×

Announcing: Slashdot Deals - Explore geek apps, games, gadgets and more. (what is this?)

Thank you!

We are sorry to see you leave - Beta is different and we value the time you took to try it out. Before you decide to go, please take a look at some value-adds for Beta and learn more about it. Thank you for reading Slashdot, and for making the site better!

The Ephemerality and Reality of the Jetpack

samzenpus posted about 10 months ago | from the up-up-and-away dept.

Transportation 127

First time accepted submitter Recaply writes "Here's a look back at the 1960's Bell Aerosystems Rocket Belt. 'Born out of sci-fi cinema, pulp literature and a general lust for launching ourselves into the wild blue yonder, the real-world Rocket Belt began to truly unfold once the military industrial complex opened up its wallet. In the late 1950s, the US Army's Transportation Research Command (TRECOM) was looking at ways to augment the mobility of foot soldiers and enable them to bypass minefields and other obstacles on the battleground by making long-range jumps. It put out a call to various aerospace companies looking for prototypes of a Small Rocket Lift Device (SRLD). Bell Aerospace, which had built the sound-barrier-breaking X-1 aircraft for the Army Air Forces, managed to get the contract and Wendell Moore, a propulsion engineer at Bell became the technical lead.'"

Sorry! There are no comments related to the filter you selected.

Almost as if (0)

Anonymous Coward | about 10 months ago | (#46384291)

the technological fantasies of the past don't always make sense. But space elevators and asteroid mining totally make sense.

Re:Almost as if (3, Insightful)

phantomfive (622387) | about 10 months ago | (#46384375)

Jetpacks make sense if you can get them to work. If you can get one to every person in your army, imagine the mobility you would have. Think of the kinds of flanking maneuvers you could perform. The same would be true for flying cars. Of course, the barriers are cost, controllability, range.....things like that.

Space elevators and asteroid mining can make sense too, but in those cases (assuming the space elevator can actually be built, which it can't with today's materials) it becomes a cost/benefit analysis. Is it cheaper to mine asteroids, or get the same materials here on earth? As soon as it's cheaper to get them from asteroids, we will get them from asteroids. Is it cheaper to get things into orbit via space elevator? We don't know yet, but if it is, then we will build a space elevator.

Re:Almost as if (0)

Anonymous Coward | about 10 months ago | (#46384389)

Jetpacks make sense if you can get them to work. If you can get one to every person in your army, imagine the mobility you would have. Think of the kinds of flanking maneuvers you could perform. The same would be true for flying cars. Of course, the barriers are cost, controllability, range.....things like that.

Flanking maneuvers? "Hey everybody, shoot the loud flying things over there!" I don't know what place they would have on a modern battlefield. At best, if there was a miniature, silent version, there could be some use for special forces, but that violates laws of physics, so ... yea, seems pointless.

Re:Almost as if (2)

phantomfive (622387) | about 10 months ago | (#46384403)

Flanking maneuvers? "Hey everybody, shoot the loud flying things over there!"

A flanking maneuver doesn't need to be a surprise. It just needs to be fast enough to get into position before the defenders can rearrange themselves.

I don't know what place they would have on a modern battlefield.

Whether they have a place on the modern battlefield is equal to the question of whether infantry has a place on the modern battlefield. If they do, then having a mobile infantry is an advantage.

Re:Almost as if (0)

Anonymous Coward | about 10 months ago | (#46384489)

You know Batman isn't real, right? If the ability to fly is important, as opposed to traveling over the ground, you're close enough to get shot while you're flying. If not, give everyone motorcycles in your imaginary world.

Re:Almost as if (1)

phantomfive (622387) | about 10 months ago | (#46384577)

If the ability to fly is important, as opposed to traveling over the ground, you're close enough to get shot while you're flying

Don't fly so close to the guns!

Re: Almost as if (0)

Anonymous Coward | about 10 months ago | (#46385317)

no, it is "get out of range of those guns"

Starship Troopers (1)

rossdee (243626) | about 10 months ago | (#46384571)

"Whether they have a place on the modern battlefield is equal to the question of whether infantry has a place on the modern battlefield. If they do, then having a mobile infantry is an advantage."

There is a big difference between what the jet pack can do, and what the armored suits of the "Mobile Infantry" could do. For a start they had nuclear power, so could keep flying for hours not minutes. And of course they were fighting in alien worlds, there were no civilians around to worry about collateral damage.

Re:Starship Troopers (1)

phantomfive (622387) | about 10 months ago | (#46384589)

There is a big difference between what the jet pack can do,

Yes, that is why the discussion is about what a jet pack could do if the practical limitations were overcome. Context is important.

Re:Almost as if (2)

gmhowell (26755) | about 10 months ago | (#46385575)

Whether they have a place on the modern battlefield is equal to the question of whether infantry has a place on the modern battlefield. If they do, then having a mobile infantry is an advantage.

