Tethered, Water-Powered Jetpack Provides Two Hours of Flight Time 170
arshadk writes "Unlike 'ordinary' jetpacks, the JetLev is actually two vehicles, tethered by a hose the thickness of your thigh. On the water is a small speedboat-like unit which contains a 250 horsepower motor and a pump. This is connected to the pack — into which you strap your frail body — by a 10-meter hose. The water is pumped from the sea or lake below up to the nozzles on the jetpack, providing a 1,900-Newton thrust, enough to lift a human weighing up to 150 kilos."
Fire hose (Score:3, Interesting)
This is like hanging onto a firehose.
Re: (Score:2)
Exactly what I thought. The background music was also well selected as it sounds like something from a cruise line/vacation spot advertisement. This is the new Parasailing.
Meh. (Score:2)
Re: (Score:2)
Re: (Score:3)
If Americans read that as pounds they'd tell you that's actually quite a small person.
On second thoughts, even if they understood it correctly they'd say the same thing.
Re: (Score:2)
But let us read the fine submission again:
enough to lift a human weighing up to 150 kilos.
That is one fucking big human that has no business being in the air.
or in the water...
Re: (Score:2)
But let us read the fine submission again:
enough to lift a human weighing up to 150 kilos.
That is one fucking big human that has no business being in the air.
or in the water...
Its the new kamikaze, they drop him on the enemy. They have to do something with the fat kids when the draft starts.
Re: (Score:2)
Speaking as someone trying (not very hard) to get my weight down from ~95kg to ~85kg, you're not terribly wrong.
On the other hand, since I'm currently working at sea where there are sometimes operations on the vessel which require "overside" work ... I read that as being quite useful for a 100kg human plus around 30 kg of tools, spare parts, that sort of thing. I'm not sure that I'd want to
useless (Score:1, Offtopic)
Re: (Score:2)
Re: (Score:2)
What I don't get is why the promo video made it look SOOO boring! If this is a way to live out childhood fantasies, fly around a little. Do something more than just hang in the air like you were attached to a rope!
d
Re: (Score:3)
Its the other way around. Think like a canister vacuum cleaner, you tow the vessel. The article says 35MPH for 2 hours if you wanted.
Re: (Score:2)
Re: (Score:2)
Most useless invention ever...
Re: (Score:2)
Most useless invention ever...
It's called entertainment. Some may call it useless. Frankly, I would say it's the only inherently useful thing humans create -- all other "useful" inventions are useful only to the extent that they further our ability to enjoy. The only useless invention is one that never leads to any increase in human joy. Anything that is properly classified as entertainment does, by definition.
Re: (Score:3)
Re: (Score:2)
So you have Christmas at Easter?
Ah, I get it. You live in Australia!
Anyone hoping the guy would run out in mid air? (Score:2)
Maybe it's the American in me, but I was hoping to see the jet pack fail in mid flight as the guy takes a Red Bull flight contest dive.
Re: (Score:2)
You might try telling him you've agreed to a democractic process for choosing your breakfast and ask him to leave.
Re: (Score:3, Funny)
"human weighing up to 150 kilos" You have to wait until they come out with the American version.
Re: (Score:2)
Indeed, but not because of the units. Just the amount....
could it be scaled up (Score:2, Interesting)
Re:could it be scaled up (Score:5, Insightful)
You're then pulling along a 20km hose behind your rocket, and that hose has to be strong enough to support its own weight. You're going to add more weight than you're subtracting.
Unless you built a 20km tall tower that the hose hangs down from and as the rocket ascends you retract the hose so the rocket doesn't have to carry the slack. But then you have to build a 20km tall tower that can hold an enormous amount of hose (still sturdy enough to be 20km long) and the weight of the fuel item you're moving, and since that weight is going to be on one side of the tower you'd have to counterbalance it on the other side. Tricky.
Re: (Score:2)
But then you have to build a 20km tall tower that can hold an enormous amount of hose (still sturdy enough to be 20km long) and the weight of the fuel item you're moving, and since that weight is going to be on one side of the tower you'd have to counterbalance it on the other side. Tricky.
If you build it high enough, then you can just toss the satellite of the roof to get it into orbit. Didn't I read something about this idea in the Bible? The Tower of Babel?
