Quote: "What is the advantage of starting with a small tube and progressively increasing the tube diameter through the monotube boiler?"
I'm not sure exactly why, I have little interest in monotubes so I don't pay much attention towards them. I think what it is, the larger tubing acts a pseudo-reservoir and separator. A steam bubble low in the coil will push a slug of water ahead of it, when it reaches the larger diameter tube, the volume increases and the velocity drops, providing an opportunity for the steam to surpass the water. Also, the larger volume acts as a reservoir for better stability overall.
Fred, Thanks for the clarification on that.
Quote: " Impressive bits of kit. ..I think all in this book were being fired by Paraffin burners...."
Which is understandable, Paraffin, we Yanks call Kerosene is quite a bit hotter burning than gasoline or Petrol, more carbon atoms per molecule and all that. I run straight Kerosene in my car and and my buddy runs straight gasoline, I make more steam. Diesel fuel is a bit hotter than Kerosene. Diesel and Kerosene are roughly 5 or 6 times (based on vaporizer length and heat applied) more difficult to vaporize vs Gasoline.
A section for all non-Steamboat things and machinery - Steam vehicles, trucks, plant, cars etc...