Mobile infantry made me the man I am today.

Re:Almost as if (2)

LordLimecat (1103839) | about 10 months ago | (#46385907)

Whether they have a place on the modern battlefield is equal to the question of whether infantry has a place on the modern battlefield.

No, its not.

Infantry are mobile, versatile, able to perform precision strikes, able to adapt to many situations.

Rocket belts are heavy, unwieldy, unreliable, expensive, noisy, and incredibly niche. Im sure there are circumstances where it happens to be the right tool for the job, Im just not sure what that might be or why youd want to weigh all of your infantry down with it for that one circumstance.

Re:Almost as if (1)

phantomfive (622387) | about 10 months ago | (#46385965)

You clearly missed the part where we're talking about hypothetical future jetpacks. Context man, context!

Re:Almost as if (1)

gIobaljustin (3526197) | about 10 months ago | (#46385971)

That might be the case, but it might also not be the case.

Re:Almost as if (1)

AK Marc (707885) | about 10 months ago | (#46385345)

Flanking works great in today's wars because the armor goes at the front and the squishies in the back. If you come at them from the side/back, you get to take out more of their squishies than they get of yours. If you get them directly from both sides in a crossfire, then they must split their forces for a 2-front defense, greatly reducing their defensive effectiveness.

Re:Almost as if (0)

Anonymous Coward | about 10 months ago | (#46385667)

Flanking works great in today's wars because the armor goes at the front and the squishies in the back. If you come at them from the side/back, you get to take out more of their squishies than they get of yours. If you get them directly from both sides in a crossfire, then they must split their forces for a 2-front defense, greatly reducing their defensive effectiveness.

You in the army? Because my understanding is that's completely backwards [slashdot.org] for even WWII-era thinking, and since then combined arms has been transformed by the use of air power. So unless you're fighting for the Serbian army, this sounds like computer game logic, not military thinking. Or perhaps military thinking for late WWI, early WWII.

Re:Almost as if (1)

AK Marc (707885) | about 10 months ago | (#46385715)

Nope, flanking is still a good idea. It's just that with air power, you flank from above. Or so says your link, which does agree with me.

this sounds like computer game logic, not military thinking.

Wars are games. Like Risk or Chess, but with real people. Many of the tactics used were thought up in game-like ways.

Re:Almost as if (0)

Anonymous Coward | about 10 months ago | (#46385803)

"Flank from above"? Seriously? We call those planes. And they're easier to automate than soldiers on foot, hence UAVs. Dear god, I hope you're not actually in charge of people's lives.

Can't you visualize these flying people you speak of? They won't be moving fast, so they'll be easier to hit than the slowest of planes, and they won't have a stable platform to shoot from like a helicopter. If they have any altitude worth a jetpack, they'll be extra visible. If they are far enough from the front line for that not to matter, who gives a damn whether it's a jetpack or a jeep?

Wars are games. Like Risk or Chess, but with real people. Many of the tactics used were thought up in game-like ways.

Well, you import an army of jetpack people into a modern wargame which could realistically simulate them, and I'll gladly kick your ass.

Re:Almost as if (1)

AK Marc (707885) | about 10 months ago | (#46386151)

"Flank from above"? Seriously?

That was a direct quote from the person I was responding to (well, their link).

Re:Almost as if (1)

pepty (1976012) | about 10 months ago | (#46385743)

In today's wars only one side has any armor or an air force to speak of. If not at the beginning then at least by the time the winning side's "squishies" are brought forward.

Re:Almost as if (1)

pepty (1976012) | about 10 months ago | (#46385749)

miniature silent version

Ah.

That would be called a drone.

Re:Almost as if (0)

Anonymous Coward | about 10 months ago | (#46386107)

miniature silent version

Ah.

That would be called a drone.

You know that they're anything but "silent", right?

Re:Almost as if (0)

Anonymous Coward | about 10 months ago | (#46384497)

Um, you're joking, right? You have to be kidding.

Re:Almost as if (4, Funny)

fahrbot-bot (874524) | about 10 months ago | (#46384627)

Jetpacks make sense if you can get them to work.

As would many, many other things, like Warp Drive [wikipedia.org] and the G Spot [wikipedia.org] .

Re:Almost as if (1)

ColdWetDog (752185) | about 10 months ago | (#46384985)

G-spot? That's crazy talk.

Re:Almost as if (1)

plover (150551) | about 10 months ago | (#46385157)

I think the biggest problem with jetpacks is the logistics of carrying them when you're not actually jetting about with them. They were simultaneously bulky, fragile, and extremely combustible. Plus, the things weighed 60 kg when fueled, and this would almost double the normal amount of weight the average infantryman is required to carry. Even if they had a specific military purpose, getting them to the soldiers who need them at the exact time they need them is problematic.

