Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?

Martin Jetpack Climbs 5000 Feet Above Sea Level 178

rh2600 writes "For years the Martin Jetpack has stayed just a few feet off the ground, invoking frequent suspicion about its true abilities. Well, today that all changed [video] with the first climb test in New Zealand (with weighted crash-test dummy) reaching over 5,000 feet above sea level. The emergency parachute test was also a success. Kiwis can indeed fly."
This discussion has been archived. No new comments can be posted.

Martin Jetpack Climbs 5000 Feet Above Sea Level

Comments Filter:
  • Now I can FLY!!!

    Where was this thing when you needed it the most???
    • by 0100010001010011 ( 652467 ) on Sunday May 29, 2011 @10:06AM (#36279184)

      Now I can FLY!!!

      Yeah, but did he solve the icing problems?

    • by yog ( 19073 ) *
      I'm waiting for one of these babies to get me 6 miles to work. Man, would it be nice to fly right over the cars which are all stuck at a light, and buzz a cop car at 70 mph! It would make going to work a joy instead of the tedious trudge to cube farm hell that it is.

      Ever since reading Heinlein's The Puppet Masters [], I have yearned for a sky car to go hundreds of miles in a few minutes. Of course, I haven't yearned for the accompanying alien parasitic slugs, but like with everything else in life, there'
  • So it can go up to 5000 ft if it uses up all its fuel getting there, and then parachutes back down? Still not totally practical.
    Also they used a crash test dummy? Couldn't they find a darwin award volunterr?

    • Re:Endurance (Score:5, Informative)

      by Anonymous Coward on Sunday May 29, 2011 @09:34AM (#36279064)

      Earlier in the program [2:03] Mr. Martin refers to 'flying around for up to 30 minutes'. and at [7:17] in the video there's a call of 800 ft/min climb rate. Methinks you can get a lot better than just up to 3500 ft AGL.

      BTW - Aviation authorites have little or no sense of humour. Testing equipment with live (perhaps deserving) volunteers without testing the safety systems will get you shut down, in a very official and unpleasant manner.

      • by LWATCDR ( 28044 )

        Not likely, rate of climb drops a lot as altitude goes up. I am not sure that these engines are turbocharged but if not then the power really starts to drop as you go up as the air gets less dense. But that depends on what you mean by a lot. If you mean 6000 ft above sea level then maybe If you mean 10k I just don't think so. Oh AGL? That is all about safety not performance, above sea level is what really matters from a performance issue.

    • Re:Endurance (Score:5, Insightful)

      by Anonymous Coward on Sunday May 29, 2011 @09:45AM (#36279092)

      Not quite. That was an test of the new parachute system that is designed for catastrophic situations, something any sane test pilot is going to want before climbing on board and soaring more than a couple feet off the ground. Not sure they discussed flight duration, but soaring to 3000 feet and back to the ground under it's own power is certainly a minimum flight time.

    • by definate ( 876684 ) on Sunday May 29, 2011 @09:47AM (#36279104)

      Darwin is pretty far away from Christchurch. I guess they could get someone from there to volunteer, but I doubt anyone who has won some prestigious award would be into it.

      Hell, Google Maps [] can't even figure out how to get there!

    • Everytime you jump from a building you realize that the flying is not the problem, but the landing is the thing you have to worry about.

      • Only the first time. If you manage to figure it out before you make it to the bottom, you can apply that solution to all subsequent jumps.

    • by Dunbal ( 464142 ) *
      It climbs at 800 ft per minute (according to the vid) which means 6 minutes to 5000 feet. It carries 45 minutes' worth of fuel (also from the vid). Not sure if you will get an 800 ft/min climb with a full tank though. Also I'm not sure you'd be able to get permission to go to 5000 feet without a private pilot's license.
      • I missed the 800fpm bit, but according to their site, the design is an part103-compliant ultralight which requires no license (though Martin will require a training program when they start selling them), Fuel capacity is 5gal (by FAA requirement) / 30min / ~30mi range.

