Another one for the brains trust after another wet weekend.

I was looking at the equations for flywheel weight for steam engines. If the same equations hole for scale models then the flywheel would have inadequate mass for smooth motion of a model running at original speed and the model would have to run faster - e.g. 12 times faster for a 12th scale model, or the motion would be jerky or stop.

But then I started to think about bearings. The mass of a 12th scale model is reduced by 12 X 12 X 12, the bearing area is reduced by 12 X

- So the bearing area on the model is 12 times larger than is actually needed to support the mass (good), but that means 12 times the viscous drag, and if the model is running 12 times faster too, then 144 times the viscous drag.

And then I started to think about flyball governors ....er.... and rapidly decided to give up and ask the newsgroup if there have been any ME articles or books published on the problems of scale? Its fairly fundamental stuff that must have effected everyone making scale models - but I don't think I have ever seen a nice clear article on the topic.

Steve