Man's Gravity Assist Flight

Discussion in 'Hangar Flying' started by Voyeurger, Feb 2, 2011.

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  1. Feb 2, 2011 #1

    Voyeurger

    Voyeurger

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  2. Feb 2, 2011 #2

    Autodidact

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    That was one helluva shot, are those guys French?:beer::whistle:

    Note:
    Since medieval times the French have been renowned for their marksmanship. A Englishman was giving orders at a siege in southern France, I think, and then there was a whistling doppler effect type sound and the next instant he was off of his horse with a large rock on top of him. Or so the legend goes.
     
    Last edited: Feb 2, 2011
  3. Feb 2, 2011 #3

    Robby

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    Um, this one's been floating around the internet for some time and while it LOOKS

    good, that's all it is - looks.

    It's a fake.

    Sorry.
     
  4. Feb 2, 2011 #4

    oneturboneeded

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    Mythbusters ... Busted...
     
  5. Feb 2, 2011 #5

    skeeter_ca

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    no way, it's fake!
     
  6. Feb 2, 2011 #6

    WonderousMountain

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    Wow , that's fake? Hate to be the guy who landed on the rocks rather than in a rubber pool.

    "Believe it"-Naruto

    Wonderous Mountain
     
  7. Feb 17, 2011 #7

    Voyeurger

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  8. Feb 17, 2011 #8

    Inverted Vantage

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  9. Feb 18, 2011 #9

    MicRuler

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    What do you guys mean by fake, this is simple pyshics. If you substituted the guy on a slide with a guy on a motorcycle this stunt would be more believable wouldn't it. Just because it's stupid doesnt mean it impossible.
    Those guys must be a couple of crazy college kids who just walked out of physics class. All they did was use a ramp to convert the momentum gained from sliding downhill to energy used to sling the guy into the air. They also could have calculated formulas to figure out the foundamentals needed for the stunt to be successful such the length of slide they needed, the ramp angle and exactly where they needed to place the pool.
    Man, Who would've thought someone such as a experimental aviator could be so negative over a video. its like some old man's mentality "Nope I never seen it so it must be fake/impossible"
     
    Last edited: Feb 18, 2011
  10. Feb 19, 2011 #10
    Physics
    Well, sorry but it is definitely fake , for many reasons, although just one reason would be enough:

    That long slide of the supposed ultra-low-friction material, is... ridiculously bumpy!!!
    That's because it's just laid on the grass downhill, except for the final fancy part. What's more, the man who slides at that extreme speed, doesn't seem to be affected at all by the bumps, like he was sliding on a precision-made, space-tech slide!

    Also: We all know -since we we're kids, that slides are made curved like a semi-cylinder to keep us on track but this one was not! Still, he managed to slide perfectly straight up to the far edge like he was rolling on rails! In sort, you can't just wish you'll go straight, gain the calculated momentum in a ...bumpy slide and then land precisely at a pool 35.2 meters (115 feet) away! That would be magic, not scientific!

    Logic
    The remaining reasons are not about defying physics, but about defying logic, in a funny, parody-like style: On the supposed "project's" site, there are photos of a crew, scientific instruments and a giant rat wheel where the inventor did ...5000 km (3125 miles) by sliding inside the rat-wheel on his back, dressed like a frictionless-superhero -sorta friction-fiction! :gig:

    Now despite all the scientific detail and the giant motorized rat-wheel, the materlal itself wasn't even stretched -it was full of wrinkles! Also the boom-man in the TV/film crew (the one who holds the microphone on a pole) was appearing in almost every picture like he was the most critical person for the project!

    Viral Marketing
    And finally, it seems Microsoft was behind all this, in order to promote their software using viral-marketing techniques which offered them >1.4 million views, spread all over the net!

    On the project's web site a Microsoft advertisement:
    "The man not afraid of great ideas – does he really exist?
    Even if Bruno Kammerl remains a fiction. The time is ripe for new heroes.

    Do it like Bruno - make your plans real
    With Microsoft ******* 2010."


    Or make it ...look like real, like "Brunno" did, if you can't! :gig:
    As Bill Gates once said: "If you can't make it good, make it look good"...

    Make it doable
     
    Last edited by a moderator: Feb 19, 2011
  11. Feb 19, 2011 #11

    autoreply

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    No, it wouldn't. In fact, there's a television show in the Netherlands that does almost exactly this, albeit at a more limited scale (distance/speed). None of your concerns are unsolvable and people can perfectly achieve this. In fact, I've descended in swimming pools, completely proving the above wrong ;)

    Anybody with some basic skills in physics can lay out this and perform it in real life, even though this one is fake. You only need a lot of courage (read, be stupid) and some good estimations of resistance, which can be corrected by some trials..
     
  12. Feb 19, 2011 #12
    I have tried giant water slides and I know something about physics. Using physics you can achieve such a long flight-jump, but only if you control all the critical parameters. What I'm saying is that the above experiment as shown and as implemented, is completely impossible for the reasons I elaborated. Chaotic parameters like a randomly anomalous, unstable surface with wrinkles etc are NOT "solvable" for such a precision-demanding attempt, with the specs shown on the video. Now if you change the specs and the goal a lot, then that would be a totally different problem.
     
