USS Monitor Steam engine

[nlancaster]

I saw this incredible working model

YouTube - USS Monitor Steam Engine Model

YouTube - USS Monitor Steam Engine Model

and would love to build something like it some day, but I have a question.

It has 2 valves per cylinder and I wonder how this works. Most steam engines I have seen only have one sliding valve per cylinder and I understand how that works pretty well. Do these valves help the engine with efficancy? and are they needed to make it work or could a similer compact engine be built with only one sliding valve?

[Rich Carlstedt]

You are right,there are two valves per cylinder.
One is on top of the other.
In many engines, it is called a "riding cutoff", but in this engine
the valves seperate chests, with a mutual port
The "Cut Off" valve is an efficiency mode to reduce steam consumption.
You can see it be engaged when the guy moves the hand lever, and the engine barks a little. About 50 % of the steam is saved, but full power is needed for "battle" conditions

[the4thseal]

that is inane , my hats off

[vlmarshall]

Awesome. I was looking at the full-size model here a few months ago.. now I need to go look at it again. ;D