Oh, yeah, that kinda sorta fell down. But with modern nanotube technology, maybe we can work something out?
Re: (Score:3)
If you build it high enough, then you can just toss the satellite of the roof to get it into orbit.
Orbit is about velocity, not altitude. You would have to "toss" it at orbital velocity, otherwise it would just drop...
Re: (Score:2)
Not true if you have a 36,000 km tall tower -> geostationary orbit, taller than that you actually need to slow the object down so it would stay in orbit.
Re: (Score:2)
Re: (Score:2)
Note: a 22,000 miles tower would actually be needed to achieve what I describe, 22 miles wouldn't do it.
Then again, you could always use a geostationary satellite with a large mass and attach a rope to it instead of building a tower and make other satellites to be launched climb up that rope instead.
Build up the mass of the pulling satellite slowly, in many operations ($$$). Take pieces of that rope gradually to the pulling satellite and have space welders assemble it in the way back to Earth.
The nice thing
Re: (Score:2)
I see that you're already aware that you just reinvented the space elevator [wikipedia.org] :)
The nice thing is there is no "you need to support the weight of the rope" non-sense because with centripetal forces, it all equates out and the rope doesn't have to support its own weight.
While the space elevator is a really neat idea, the problem is that your rope unfortunately *does* need to carry its own weight. And for that you need a "rope" with some amazing properties, specifically immense tensile strength.
Carbon nanotubes theoretically have high enough tensile strength, but it's not yet possible to manufacture them in the quantities and with the properties required. If we do manage to construct a space eleva
Re: (Score:3)
First some definitions. For the purposes of this post
Tope is defined as a construction that is built to withstand tension but will simply bend out of the way if subject to compression. Further it has mass. The mass and strength of a rope may or may not be uniform (for a space elavator it most likely wouldn't be)
A space elavator is a rope running from the earths surface and held up by cetrifugal force.
The nice thing is there is no "you need to support the weight of the rope" non-sense because with centripeta
Re: (Score:2)
Weight is proportional to the objects mass multiplied by the inverse square of altitude. Centrifugal force is proportional to the objects mass multiplied by altitude.
Just to clarify those altitudes are relative to the center of the earth not to the earths surface.
Re: (Score:2)
Erm ... that's 22 THOUSAND miles!
Re: (Score:2)
And what we love about PHBs is that they divide by a thousand and think it doesn't make any difference.
But details are for minions. I'm sure that if he doesn't want to build it, you'll find someone else with the right attitude...
Re: (Score:2)
Ha, someone that actually understands PHBs! Mods if I had any.
Space elevator (Score:2)
For a long enough tower (too lazy to compute now, but much larger than the distance Earth-Moon), the velocity given by a normal human toss would be enough
Much lower than that, it's geostationary altitude.
Re: (Score:2)
Re: (Score:2)
except if it's windy, or if everyone suddenly runs to one side.
Re: (Score:2)
Re: (Score:2)
20km is 140km short of low earth orbit. Though you'd have to talk to someone with more structural engineering knowledge than I have to know how impractical a 20km tall tower is this week. And someone with more rocket science knowledge to tell you if this scheme of whatever quantity of fuel this would offload is of any benefit at all.
As for nanotubes, it's my understanding that they have excellent tensile strength but poor compressive strength, making them useful for a "hanging" space elevator but useless
Re: (Score:2)
http://www.howstuffworks.com/space-elevator.htm [howstuffworks.com]
Re: (Score:2)
Better yet, http://www.ebook3000.com/The-Web-Between-The-Worlds_115648.html [ebook3000.com]
Re: (Score:2)
Kinda sorta never existed is more accurate.
Even readers of Snow Crash know that there is historical precedent for the existence of a tower of babel. I'm getting the idea that this Jehovah guy was just some amazing badass with lost alien technology who wanted to rule the world. I mean, where did all that stuff from the Vedas come from anyway? It's 2011, where is my sky chariot!@#~!
Re: (Score:2)
Ah, Slashdot!: Where no creative idea is too good to be voiced without being shot down by a dozen technical objections before it can even take flight.
The OP's idea is speculative, but could be a good way of saving fuel in the first few seconds of rocket flight. But if the general community of engineers has the kind of attitude on display around here, I doubt anyone will even bother to do the calculations.
