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DARPA’s silent MHD magnetic drives for replacing naval propellers

naval-technology.com

81–90 of 109 posts

Re: DARPA’s silent MHD magnetic drives for replacing naval propellers

#81
post #6

Isn't this the plot for Hunt for Red October?

I thought that was ducted props?

The book has ducted props (which is where the distinctive noise comes from, a unexpected resonance from the length of the duct), the movie substituted MHD for the impeller.

Re: DARPA’s silent MHD magnetic drives for replacing naval propellers

#82
post #11

If they meet their 90% efficiency target, that's exceeding the efficiency of a normal boat. Just the propeller losses are higher than that (at ~80% efficient [1]). If it's just some REBCO super-conducting magnets and conductive surfaces it might be reasonably inexpensive too. And without moving parts it could be a maintenance win as well. I'm no sailor, but at first glance this seems like it would potentially replace…

MHD is nothing new though, so if it has not yet replaced propellers I'm guessing it is because of practical issues like corrosion, electrolysis and so on alluded to in the article that DARPA seems to have found solutions for but which are not going to be available for the general public for obvious reasons.

Also it's all electric so it poses the usual problems like the added complexity of an on-board electric generator or the added weight and cost of a battery system.

Re: DARPA’s silent MHD magnetic drives for replacing naval propellers

#83

Earlier quoted context omitted.

I agree that an innovation of this magnitude would have a huge impact on naval propulsion if it were publicly available though I’d imagine the tech would be locked down to a ridiculous level. It’s likely destined to only appear in nuclear submarines.

I'm not sure it would be restricted so much as just way too expensive to be practical. There is also the practical considerations of generating 20T magnetic fields out in the real world and around people.

Or on the vessel itself it would have to be shielded for the people and for any equipment.

I've seen experiments where a device using a paddle was put against a person's head and a strong magnetic field emitted. It was a TV reporter for Discovery Channel Canada and her jaw convulsed, she did not look pleased.

I think the experiment was about spirituality of all things. How to induce a feeling of a presence to a person. I believe it was called the God helmet but in the video I saw it was a paddle.

Re: DARPA’s silent MHD magnetic drives for replacing naval propellers

#85
post #6

Isn't this the plot for Hunt for Red October?

"The thing about a new propulsion system, Captain, is its silence... and you don't have to touch a thing. It's all moved by electric currents and magnetic fields. Just one more step towards making submarines even more silent. The next 'Red October', if you will."

Re: DARPA’s silent MHD magnetic drives for replacing naval propellers

#87
post #15

Earlier quoted context omitted.

Yes! I was thinking that as I read it. Alec Baldwin even says magneto hydrodynamic drive. Yet another example of Tom Clancy’s incredible knowledge of the intricacies of what the military had on their radar and working that into great stories.

Magneto Hydrodynamic Drives have been a publicly researched concept since the 60s. Magnetic pumps are used routinely in industry. You're definitely exaggerating how visionary Clancy was.

He did write about using an airliner as a missile years before it happened.

Re: DARPA’s silent MHD magnetic drives for replacing naval propellers

#88
post #65

Yamato-1 looks so fast. I saw this ship in Kobe and i felt like in a Science Fiction movie. But .. > these ships were only able to reach speeds of 15 km/h. https://en.m.wikipedia.org/wiki/Yamato_1

The 70,000 ton Yamato battleship could go 50 km/h circa 1940: https://en.m.wikipedia.org/wiki/Yamato-class_battleship

Not to speak of its later wave-motion engine: https://yamato.fandom.com/wiki/Wave-motion_Engine_(2199)

Re: DARPA’s silent MHD magnetic drives for replacing naval propellers

#89
post #82
post #11

If they meet their 90% efficiency target, that's exceeding the efficiency of a normal boat. Just the propeller losses are higher than that (at ~80% efficient [1]). If it's just some REBCO super-conducting magnets and conductive surfaces it might be reasonably inexpensive too. And without moving parts it could be a maintenance win as well. I'm no sailor, but at first glance this seems like it would potentially replace…

MHD is nothing new though, so if it has not yet replaced propellers I'm guessing it is because of practical issues like corrosion, electrolysis and so on alluded to in the article that DARPA seems to have found solutions for but which are not going to be available for the general public for obvious reasons. Also it's all electric so it poses the usual problems like the added complexity of an on-board electric generat…

So, the USN actually did park that Soviet sub captained by James Bond in a creek somewhere. I knew it!

Re: DARPA’s silent MHD magnetic drives for replacing naval propellers

#90
post #15
post #6

Isn't this the plot for Hunt for Red October?

Yes! I was thinking that as I read it. Alec Baldwin even says magneto hydrodynamic drive. Yet another example of Tom Clancy’s incredible knowledge of the intricacies of what the military had on their radar and working that into great stories.

I recently re-read The Hunt For Red October, and what struck me was that there actually wasn't and mention of Magneto-hydrodynamic drive. As I recalled, the book describes a series of propellers in a duct. Certainly interesting for isolating sound, but it struck me as much more simplistic from the superconducting systems described in the movie.

No shade intended towards Mr. Clancy however. I got the impression that he was quite lauded for not simply describing tech (which other thriller writers did as well) but getting into the nuts and bolts of how they operated. That was what really set him apart.

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