Re:Almost as if (1)

AK Marc (707885) | about 10 months ago | (#46385371)

For the military, I'd go with jump-jets. The "launch" is taken care of by a catepult. The jet pack needs half the fuel and only turns on at the apex. Parachute as backup for pack failure. You strap in at launch points (in a jump vehicle) and get shot out like meat-artillery. You then "glide" to the earth, maybe with a small gliding device and the pack for more lift.

How about an army of autogyros, droned with the human shooting from it as a flying weapon platform? That sounds like an evolution of the flying infantryman. Or whatever they call it when you have a parachute, and a huge fan on your back, giving you thrust and the chute lift, so you have the ability to climb or go long distances. That's more practical than the jump packs.

Re:Almost as if (1)

LordLimecat (1103839) | about 10 months ago | (#46385913)

Youre still carrying a massive extra load just for that one time you happen to need jumpjets.

We have a lot of other ways of accomplishing the things a jumpjet does without all of the ridiculous complexity and logistics it requires.

Re:Almost as if (1)

AK Marc (707885) | about 10 months ago | (#46386155)

But it'd be cool.

Re:Almost as if (1)

LordLimecat (1103839) | about 10 months ago | (#46385895)

Alernatively, imagine how many more soldiers you could pay for and equip instead of issuing these jetpacks to all of them. You essentially have a choice between more soliders with more versatile gear and better mobility, or rocket soldiers who get one 20 second instance of unstable flight before needing to refuel-- not to mention the tax on their mobility all the rest of the time.

Yea, Ill take more soldiers, thanks. If you need air support, thats what the air force is for.

Re:Almost as if (1)

delt0r (999393) | about 10 months ago | (#46386343)

Jetpacks from a 100% efficient physics perspective can't work unless you have an arc reactor. They will always have very poor range, and huge jet/prop blast. As for military applications, well its not going to be too far into the future where it won't be fleshy meat bags doing the shooting.

Space elevators proponents always miss one very important detail. If you have the material to make the elevator, you can use that material to make traditional rockets too. And it may well make rockets cheaper than a elevator.

Re:Almost as if (1)

phantomfive (622387) | about 10 months ago | (#46388073)

Space elevators proponents always miss one very important detail. If you have the material to make the elevator, you can use that material to make traditional rockets too. And it may well make rockets cheaper than a elevator.

I always thought the most expensive component of a rocket was the fuel, but who knows

Re:Almost as if (1)

mrchaotica (681592) | about 10 months ago | (#46388195)

Space elevators proponents always miss one very important detail. If you have the material to make the elevator, you can use that material to make traditional rockets too. And it may well make rockets cheaper than a elevator.

Although making rockets out of nanotube carbon fiber would certainly reduce the weight, it wouldn't reduce it that much. You forget that the bulk of a rocket's weight is fuel; eliminating that is the "big win" a space elevator provides.

Re:Almost as if (2)

rgbatduke (1231380) | about 10 months ago | (#46387337)

There are a few minor practical problems with jet packs, or more properly, rocket packs as these devices are rockets, not turbojets, and it matters. It matters because there are some pretty fundamental limits on how much fuel/reaction mass a soldier can carry, especially when they have to carry other stuff like body armor, weapons, helmets, ammunition, food, shelter. Let's imagine that a stripped down soldier carrying little but armor, ammo and a rifle has a mass of 100 kilograms, 90 kilograms of which are the actual soldier. The rocket pack described above had a mass (full) of 57 kilograms and required the pilot to wear heat-protective clothing -- let's call it 60 kilograms. So wearing it and suitable armor and carrying weapons would be a roughly 70 kilogram burden on a 90 kilogram soldier, sort of like wearing a liquid nitrogen and hydrogen-peroxide-filled teen-ager on your shoulders as you wade into battle.

Sadly, this model would not work at all for the current rocket pack designs -- they provide less than 1500 N of thrust, and our soldier now has a weight of 1600 N. He would burn half of his fuel (give or take) waiting for the fuel levels in the tank to drop to where he could take off at all. The troop of rocket-equipped soldiers would all have to be "feather merchants" -- mass 70 kg or less -- and be armed with plastic squirt guns to get off of the ground at all.

Even with modern improvements, nobody has been able to increase flight time beyond around 30 seconds. The practical range in 30 seconds is perhaps 200 to 300 meters, at a height of ten meters -- a height great enough that it is already dangerous to fatal if one falls from it wearing an explosive, superheated massive outfit on your back. One cannot expect to increase their range or flight time because rockets eject mass backwards at high speed in order to provide thrust forward. The backward speed of the reaction mass is determined and limited by thermodynamics and chemistry and the need not to cook the soldier to extra crispy in a 30 second flight. There isn't that much variation in what's available to use for thrust in this context -- one could probably improve on the 740 C exhaust temperature, but only at the expense of adding a lot more shielding (and weight) and much more protective clothing.

