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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.
Why do people think that jet fuel is some futuristic stuff? It is basically kerosene.
A not so big secret is that jet engines became popular, not because they were super-efficient, but because they could burn crappy cheap jet fuel. Thus a less efficient jet engine could run faster and cheaper than a piston-engined aircraft.
Is the obsession with jetpacks just about being like a comic book superhero?
Pretty sure the answer is yes.
If one wants to fly without an airplane around them, an approach like the Martin Jetpack works much better. Far longer flight time and much more altitude. Cheaper fuel too.
upon the advice of my lawyer, i have no sig at this time
On a full tank of hydrogen peroxide the belt weighs 124 to 139 pounds (the bigger the pilot, the bigger the belt), and provides 30 seconds of flight.
From TFA.
The article appears to be from June 14, 2007. Here's one from this year:
http://www.popularmechanics.com/technology/aviation/diy-flying/martin-aircraft-jet-pack-for-sale
... 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
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
Virtually serving coffee
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.
When information is power, privacy is freedom.
Instead of a hot air balloon, why not inflatable wings? You strap on the pack (which really should come with 'training wheels' so you don't crack your knees on landing) and when you get to 100' and have some horizontal velocity, out pop the wings to give you some extra lift.
It's not as crazy as it sounds; Back in WWII we had entire ultralight airplanes that would inflate out of a suitcase... and apparently the test pilots said they were very smooth in flight.
until the sky fills with jetpack equipped people, and one gets there faster by walking.
comment first, facts later. http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm
Bottom line: above a few thousand KW, piston engines for aircraft are simply too complex, expensive and unreliable. The fuel is immaterial.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."