs
| like Voith Schneider. I think when they compare against
| "conventional shaftline configurations" they are talking
| about ordinary screw props.
| mlhpdx wrote:
| I can see the potential for dramatic improvements in
| efficiency and control using individual blade tuning,
| particularly during maneuvering, to increase or decrease
| turbulence depending on the desired effect. It sounds like
| a really fun control system problem.
| supportengineer wrote:
| They had these for radio-controlled boats in the early 1990's.
| pixelesque wrote:
| And many smaller ferries.
| godelski wrote:
| If you simplify anything enough it isn't new.
|
| If we required everything to be done in leaps and bounds, we'd
| never get anything done. Better to re-frame this as "looks to
| be an improvement on Voith Schneider Propellers". We can
| recognize the history while recognizing improvements. Progress
| is made by continual small steps, not giant leaps. If you see
| giant leaps, it is generally because you just aren't familiar
| with the topic enough (they do happen, but they are quite
| rare). Over trivializing improvements and dismissing them
| because they are abstractly similar only stops the world from
| moving forward. To reference a clique (something everyone can
| recite but something nobody knows): "the devil is in the
| details."
|
| If you read the article, they say that the propeller decrease
| energy consumption by 22% from conventional shaftline (the
| video says "up to 25%" though...), that seems like a pretty big
| win to me. And seems like something that you shouldn't so
| quickly dismiss.
|
| This kind of issue seems prominent around here and among
| engineers. Just remember how your work's merit relies so much
| on the details. What makes you think that this is any different
| for others? Why conclude that just because you understand
| something at an abstract level that you understand it at a
| nuanced level?
|
| Edit: don't use this comment as a reason to downvote them. If
| you actually like this message upvote them to make this more
| visible because you're probably frustrated with this issue too.
| tda wrote:
| The article is to light on details to claim anything radical.
| The operating principal is the exact same principal as a
| Voith Schneider Propeller, but then with more actuators and
| less linkages. That too me could just as well be a cost
| saving thing. Especially as they compare it too "conventional
| shaftline", and not to a Voith Schneider (I think). Also
| Voith Schneider's are already available in a in an electric
| version (eVSP) for diesel-electric drives.
|
| Perhaps this new Dynafin is much more efficient than an eVSP
| because better tuned individual control optimised by AI and
| industry 4.0 allows for much better control. But it is
| equally possible that there is exactly zero advantage to this
| system and all we read is marketing BS. Hefty improvement
| claims without details are usually BS in my experience
| godelski wrote:
| > The article is to light on details
|
| Yeah I mean I'm not sure why this article was posted to HN.
| It might as well have been an IFLS link because New Atlas
| is similar shit quality. But what can we do?
|
| They at least link to the company's website where much more
| detail can be found (Remember, this is HN, we can get links
| changed!). If you're going to dismiss a technology, I'm
| saying be specific (Remember, this is HN, we have engineers
| and people with actual expertise. This is a technical
| website, be technical!). I don't know enough about this
| tech though I do have experience in physical engineering
| (I'm not in ML, so I'll keep any strong claims to that
| area).
|
| I can't say much, but at least what I can tell is that the
| Voith Schneider is made by a single company (according to
| Wiki). If all this is is a different enough Voith Schneider
| motor and now there is competition in the space, I'd be
| okay with that too and wouldn't phrase it like the OP bur
| rather make this the point and note that the rest is
| market. But again, I don't know much about motors and even
| less about marine motors, so I'm not really going to make
| any hard claims because I don't know. But if this is all
| that it is, I think my point still stands and you can make
| a reasonable enough inference of the main point to adapt to
| competition and improvements (which again, are small
| steps). Clearly this isn't an exact clone.
| michaelcampbell wrote:
| This intrigues me although I'm convinced almost anything that
| touches water is more expensive than I'm willing to pay for a
| hobby/pastime, but I went and looked up to see how these work.
| Neat.
|
| https://www.youtube.com/watch?v=Ub563Yc3xls
| lawlessone wrote:
| looks like bundles of kitchen knives.
| nickpinkston wrote:
| That was my thought too, shoved through slots in a marble
| countertop.
| interstice wrote:
| As if I wasn't already reasonably scared of swimming near boats
| apendleton wrote:
| If it's any consolation, I'm pretty sure the leading edge is
| the blunt one, not the sharp one.
| vlachen wrote:
| Further more: sharp or dull, Ginsu-style or traditional
| prop, putting a part of your body in the interaction zone
| is a bad day. The article's style just gives it a more
| body-horror feel.
| klyrs wrote:
| I'm not a swimmer but that sounds like a pretty reasonable
| fear. A propeller of any sort will mess you up pretty bad.
| And if I understand correctly, the larger vessel gets the
| right of way so if you aren't in a vessel you just go smoosh.
| scheme271 wrote:
| Unpowered (e.g. kayaks) or sail powered vehicles have the
| right of way unless you're in a channel with restricted
| movement. But practically speaking, large vessels aren't
| all that agile and may have limited visibility so while the
| right of way would be great for your estate, it probably
| won't help you much if you get run over.
| AYBABTME wrote:
| "great for your estate" is a great way to put it, had
| never heard that!
