Maple seed Personal Transport

  1. Hello
    i just joined this forum because i had an idea that i think, if it hasnt already been thought of would be a unique mode of transport over short distances, its based on the maple seed, basically it would be a single seat mono blade helicopter, the actual blade would be above the pilot, who would be sat on a seat with footrests extending down and handles extending outwards from the central pole, i havent done any drawings yet, this is basically just the idea based on what ive seen a maple seed do, i am unsure as to what span the blade would need to be in order to support the weight of a person, also unsure of how it could be made to turn, altho i suspect that something as simple as leaning as you would in a hang glider would possibly do it, please understand that i am basically not an engineer, i have ideas but thats why i have brought this to the attention of the forum, would very much like some feedback on this, unless its already been thought of.
    i will run up some rough designs over the next few days, but it would be helpful to know what you guys with more knowledge than i have think.
    Michael
     
  2. jcsd
  3. russ_watters

    Staff: Mentor

    Welcome to PF.

    How would you avoid making the occupant dizzy?
     
  4. boneh3ad

    boneh3ad 1,655
    Gold Member

    That was the first thing that came to my mind as well.
     
  5. Danger

    Danger 9,879
    Gold Member

    Good point, but perhaps the least of his worries. I assume that something equivalent to a tail rotor would be utilized.
    A maple seed behaves pretty much like an unguided autogyro or parachute. Gravity is its driving force, and it's always a one-way trip. It's like the weed equivalent of a flying squirrel.
     
  6. I think this is the sort of thing you're thinking of:



    More of a personal helicopter though. The pilot tilts the rotor by a handle bar to control the craft.
     
    Last edited by a moderator: Sep 25, 2014
  7. hello Gentlemen and thankyou for taking the time to read and comment, to answer your questions i have run off some very basic drawings that i hope will answer these question, i will be designing a basic model in 3D and animating it so that it becomes clearer how i envision this working, the point about it being a downward only trip i think could be addressed with some sort of powered engine that would create more lift, but as i said i am no engineer.

    http://mikey7963.deviantart.com/
     
  8. boneh3ad

    boneh3ad 1,655
    Gold Member

    You have no way to counteract the torque generated by the rotor. As is, when the blade spins one way, the chair will spin the other direction at a rate that will match the torque of the blade. That is why modern helicopters have a tail rotor.
     
  9. so if i added a rotor blade behind the pilot that would solve that problem, correct, i'm also wondering, if its at all possible to have the main blade act as some sort of generator, not sure how this works, but if the blade spinning could be made to generate some form of power, that could then be used to power a secondary rotor could it not?
     
  10. I must point to the video I posted. Did anyone watch it?

    It is a personal flying machine (without tail rotor). Using counteracting rotor blades to remove torque issues.

    Your mono blade design wouldn't be very effective - hence helicopters having a minimum of two.

    Even with four engines and counteracting rotors (two blades per rotor assembly), the craft in the video isn't very powerful.

    The design of your 'maple seed' craft is virtually identical to the one in the video, minus the mono blade design.

    The rotor would solve torque issues.

    The main blade acting as a generator would simply draw power from it, reducing the efficiency of the craft (engine turning main rotor which is then turning tail rotor). You would be better off using the engine to drive both from the start.
     
    Last edited: Sep 20, 2010
  11. boneh3ad

    boneh3ad 1,655
    Gold Member

    I have seen those before. They are certainly possible, but very complicated. The Soviets had a gunship that operated that way if I remember right but it didn't get very popular because it was complicated.

    Not to mention it would likely have stability issues and efficiency issues. Those are other reasons for multiple blades.

    Any reason why you would like to make a single-blade rotor instead of just using multiple blades like most helicopters?
     
  12. I've never really looked at counter rotating prop systems in detail, but there are a few helicopters that use it and there are also a lot of toy rc models which utilise it. (Not saying that means it's simple).

    That's what I was going for.

    I can't answer this for the OP, but my take on it would be:
    If you look at the seeds falling, they are fairly stable and consistent in their descent. The rotor is balanced by the weight of the seed which provides stability.

    If you were to try and force rotation via an engine and add controls, you would lose that stability. Controlling the craft would be a difficult task to achieve if everything isn't perfectly balanced.
     
