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Thread: Freewheel- v.2, electric??

  1. #1
    Senior Member Joe-MN's Avatar
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    Freewheel- v.2, electric??

    Something I thought of a while back, and since I am trying to learn CAD. There was no actual engineering involved when I drew this up.

    What do people think? I know you are all shy and blushing about giving your opinions, but speakup.

    Thanks
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  2. #2
    Senior Member pfcs49's Avatar
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    It would be much easier to steer if there was a tiller at the center.

    There would be a lot of stress at the fork-bearings because they are so near to each other. Look at how it's dealt with on bicycles (yours could be less sturdy/closer together than bikes I think)

    It's hard to discern in your illustration (side view would help), but looks like zero to very little caster, which will make for poor directional stability and possible flutter problems. Casters as seen on furniture and wheelchairs etc have a much different function and need to NOT have what is called caster in a steerable suspension or in those terms to have zero caster.

    Hint: caster in the context of cars and bikes will cause the vehicle to rise when steered off center and thus the suspension will want to return to center when steering force is removed.
    Bikes and cycles accomplish this by the rake angle in the frame head (top is farther back than bottom) and the offset between the axis of the fork bearings and the wheel's axle, and clearly seen in bicycles where the forks curve forward at the bottom.

    Now, the "art" of that drawing? I couldn't do it. Very great! Don't let an old nitpicking fart deter you from going forward!
    And, your premise and intention is highly valid! Someone needs to produce a very simple, straightforward design which this implies. It would be like the model T of powered wheelchairs!
    I'll take one!
    69yo male T12 complete since 1995
    NW NJ

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    Having seen my son use both a Firefly (lots) and a Dragonfly (once) I’d suggest:
    - there’s not enough weight on that powered hub to provide traction
    - how do you control the speed of the motor (both acceleration and braking)?
    - steering wouldn’t be easy as it looks like you’d need to lean forward.

    To solve those issues, you’d probably come up with a Firefly!

    But please don’t let me stop you thinking up ideas or continuing CAD...that’s how all the good designs must have started!
    Gordon, father of son who became t6 paraplegic at the age of 4 in 2007 as a result of surgery to remove a spinal tumour.

  4. #4
    Senior Member NW-Will's Avatar
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    yeah keep up the good work...
    but second the fact, not enough traction.
    I'd say you'll end up with a smart drive. that is my vote for best solution so far with the freewheel etc..

  5. #5
    Front wheel drive with one wheel in front is scary. Do they make front wheel drive motorcycles?

  6. #6
    Sweet drawing! Is that sketchup or autocad? So my thoughts, and I have had some or a lot of experience with front wheel drive and freewheel type wheelchair design with my Quickie 3D conversion. Get some trailing on the wheel, that is get the axle behind the steering wheel. That is simple, but otherwise the chair will wander. Now the harder parts, first is traction, you need weight up front. Doing so will make the chair tippy. To counteract tippyness, make the chair a buggy, using two of these, one on each side. As for acceleration, that is not an issue, just use bicycle motorcycle style twist grips. Better yet, put the motors on the rear wheels...never mind I'm going back into hibernation.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  7. #7
    Don't be discouraged with all the concerns. Where there is a wheel, there is a way. Just find a way to keep it safe.

  8. #8
    Senior Member Joe-MN's Avatar
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    Thanks for the replies. I will try and answer some questions or concerns. A top view is below. Note that this is a concept and no engineering was involved. I got the idea after seeing how popular (it seems) the Free Wheel is. Going this route, vs the Firefly or Dragonfly, has a lot few parts (frame), so hopefully would be cheaper.

    pfcs49 - not sure what you mean by a tiller, directional control would come from the rod and handle shown at the top left in the first post, and left in the top view pic which should be below.

    - I did not add any angle to the fork. Not sure how much will be needed.
    - I agree on the lack of traction because of low weight, but it would be similar to the Firefly and Dragonfly. Probably put the battery (which I forgot to show) as far forward as possible.
    - I did not get far enough to show a throttle or brake, but would expect them to be needed.
    - Using Solidworks student version

    Thanks again for all the comments
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  9. #9
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    Quote Originally Posted by Joe-MN View Post
    I got the idea after seeing how popular (it seems) the Free Wheel is. Going this route, vs the Firefly or Dragonfly, has a lot few parts (frame), so hopefully would be cheaper.
    If you were purchasing items in the US only, then you might be correct. FreeWheel cost $600 vs Firefly cost $2400, so you’ve got a bit of $$ to play with (and obviously your frame would cost less than the FreeWheel cost).

    But CNEbikes (Chinese company via Alibaba) sell the equivalent of a Firefly for <$500. Plus shipping of course, and I don’t know what US taxes may apply on top of that (if any), but I think you’d struggle to make a “powered FreeWheel” for less....
    Gordon, father of son who became t6 paraplegic at the age of 4 in 2007 as a result of surgery to remove a spinal tumour.

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