Underwater Jetpack is Almost Practical
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 itβs such an iconic idea, we canβt get away from it. What if there was a better environment, one where your jetpack dreams could come true? [CPSdrone] has found one: the worldβs oceans, and have taken that revelation to build the worldβs 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 donβt 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 βjetpackβ 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 βhullβ of the jetpack. Thatβs necessary because while the motors might be rated for submersion, but the rest of the electronics arenβt.
Alas, wearing the device on the back is considerably less hydrodynamic than hanging on behind in the standard βwater scooterβ configuration. While theyβre able to go faster than a swimming human, the ESCs werenβt able to handle the motors full power so we canβt tell you if this device would allow [CPSdrone] to outrun a shark with those 220 lbf on tap, which was the design goal. Apparently theyβre working on it.
From the testing done on-screen, itβs safe to say that theyβd 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.