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Scale And Model Locomotive's Engines

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  • Member since
    July 2004
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Posted by Paul Milenkovic on Saturday, March 11, 2017 9:21 PM

alloboard

     Why don't they make engines that resemble the FDL-16 engine for model locomotives N-G scale. Why are engines in HO scale locomotives flywheels, but model locomotives are strong as hell. Why don't they make the engines found in model locomotives for scale locomotives?

 

OK, the first person who chimes in "take this over to the MR Forum" get's slapped across the face with a slimy, wet fish -- see "fish slapping" https://www.youtube.com/watch?v=IhJQp-q1Y1s

A lot of this has to do with physical laws that do not scale proportionately.  One of them is the centrifugal force being proportional to velocity-squared divided by the curve radius.  In going from, say, HO scale to full scale, the curve radius is multiplied by 87.1 whereas the velocity-squared term needs to be multiplied by 87.1 squared.  The consequence of this is that an HO scale model train can negotiate at a scale 150 MPH a scale curve so sharp that it would only be found on an industrial siding.

Things like mass-volume-strength relationships, friction, and heat transfer do not scale in linear proportion.  This means that even if you could build an FDL-16 Diesel in HO scale, perhaps by using 3-D printing or maybe even MEMS (used for miniaturized mechanical force sensors used to trigger your car's airbag in a crash), it wouldn't be able to operate anything like a proportionally scaled version of the prototype.

This doesn't stop model engineering hobbyists from trying.  Live steam is popular.  There is G-scale live steam -- I just saw it being exhibited this last weekend -- and I am told there are even live steam models in HO (or maybe the slightly different OO scale as this has been done in England).  That one is able to make small steam engines perhaps speaks to the inherent simplicity of steam power.  Or maybe it speaks to our fascination with steam power along with the lack of interest in "live Diesel" models?  But even with steam there are many compromises and changes made between full-scale and the model.

If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?

  • Member since
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Scale And Model Locomotive's Engines
Posted by alloboard on Saturday, March 11, 2017 8:57 PM

     Why don't they make engines that resemble the FDL-16 engine for model locomotives N-G scale. Why are engines in HO scale locomotives flywheels, but model locomotives are strong as hell. Why don't they make the engines found in model locomotives for scale locomotives?

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