Question Rokuhan Z Shorty?

Raytl Dec 3, 2016

  1. tracktoo

    tracktoo TrainBoard Member

    That unit looks really good and seem to run well.:cool: That said, those amp draw numbers sound awfully low. Based on general experience are you sure they're not more like 20mA and 80mA instead of 2 and 8?

    The varying performance between forward and reverse may have to do with coupler height. When the coupler height relative to the axle C/L is higher it will tend to pull strongest when the power truck is closest to the coupled end and pulling away, less when the power truck is furthest away from the coupled end and pulling away. It effects the weight/ friction on the wheels due to the effect of the leverage caused by the coupler height. Helps one way, hurts the other way.
    Last edited: Apr 11, 2018
    jdmter likes this.
  2. woodworker19

    woodworker19 TrainBoard Member

    I usually see 50 - 60 mA's on my MTL loco's so yes, at first they seemed low. In the attached photo the top row is the voltage. The bottom row is current on a 0 - 3A scale. The Shorty is the only thing under power. When I've compared this meter with others it's been spot on so I don't have a reason to second guess it now. Seeing the motors and considering the price point, I do have some concerns on just how much work are these little motors going to take. I run straight DC, no pulse so I think that's in my favor. I also figure lowering the voltage (rpm) will help reduce heat build up and increase longevity. Adding a couple cars didn't move the current needle much. I plan on running shorter trains for a while and see how they seem to behave. Time will tell.

    Attached Files:

    bostonjim likes this.
  3. shortpainter

    shortpainter TrainBoard Member

    My testing has proven this to be true but it only affects pulling performance by one car. The biggest factor in pulling power is in which position the axle with the traction tires is placed on the truck. I noticed the pulling performance is almost perfectly flipped depending on traction tire placement. You'll get the most pulling power if the axle with traction tires is on the opposite position of movement direction. Tonight, I'm going to put one traction tire one each axle to see if that evens out the performance.
    Last edited: Apr 11, 2018
    bostonjim likes this.
  4. shortpainter

    shortpainter TrainBoard Member

    That did it! Putting one traction tire per axle on the truck evened out the pulling power. I tested 10 cars in both directions and it works great. In other news, I have completed all the revisions of the shell and frame designs. The new shell has open windows! As you can see in the image, I have also completed the designs for the photo etched handrails. I got the ball rolling on the handrail manufacturing but it will likely be six weeks or more before I get them. I have no clue how I will distribute them. As a kit? Anyway, the shell and frame will be available in just over two weeks. Thank you all for your help and input.

  5. bostonjim

    bostonjim TrainBoard Member

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  6. zscaler

    zscaler TrainBoard Member


    Running on DC.
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  7. Mark Watson

    Mark Watson TrainBoard Member

    This is a test run of my N Scale Hydraulic Service MOW Truck, using a cannibalized Z Shorty mechanism.

    (my take a few seconds to load)
  8. HoboTim

    HoboTim TrainBoard Supporter

    Looks good! About 10 years ago a Z scale MOW truck was built that was controlled by DCC.
    Not quite as slow as the shorty mechanism. But it ran.
    Mark Watson and Kez like this.
  9. Kez

    Kez TrainBoard Member

    Hey Tim, it's about time to finish a few more of those, isn't it? :)

    Nice to see you here again. What's new?
  10. Mark Watson

    Mark Watson TrainBoard Member

    Yep, ever since following that project long ago I've dreamed of building my own 'someday'. This Z Shorty was the final catalyst.

    Since the Z Shorty runs so well itself, I'm just planning to finish this build and move on. But if I ever get the itch to build another, I'd try swapping the motor for one of those Gizmoszone 1:5.14s.

    In fact, I'm a little surprised I haven't seen that done for any of the critter bashes with the ZShorty yet.
  11. SJ Z-man

    SJ Z-man TrainBoard Member

    Animation killed me Mark. Now I have a new bucket list item. That's the kind of stuff to put on the show layouts !
  12. HoboTim

    HoboTim TrainBoard Supporter

    You're killing me!

    How do you know what's been cooking in my kitchen?
    You been talking to Jeffrey White?

  13. HoboTim

    HoboTim TrainBoard Supporter

    I have some of those gizmo geared down motor assemblies. Too long. I have one modified with a Marklin worm. Works great, just too big & too long. I have several shorty's I am considering for bashes.

    Hiding the motor assembly under the MOW truck chassis is key in this. Needs to look as normal as the real thing. A real challenge, especially for one who knows not 3D for dummies.
  14. craz3474

    craz3474 TrainBoard Member

    Sooooo.....any updates?
  15. southernnscale

    southernnscale TrainBoard Supporter

    Yep! Waiting for any updates on the SW!!!! What happened?
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  16. shortpainter

    shortpainter TrainBoard Member

    Hi, thanks for asking. Things have moved forward but, of course, real life has caused some delays. Recently, version 2.0 of the SW shell and the frets for the hand rails were delivered. I am assembling the first prototype model to verify all parts fit. I painted it in Conrail colors. My Conrail decals arrived today, yay! My plan is to make a kit that includes one set of hand rails, two pieces of pre-cut wire, and a 330 ohm electronic resistor. These are all the parts needed for a fully functional model. My next step is to set up an online store to sell these kits. I will finalized the shapeways model as soon as possible and put it up for sale. The steps to get an SW will be;

    1. Go to Shapeways and order the shell/frame and trucks
    2. Go to online store to buy optional handrail kit.
    3. Buy a Rokuhan Shorty at your favorite retailer.
    4. Build it

    I hope to have assembly instructions posted somewhere online soon. Perhaps it will be the same place the handrail kit is purchased, not sure.

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  17. Kurt Moose

    Kurt Moose TrainBoard Member

  18. ddechamp71

    ddechamp71 TrainBoard Member

    Step 2 above : which online store ? :)

  19. shortpainter

    shortpainter TrainBoard Member

    That's the part I have to figure out. I'm leaning toward my own website or possibly an ebay store. I'm open to suggestions. I'd like to make the process as easy as possible for everyone.
    ddechamp71 and jdmter like this.
  20. rvn2001

    rvn2001 TrainBoard Member

    Maybe some of the dealers who handle the Shorty would be willing to distribute your parts as a detail kit... That might save you the expense of your own website. I'm ready to buy when you're ready to sell.
    jdmter likes this.

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