The more interesting possibility is to build an actual jet pack -- jets of course use air for thrust mass and use fuel just to heat and compress the air, so they potentially have a much greater range. Small jet engines are mostly hobbyist stuff at the moment, but can produce order of a kilonewton of force at a mass cost of maybe 20 kilograms for the engine itself. One would need two, still further efficiency improvements, serious hearing protection, better shielding in the clothing (jet exhaust is still hotter than the "rocket" exhaust of hydrogen peroxide catalysis to water and oxygen). There is even military technology associated with cruise missiles that could be adapted.

We could learn another lesson from cruise missiles as well. Wings help. Wingsuits, for example, increase the glide ratio of skydiver to six. Hang gliders can achieve 17 to 20. Equipping a small hang glider with a small jet engine (one engineered to run without overheating for indefinite periods of time, unlike many of the powered hang glider engines currently available that tend to be based on two stroke chainsaw motors) could conceivably result in a wearable harness with a comparatively small wingspan in which a fully equipped soldier would have a range of tens of kilometers in tens of minutes at heights ranging from 10s of meters to a thousand meters or so. After powering up and attaining height, the engines could be shut off and the gliders could passively and silently descend from a height of a kilometer to a target 10 kilometers away.

The wings would have to be designed to be "compressible" to a comparatively small pack and quickly and easily erected into a structurally stable functional form, and would probably mass 50 to 70 kg including fuel, but this just puts them into the exact same range as rocket packs -- barely light enough to be useable by a soldier small enough to fly and large enough to lift it.

The good thing about this is that hang gliders are cheap, established technology, and small jet engines are straightforward to design and build, using readily available kerosene as fuel. The bad thing is that powered or not, a troop of soldiers in hang gliders would be a skeet shoot. As would soldiers with rocket packs.

There is a reason the military has focused on armed and armored helicopters to accomplish exactly the same purpose as rocket pack or jet powered wing, and has concentrated an entire branch of the military on the far more interesting problem of delivering death and destruction on a ground based enemy from the air or moving soldiers and material longer distances. It is a lot more cost effective, requires a lot fewer trained flight personnel, is vastly safer, provides enormously greater protection for the troops en route, has active offensive capabilities while in the air, and doesn't have to travel "with" the soldiers in the field to be of use as it is capable of going to them wherever they are.

So whether or not one can come up with imaginative rocket pack designs or more practical jet pack or jet wing designs, I'm pretty sure the military abandoned the idea because even if they worked perfectly at a nearly science fiction level the idea is dumb. Between the limitations imposed by physics and chemistry on any of the various design families and the fact that troops travelling slowly through the air using expensive, massive equipment that has to be kept with them at the front lines to be of any use might as well have big targets painted on them all the time that they are in the air, just dumb.

One could conceive of keeping a single unit in the army for "special ops" kinds of missions where they might be equipped with such things, and I wouldn't be at all surprised if they don't already have one. But equipping any significant fraction of front-line troops in a modern battlefield with such devices? Sheer madness.

Re:Almost as if (0)

Anonymous Coward | about 10 months ago | (#46387615)

If you have them, the enemy has them. Your flanking supposition doesn't include for that.

wrong (0)

Anonymous Coward | about 10 months ago | (#46388135)

Rocket belts make no sense and that's why they've never been used other than for research and demonstration purposes. They're incredibly expensive, heavy, offer no margin of safety since you're too low for a parachute to of any use in case of failure.

Oh and you can't ever fly longer than 30 seconds.

FUCKING DUH

Re:Almost as if (1)

hey! (33014) | about 10 months ago | (#46388321)

Jet packs make sense if you can get them to work.

There's the rub right there. Feasibility is a prerequisite of "making sense", and in the real world you have to deal with physics and the physical limitations of human beings. Antigravity would "make sense" if you could get it to work.

The physics of a jet pack are governed by the rocket equation: V = Ve * ln(Mt/Mp). You need to carry enough mass, ejected at a sufficient speed, to produce 9.8 m/s v every second.

The upshot is that to counterbalance the weight of a soldier and his gear you can either have your rocket eject a lot of mass at low velocity or a small amount of mass at high velocity. That's why the rocket belts thus far have only had a very, very short burn time. To increase the burn time you'd need to carry more fuel than a man could lift.

A typical infantry solider or marine carries over a hundred pounds of gear into battle. Even accounting for things he could dispense with if he had greater mobility, he can't carry much fuel to power his rocket belt. A practical battlefield air transport machine would be a small vehicle which carries more weight than an individual solider can. In other words: a helicopter.

Similar concerns attach to asteroid mining. You *can* physically go out there and return materials from asteroids, just like you *can* strap a rocket belt on a soldier. The question isn't whether physics permits it, but rather whether physics permits economically feasible retrieval of asteroid material, and that's a lot tougher than it sounds. Even the "asteroid belt" is practically empty by terrestrial standards; your chance of randomly encountering anything larger than a dust speck while crossing it is less than hitting the lottery. So prospecting for nuggets of stuff like platinum is physically possible, but not feasible. Unless we hit the jackpot with a near earth object like 433 Eros, we won't see asteroid mining until v in space becomes much, much cheaper.

sound-barrier-breaking X-1 aircraft (2)

Deadstick (535032) | about 10 months ago | (#46384347)

...as opposed to the rocket belt, which was merely eardrum-breaking...