  • Not really a jetpack (Score:3, Interesting)

    by Anonymous Coward on Sunday May 29, 2011 @09:41AM (#36279082)

    A jetpack should be no bigger than a hiker's backpack. This thing is more like a small aircraft.

    • by geogob ( 569250 )

      I think letting pseudo-sci-fi action flicks to set technology and engineering guidelines is neither sane nor practical.

      • The word itself seems to have a well-defined meaning akin to "backpack, but one that makes me fly". It almost seems to me this thing should have another name, unless they're planning on making it much smaller and just can't or haven't quite yet.
      • by slick7 ( 1703596 )

        I think letting pseudo-sci-fi action flicks to set technology and engineering guidelines is neither sane nor practical.

        This [] is a jet pack. It was developed by Bell Helicopters in the late 60's.Since there seems to be little information on the power plant it's difficult to critique the system. This design was prior to the T-400 jet engine that is used on the Blackhawk helicopter. I believe the T-400 would be a better power plant.

        • by rednip ( 186217 )

          The Bell Rocket Belt [] used hydrogen peroxide as it's fuel for the 'flight', which typically lasted about 20 seconds, a helicopter engine is very much a different beast altogether. Its best known use was in a James Bond movie 'Thunderball' and as a halftime act for at 60's Superbowl. The fuel was so volatile that each launch took special preparation. Not that long ago there was still a stunt man who had built one which had a limit of 30 seconds, but it's easy to see why it would never be practical for any

    • by Anonymous Coward on Sunday May 29, 2011 @10:11AM (#36279202)

      Look at your smart-phone. Did it *start* that size?

      • Apples and oranges. When portable phones were invented, the electronics in them were nowhere near their theoretical size limits. They had room to both shrink and grow in performance.

        Jetpacks like this are already very near their theoretical limits just to fly at all. There's no magical chemical fuel waiting in the wings. (Excuse the pun.) There's no magical ducted fan or propeller design that will dramatically increase performance. There's no magical material that will dramatically decrease the weight.

        • There's no magical chemical fuel waiting in the wings. (Excuse the pun.) There's no magical ducted fan or propeller design that will dramatically increase performance. There's no magical material that will dramatically decrease the weight. Etc... etc...

          I'm curious... how do you know there isn't?

          There are a lot of discoveries that have already been made that do exactly what you said. The ducted fan design can be improved... GE is working on several designs that do exactly that. There are materials that do dramatically decrease weight... Carbon Fiber is an example... and the science behind those materials (and others) is continuing on. Don't underestimate the power of the imagination to think things up. If someone sees a problem, an engineer somewh

          • In the end you still need a certain amount of energy to lift a person. No matter how light the equipment is lifting a few hundred pounds in a controlled manner takes a lot of energy, and there are theoretical limits as to how much chemical energy a fuel can hold. If we can get a nuclear or antimatter system down to that size then maybe, but I don't think I'll volunteer to be the one to fly around with that on my back.
            • And we're nowhere near that limit. Using Frink []:
              535lbs gravity 5000ft -> gal gasoline = 0.0259...
              Even assuming 25% efficiency, it's still about 1/10 of a US gallon of gas. (the 200hp Martin engine burns 10gal/hr, so it could be as much as 38% efficient, but the transmission, fans and est.90% throttle pull that figure down.) The actual gas burned, though, to get to 5000 ft was likely about an order of magnitude greater. (~4000ft/800fpm=5min; 10gph*1/12hr=5/6gal)

              The energy mostly goes not to lifting the cra

              • it could be as much as 38% efficient

                Two stroke engines don't run anything close to that efficiency, and the more highly stressed they are, the more unburned oil you mix into the fuel for lubrication.

              • The energy mostly goes not to lifting the craft from one height to another but rather to accelerating air simply to maintain altitude.