If this place had been around in earlier years, I doubt space flight, microwave ovens or integrated circ
Re: (Score:2)
The OP's idea is speculative, but could be a good way of saving fuel in the first few seconds of rocket flight. But if the general community of engineers has the kind of attitude on display around here, I doubt anyone will even bother to do the calculations.
No need to bother with the numbers. That is optimizing the, by far, cheapest part of a spacecraft flight by a very small percentage indeed at a staggering capital cost. Its merely pointless.
The other "minor" engineering problem not discussed so far is the tiny problem of maximizing both the height of the building and the lifetime of the building, because to make a profit vs just burning a little more cheap fuel is going to take centuries, eons. We're talking about budgeting around, thru, and long after t
Re: (Score:2)
Although fuel is the cheapest part of the spacecraft flight, it still makes sense to optimize on it, because the sheer quantity of fuel required, as expressed as fraction of the total mass of the vehicle, means that the structures always have to be gossamer things with exotic enough materials and calculations out the wazoo to make that work.
If you could cut the fuel mass to even 50% of the total, you open up a whole slew of possibilities for economizing and safety that just aren't available at our current b
Re:could it be scaled up (Score:4, Insightful)
Space flight was achieved by addressing technical objections, not by ignoring them and pretending "creativity" is all there is to it.
So for instance, if your creative idea requires a 20km high tower made of solid unobtainium, then you have a problem, until you actually succeed at coming up with a material with the required properties.
You're proposing the idea, it's your job to prove it can be done. So go provide some calculations.
Re: (Score:2)
We invite you to do them for us. But I have intuitively strong objections to dangling a hose full of combustible fuel behind a rocket that is trailing a long, hot flame.
Re: (Score:2)
Re: (Score:2)
That depends on the mass of the fuel and the friction of the hose. You could get something like a small-scale orbital fountain effect, so the hose could be designed to be self-supporting.
The problem of how you dispose of a 20 km hose after it detaches would still remain.
Re: (Score:2)
Re: (Score:2)
Easy to calculate. The nice thing is that you don't need to worry about any properties of the elastic band. We will simply assume that you want to replace the thrust available for the length of the launch tower with a mechanical pusher, for some existing rocket.
Let's say we were to "optimize" Falcon 9 that way. Falcon 9 has qty 9 Merlin-1C engines, each operating at isp=300s and thrust=560kN at sea level.
From that we get that each of those engines consumes about 190kg/s of combined propellant (fuel+oxidizer
Re: (Score:2)
Forgot to say the obvious: yes, you could say a little bit over 1% of the propellant (combined fuel+oxidizer). You'd still have to assume that whatever mechanical strong points needed to apply the pushing force come for free in terms of weight -- that's a rather unlikely scenario. Never mind loss of fault tolerance.
Re: (Score:3)
10-20km of hose would be kind of heavy. Especially the top of the hose which has to hold up the rest...
Re: (Score:2)
Re: (Score:3)
Not just tensile strength. 10km of head of pressure is not insignificant, and would require one hell of a pump to push it up there, and a lot of strength to hold it in.
Re: (Score:2)
Not just tensile strength. 10km of head of pressure is not insignificant, and would require one hell of a pump to push it up there, and a lot of strength to hold it in.
Well, you could put multiple pumps along the hose. Of course there will be problems supplying them, so how about distributed tankage along the hose.
Then maybe you could optimize that, by simplifying, by installing all the pumps and tanks in the vehicle. Hmm. I think this idea has promise, powerpoints and promotions for all!
Re: (Score:2)
Not just tensile strength. 10km of head of pressure is not insignificant, and would require one hell of a pump to push it up there, and a lot of strength to hold it in.
Not just tensile strength and massive pumps, but that hose is going to be trailing through the exhaust plume of a rocket. It's going to have to have enormous insulating properties for it to maintain cryogenic temperatures within the hose while facing 3000C temperatures on the outside.
Replace HOSE with LASER and they are working on it (Score:2)
This is the idea behind laser powered flight. Rather then carry the energy (fuel) up with you, you fire the energy at the craft and save a lot of weight. The reason they want to use a laser and not a fuel hose is that nobody is willing to untangle several kilometers of hose after the launch and put it in the rather large garden shed.