  13. Feb 19, 2011 #13

    autoreply

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    Sorry, but that's simply wrong.

    Accuracy and wrinkles: YouTube - MythBusters - Waterslide Wipeout part 2 of 2 09:30 and further on
    No "side-rails": YouTube - MythBusters - Waterslide Wipeout part 1 of 2 02:00 and further on.
    Myth-busters conclusion: YouTube - MythBusters - Waterslide Wipeout part 2 of 2 10:10.

    Bottomline; it's perfectly possible (though you need much more vertical height as their estimate, taken from a video.)

    [video=youtube;pG68IU2ztWc]http://www.youtube.com/watch?v=pG68IU2ztWc[/video]
    [video=youtube;2V1BhagVjF0]http://www.youtube.com/watch?v=2V1BhagVjF0[/video]

    A bit less nay-saying and a bit more physics please ;)
     
    Last edited by a moderator: Mar 20, 2019
  14. Feb 19, 2011 #14
    Let's see:

    1. Bruno Kammerl's slide: "ridiculously bumpy".

    Mythbusters' slide: Quite smooth and better supported.


    2. Bruno Kammerl's slide: Flat.

    Mythbusters' slide: Curved to keep him on track, as well as the water.


    3. Bruno Kammerl's jump: 35.2 meters

    Mythbusters' jump: Half that distance.


    Conclusion: Far improved slide, half the goal. Two of the most important "reasons" I mentioned (bumps, non-curved slide) do not apply here. Add the half achievement and that makes it a totally different case. The original slide with the original specs remains impossible.

    I always like to support my opinions with arguments. Is that nay-saying?
     
    Last edited by a moderator: Feb 19, 2011
  15. Feb 19, 2011 #15

    autoreply

    autoreply

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    While that's judgemental, I see a LOT of wrinkles and some bumps. From my experience, bumps aren't a major problem (except for comfort) and which physical principles would say so escapes me completely. It's potential vs kinetic energy and not a whole lot more if you subtract the (low) friction. This is well known from bobsleds and ski-jumps.
    Please have a look at the video, because I wrote:
    As said, based on an estimate from a video.

    Ow, and there's another difference between both vids, it looks like the original ramp is a lot steeper (close to the 45 degrees max). That alone gives you 50% more range...

    120 meter slide and 24 degree angle is 49 meters vertical. That gives you a terminal velocity of 31 m/s. Angled upwards at 45 degrees, that gives you a vertical and horizontal speed of 22 m/s or 4.5 seconds of flight and a total distance of 98 meters.

    In fact, you only need a 17.5 meter drop to get that far.

    Of course, the above is neglecting drag, friction and a non-ideal angle. But it's perfectly feasible.
     
    Last edited: Feb 19, 2011
  16. Feb 19, 2011 #16

    MicRuler

    MicRuler

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    Can't we all agree to disagree only the guys in the original video know the real truth. Mythbusters already proved the concept possible, it's just the distances and slope angles that need tweaking to make the stunt realiably possible.

    Those bumps aren't serious enough to be mentioned.

    Those barriers are for backup safety purposes only. Not once did I notice them interfering with the slide path of Jamie or Adam, so they might as well not be there.

    It's near impossible for Mythbuster's to get every variable correct when estimating numbers off of a video. In order to test it correctly they need to replicate all conditions to within 100% accuracy.(find someone same weight, height, and body structure of the stunt man/ use the same slope hill and ramp/ same materials and contruction method used for slide, ramp, body suit and lubricant, etc.)

    BTW what the heck those have to do with airplanes anyway.:gig:
     
  17. Feb 19, 2011 #17
    There are three properties of the original slide's bumps that make the slide impossible:
    A) Asymmetry, where the bump change the slide's curvature in two axes. That alone can immediately send you jumping off-track for a new record! :)

    B) Soft slide support (grass vs plywood). With soft sudden bumps, a large part of kinetic energy is absorbed by large friction because in that case the bump acts as a break. But it applies the other way around too: A soft human body, on a sudden, solid bump.

    C) Size (negative only in combination with A and B).

    Compare that to the ground smooth out on the hill side that Mythbusters did with bulldozers and the added layers of plywood as a support, with an additional intermediate synthetic layer!
    You can see clearly the original slide's "specs" on the photos on this page: Megawoosh - Making Of: Drehtag 2

    The scaled ramp is near-perfect compared to the Bruno Kammerl's slide, no 2-axis change in slide's curvature, no random bumps, no softness, not scaled friction -no comparison.


    And that's enough to distinguish reality from fantasy, take off or not, jump precisely or not, etc! :)






    EDIT: @MicRuler
    Take a look at the above link too, to see the quality of their slide and their "project" in general.

    EDIT#2: You're right, it doesn't have to do much about airplanes, just about an impossible jump-flight! :)
     
    Last edited by a moderator: Feb 19, 2011
  18. Feb 19, 2011 #18

    Kristoffon

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    Regardless of the merits of accuracy or range the pool used doesn't have nearly enough depth - and length - to break that fall. If the guy had landed on that for real for he might as well have landed on the ground and wouldn't be walking home that day.
     
  19. Feb 19, 2011 #19

    MadRocketScientist

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