A Hybrid Stirling Trike

Discussion in 'Motorized Tandems, Trikes and Recumbent Bicycles' started by Intrepid Wheelwoman, Feb 21, 2015.

  1. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    While I had my brazing gear out this afternoon I converted the trike's seatpost into a 'lucky 7' type which has improved the seating position no end. The handlebars were also cut off short and re-positioned into a tiller-like position, but I still need to do further adjustments on this before it's properly workable.

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    The next task will be to mount that blue Raleigh 20 bottom bracket post on the frame to put the pedals in a feet forward position.

    I took apart the exercise machine I was going to strip for handy tubing and the part that's sitting on the front wheel in the picture will become the front part of the bodyshell framework after it's been pruned a bit. It even has a bracket on it that I can use to mount the headlamp.

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    Dense polyethylene foam has been used to make velomobile bodyshell cladding and I was thinking about using it, but I most probably won't as it's too suspiciously hi-tech a material for old fashioned me.

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    I purchased a cheap camping mat made from the stuff with a thin alumminiumm foil backing for research purposes which I'll have a mess about with and report my findings so I'm not totally close minded about the possibility of using it.
    By the way posh Yoga places sell this stuff as yoga mats at a truly horrible price when it can be purchased at the Chinese discount shops for 1/10th the price so don't get stung if you're interested in making use of it.
     
  2. silverbear

    silverbear The Boy Who Never Grew Up

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    Anne,
    Did you make up the lucky 7 seat post with your new maps gas brazing torch? And did what... took a seat post, cut out a wedge, bent it over and then brazed it shut? Is that it? I think I need one of those torches. Does it put out enough heat to be able to bend a pedal crank? I've done ones cold bending, but at risk of breaking my too small vice and I'm not as strong as I was even a year ago to be doing things by the armstrong method alone. I keep hoping to see one of those torches used at a pawn shop or garage sale. Sigh...
    SB
     
  3. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Yes that's it Silverbear. I took a standard seat post and cut a wedge out of it, bent it over and brazed it together. The brazing was done with MAPP gas and not propane by the way. I had no problems at all with building up a nice fillet of brazing metal and making a sound job of it.
    It certainly didn't break when I sat on it and bounced up and down a bit so I think I can call it a success :D

    Remember when you're looking for a torch Silverbear it has to be a turbo or swirl torch in order to successfully braze with it.

    Oh and I haven't tried using it to bend anything yet, but will report back when I do.
     
  4. bluegoatwoods

    bluegoatwoods New Member

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    Yes. I saw the seatpost post and had vague thoughts of 'nice' plus 'can that be strong enough?'.

    It's kinda looking as though the ability to braze is a handy skill for making bikes, isn't it?

    Nice job, Anne.
     
  5. curtisfox

    curtisfox Active Member

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    Yep for sure and that is the way most were done way back in the good old days,just sand blasted a older fork and full of bronze weld. Good skill to learn and not that hard as just i forum of soldering just more heat. ................Curt
     
  6. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Thanks Jim :)

    I never much liked arc welding or MIG welding even though I've got both types of machine in my workshop. Torch welding and brazing have always been my first love and always will be.
    It's beautiful to watch that moment when the workpiece reaches the right temperature and the brazing rod 'wets' the metal and it flows into the joint.

    With the seat post I built up a good fillet along the join so I don't think it's going to let go, - but then I'm a skinny vegetarian lady who weighs the same as she did when she was 19 so I tend not to stress anything much. :)
     
  7. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    I'm still waiting for the crankshaft I ordered to arrive which is very annoying because I can't do a lot on the Stirling engine until it arrives. Stored engines on shelves in my workshop have been nervous whenever my gaze falls upon them because if my patience fails I just might disembowel one of them to steal away its crankshaft. [​IMG]

    I've had one spot of luck though as I was able to purchase quite cheaply and locally too a copper fire extinguisher casing which will make a perfect cooling reservoir for my Stirling engine.

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    One more piece of the puzzle and all that :)

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    #67 Intrepid Wheelwoman, Mar 21, 2015
    Last edited: Mar 21, 2015
  8. silverbear

    silverbear The Boy Who Never Grew Up

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    Ummmm, copper, eh?
    SB
     
  9. boxcar

    boxcar New Member

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    Nice find...
     
  10. Citi-sporter

    Citi-sporter Member

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    IWW,,

    have you considered doing a thermo-siphon type of radiator, with a larger diameter, upward sloping hot water pipe? It will probably work better at the heat levels you're using and no need for an electric water pump.

    I have to say, although I like Stirling engine concepts, the power outputs, at least to this napkin drawing engineer like myself seem like it would be better to maybe make a slow turning IC engine. How many watts would you envision this motor producing, and accounting for mechanical losses would the generator provide enough electricity to make the fuel used for the energy provided have a better return than some small engine running at a constant speed on either producer gas or maybe a hybrid hot bulb, kerosene engine.

    Just some thoughts it seems that Stirling engines all seem to be really low output for the weight and energy consumed.

    Then again after looking at what is being done with modern materials for Sterling engines now.. https://www.youtube.com/watch?v=lvvyjJ8wz3Y
     
    #70 Citi-sporter, Mar 22, 2015
    Last edited: Mar 22, 2015
  11. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Yes C-S I'm going to setup the cooling system as a thermo-siphon system with the copper fire extinguisher casing as the water reservoir. I thought about using a radiator instead, but I think a reservoir type cooling system should work fine as well as being a lot more robust.

    Because I haven't built a Stirling engine before I wanted to give it a try. If it doesn't work out then it can be used to run a fan in my workshop which the vertical gamma type are very good at doing.
    I suppose this project is about the joy of building something from collected bits and pieces and if it all works then that's a bonus. Producer gas and other species of engines are quite possible as well, but we shall see how we go.
     

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