| gravescale wrote:
| > Each blade is individually controlled by an electric motor, a
| frequency converter (to control torque and rpm) and control
| logic"
|
| I know it's far from the only, or even most critical, embedded
| system on a ship, but being stuck at sea because your propellor
| CPU crashed, bricked during an OTA update or got taken over by a
| crypto miner does feel like it lies squarely on the current
| trajectory of reality.
| TeMPOraL wrote:
| Reminds me of a seaQuest episode, in which they had to hit a
| black market for an A/C chip for their sub; the captain was
| complaining that they can't get it through procurement, but
| were he to ask for a nuclear warhead, he'd have the weapon
| helicoptered in a hour later.
| gravescale wrote:
| I don't think ABB would sell you just the chip, you just know
| that's going to be a sealed module that costs POA dollars per
| unit!
| ermir wrote:
| So this is like a helicopter propeller system, but the individual
| blades point upwards.
| t0mas88 wrote:
| Jup, except that a helicopter system does not use independent
| control. The blade angle is controlled mechanically, each next
| blade will at the same position have the same angle. This new
| thing seems like it has independent control of each blade. But
| I'm not sure what they can do with that that wasn't possibe
| with a helicopter-like setup.
|
| I think it's unlikely you'll see a helicopter with this tech
| soon. This runs at 40 rpm. A helicopter main rotor is more like
| 400 rpm. And getting a blade "misaligned" at speed in a
| helicopter would immediately tear the whole thing apart.
| hasoleju wrote:
| During the last centuries there was a technological shift in
| cargo ship drives roughly every 100 years. From sailing to steam
| boat over combustion engines to these drives?
| psunavy03 wrote:
| The basic principle has been around for decades.
| sp332 wrote:
| > 85% efficiency
|
| Hm, is that a lot?
|
| > independent testing of a passenger vessel fitted with different
| propulsion systems found that the ABB Dynafin solution managed
| energy savings of 22% compared to conventional shaftline
| configurations.
|
| Oh. That's a lot!
| pixelesque wrote:
| That's compared to propeller shafts I think (and powered by
| what? Diesel, Gas turbine?).
|
| Voith Schneider systems are generally used on tugs and smaller
| ferries due to the manueverbility control they provide, it's
| not clear how energy efficient Voith Schneider systems are to
| shaftline systems.
| ilove_banh_mi wrote:
| In case you wonder how landlocked Switzerland would be so
| involved in such marine work, ABB is a Swedish-Swiss corporation
| and the pictures were clearly taken in the Baltic Sea (in the
| Gulf of Bothnia or Gulf of Finland).
| psunavy03 wrote:
| Still not unusual. MSC is one of the largest ocean shippers and
| based in Switzerland.
| perlgeek wrote:
| I really hope this works out.
|
| The cynic in me immediately says "so many moving parts,
| maintenance will be quite a problem", but I don't really have the
| expertise to make that a argument against the success of this
| concept.
| n3storm wrote:
| I am more worried about there is no video of a ship moving on
| three main website and youtube videos. One is 12 min. Only men
| talking, 3d animation and lots of waves. Did not search further
| though.
|
| Should this be called foamware?
| TaylorAlexander wrote:
| Wikipedia says this type of propeller is widely used on tugs,
| so I guess the ABB product is either just their own version of
| this tech (maybe a patent expired) or they have evolved it
| somehow, maybe to increase efficiency depending on how you
| interpret the article.
|
| https://en.wikipedia.org/wiki/Voith_Schneider_Propeller
|
| Here is a video of a tug boat using this technology, sadly only
| showing the boat moving but no close up of the propeller.
|
| https://www.youtube.com/watch?v=u6uNECa_X8Q
| Tuna-Fish wrote:
| It's not quite the same.
|
| In a Voith Schneider propeller, there is one power input (as
| in a rotating shaft) plus a second shaft input that gives the
| desired thrust direction, and a complex gearbox that drives
| all the blades and the collective. These are in wide use in
| tugboats and the like, desired for their ability to output
| thrust in any direction at a moment's notice. However, their
| disadvantages are that they are less efficient than
| traditional propellers, and they don't scale up to high revs
| or high power output all that well, because of the gearing
| and the mechanical losses involved.
|
| In this design, there is one large electric motor that drives
| the collective, and an individual electric motor at the base
| of every blade. The claim is that this gets you the
| maneuvering advantages of a V-S, while not suffering from the
| same disadvantages, and because of better control over the
| blades is not just more efficient than a V-S prop, but more
| efficient than traditional screws. And in theory it should
| scale as big as you want it, which would genuinely make it a
| significant advance that would see fairly rapid adoption.
|
| That's if it actually works in practice, the only prototypes
| so far are very small and you don't really know if something
| scales until you actually scale it.
| ChrisMarshallNY wrote:
| Looks like a Ginsu Propeller(tm). Slices, dices, etc...
|
| In all seriousness, it would be great if it worked out, but we
| are constantly seeing marine tech being messed up by the marine
| environment.
|
| There's a reason that every damn thing that has "Marine" in its
| title, costs ten times as much.
|
| It really, _really_ sucks to be stuck out in the middle of the
| ocean, because your shaft rusted.
| geor9e wrote:
| I'm so confused how this works, but based on this animation I
| found, it seems like it just shoves the water sideways in the
| direction of thrust, then turns so it's cutting though the water
| in the opposite direction
| https://www.youtube.com/watch?v=Ub563Yc3xls
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