                Right, afaict jetpack implies small nozzles which implies high exhaust velocities which implies most of the energy ends up accelerating air downwards rather than accelerating the craft upwards (momentum is proportional to MV while kenetic energy is proportional to MV^2).

          • I'm curious... how do you know there isn't?

            Because I actually pay attention to and have a working understanding of engineering, physics, and chemistry.

            There are a lot of discoveries that have already been made that do exactly what you said. The ducted fan design can be improved... GE is working on several designs that do exactly that. There are materials that do dramatically decrease weight... Carbon Fiber is an example...

            They key words of course being "have already been made". Yeah, GE may be wor

        • Nuclear.

        • please don't point out your own puns []
          • by Velex ( 120469 )

            Holy shit. I never realized I was supposed to be so completely offended by the phrase "no pun intended."

          • by AK Marc ( 707885 )
            Some irate blogger doesn't get to set etiquette. "No pun intended" is often to indicate that the person is being more serious than an accidental pun would tend to indicate. It isn't saying "look I'm so smart I have to point out when my puns are just a by-product of my smartness and not because of deliberate punnyness." It's saying "I think I'm cute" (when the pun is intended and the "no pun intended" is stated as a cutsey banter thing) or trying to indicate that they are serious when a pun could actually
        • The jetpack produces ~600 lbs. thrust at 10 gph = 61lbs/hr.. Empty weight is 250lbs, max takeoff weight is about 535lbs.. A 180lb pilot could carry over 15gal of fuel, sufficient for 90 minutes of flight. The excess thrust over takeoff weight ensures a rapid climb and a decent forward velocity.

          The test did not start at high altitude, but on the Christchurch plain in South Island, NZ which slopes gently from 30ft to 1900ft over about 20 to 35 miles. The test takeoff was likely at less than 1000ft, and the cr

        • He clearly said in the video that it was at 3500 feet which was 5000 feet above sea level. So they started around 1500 feet above sea level. I wouldn't knock the guy for ONLY flying up 3500 feet.

    • by mrmeval ( 662166 )

      Baby steps.

      They miniaturized jet engines enough to do this and it seems pretty damn good now. Maybe if you can get an engineering degree in fluid dynamics and one in materials science you can develop a continuous detonation wave engine that would be smaller.

      • Strap a couple of those miniature jet engines (you'll probably need four for your weight, their weight, and a decent amount of fuel) to your back side, and if you don't burn your legs off, you'll at least start a brush fire. As simple as you make the concept out to be, the reason no one has ever bothered to do that is because no one has figured out a way to resolve the problem of exhaust temperature.

        Meanwhile a large ducted fan means significantly lesser power requirement, and similarly, significantly less

      • There are real physical limitations however. Even with perfect engines. Since lift is a reaction force we can calculate some BOTE figures. A lifting disk area of about 1m2 needs a downdraft velocity of 31 m/s for 1000N of thrust assuming a air density of 1kg/m3. That is 113km/h blast. The power required is 15.8kW (21hp) assuming a perfect engine to air coupling. This seems pretty reasonable. A pair of ducted fans need a diameter of about 80cm for a total disk area of 1 meter. Perhaps they can get a bit sma
    • There are three factors you have to consider when building something like this: thrust to weight, thrust to power, and jet temperature. Your thrust to weight needs to be above unity, for obvious reasons. The most efficient way to achieve that thrust is a very large fan, at a very low flow velocity. As you try to shrink the unit, your fan becomes smaller, you need higher and higher flow velocity to achieve the same thrust. As you trade size for power, you go from reciprocating ducted fan, to high bypass

    • It straps onto your back, and it achieves all its lift using a jet. Sounds like a jetpack to me.
    • A jetpack should be no bigger than a hiker's backpack and spit flame. This thing is more like a small aircraft.

      There fixed that for you.

