
The Taming of the Screw (2000) - thicknavyrain
http://www.americanhistory.si.edu/subs/anglesdangles/taming.html
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grendelt
It's not perfect, by I made a more legible single-page layout here:

[http://n5dux.com/taming/](http://n5dux.com/taming/)

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agumonkey
Very nice

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jstanley
I thought the most interesting part of this was the part about the internal
structure being classified.

Naively I assumed that they were cast solid and then the surface machined to
the exact shape, but it sounds like they either have internal passages or
they're made of some sort of honeycomb to reduce weight? What else could be
inside?

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petee
It could have been done like some jet engine blades, where a thin skin
'pocket' is pressured or vacuumed into shape during forging. Or perhaps
simply, they are not made of metal anymore, albeit unlikely.

You're probably closest with the internal passages though; if one of the
primary issues is cavitation, there must be some solution to relieve that
vacuum pressure from becoming too great, or absorbing the shock when it does

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dsfyu404ed
I would suspect that there's some internal structure made of a different
material (steel, air, silly putty, whatever) that is tuned to act as a damper
or allows the screw to flex in a certain way that changes its acoustic
signature allowing it to be quiet at higher speeds like those crappy flex fans
for car radiators.

Casting in an internal pocket with sufficient accuracy(!) in a part so massive
would have been very, very, very difficult/expensive if not impossible with
the kinds of industrial process control that were available in the 1960s.

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lokopodium
Remember how Bing Maps had a picture of a classified screw?
[https://ogleearth.com/2007/08/microsofts-birds-eye-view-
catc...](https://ogleearth.com/2007/08/microsofts-birds-eye-view-catches-navy-
propeller/)

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trhway
reminded the 198x scandal of Toshiba CNC used to machine USSR submarine screws
[https://en.wikipedia.org/wiki/Toshiba-
Kongsberg_scandal](https://en.wikipedia.org/wiki/Toshiba-Kongsberg_scandal)

The high precision allowed for very quiet screws and that caused all that such
a screaming noise back then :)

[https://www.nytimes.com/1987/06/22/opinion/submarined-by-
jap...](https://www.nytimes.com/1987/06/22/opinion/submarined-by-japan-and-
norway.html)

~~~
gregschlom
I believe that story is actually mentioned in the article.

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gwern
Ah, so that's what that bit about the TV was alluding to.

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userbinator
I am reminded of the blade shape of quiet computer fans --- although designed
to work in a different fluid, I bet a lot of what applies to making a quiet
fan blade also applies to propellers in water.

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bediger4000
I don't think air cavitates. There's a fairly gradual transition from
incompressible to compressible flow for air, but I don't think that's true for
water.

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adrianN
How would air cavitate if it is already a gas?

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_archon_
If you cross the speed of sound with any part of your design or airflow, air
can be pretty destructive if your design isn't up to it.

~~~
jacobush
Can’t help but think of computer fans approaching speed of sound! :-)

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nigrioid
Cool old-style website! Look at the source; there's no CSS.

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jacobush
There is something even more silent prowling (occasionally) the high seas:

[https://www.popularmechanics.com/military/navy-
ships/a197847...](https://www.popularmechanics.com/military/navy-
ships/a19784775/gotland-class-sub-ronald-reagan-war-games/)

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lukego
Sounds a lot like trying to get computer hardware interfaces published so that
people can write their own drivers for them!

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agumonkey
wow, that website design.. much memories