This Day on Slashdot (1)

Anonymous Coward | about 10 months ago | (#46384353)

I know it's offtopic and all, but is it just me, or has this not changed in like a week or more?

Re:This Day on Slashdot (2)

Soulskill (1459) | about 10 months ago | (#46385795)

We had to disable updates to most of the Slashboxes, including 'This Day on Slashdot' in order to fix an underlying issue in the code. The work should be completed soon, at which point we'll re-enable everything. Apologies for the inconvenience!

Re:This Day on Slashdot (1)

ObsessiveMathsFreak (773371) | about 10 months ago | (#46387203)

I am detecting a significantly elevated level of story quality and of course, beta changes, in the last week or so. I guess you guys really did listen...eventually.

Can we discount the possibility that the (1)

rmdingler (1955220) | about 10 months ago | (#46384357)

Chuck Taylor's weren't responsible for the gain in vertical leap?

Re:Can we discount the possibility that the (1)

rts008 (812749) | about 10 months ago | (#46384419)

No.

Kids these days...*sigh.

Chuck Taylor's couldn't hold one of the PF Flyers shoestrings!

PF Flyers even came with a 'Magic Ring' that done encoding and decoding...Johnny Quest would never lie to me.

Ankles are lousy landing gear (4, Interesting)

Animats (122034) | about 10 months ago | (#46384401)

A big problem with jetpacks is that human ankles are weak landing gear. You can't do a parachute landing fall while wearing a jetpack; you have to do a standing landing. With all the mass of the gear on your back.

The other big problem is that rocket systems have a short flight time, and jet engine systems are too expensive. The jet engine powered backpack [youtube.com] worked well, but cost too much. That used a small Williams jet engine. Williams International has tried and tried to make small jet engines cheaper. So have many others. Unfortunately, that's a very hard problem, which is why general aviation is still piston-powered. Below small-bizjet size, jet engines don't seem to get much cheaper as they get smaller. There was a big effort about a decade ago to develop "very light jets", but they ended up costing well over $1 million, most of that being engine cost.

So it can be done, and it has been done, but it just doesn't work very well.

Re:Ankles are lousy landing gear (-1)

Anonymous Coward | about 10 months ago | (#46384437)

Price will lower when they will be able to simply print it.
No other way around.

Re:Ankles are lousy landing gear (2)

phantomfive (622387) | about 10 months ago | (#46384473)

Price will lower when they will be able to simply print it.

Pretty sure 3-D printing is more expensive than other mass-manufacturing processes (injection molding). The advantage of 3-D printing is, you can do it at home, and in single quantities, it is cheaper.

But if you're expecting 3-D printing to eventually make everything cheaper, you'll probably be disappointed. The most that could be expected is to bring the costs of custom items be the same as mass-manufactured items. Which is still a good thing.

Re:Ankles are lousy landing gear (2, Insightful)

ColdWetDog (752185) | about 10 months ago | (#46385005)

Anyone expecting printed materials to survive environments typically found inside jet or rocket engines needs to be awfully patient.

Re:Ankles are lousy landing gear (1)

50000BTU_barbecue (588132) | about 10 months ago | (#46385321)

Well, selective laser sintering seems to be at that stage, however from what I understand, it's still a huge machine, a slow process and requires as much if not more skill and knowledge as machining from stock.

You aren't going to see huge improvements in designs anymore IMO, just some tweaks in manufacturing processes. SLS can do things like progressively blend from one alloy to another in one part. How much that helps I don't know.

Re:Ankles are lousy landing gear (0)

Anonymous Coward | about 10 months ago | (#46385663)

In high performance parts like turbofan blades, you absolutely must control the microstructure of the steel to within extreme tolerances. I don't believe laser sintering can accomplish that. From everything I've read, the tensile strength of sintered steel, for example, is several times weaker than cast steel. And that's using state-of-state, very expensive printing techniques (in nitrogen vacuum, etc). You can improve strength by subsequent annealing, but you still can't match existing techniques.

Given the performance demands of something like a jet engine, I'm going to go out on a limb here and guess that it'll be one of the very last applications for 3D printing, many decades from now, if ever. I can just imagine a whole plane being printed, with hollow cavities for the engines.

Re:Ankles are lousy landing gear (0)

Anonymous Coward | about 10 months ago | (#46386281)

I can just imagine a whole plane being printed, with hollow cavities for the engines.

And crew, hopefully.

