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  • Human powered helicopter :)

    For some reason this has always been a fascination of mine - I suppose its my love for both flight and self propulsion.

    they just set a new record of 50 seconds of flight...


    http://news.discovery.com/tech/human...ht-120625.html


    going to try and post a pic of one of the transmissions to one of these unit's --- u guys are in for a real surprise


    http://www.humanpoweredhelicopters.o...ird/xsion8.jpg

    there it is --- little bit of HP's being handed over to father friction - and then youv got to try and lift the dang thing with the remaining fraction of whats left, perhaps the reason this one isn't the record setter....
    Last edited by A.K. Boomer; 06-27-2012, 10:19 PM.

  • #2
    All I can say is WOW!
    I'm huffin' n puffin' just thinking about the total amount of energy and exertion the pilot/motor had to expend for that effort.

    Good point about the complexity of the transmission, an awful lot of directional power/ratio changes in the system. Doesn't leave much left over for the actual thrust or lift energy.

    Still an absolutely amazing effort.
    Thanks for the links.
    Home, down in the valley behind the Red Angus
    Bad Decisions Make Good Stories​

    Location: British Columbia

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    • #3
      Sadly, this is no more a helicopter then a hovercraft is. It operates in ground effect and has no stability should it ever achive flight. And it can't because its just too big and heavy.

      The trusses made of smaller trusses made me laugh however. Maybe by time they can make the smaller trusses out of carbon nano tube trusses.. :P
      Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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      • #4
        Not the first to make trusses of trusses...



        ....but I agree regarding ground effect.

        I think that even if they did get it to 'fly' they would be pushing it uphill in the building as I expect the air would begin to circulate and they would soon be settling with power.

        Maybe they are smarter than me (almost certainly so) and they have my best wishes for eventual success.

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        • #5
          Way over engineered. Like the others have mentioned the weight, friction loss, and hovercraft.

          I would think a single seat with a single rotor with a near direct shaft from the peddles to rotor could accomplish the same thing with less effort.
          Andy

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          • #6
            Vpt -- how are you going to stop yourself from getting dizzy?




            Yes they are typically ground effect machines --- I don't think they should make the competition how long you can stay up just off the ground --- I think they should make it how high you can get period...

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            • #7
              As a cyclist, it makes my knees hurt to watch the "pilot" bend his knees so much. Cool technology though.

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              • #8
                Originally posted by A.K. Boomer
                Vpt -- how are you going to stop yourself from getting dizzy?


                Well someone has to hold the rope.

                50 seconds of spinning I don't think will make you dizzy.
                Andy

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                • #9
                  Originally posted by vpt
                  I would think a single seat with a single rotor with a near direct shaft from the peddles to rotor could accomplish the same thing with less effort.
                  Low speed aerodynamics/Reynolds number is a thoroughly documented subject. Rules is rules.

                  The span of a 2 blade rotor with the same lift would be too large to fit in their available building not to mention the weight gain of the structure required. A single counterbalanced blade (think maple seed) would be the most efficient aerodynamically but again span/space/structural limitations would preclude that design.

                  I think the most gain in their design will come from transmission design changes. Way too much heavy metal there. C/fiber could be used in many areas to save weight plus their gears have got to be soaking up a lot of power with all the racket they make.

                  Just my 2¢ worth.
                  Milton

                  "Accuracy is the sum total of your compensating mistakes."

                  "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

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                  • #10
                    Why always 2 blade rotors? You already wasted all the weight, gearing, friction to get the power to the rotor, why not use all the power there instead of adding more?

                    Andy

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                    • #11
                      Originally posted by Harvey Melvin Richards
                      As a cyclist, it makes my knees hurt to watch the "pilot" bend his knees so much. Cool technology though.

                      Yes good observation --- It's not just tough on the knee's it's piss poor for making optimum power as the more the leg is kept bent the effective torque that you can achieve goes way down ------ there's only one real reason to keep a slightly bent leg and that is it keeps muscle speed down,
                      this can be ideal for extremely high rpm cadence,

                      but here again - he's nowhere near what proper good hp producing cadence should be --- he's only @ approximately 70 rpms - this is most likely due to the awkward "hand apparatus"

                      I seriously question going that rout due to the fact that when I was on top of my game I could rap out at a cadence of over 140 rpm's

                      HP is a derivative of both torque AND rpm's...

                      Not only that ---- at 70 rpm's he's going mostly anaerobic --- this means he's not burning his glycogen stores in exchange for oxygen -- he's burning them more like a weight lifter would ------ the result's are that you cannot keep this up for too long ----- the by-product is severe lactic acid build up ---- had he really been able to fly he most likely would have cramped up and then had some G-forces to contend with....

