Prop Bike Trailer - Suggestions?

Discussion in 'Motorized Bicycle General Discussion' started by Nehmo, Mar 14, 2013.

  1. Nehmo

    Nehmo Member

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    A air propeller driven bike - actually, I'm considering a trailer.
    The Wright Brothers were bicycle mechanics before they were airplane mechanics,[​IMG] so the concept has been floating around for a while.
    (Previous discussion in this form is meager.) Endless Sphere thread
    [​IMG]

    There are prop venders.

    • I plan to use a cowling around the prop as a guard and to channel the air.
    • Since the bigger the prop, the better, the limiting factor is unwieldiness. I'm thinking the prop can be a meter in diameter.
    • I plan on using the Harbor Freight Predator 79cc engine. I'm familiar with it, and it's cheap (US$80. with coupon and tax exempt).
    • Direct drive: the prop will attach to the shaft of the engine.
    • Trailer hitch will probable be a swivel universal joint at the seat post.
    • Kill switch wires and the throttle cable go from the trailer to the handlebars.
    • I'll use 26" wheels spaced as wide as I can to the sides of the cylinder cowling.
    A big objection is that air drive is inefficient contrasted to a drive using the friction of the surface for traction.
    True, but an air drive, particularly a detachable one, has advantages to compensate for the lack of efficiency, simplicity, for starters.

    Yes, I'll surely peg the dork meter on this one, but, you know, they laughed at Robert Fulton. Fulton's folly

    Yes, I realize pushing bike trailers are reportedly problematic at higher speeds. I'll deal with this by making the point of attachment as far forward as possible, and I don't expect to go fast, anyway.

    Since the the Prop-Pusher-Trailer is transferable from any bike to any other, I can't see this becoming a waste. But if it's worthless, I can use the engine elsewhere and I'll have a trailer.

    Criticisms, Suggestions, Comments, etc.?
     
    #1 Nehmo, Mar 14, 2013
    Last edited: Mar 14, 2013
  2. maniac57

    maniac57 Old, Fat, and still faster than you

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    BE CAREFUL around any engine driven prop.
    They can easily maim and kill instantly!
    I would not attempt this due to safety concerns....
    (and my nickname is Maniac!)
     
  3. Nehmo

    Nehmo Member

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    Regarding the danger, I plan to completely enclose the prop inside a large cylinder.
    I looked at a wheelchair today. [​IMG] Maybe I could mount a engine mount, a cylinder, and a central tongue.
     
  4. WightBoy

    WightBoy New Member

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    Too funny! But at least if S***hits the fan you will already be in a wheel chair!
     
  5. 2door

    2door Moderator
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    Dave31 Moderator
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    CTripps Active Member

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  8. maniac57

    maniac57 Old, Fat, and still faster than you

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    A shroud would have to be quite heavy duty construction to contain a spinning prop.
    Be aware of the dangers and do your homework on design first.
    In order for a shroud to improve thrust, there has to be super precise tolerance on the blade to shroud clearance.
     
  9. Maxvision

    Maxvision New Member

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    Kinda like sticking your head in a blender if you ask me!

    but then...you didn't ask me...

    There's a guy in San Diego who owns Rusty Spokes bike shop. He built a prop driven bike with an electric motor. Normally I'm an adrenaline junky myself and willing to try most anything. I took one look at that bike and all I could see in my mind's eye was blood, guts, flashing lights and ambulance sirens.
     
    #9 Maxvision, Mar 16, 2013
    Last edited: Mar 16, 2013
  10. Nehmo

    Nehmo Member

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    The prop spins without touching the shroud. Are you saying the shroud should be bullet-proof, able to withstand a catastrophic failure of the prop?
    Actually, the ducting-trust-improvement was a secondary possible benefit of the shroud, but I'm certainly interested. Do you have any information on the effect of varying the size of the margin between the inside shroud diameter and the prop diameter?
     
  11. Nehmo

    Nehmo Member

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    Pointing out perils that someone has already (more than once in this thread alone) pointed out is redundant.
    The idea is to enclose the prop in a guard, like on most swamp boats. [​IMG]
     

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