Oh look it's Super Mario! (Score:3, Interesting)
Oblig. Warning (Score:3)
WARNING: Jet Pack does not function as a flotation device.
HEX
"Hi, I'm Johnny Knoxville, and this is . . . (Score:2)
The Tethered, Water-Powered Jetpack. With 1,900-Newton thrust.
Falling 30 feet onto water might not be pleasant, but neither is it going kill you.
"Do you care to comment, Mr. Knoxville? We would like an expert opinion.
Re: (Score:2)
I don't know exactly where "painful bruising" ends and "flaying" begins; but I don't really want to find out the hard way...
2 hours? (Score:5, Insightful)
That said, it sure looks fun to try.
Re: (Score:2)
Depending on the lake, 2 hours might not even be enough time to get across. It's only vertical distance that's tethered. Horizontal movement is free.
I mean, when you think about it "why would anyone want or need to walk around on the surface of the ground for two hours nonstop"?
Re: (Score:2)
Jet packs, by comparison, average about 20 seconds...
Re: (Score:2)
Flying at 35 milies an hour with 30' off freedom would be awesome. You could travel up to 70 miles with this. I assume the mileage per gallon of fuel is pretty terrible (maybe 2 miles per gallon?)
However, I can also see this as a way to do certain kinds of maintenance work as well.
Falling 30' could kill you- the odds are slim. But it's possible. But fun!
Re: (Score:2)
From the video I watched it looked like if you wanted any kind of speed you couldn't be as high. The concern I would have with that is assuming you got up to a good clip and assuming you are only 4 feet off the water. If the pump happens to go through a wake and gets slowed down. Which would hit the water first, your feet or your face?
Basically it looks like if all you want to do is hover then this is great, if you want to get anywhere in a reasonable amount of time, 100k can get you a pretty decent boat.
Re: (Score:2)
Alternatively a parachute connected to a boat.
Re: (Score:2)
It isn't world peace, but I could imagine paying $10 for a 5 minute ride on it.
Compared to a jet ski, not jolting along the chop would be nice.
Re: (Score:2)
Until you realise you forgot to put fresh batteries in the remote.
Dupe? (Score:2, Informative)
Re: (Score:2)
Re:Dupe? (Score:5, Informative)
old joke (Score:3, Funny)
Reminds me of an old joke about a wrist watch with a built in TV and built in radio and photo-camera and various other tools.
The only catch was that if you bought that watch you always had to carry 2 suitcases with you.
They were filled with batteries.
Re: (Score:3)
Reminds me of an old joke about a wrist watch with a built in TV and built in radio and photo-camera and various other tools.
Old indeed. Now it's hard to find a smartphone that doesn't have these features.
How about using it underwater? (Score:3)
I'm watching that clip and wondering if you strap on SCUBA gear, make the engine neutrally buoyant, include oxygen tanks for its engine, and just go nuts under water.
Now you have a jet-powered underwater propulsion system. That's got to be rather cool and maybe even useful?
Re: (Score:2)
Re: (Score:2)
There are already more versatile underwater propulsion systems that do not require a tether. There is even a "dolphin" high performance submarine that is more suited to the task. Plus, couple that with the potential risk for an air-embolism if you descend or ascend quickly and you have a recipie for disaster. It makes considerable more sense (and fun!) to use above the water.
Re: (Score:2)
Slashdot's Trusty Time Machine at work! (Score:5, Informative)
Jet Pack Runs For Hours On Water [slashdot.org]
Posted by kdawson on Tuesday February 17 2009, @06:11AM
from the got-your-back dept.
Ponca City, We love you writes
Jet packs have been around for half a century, but there's always been one problem: they run out of fuel in around 30 seconds. Now a German company has taken the standard jet pack design, run a fat yellow hose out the back, and connected it to a small unmanned boat that houses an engine, pump, and fuel tank and sends pressurized water up the hose, where it's shot out by two nozzles just behind the wearer's shoulders. Called the JetLev-Flyer, the design purportedly can reach a height of 15 meters, a speed of 72 kph, and a range of 300 kilometers based on four hours of flying time. A digital fly-by-wire system is used to control the throttle. Future designs may achieve higher altitudes, higher top speeds, and extended range, and even travel below the water's surface. The American manufacturers claim it is 'amazingly easy to learn and operate' and they're taking orders now at $130,000 each.