                      Another observation of this particular machine is the fact that there are no self leveling speed or pitch controls on any of the four blades ----- what it does is use the ground effects to keep the system in check ---- again - had this thing really been able to fly he would have a rude awakening in control balance once leaving the ground behind....

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                      • #12
                        Originally posted by vpt
                        Why always 2 blade rotors? You already wasted all the weight, gearing, friction to get the power to the rotor, why not use all the power there instead of adding more?



                        It's a good question VPT but tons of factors - including the blades not tripping up on the other's wash - and top speed of the craft and on and on.

                        the old cobras were only twin blades but the blades were as wide as the craft itself...

                        Last edited by A.K. Boomer; 06-28-2012, 12:33 PM.

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                        • #13
                          My attemp at a HPH

                          I just came up with a design this morning over a cup of joe,

                          so - for what its worth here's what I would do --- the unit would be two counter rotating props --- but not stacked - there would be an outer ring revolving opposite of a smaller higher speed inner,

                          For one I would forgo the clumsy hand apparatus (that sounds like its grinding up parts) in favor for a highly efficient conventional leg crank that I could rap out to approximately 115 to 120 rpms cadence (spin to win) - yet the blades would be for the most part low speed....

                          Two; My transmission would be one of the simplest, strongest, lightest yet most efficient designs in use, in effect all it would be is a planetary gear system, my crank would direct drive a sun gear - the planetary's would drive the inboard prop and the ring gear would drive the outer...

                          Three; in order to achieve the simplicity, efficiency, strength, lightweight of #2 I would have to make one huge uncomfortable sacrifice - and that would be pedaling sideways to the ground --- but - feet are anchored into clipless pedals - a hip strap to hold you firmly up and your upper body totally supported - it could be done ----------- I would train in this position - I would study which side would be best for the heart to circulate blood - I would train until one of my eyes migrated over to the other side of my head - hence the nickname of why my incredible flying machine would be called the "halibut" (and hopefully not the "flounder" by cruel people who want to be mean and tease me )

                          last but not least a small tail from the machine would reach out to the outer parameter of the first inner blade - and it would have a vertical fin on it for adjustment to take up the finer details of deviance that the two counter-rotating props did not catch... because the only thing more freaky looking than a guy who's over a half of century old pedaling on his side would be a guy who's over a half century old pedaling on his side whilst spinning around in circles while doing it... it would be the ultimate position for projectile vomiting...
                          Last edited by A.K. Boomer; 06-28-2012, 01:01 PM.

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                          • #14
                            Two blade rotors have a huge drawback which is why they aren't used much in wind power turbines. If the machine is rotating along an axis that is perpendicular to the rotor plane of rotation there are two points in the plane of rotation of the rotor where the angular momentum change required to take the rotor out of the plane of rotation is essentially zero.

                            Hard to explain clearly but an example may do better. If a two bladed wind turbine is shifting azimuth direction because of a change in the wind it will be rotating the rotor shaft around the z axis. When the rotor blades are exactly vertical it then takes almost no force to rotate the disk of rotor rotation around the same axis. That then produces a huge change in the plane of rotation of the rotor. As the rotor continues rotation the angular momentum of the blades will try to make them continue in the same plane they previously occupied. The rotor shaft is no longer pointed in that direction so a huge torque couple exists trying to twist the rotor off the rotor shaft.

                            A rotor with more than two blades always has at least one blade that is not aligned with the z axis on a wind turbine so you don't end up breaking off rotor blades with sudden changes in rotor plane. The blade(s) that isn't aligned has sufficient angular momentum to prevent fast changes in the disk of rotor rotation.

                            Exactly the same problem applies to helicopters and the slower the rotation of the rotor the more severe it is.
                            Last edited by Evan; 06-28-2012, 01:53 PM.
                            Free software for calculating bolt circles and similar: Click Here

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                            • #15
                              Originally posted by vpt
                              Why always 2 blade rotors? You already wasted all the weight, gearing, friction to get the power to the rotor, why not use all the power there instead of adding more?

                              I believe blades are added in helicopter design more for responsiveness than efficiency. Obviosly there is also the factor of rotor size, but like was said before, blades going into the wash of the previous blade reduces lift. I seem to remember that the Bell Ranger (2 baldes) is quite a bit more efficient than the Hughes 500 (5 blades), but I know from experience the responsiveness between the two is night and day.

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