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DARPA’s silent MHD magnetic drives for replacing naval propellers

naval-technology.com

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

#21

Post by aardvarkr »

gpm wrote: 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…

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.

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

#22

Post by ethbr0 »

zrail wrote: post #6

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

It was published by the (US) Naval Institute Press, their first published work of fiction. [0]

And yes. https://m.youtube.com/watch?v=SMCoIwsaRVw&t=1m31s

[0] https://en.m.wikipedia.org/wiki/The_Hunt_for_Red_October#Com... https://en.m.wikipedia.org/wiki/United_States_Naval_Institut...

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

#23

Post by mepian »

beambot wrote: post #19
eqmvii wrote: post #7

Earlier quoted context omitted.

semi absurd is kinda why DARPA exists!

While we all communicate using TCP/IP, invented as a DARPA program for robust communication in the event of nuclear conflict...

It's an urban legend. ARPANET was an overgrown university network.

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

#25

Post by ethbr0 »

atonse wrote: post #16
2OEH8eoCRo0 wrote: post #9

Earlier quoted context omitted.

Yes. "Caterpillar drive". Fantastic book and movie.

I have watched the movie dozens of times. I really need to read the book.

The book's better, if you liked the movie.

It was actually the first "adult" book I read. Maybe when I was 9? I told my father I was bored of school books, and he handed it to me.

As well as Clancy's other stuff!

Just stop reading at 2000 (last recommended book: The Bear and the Dragon). After that he started phoning it in / lending out the name as ghostwritten brand.

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

#26

Post by Guthur »

mepian wrote: post #23
beambot wrote: post #19

Earlier quoted context omitted.

While we all communicate using TCP/IP, invented as a DARPA program for robust communication in the event of nuclear conflict...

It's an urban legend. ARPANET was an overgrown university network.

And TCP/IP was one of many potential standard protocols

https://en.m.wikipedia.org/wiki/Protocol_Wars

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

#27

Post by wrycoder »

atonse wrote: post #16
2OEH8eoCRo0 wrote: post #9

Earlier quoted context omitted.

Yes. "Caterpillar drive". Fantastic book and movie.

I have watched the movie dozens of times. I really need to read the book.

I remember sitting in the dining room at four AM. JUST ONE MORE PAGE.

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

#28

Post by temporallobe »

zrail wrote: post #6

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

Beat me to it. Happens to be my favorite movie, ever. I’ve watched it so many times and I’m still not sick of it. What’s so beautiful about it is that it’s pure storytelling without a preachy agenda, though the irony is that it’s very much about politics and patriotism.

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

#29

Post by murillians »

mrcode007 wrote: post #10
mLuby wrote: post #8

Wouldn't the intense electro-magnetic signature of this drive make it highly detectable in an otherwise quiet ocean?

Bay area waters were (are?) used as a naval magnetic silencing range. Most navy ships have degaussing coils that calibrate with magnetosphere https://www.dropbox.com/s/qansmciigewti4n/IMG_2957.JPG?dl=0

Degaussing in a bay is much different from trying to cancel out 20T(!!!) of EM signature
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