
Waterproof Quadcopter Is Also a Submarine - jonbaer
http://www.popularmechanics.com/flight/drones/a18419/waterproof-drone-transforms-from-quadcopter-to-submarine/
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vlehto
I think this has biggest advantage in military submarine communications.

You launch a drone underwater. Drone flies off, sends radio message, records
another from headquarters. Then flies to preprogrammed place. Then dives to
another preprogrammed place and is recovered by sub.

This would me major improvement over communication buoys. Currently when buoy
is transmitting, you can guess that the sub is 0,5km away in the general
direction of movement of the buoy.

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Retric
Subs are not really weight limited, so you could have a 20+ mile long cable
attached to a buoy giving 2 way communication. Which creates ~1200+ square
mile search area assuming you can't just follow the cable.

~~~
dkbrk
But they are volume limited, though I believe they generally store the towed
array sonar in the ballast tanks, so the same thing could be done.

More serious problems are the time it would take to extend and retract the
buoy, speed limitations while the buoy is being deployed, and noise mitgation
on the buoy and cable.

Right now, submarines carry disposable communication buoys that can be
deployed from depth and sent a pre-recorded message via satellite. Submarines
can be alerted to a pending message while at depth through Extremely-Low-
Frequency radio communication that can penetrate water, at which point the
submarine can move to periscope depth and communicate via satellite without
actually surfacing.

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PhantomGremlin
Neat stuff. Still needs tethering, which makes sense while it's being
developed.

However, reality is no match for imagination. When I was a kid the TV show
_Voyage to the Bottom of the Sea_ was popular. One of the absolute coolest
things was the Flying Sub[1][2]:

    
    
       36 foot wide and long, flying submersible,
       aptly called the "Flying Sub"
       ...
       It was deployed through bomb-bay like doors.
       As it broke the surface, its engines could
       generate enough thrust for the vehicle to
       take off and fly at supersonic speeds.
    

[1]
[https://en.wikipedia.org/wiki/USOS_Seaview#Refit_and_the_Fly...](https://en.wikipedia.org/wiki/USOS_Seaview#Refit_and_the_Flying_Sub)
[2]
[https://www.youtube.com/watch?v=WHNNXVZ1mYg](https://www.youtube.com/watch?v=WHNNXVZ1mYg)

~~~
anonymfus
[https://en.wikipedia.org/wiki/Master_of_the_World_(novel)](https://en.wikipedia.org/wiki/Master_of_the_World_\(novel\))

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richerlariviere
This is cool but the autonomy problem remains. Most (aerial) drones can't fly
more than 15 minutes. I am curious about the power used underwater to move it.

~~~
jessriedel
The ~15 minute lifetime comes from needing to continuously tread air to stay
aloft. (You can use up the battery faster by going fast, but there is a max
time to just hover.) In contrast, a water-density vehicle could float around
and leisurely collect data for almost unlimited amounts of time so long as it
doesn't need to get anywhere quickly. (Currents will complicate this.)

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heydenberk
Reminds me of one of my all-time favorite Wikipedia articles:
[https://en.wikipedia.org/wiki/Tradeoffs_for_locomotion_in_ai...](https://en.wikipedia.org/wiki/Tradeoffs_for_locomotion_in_air_and_water)

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Shivetya
If the public can come up with them surely there are some cool military
versions already out there. While it is interesting what was shown in the
video it clearly is not designed for two mediums. If anything you would add
features like putting the motors on gimbals and feathering of the motors not
used. You should not need to tilt the whole thing to change directions
underwater, surely a better solution exist

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cpkpad
This isn't the public. This is military-funded research at Rutgers. The
military generally doesn't have a reason to fund things it has (although DARPA
might just not know about classified technologies developed by different
branches). But in most cases, the military funds things in academia, a
fraction of which become militarized later.

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aluhut
Now we "just" need proper batteries...

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danepowell
Sounds great, if you stop reading before the second-to-last sentence:

"Because radio transmission through water is difficult, the craft must be
tethered at this time to provide continuous communications."

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mark_l_watson
Artificial intelligence will help with that. For high value activities like
detecting underwater mines and collecting data for underwater oil spills,
etc., there should be enough funding to make these autonomous.

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cushychicken
That's not the fundamental problem if you want a real-time communication link
for something like, say, an inspection or a search and rescue operation -
transmitting radio through water is. Water is a pretty bad medium for
transmitting RF energy.

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Sanddancer
Looks neat, but underwater, it seems more than a big awkward in maneuvering.
Makes me curious if a tiltrotor design would be better here in terms of
efficiency and speed.

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Patronus_Charm
The possibilities here are quite diverse.

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ck2
They say underseas drones are the future.

Sadly (horrifyingly?) they are also going to be used for nuclear weapons.

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deugtniet
Horrifyingly, drones are already being used as nuclear weapons. The Russians
recently 'leaked' a new torpedo design with all the characteristics of a
drone, being able to find its way through thousands of miles of ocean, finding
a target and if this target is acceptable destroying a whole harbor zone.
Doomsday drones --or machines if you will-- are likely already in place and
able to decide to blow up the world in an instant. I don't like thinking about
the capability of these superpower nations.

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jacquesm
> Doomsday drones --or machines if you will-- are likely already in place and
> able to decide to blow up the world in an instant.

What do you base that on?

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deugtniet
No facts, only that it's relatively easy to implement such a system. Add to
this the fear that the other party may have implemented a doomsday device, and
it becomes easy to rationalize the need for such a device.

I would even argue the operators in nuclear bunkers are already part of a
doomsday device if they have orders to automatically launch an attack if their
country has been struck by nuclear weapons.

