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Voith Schneider Propeller

en.wikipedia.org

31–40 of 45 posts

Re: Voith Schneider Propeller

#31
post #15

Cool, similar to helicopters which can also control direction indepentendent of thrust, which leads to RC helicopters being able to pull of crazy, physics-defying moves like here: https://www.youtube.com/watch?v=QSiwyoQldfo

Thanks! I’ll keep this on hand for next time I hear that a UFO proof video comes out saying that an object can’t move the way it does on screen.

Re: Voith Schneider Propeller

#32
post #15

Cool, similar to helicopters which can also control direction indepentendent of thrust, which leads to RC helicopters being able to pull of crazy, physics-defying moves like here: https://www.youtube.com/watch?v=QSiwyoQldfo

See also: https://en.wikipedia.org/wiki/Swashplate_(aeronautics)

Re: Voith Schneider Propeller

#33
They're really useful for tugs and other specialty applications that need the ability to have differential thrust in arbitary directions with lots of thrust at low speed, but loose to Azipods on faster and larger ships.

Re: Voith Schneider Propeller

#34

Earlier quoted context omitted.

If that's machined, that's impressive. I've seen some crazy 5-axis CNC examples, and it's usually some bladed turbine fan. Not sure how many axis (axii??) this would require, but it looks cool nonetheless.

It looks bent to me, or potentially stamped.

It's a casting which was machined to final dimension

Re: Voith Schneider Propeller

#35
post #11

The coolest recent development in marine propellers is toroidal propellers which are now commercially available and seem to perform significantly better than standard propellers: https://www.sharrowmarine.com/

For the most part the Sharrow props have not proven to be much of an improvement, particularly for the high price. The tests that have shown "significant" improvements have frequently compared the Sharrow to a sub-optimal prop. Feedback from many actual users is that the gains are moderate over a narrow RPM range.

Do you have any more information/sources to share on this? I have an Eastern 18 powered with a Yamaha 60hp 4 stroke and I've been struggling to dial the prop right. I don't know off the top of my head what the specs of my current prop are but basically I feel like I'm not taking advantage of the engine's torque at less than WOT, so I basically just run it flat out. If I could extract just a little more thrust out of the prop at lower RPMs it feels like the engine would have enough grunt to make the boat plane in the mid-high 4000s instead of 5000-5200rpm where I currently run it. Ideally, given the bsfc/hp curves, I'd like to run the engine at a bit lower RPM, but the way it's currently set up at ~4600rpm it's not fully up on the step. I was (perhaps wishfully) thinking a little more efficient prop design might help.

The other thing I was thinking of trying is swapping in a different "high torque" lower unit with a lower gear ratio and running a significantly larger prop.

Re: Voith Schneider Propeller

#37
post #15

Cool, similar to helicopters which can also control direction indepentendent of thrust, which leads to RC helicopters being able to pull of crazy, physics-defying moves like here: https://www.youtube.com/watch?v=QSiwyoQldfo

That's the worst lawnmower I've ever seen. It didn't even cut the grass as much as it just bothered the blades of grass. 0 out of 5 stars. What's that? It's not a mower. Oh, well then, that thing is cool as hell, but not as cool as the pilot that looks like he's just casually standing there.

This made me chuckle:)

Re: Voith Schneider Propeller

#38
post #31
post #15

Cool, similar to helicopters which can also control direction indepentendent of thrust, which leads to RC helicopters being able to pull of crazy, physics-defying moves like here: https://www.youtube.com/watch?v=QSiwyoQldfo

Thanks! I’ll keep this on hand for next time I hear that a UFO proof video comes out saying that an object can’t move the way it does on screen.

Wing area (roughly) scales by n² and mass by n³, so size matters for this kind of thing.

See https://en.wikipedia.org/wiki/On_Being_the_Right_Size (PDF at https://www.phys.ufl.edu/courses/phy3221/spring10/HaldaneRig...)

Re: Voith Schneider Propeller

#39
post #15

Cool, similar to helicopters which can also control direction indepentendent of thrust, which leads to RC helicopters being able to pull of crazy, physics-defying moves like here: https://www.youtube.com/watch?v=QSiwyoQldfo

Thank you for that. That was the most astonishing display of precision (in any field of endeavour) that I have seen in quite some time.

Re: Voith Schneider Propeller

#40
post #15

Cool, similar to helicopters which can also control direction indepentendent of thrust, which leads to RC helicopters being able to pull of crazy, physics-defying moves like here: https://www.youtube.com/watch?v=QSiwyoQldfo

That's the worst lawnmower I've ever seen. It didn't even cut the grass as much as it just bothered the blades of grass. 0 out of 5 stars. What's that? It's not a mower. Oh, well then, that thing is cool as hell, but not as cool as the pilot that looks like he's just casually standing there.

is mowing grass with a helicopter an actual commononly attempted trick like a kickflip with a skateboard?
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