  • by hackertourist ( 2202674 ) on Sunday May 29, 2011 @09:52AM (#36279128)

    The pack is big and bulky enough that the addition of a small wing won't make much of a difference. With a wing, you can transition from vertical takeoff using thrust only, to horizontal wing-borne flight which uses much less power (and/or achieves a much higher speed).

    • by jcwayne ( 995747 )

      My thoughts exactly. Even helicopters and VTOL airplanes spend as little time as possible hovering or in straight vertical motion, both because of how fast it burns fuel and because most (all?) aircraft are more stable when moving horizontally.

      Having a wing capable of providing enough lift for an unpowered decent and landing would also make the parachute the last resort that it should be. With the current configuration, the only solution for running out of fuel in flight is deploying the chute. While the la

      • by AK Marc ( 707885 )
        Helicopters don't hover because that's the least efficient pattern possible. Traveling forward at a reasonably slow speed will get the helicopter out if its own downwash and into "clean" air and greatly improve performance. However, when you have the blades enclosed and with a tube above and below the blades, then the "clean" air is closer to the same whether one is in a pure hover or traveling slowly forward.

        Now, if they had small wings (a la Buzz Lightyear) that could provide some lift, then the fuel n
    • I think it should have a folding ultralight wing. That is hard to do but with the small size it should be doable. Then it won't be contributing so much drag during non-wing-based flight. Plus you could ditch it if you had to.

    • The pack is big and bulky enough that the addition of a small wing won't make much of a difference.

      You're right - a small wing won't make difference, so it's stupid to add one. To get a weight/sq ft ratio low enough for any kind of performance is going to require a fairly large wing. The Rocket Man requires an eight foot wing just to *glide* - and he and his pack are almost certainly lighter (or very close to) the dry weight of just the [Martin] jet pack all by itself.

      • by AK Marc ( 707885 )
        It's easier to fly than glide. Look at the wing area of a glider to a little Cessna and compare the weights. The glider has more wing per lb. But with power, you can be a little less efficient and still get where you are going (and because of the speeds involved and such, you want smaller wings in powered craft for better fuel economy at higher speeds, when gliders don't hit those higher speeds and you want to optimize on other parameters).
    • ...big and bulky enough that the addition of a small wing won't make much of a difference...

      Actually, that's not true. They are designing it to fit within the US Ultralight category. By adding a wing, you're adding weight, however he is only allowed 254 lbs. The craft is already at 250 lbs. As for speed... again, he is limited to 60mph due to the same restrictions... which he can easily achieve without the addition of a secondary lift device.


    • by hey! ( 33014 )

      If you're considering a wing, why not an autogyrating rotor?

  • by kenh ( 9056 ) on Sunday May 29, 2011 @10:06AM (#36279174) Homepage Journal

    After the first twenty feet the ascension would be much easier as my bladder and bowels empty out, lightening the load...

    • making the weather forecast a light sprinkle with a chance of turds?

    • Unless you're planning to forgo pants for the flight all this will achieve is a slight offset to the center of mass.

      • by youn ( 1516637 )

        Please put in consideration some people's fart power... I bet some people could do without a jetpack altogether :)

  • This is very cool, but it looks more like a personal helicopter than a true jetpack. Certainly could get people into inaccessible areas, but with how much gear, and you couldn't bring much of anything back (like an injured hiker, etc..). Still, quite a feat of engineering. I hope he gets investors!
    • Considering that most previous "jetpacks" used "rockets" instead of "jets" I think this one is closer to a jetpack than the rest IMO.
      • A rocket is a type of jet.
    • Those two spinning rotors in a duct, those are called jets.
      • by iksbob ( 947407 )

        Or possibly a ducted fan... It really depends on the construction of the device. If the outlet is smaller than the rotor's swept area, that suggests compression of the air is involved and it would be a jet. If there's no compression, it would be a rotary wing with a cowling (possibly to reduce wing tip vortices), known as a ducted fan. Disclaimer: I am not an aeronautical engineer.

