[HN Gopher] Hybrid Aerial Underwater Drone - Bachelor Project [v...
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       Hybrid Aerial Underwater Drone - Bachelor Project [video]
        
       https://www.energy.aau.dk/aau-drone-can-both-fly-and-dive-un...
        
       Author : nhma
       Score  : 27 points
       Date   : 2025-12-22 08:37 UTC (14 hours ago)
        
 (HTM) web link (www.youtube.com)
 (TXT) w3m dump (www.youtube.com)
        
       | bestouff wrote:
       | The manhunt from a drone becomes more of a nightmare.
        
       | idiotsecant wrote:
       | Variable pitch! Waterproof! This thing is awesome. Surely there
       | is different tuning when it's in water vs when it's not, right?
       | How do you detect the transition? Motor currents? This is a
       | really neat project!
        
       | thatoneengineer wrote:
       | Obligatory: https://xkcd.com/2128/
       | 
       | Or for the more cynical, replace "search and rescue" with
       | "military covert ops".
        
       | Stevvo wrote:
       | SciFi becomes reality.
        
       | ch4s3 wrote:
       | It's interesting how simple this looks, off the shelf parts, and
       | 3D printed components. I'm almost surprised this doesn't already
       | exist after looking at it.
        
         | alexpotato wrote:
         | If this what can be done with off the shelf parts and 3D
         | printing, imagine what DARPA and the like have been doing for
         | the past 20 years.
         | 
         | Makes the UFO/UAP stories about "it transitioned from the water
         | to the air and back to the water!!" seem way more plausible.
        
           | ch4s3 wrote:
           | > imagine what DARPA and the like have been doing for the
           | past 20 years.
           | 
           | People always say this, but anyone I know who's ever worked
           | in one of these companies that contracts for the DoD or DARPA
           | always complains about how behind the market government tech
           | is. Obviously private industry isn't producing competitors to
           | the F35, but for less complicated kit the government doesn't
           | seem to be doing anything super sophisticated. In fact a
           | bunch of people I knew who went to Iraq bought supplemental
           | gear on the private market.
        
             | engineer_22 wrote:
             | > In fact a bunch of people I knew who went to Iraq bought
             | supplemental gear on the private market.
             | 
             | Like, photography gear?
        
         | lm28469 wrote:
         | > I'm almost surprised this doesn't already exist after looking
         | at it.
         | 
         | What's the use case? We have very good dedicated aerial drones
         | and very good dedicated submarine drones. If something is
         | technically possible but no one makes it usually it means it's
         | not that interesting
        
           | engineer_22 wrote:
           | If your mothership is low-observable/submersible you could
           | park it in a harbor and when time is right unleash a swarm of
           | hybrid aerial underwater drones with mission payload.
           | 
           | This design uses 1 swashplate server plus 1 brushless drive
           | motor for each prop for a total of 8 motors. Designs in
           | Ukraine are now using 1 brushless drive motor to
           | synchronously drive all 4 props and 1 swashplate servo each
           | prop, reducing total number of motors to 5, which might be a
           | natural path of optimization for this type of hybrid aerial
           | underwater?
        
       | wumms wrote:
       | I suppose that pool is the ~max RF range under water? Is prop
       | pitch mandatory for underwater use?
        
       | stoev wrote:
       | Any ideas how the signal is transmitted once the drone is
       | underwater? Typical RC transmitters run 2.4 GHz. Some systems use
       | 700 MHz. The former wouldn't penetrate at all, the latter might
       | penetrate to a shallow depth, but I think that what's shown in
       | the video is deep enough that the signal would get attenuated.
       | There doesn't seem to be a tether and the drone doesn't seem to
       | have any computer vision capabilities to fly itself whilst under
       | water. I wonder how they solved this.
        
       | hermitcrab wrote:
       | Very impressive. I assume that underwater propulsion uses a lot
       | more energy per meter moved?
        
       | hermitcrab wrote:
       | Maybe you will be able to us these to defend Greenland?
        
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       (page generated 2025-12-22 23:00 UTC)