  13. some very interesting points , i was thinking about the torque issue, and what keeps coming into my mind is this, the torque problem that needs the counter rotation to create stability, isnt that due to the rotor blades being physically attached to the body of the craft, this design doesnt have the mono blade anchored to the central column, its free floating in a magnetic field, im probably mistaken but if the blade has no physical connection to the body of the craft wouldnt that eliminate the torque problem.
    the reason i have gone for the single blade option rather than a dual bladed option is because its nature, and lets face it nature does produce some very efficient designs, what is concerning me is the potential span of the monoblade, its going to have to support the weight of a person, which makes me wonder how big this would have to be.
    soon as i can get the design to a workable quality i am going to try and get a small prototype made so that weight tests can be done, i think once these have been done and the results are there it will be easier to see where this is heading, even if it cant be made into an actual transport system it could be used as a descent system, like a parachute, but for now , thankyou gents for all your input
     
  14. Nature made these seeds for small things which don't care if they are rotated :-)

    But for the N-SAT to be blowed up in the Space Hose that I suggested maybe this could be an interesting alternative to the parachute and balloon I planned to use - it generates quite a lot of lift probably sufficient to keep the needed 10-20grams floating in the air moving upwards.

    But I'm not sure if it would work at all airspeeds, because propellers normally are optimzed for a speciffic one, no matter if single or dual blade.

    gutemine
     
  15. Do a google search on the word "Samara" as opposed to maple seed. The torque will still be an issue because of Newtons 3rd law. Every action has an equal and opposite reaction, magnetic field or not. The way around it is to have a reaction drive system. My friend is finishing his PhD on Maple seed UAVs. I helped him do some drop tests from an RC airplane.

    http://www.avl.umd.edu/projects/proj11-robotic-samara.html
     
    Last edited: Sep 20, 2010
  16. See Cyrus answer above.

    The mono blade would have to produce enough lift to allow the vehicle to ascend (or simply descend in a controlled manner), remember, the maple seeds do not have a load to lift (nature has used the seed which is the load as a natural counterbalance). You would need such a counterbalance, plus additional blade span to support a load.

    Google "Monoblade Helicopter", there are plenty of model rc toys out there that employ this technique, but it's only on a small scale. And they don't really have full control.

    It would be heavier, more expensive, more complex and more difficult to deploy than a parachute. I don't see it being a viable replacement. Perhaps as a bit of fun maybe, but not going to be in the hands of the SAS anytime soon.
     
    Last edited: Sep 20, 2010
  17. boneh3ad

    boneh3ad 1,655
    Gold Member

    Maple seeds also don't have an inner ear or a the capacity to vomit from rotation or the capacity to pass out from g-force. If you watch a maple samara fall, you can see that the seed itself (playing the part of the person in your craft) isn't stationary. When they spin, the center of mass is stationary, and that is not where the seed is. To counteract that, you would need a counterweight in your design so that the center of mass is along that center axis. That still doesn't solve the torque issue though.

    I can see how my post was confusing. I wasn't directing that question at you. I merely quoted you to expand on your thoughts. My mistake.
     
  18. By adding a second blade to a mono-blade helicopter, you just might generate twice the lift for nearly the same power output.
     
  19. Might as well just make a helicopter then, eh? LOL.
     
  20. With two of them, interlinked, and counterrotating.

    The vibration would be something fierce, though, even with counterweights, as any adjustment to the blade angle would produce additional forces.

    It sounds like an expensive and complex alternative to a simple and inexpensive ram-air sport parachute.
     
  21. Danger

    Danger 9,879
    Gold Member

    I lost track of this thread, and therefore just now saw Miey's illustrations. I was quite mistaken in my visualization of what he wants to do. Now that it's clearer, I have a different concern than I did before.
    Cyrus, the link that you provided looks suspiciously as if pursuing it will lead to a confrontation with math, so I'm going to stay away from it. :eek:
    I'm going to quote just a wee bit of it, which I believe will fall within "fair use" boundaries of copyright, and which seems to be approaching the issue that I'm having trouble with.

    The small perturbation equations of motion are used to calculate the forces necessary for flight along a trajectory recorded by a visual motion capture system. The result of this work is that the robotic samara is controllable in unpowered autorotation as well as hovering and directional flight.


    We've all been discussing the necessary counteraction of rotor torque, but what about the shift of mass around the main column? (I'm thinking that such is the meaning of the "perturbation" mentioned in the quote.) Wouldn't the stresses be similar to those encountered by a hammer-thrower in an athletic competition, wherein the entire body will want to whomp about in a circle because the centre of mass isn't in the structural centre? I'm probably overlooking something simple here, but I can't figure out what that might be.
     
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