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.

Comments

Re:I've always wondered

[compro01]

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.

30s flight????

[miknix]

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.

News from 2007 now?

[Anonymous Coward]

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

Re:Longer flight possible

[infolation]

(from TFA) 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.

Re:What?

[Anonymous Coward]

I think this is fairly informative

Er,no - it's engine scalability.

[Kupfernigk]

Completely wrong. Piston engines are limited by the essential geometry of the cylinder/valve combination, plus the maximum piston speed which is geometry independent. Once a spark ignition cylinder exceeds about 500cc, its specific output starts to drop. Beyond 2 liters, diminishing returns set in with a vengeance. Mechanical complexity thus sets a limit to aircraft engine horsepower. (Marine engines can be huge because they don't have to worry about weight.) Turbocharging and supercharging eventually reach the point at which a lot of the thrust is being produced by the exhaust - at which point, replace the mechanical complexity of the piston engine with a relatively simple burner, and you have a jet engine which is simpler, lighter and more reliable.

Bottom line: above a few thousand KW, piston engines for aircraft are simply too complex, expensive and unreliable. The fuel is immaterial.

Re:Er,no - it's engine scalability.

[westlake]

One prime candidate for the largest piston-driven aircraft engine ever built, the Lycoming R-7755

You think you have oil consumption problems? Meet the Lycoming R-7755, a 36-cylinder, 5000-hp, turbosupercharged monster displacing 7,755 cubic inches (bore/stroke 6.375 X 6.75 in.) and weighing a mere three tons, give or take a beer keg.

Two of these babies were built in 1946 (one carbureted, one fuel-injected), for the Convair B-36. Pratt & Whitney won the engine contract, ultimately, with its 28-cylinder R-4360 after the Lycoming proved too unreliable. Had Lycoming gotten the contract, the B-36 would have gone into the air with 216 cylinders and 432 spark plugs. Imagine trying to keep 432 spark plugs clean, operating on postwar 115/145 avgas.

The R-7755 was innovative in a number of ways. It was liquid-cooled, which is why the cylinders line up in a perfect line (in 9 rows of 4). Each bank of cylinders had an overhead camshaft. (I don't know of another radial with an overhead cam, do you?) Each cam, in turn, had two sets of lobes: one for high power, the other for long-distance economy cruise. When the pilot chose a different setting, the entire cam would slide lengthwise a couple inches to engage the other set of lobes.

The Air Force spent 10 years battling engine problems in the B-36, many of them related to poor cylinder cooling, others involving carb ice and carburetor fires. None of which would have been a problem with the Lycoming R-7755. Largest Lycoming

Obviously, you are not a golfer...

[denzacar]

Batman has plans for every situation EVER.
In fact, someone "spilling" his plans online was probably his plan all along.

Heck... he has plans about things we can't even imagine happening.
Like DayGlo elephants with machine-guns for limbs raining from the sky. Why would he plan for such an occasion?
Because he is The Batman.