  • by clyde_cadiddlehopper ( 1052112 ) on Sunday May 29, 2011 @10:19AM (#36279234)

    Despite Martin Jetpack's talk of its usefulness for remote search and rescue, the real money is for military purposes. This piece [] describes the first practical uses of helicopters in Korea for reconnaissance, supply, and medivac. A decade later, the next generation of choppers -- Chinooks and Hueys -- were doing serious delivery work in combat.

    I, for one, welcome our new kiwi jetpack flying overlords.

  • The emergency parachute test was also a success.

    Personally, I would have performed that test quite a bit beforehand.

    • Actually you can't test the parachute beforehand..... because the test was for rocket deployment, at altitude, from a machine that was recently operating... anything less (even tossing it from an airplane and triggering the parachute) would be considered only a partial test in aerospace circles.

      • by LWATCDR ( 28044 )

        and it was unmanned. I will say that the ride down didn't look like a lot of fun. Well better than the alternative might be but...

  • Maybe I can get a FEMA grant for one for Search & Rescue. Probably cheaper than a Robinson heli. (Yes, I know you can't pick up search subjects but you can't do that in a two-place Robinson either).

  • Of course a Kiwi can fly! []

  • Really where is the metric whiners complaining about them using the term feet? Oh because it was a NZ newscast and a NZ citizen using them?

    • by agm ( 467017 )

      As a NZer myself, we don't use "feet" as a measurement except, oddly enough, when referring to altitude. Not sure why. Perhaps to remain standard around the world in aviation circles. When in an aeroplane, 30,000ft seems a lot less scary than 10,000m, which my mind instantly translates to "10km".

      • by LWATCDR ( 28044 )

        Why do find 10km scary. To me is is comforting but not as much as 30,000ft which I round to six miles up. In aviation speed is life, altitude is life. Thing only really suck when you run out of one or both of them.
        But 30,000 ft isn't really 10,000 meters or even six miles. You see people as a whole are not too dumb to translate between system on the fly for things like news stories. The only time people should bent is when dealing with technical documentation.

    • Cause it's an avation story and feet is pretty much the global standard (for better or worse).

      I'm in a metric country (Australia) and I think in metric for everything. In fact I barely know what most imperial/US measurements even are. This normally includes altitude - I think in metres for altitude above sea level on land (i.e. I know my house is 576m above sea level, and the summit of a nearby mountain is at 880m). When hiking I have a pretty good feel for how far I have ascended or decended, in metres. Et

  • The basic trouble with jetpacks is that knees are terrible landing gear. You have to land vertically with a huge mass to stop, and you can't do a controlled fall like a parachute landing. Achieving altitude is not the problem. Landing is the problem.

    This thing, like the Solotrek, has landing skids, which take the landing shock. But then it's not really a jetpack. It's more like the Williams X-Jet Flying Platform [] from the 1980s, probably the best flying machine in this category.

    • knee landing doesn't seem to be a problem with the compressed-air jetpacks from the 60's. Every landing I've seen was like feather. As long as the guy flying is not a total noob, and he has some thrust left, he can control the rate of descent that results in a super-soft landing every time.
      • by Animats ( 122034 )

        Every landing I've seen was like feather.

        That's because you're looking at really good pilots, in really good shape, flying under near ideal conditions, being very careful. Even with that, one test pilot has had six knee injuries. [] Just walking downstairs with 170 pounds on your back is tough.

  • The thing just guzzles fuel for the load that it is carrying and it's not a jet. The word "jet" is marketing and fraudulent because there is no jet propulsion. It's two inefficient ducted fans that are inappropriate for hovering compared to a small helicopter rotor. This is why the thing can only fly for 30 minutes.

"Oh my! An `inflammatory attitude' in alt.flame? Never heard of such a thing..." -- Allen Gwinn, allen@sulaco.Sigma.COM