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$100K Jetpack Flies to 5000 ft. — Parallax Forums

$100K Jetpack Flies to 5000 ft.

ercoerco Posts: 20,260
edited 2011-06-02 21:37 in General Discussion
http://www.rdmag.com/News/2011/06/Industries-Aerospace-Engineering-Modern-day-jetpack-takes-flight/

They HOPE to reduce the cost to $100K/unit.

Risky to operate, but at least it's expensive. I'll stick with my Cessna for now.

Comments

  • Spiral_72Spiral_72 Posts: 791
    edited 2011-06-01 10:13
    Hey that looks very similar to the one Mythbusters made!
  • davejamesdavejames Posts: 4,047
    edited 2011-06-01 11:37
    I would definitely NOT call this a "jet pack" - but it is absolutely COOL!

    The article/video did not state normal flight time, so I wonder what the MPG might be.
  • RDL2004RDL2004 Posts: 2,554
    edited 2011-06-01 12:14
    Looks more like ducted fans to me, but I guess Jetpack has more marketing buzz. I thought the guy said 30 minutes run time.

    It was interesting that the inventor's name is the same as the famous American aviation pioneer, Glenn L. Martin.
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-06-01 12:17
    Not sure why they couldn't use smaller engines that were actually 'jets' to increase their flight time and flight speed ... 600 pounds of thrust isn't that much for a jet engine. A Friend of mine used to fly 1/6th scale (<- yes 1/6th scale) RC aircraft with for all practical purposes ... real jet engines.
  • Pharseid380Pharseid380 Posts: 26
    edited 2011-06-02 16:00
    They would probably have to make their own engine (there's a active community that does that too, of course). I don't know that there's an engine in that power range. The largest RC engine I've even seen proposed had 80 pounds of thrust and the company never brought that to market. Engines for various forms of full sized aircraft are much larger. The RC engines have excellent thrust to weight ratios, but poor fuel efficiency compared to their big brothers. I saw a web page a couple years ago advertising both a rocket belt (hydrogen peroxide powered giving about 25 seconds flight time) and a jet pack (gas turbine providing about 4 minutes flight time), but I didn't see any evidence they'd ever sold one. $100,000 for the rocket belt and $250,000 for the jet pack. I remember being suspicious. Also, some guy tried to go into the piston powered ducted fan gizmo business a couple years ago and it didn't go anywhere, he ended up putting his prototype up for sale for a lot less than $100,000. It looked like a less slick version of the "jet pack" in the above video. I think some of these ventures are legitimate attempts to start a business, but others are just shows by scam artists to lure in investors.

    -phar
  • ercoerco Posts: 20,260
    edited 2011-06-02 16:22
    How long has that Moller guy been bilking investors for his SkyCar? Wasn't is called Moshier back in Popular Science back in th 1970's?

    http://en.wikipedia.org/wiki/Moller_Skycar_M400
  • W9GFOW9GFO Posts: 4,010
    edited 2011-06-02 16:42
    Calling that a jetpack is a disservice to the real H2O2 jetpacks. It is neither a "jet" nor a "pack".

    It is a small ducted fan VTOL.

    Rich H
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-06-02 18:46
    It will be a relief to finally have 535 pounds of metal and gasoline overhead being piloted by someone with only 20 hours of training.
  • Martin_HMartin_H Posts: 4,051
    edited 2011-06-02 18:46
    I understand that a ducted fan uses an engine to drive blades, while a jet engine uses the combustion of fuel to expand a gas. But I'm not an aeronautical engineer, so I have no idea why you would use one over the other.

    prof_braino, the Earth is 315,689,645,825,135,283,408,314.8694358 square feet. Assuming a person takes up 2 square feet and a short range air craft will only fly over the 1/3 that is land. I'd put the odds of one falling on you at roughly 1 in 52,614,940,970,855,880,568,052.4782393. If you never intend to go to Antarctica or Greenland we nudge the odds up a scooch.

    Although I imagine the odds of it falling on someone are much higher.
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-06-02 19:34
    Martin_H,

    With a jet, the blades 'are' the engine, in a self perpetuating combustion pressure chamber.

    With a gas engine driving the blades there is a longer drive train if you will and there are several more engine cycles.

    It all comes down to application efficiency, and for this application, I personally think a jet engine would outperform the current implementation if it were matched properly.
  • icepuckicepuck Posts: 466
    edited 2011-06-02 19:54
    This guy...
    http://www.theregister.co.uk/2008/05/15/swiss_birdman_backpack_jet_stunt/

    Used what looks like four of these
    http://www.jetcatusa.com/p200.html
    -dan
  • W9GFOW9GFO Posts: 4,010
    edited 2011-06-02 20:02
    Jet engines at low airspeeds are inefficient.

    Modern turbofan engines gain efficiency over the old turbojets by using their power to turn large fans rather than ejecting the exhaust at high speed. Only a small portion of the thrust is from the "jet", most is from the high bypass fans.

    Ducted fans are far less efficient that an open propeller, but propeller driven aircraft cannot go nearly as fast as jets due to the limitation on how fast an open blade can spin. The blade tips need to stay under the speed of sound.

    An Allison 250 or similar turboshaft engine (driving the fans through a transmission) may be a good match for this sort of vehicle but I have to strongly disagree that a pure jet engine would work well in this application.

    Rich H
  • Pharseid380Pharseid380 Posts: 26
    edited 2011-06-02 21:37
    I think people tend to use the term "jet" for the entire spectrum of gas turbine engines, be it turbojet, turbofan, turboshaft or whatever. For a real jet pack (one you could actually carry with the power off), a turbofan would certainly be the thing, but again, I'm not aware of one in that power range, I'm thinking like 350 lb. static thrust. You know, Williams Research (now Williams International I think) got into the business of building engines for cruise missiles through the original jet pack. The military wanted something with longer flight time than the Rocket Belt, Bell used the Williams engine for the first jet pack, and the military decided they didn't like that either, but the did have an application for the engine. I love Williams Research, they continued building various types of vertical take-off vehicles for decades without any market for them. Must have had a real mad scientist at the helm. As of the mid 90's, they still had one of the original jet packs which they continued to maintain in operating condition.

    -phar
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