Re:Ankles are lousy landing gear (1)

delt0r (999393) | about 10 months ago | (#46386363)

Laser sintering gets you sintered material with different properties than say single crystal material. http://www.appropedia.org/Sing... [appropedia.org]

Re:Ankles are lousy landing gear (2)

Confusador (1783468) | about 10 months ago | (#46386405)

Anyone expecting printed materials to survive environments typically found inside jet or rocket engines needs to be awfully patient.

Or, you know, NASA. [parabolicarc.com]

Re:Ankles are lousy landing gear (1)

Chris Mattern (191822) | about 10 months ago | (#46386785)

One notes that this part is not *inside* the engine, but is a port cover for a secondary system. Pump exhaust covers/baffles, yes. Turbine blades? Not so much.

Re:Ankles are lousy landing gear (2)

jstults (1406161) | about 10 months ago | (#46387741)

GE is going to production with 3D printed fuel injectors [bloomberg.com] and uses 3D printed turbine blades for testing right now.

or just competent (of course being both patient an (1)

Anonymous Coward | about 10 months ago | (#46387681)

http://www.nasa.gov/press/2013/august/nasa-tests-limits-of-3-d-printing-with-powerful-rocket-engine-check/#.UxSiDvRdU9c

Re:Ankles are lousy landing gear (1)

AK Marc (707885) | about 10 months ago | (#46385397)

One of the ways 3D printing makes everything cheaper is easier prototyping and drops in the cost of tooling, when you can make moulds out of 3D printed things, rather than by hand, then use those moulds to make the tooling, cutting retooling costs and time, dropping production cost.

Re:Ankles are lousy landing gear (1)

phantomfive (622387) | about 10 months ago | (#46385617)

That will be better when they can do that.

Re:Ankles are lousy landing gear (1)

AK Marc (707885) | about 10 months ago | (#46385693)

Or when they can build per atom with any material. They can call them "replicators". Even better if they have a fission/fusion power source that can assemble any element/compound that's atomically stable (the other excluded for safety reasons, though ordering up a 3l jug of HF or SbHF6, or some other relatively dangerous chemical

Re:Ankles are lousy landing gear (2)

phantomfive (622387) | about 10 months ago | (#46385711)

Yeah, once you have near infinite energy for cheap, then lots of other things become cheap as well.

Re:Ankles are lousy landing gear (1)

AK Marc (707885) | about 10 months ago | (#46385763)

We should start with covering the moon in solar panels and transmission stations.

Re:Ankles are lousy landing gear (1)

LordLimecat (1103839) | about 10 months ago | (#46385941)

transmission stations

Also known as "death rays". Dont let China see you pointing it at you or you may see your solar panels destroyed.

Re:Ankles are lousy landing gear (1)

delt0r (999393) | about 10 months ago | (#46386371)

And it has been used for this for decades.

Re:Ankles are lousy landing gear (2)

delt0r (999393) | about 10 months ago | (#46386357)

Printing does not the crystal structure they way you need it for high temperature metals and materials. Most metals in use today, including that outside casing on iPhones need non trivial heat treatments. In fact using the iPhone as an example, its forged then machines precisely because it was the only way to get a metal with the properties it required. In short, you can't print it.

Re:Ankles are lousy landing gear (1)

phantomfive (622387) | about 10 months ago | (#46384447)

That's a great video

Re:Ankles are lousy landing gear (1)

Recaply (3554641) | about 10 months ago | (#46384495)

Great video thanks for sharing. Added it into the post..

Re:Ankles are lousy landing gear (1)

wisnoskij (1206448) | about 10 months ago | (#46384755)

That and stabilization.

It is easy to launch someone into the air with just a moderate amount of explosives, or a jet engine strapped to your back, doing so in a slow controlled manner when we are talking at least 300 pounds of human, their gear, and the jetpack itself is a whole lot harder. Add to that this engine or rocket has to be in direct contact with a living human being for an extended period.

Practically, you are not going to create a solution light enough to carry around just in-case it is needed. Maybe you could create something that is usable, but it will be so heavy that, best case scenario, it would just be carry-able by a single man without too much extra gear, and more likely it would be a very limited range vehicle that needed to be transported to where it was to be used by plane or truck.

Re:Ankles are lousy landing gear (1)

plover (150551) | about 10 months ago | (#46385177)

I think they could solve stabilization with modern electronics. Kid's toy quadcopters are already self leveling, and as they weigh much less thank a kilogram, they're far more "twitchy" than 150kg of inertia carried about by the humans and their gear.

As you mentioned, it's the soldier who has to carry the additional 60kg pack that is the real limit.

