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Jet Packs, Finally On Sale
Bad_CRC1945 writes "The good news: Not one, but two companies are selling jet packs. The bad news: The tech has a long way to go. In the past, potential buyers have been stymied by two problems: Rocket belts aren't for sale, and even prototypes run on modern-day fuel (as opposed to whatever the Jetsons use) which means rocket belts can weigh upwards of 100 pounds, with only enough fuel to stay aloft for under a minute." That second problem's still with us, but the article hints that jet-fuel options (for the brave) could considerably extend users' time aloft.
What exactly is the point of jetpacks supposed to be? They don't seem to be useful for any civilian or military purposes that other technologies aren't more appropriate. Is the obsession with jetpacks just about being like a comic book superhero?
... and then they built the supercollider.
... neither of them provide more performance than Captain Keds got out of his when he punched out of the big paper mache football and flew around the field at halftime of Superbowl 1 in 1967. Armadillo Aerospace is top notch in H2O2 propulsion systems, and they aren't building one. I bet there's a good reason.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
That's funny. People have landed a huge commercial jet dead stick before. Nor do they fall out of the sky when something goes wrong unless they lose a wing.
Fly me to the moon Let me sing among those stars Let me see what spring is like On jupiter and mars
TFA suggests that replacing "inert" hydrogen peroxide with propane will make jet packs more dangerous. Maybe, maybe not, but hydrogen peroxide is a powerful oxidant that attacks many organic compounds (eg people) and can explode. It's not inert by any stretch of the imagination - how useful would an inert rocket fuel be in any case?
Strapping a propane cylinder to your back might not be great either, but I suspect propane is easier to manage.
There's a summary of H202 safety risks here
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The problem with jet packs has been specific impulse. You simply cannot get enough power density into something you can heft on your back and walk around with, at least not without any usable flight time or performance.
I've often thought small jet engines used in RC planes (~40lbs thrust) could be stacked up (6-8) of them to give you a jet pack. But nowadays you can buy a small jet engine designed for UAVs that might weighs 40 pounds and produces 200+ pounds of thrust, these kind of engines have been fitted to gliders.
In terms of a true jet pack. Allowing some weight for fins, a fuel tank and harness you have a 170lb dry weight with three engines. Not much of a real 'pack' then.
So the problems remain, even with the high specific impulse of a jet. You would need to add about your own weight in fuel for one hours flight time.
More ingenious gadget to me, would be a hot air balloon that fits and deploys from a backpack using the same technology that allows large parachutes to be packed into small spaces.
After logging in slashdot still does not take you back to the page you were on. It's been that way for 20 years.
I remember back in the early 80s some DoD contractor had a prototype of a flying "trashcan" like in the Dick Tray comics.
I thought it had some sort of jet engine with a steerable nozzle on the bottom. I think it was probably the Williams X-Jet, but I swear it was painted stealth black.
I used to dream about having one of those, and even as an adult I think it would be so cool to fly one of those around.
I'm guessing that the program probably got canceled because of stability problems. But I would expect that now, with high speed DSPs and gyros like Dean Kamen has used for his scooter and his ubercool wheelchair, that the stability problems could be overcome.
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Since if it's anything close to the purity they used to use in ME-163 (T-Stoff) it'd give you severe chemical burns.
Did you know 80 to 90% of the moderators on slashdot wouldn't recognize a troll even if one dragged them under a bridge.
There is a reason why the term "rocket science" is used to suggest something is more than a bit difficult. But thank you for giving an old-timer a bit of amusement at the expense of what I suspect is one of today's teenagers.
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"Thirty-three seconds of fuel makes an inexperienced pilot twitchy." The solution? Ditch the rocket belt, and build a bona fide jet pack (okay, jet belt). Widgery plans to release the T73 Turbine by the end of the year; it's a $200,000 model that will burn jet fuel, allowing it to stay airborne for 19 minutes.