The jet pack is one of those pre-war sci-fi dreams that the cold light of rational consideration reveals to be a terrible idea. Who wants to cook their legs with hot exhaust while careening out of control? Nobody. Yet it’s such an iconic idea, we can’t get away from it. What if there was a better environment, one where your jetpack dreams could come true? [CPSdrone] has found one: the world’s oceans, and have taken that revelation to build the world’s fastest underwater jetpack.
Underwater? Yeah, water drag is worse than air drag. But there are two big advantages: one, humans are fairly buoyant, so you don’t need fight gravity with rocket thrust, and two, the high density of water makes small, electric props a reasonable proposition. The electric ducted fans on this “jetpack” each produce about 110 pounds of thrust, or just over 490 N. The first advantage is helped further by the buoyancy provided by the air-filled “hull” of the jetpack. That’s necessary because while the motors might be rated for submersion, but the rest of the electronics aren’t.
Alas, wearing the device on the back is considerably less hydrodynamic than hanging on behind in the standard ‘water scooter’ configuration. While they’re able to go faster than a swimming human, the ESCs weren’t able to handle the motors full power so we can’t tell you if this device would allow [CPSdrone] to outrun a shark with those 220 lbf on tap, which was the design goal. Apparently they’re working on it.
From the testing done on-screen, it’s safe to say that they’d at least need to hang on behind to get their desired speed goals, and abandon their jet pack dreams just as we landlubbers were forced to do long ago. Well, some of us, anyway.