Re: Ankles are lousy landing gear (1)

Em Adespoton (792954) | about 10 months ago | (#46385513)

Two words:

Robotic Exoskeleton

Re: Ankles are lousy landing gear (0)

Anonymous Coward | about 10 months ago | (#46386341)

Two words:

Additional weight

Re:Ankles are lousy landing gear (1)

Anonymous Coward | about 10 months ago | (#46385433)

Practically, you are not going to create a solution light enough to carry around just in-case it is needed. Maybe you could create something that is usable, but it will be so heavy that, best case scenario, it would just be carry-able by a single man without too much extra gear, and more likely it would be a very limited range vehicle that needed to be transported to where it was to be used by plane or truck

Which is why we still use helicopters. We haven't really figured a way to scale that type of mobility down to a single person. And frankly speaking, unless we get moving on actual mechanized battle-suit technology, we won't. The ultimate problem is your power source, getting it small and light enough while maintaining enough power to be useful.

Re:Ankles are lousy landing gear (1)

jafac (1449) | about 10 months ago | (#46384803)

Based on the prices of some programs, I don't think that "too expensive" is an issue.

When killing people is concerned, I think that no price is too high for our military.

Re:Ankles are lousy landing gear (1)

pepty (1976012) | about 10 months ago | (#46385759)

The goal isn't to kill people; the goal is to distribute the project to as many congressional districts as possible. More moving parts, more better.

Williams WASP X-Jet (5, Interesting)

OzPeter (195038) | about 10 months ago | (#46384423)

This is the reality of how to make a single man fly.

Williams WASP X-Jet [youtube.com]

It worked, it flew, there was no military justification for it, it disappeared.

Re:Williams WASP X-Jet (1)

phantomfive (622387) | about 10 months ago | (#46384823)

It worked, it flew, there was no military justification for it, it disappeared.

Specifically, with fuel lasting only 30 minutes, it didn't have much practical application.

Re:Williams WASP X-Jet (1)

aliquis (678370) | about 10 months ago | (#46384907)

As I understood it the designer behind that one is a one which worked with Moore until he died (at age 54?) and later continued with the work.

I'm not all that surprised there wasn't much interest for that can though. Then again maybe it was awesome to avoid branches, offer some protection, let you carry gear / rifle, .. Maybe it just looked worse :)

They all controlled great :)

Holy Crap! (1)

Ecuador (740021) | about 10 months ago | (#46385405)

I saw that when I was a kid in the 80's on some TV program and as I grew up I was pretty sure that I had either watched something fictional, or I was too young and misunderstood. I mean, if they had that working in the 70s, they would have something even better in the 90s, 00s etc, instead of, ehm, pretty much nothing. Thanks for that! You verified my childhood memory and solved what was a "mystery" to me!!

Re:Holy Crap! (1)

LordLimecat (1103839) | about 10 months ago | (#46385943)

AFAIK power density hasnt really changed that much. You have a pretty fundamental limit on how long flight lasts given a fuel density and a payload.

Re:Holy Crap! (1)

twosat (1414337) | about 10 months ago | (#46385959)

I remember seeing this on a TV science program in the 1980's when I was at university in New Zealand. I'm pretty sure that it would have been mentioned in science magazines like "Popular Science" and "Popular Mechanics" - it was well-known at the time.

Re:Williams WASP X-Jet (0)

Anonymous Coward | about 10 months ago | (#46385569)

This is the reality of how to make a single man fly.

Williams WASP X-Jet [youtube.com]

It worked, it flew, there was no military justification for it, it disappeared.

Ya, I've seen that one before, it's brought up in a lot of Conspiracy-type books/videos.
It's not a jet pack- you can't carry it around until needed, which is the idea that would make a jet-pack useful. It's a light vehicle, and if you're going to go through everything needed to support it you may as well just scale it up a notch and go with a helicopter.

Re:Williams WASP X-Jet (1)

ObsessiveMathsFreak (773371) | about 10 months ago | (#46387231)

To be fair, it could be defeated completely by wearing the crocodile mask.

Checkout the Martin Jetpack (0)

Anonymous Coward | about 10 months ago | (#46384613)

http://www.martinjetpack.com/

Re:Checkout the Martin Jetpack (0)

Anonymous Coward | about 10 months ago | (#46385595)

http://www.martinjetpack.com/

Sigh. Calling shit like this a "jetpack" is highly misleading at best. It's not a pack, it's a light-weight vehicle with an open cock-pit that you strap yourself to.
The entire point of calling something a "jetpack" is that it's a PACK which you can strap to your back, pickup with one hand, and hike around with until such a time as you need to use it.

Me, me, me...I want to name it. (0)

Anonymous Coward | about 10 months ago | (#46384661)

Sky Segway.

1950s (3, Insightful)

djupedal (584558) | about 10 months ago | (#46384669)

I suspect they ran the numbers and decided that rather than making medicore-range quasi-flyers out of ground soldiers, the smart money was on just getting it over with and develop better helicopters, instead. Better speed; longer flights; bigger payloads - all much cheaper than adding limited flight capabilities to the individual.

Re:1950s (2)

delt0r (999393) | about 10 months ago | (#46386375)

Jet packs are like flying cars. Everyone thinks they are awesome and would make like better, but no one knows how or why it would be better. Logic is hardly going to work with these fans.