It's 2009 again!
Re: (Score:2)
Perhaps the news peg is the $30,000 price cut since then?
Re: (Score:2)
The missing bits (Score:2)
it costs $100,000 and your dragging a huge engine in a boat behind you.
would it save you from getting seasick or would you be bouncing up and down with the swell anyway?
wonder if it would be any use for sea rescue its relatively quick at 35 mph and you'd have a reasonable chance of spotting someone in the water. cheaper than a helicopter any way.
diving with it or something similar might be another interesting possibility
looks like fun anyway.
Renting it could prove popular
Meh (Score:2)
Ready market found for device. (Score:3)
Of course first US Navy and Marines will fund the R&D to develop it as AMBaIV (Advanced Marine Boarding and Inspection Vehicle) to serve in the blockade missions. The R&D Center will be in the home district of some powerful senator. So it will get funded. Then the specs will creep up, ability to hover with a machine gun ... 200 rounds of ammunition... SatNav system... eventually a 105 mm naval gun will be added (and 200 rounds of ammunition). Eventually the cost of the system will be so much that actual deployment will never get funded. But using all the R&D knowledge accumulated in the Defense Contractor, they will create a civilian version. Which will start out as a recreational vehicle. Once the production tooling and factories have been paid off the prices will drop. So the early units coming out of service will have very low resale value. These will be bought by the Somali pirates.
I'll Bite (Score:2)
Why not just... (Score:3)
Put a 10 meter scissor-lift on a boat?
I can't imagine shooting a massive fire hose directly into the water is exactly "stealthy", I'm not sure how stable the guy floating on that water jet is, making recon photos (at the least) blurry, and if you have to keep a boat and a tether with you, what are you saving versus a boat with a scissor-lift.
Or, perhaps you could use one of those "mobile surveillance towers" [policemag.com] I've seen in some parking lots/sporting events
Or a mast... (Score:2)
Where did the canoe go? (Score:2)
next invention: barge, crane, a cable tied to vest (Score:2)
LoB
Brilliant! (Score:2)
So this is jut like hanging from a crane boom mounted on a boat, just much more expensive, using much more energy and not as safe?
Brilliant.
Stop being practical everyone! (Score:3)
This device will likely be immensely popular. Even though there are dozens of posts here that dismiss it because one flaw or another, they overlook one of the most obvious and lucrative fields. Tourism. Just like getting parasailing (boat pulling a parachute) is not a practical form of travel, it is quite fun. Also, I suspect the 8.5 meter water jet flight is probably safer than the 15-20m parasail experience. Expect to see jetpack trips on every popular tourist beach in a few years.
From TFA: "The rub is that this costs $100,000 to buy. At this price, it is aimed more at water-sports–rental businesses than at the private user"
Re: (Score:2)
Not to mention any cars underneath parked within a 50 foot radius.
Re: (Score:2)
Pretty useless, as is.
On the other hand, connecting it to a fire hydrant and using it to wash the windows of a 3 or 4 story building....
Leave the pilot on the ground, and see if it can fight fires farther up. One might look at hydraulically powered fans.
Re:Wile E Coyote (Score:4, Funny)
And don't forget flying over the water falls, realizing the error, looks down and sees the boat falling fast, hose stretching and stretching, and then yeowwwwwwww!
LoB
Re: (Score:3)
This so reminds me of Wile E Coyote. Finally, the Acme Jet Pack!
I'd particularly like to watch this when the flier is up at maximum height and going 35mph, and suddenly the boat hits something and stops.
Don't forget that thrilling ride under a bridge.
Re: (Score:2)
You only live twice, twice.
Re: (Score:2)
If only /. would be so smartass as to find its own dupes. I saw the same story years ago, and i believe it even was on the frontpage.
Re: (Score:2)
150kg, though, is a fairly generous ceiling.
Re: (Score:2)
It would be interesting to see, though, for this relatively pricey device, if the users skew a bit taller than average because of the height-earnings correlation that has been observed...