Also the way things scale means its easier and cheaper to make some of these things bigger. So its cheaper to make a 2 man-4 man helicopter than a one man jet pack. Range is always a problem with smaller things because of the cube law.

Re:1950s (0)

Anonymous Coward | about 10 months ago | (#46387423)

I'm stuck in traffic. The sky is empty. If I had a flying car, I wouldn't be stuck in traffic.

I have to get across town, could walk for an hour, catch a bus or three, take a train, take a car through traffic, none of which are quick or direct. If I had a jet pack, I could go direct and quickly.

Like another problem (1)

TheRealMindChild (743925) | about 10 months ago | (#46384701)

Like the problem with a functional 5 megawatt laser, it is about a power source

Re:Like another problem (1)

phantomfive (622387) | about 10 months ago | (#46384825)

So many uses for Mr Fusion. Sigh.

Re:Like another problem (0)

Anonymous Coward | about 10 months ago | (#46386223)

Well, yes, but when this happened there were still fantasies of nuclear powered cars ....

So, not so stupid other than the wishful thinking.

It is a reality - Check out the Martin Jetpack (0)

Anonymous Coward | about 10 months ago | (#46385085)

Jetpacks are better for civilian rather than military use, e.g. search & rescue;

http://www.martinjetpack.com/

Re:It is a reality - Check out the Martin Jetpack (2)

PPH (736903) | about 10 months ago | (#46385137)

For the search part, a UAV would probably be a cheaper way to put sensors in the air. For the rescue part, you need to hover and lift quite a bit of weight. Consider that many victims need some medical attention or at least assistance in getting aboard the rescue craft. So that means a crew of several people plus rescue gear (basket, stretcher, etc.). Well beyond the capabilities of a jet pack and even some small helicopters.

Re:It is a reality - Check out the Martin Jetpack (1)

coofercat (719737) | about 10 months ago | (#46386713)

Although, much like the paramedics on bicycles or motorbikes, getting somewhere first, even if you can't get back out again is sometimes useful.

As someone above said though, lugging a couple of these about the place, just in case you need to get one person somewhere really quickly seems like an awful overhead for a one-time, niche use.

Re:It is a reality - Check out the Martin Jetpack (0)

Anonymous Coward | about 10 months ago | (#46385689)

Jetpacks are better for civilian rather than military use, e.g. search & rescue;

http://www.martinjetpack.com/

That's not a jetpack, it's a lightweight vehicle.
A Jet PACK is something you can pick up with one hand and carry around on your back. This shit isn't it, so stop whoring for page hits asshole.

Jetpacks, flying cars - same problme (4, Informative)

joe_frisch (1366229) | about 10 months ago | (#46385527)

We don't see jetpacks or flying cars for the very same physics reason. In order to hover against gravity you need to produce thrust > weight. Since thrust is proportional to (mass/second) X velocity, and power is proportional to (mass/second) X velocity^2, an efficient source of thrust you want to move a lot of material slowly (assuming you have unlimited reaction mass -> the atmosphere).

So, things that hover need to move lots of air, and have great big propellers. That is why helicopters work, and jet-reaction cars are too inefficient to be practical. It is why airplanes have big wings, not stubby lifting bodies. There may be a few spacial cases where you are willing to tolerate inefficiency, but they are rare.

Planes look like planes for a reason. Helicopters look like helicopters for a reason.

You must be looking in the wrong place (-1)

Anonymous Coward | about 10 months ago | (#46385899)

You can see a real live working jet pack here http://www.martinjetpack.com/

Re:You must be looking in the wrong place (2)

asylumx (881307) | about 10 months ago | (#46387047)

GP didn't say they aren't possible, he said they aren't practical.

no matter what, they fill fuck things up (0)

Anonymous Coward | about 10 months ago | (#46385649)

No matter how cool the device, they will find a way of fucking things up.

Just looks at the mall cops coasting around on their SHTs.

Infantry Soldier != Pilot (0)

Anonymous Coward | about 10 months ago | (#46386325)

Also consider that having an infantry of just barely high school graduates zipping around in 3 dimensions with jet packs and guns would probably be more dangerous to the home team than the enemy.

Schlock says... (1)

Anonymous Coward | about 10 months ago | (#46387121)

Wisdom from http://www.schlockmercenary.com/2011-05-28
corporal: "Do you know what we call flying soldiers on the battlefield?"
private: "Air support?"
corporal: "skeet"

What if multiple contracts were awarded? (1)

RogueWarrior65 (678876) | about 10 months ago | (#46387779)

I wonder how things would have been different if multiple identical R&D contracts were awarded to several companies so as to set up competition for the best technology. Basically, set aside R&D money to be given to a company so there is disincentive to risk their own money. I would also throw in there that R&D awards be given to startups rather than huge public companies.

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?