MadModder

The Craftmans Shop => Model Engineering => Topic started by: Knock-wood on November 30, 2015, 02:46:22 PM

Title: Block port size. Bogstandardís Paddle Duck Engine
Post by: Knock-wood on November 30, 2015, 02:46:22 PM
Iím starting my first model steam engine and have decided to use the great plans from Bogstandard. I have decided to make mine a bit bigger and have doubled the size. (20mm bore X 40mm stroke)
I see on the plans that the block port size is ō 1.6mm this would appear to be a critical size as all other dimensions are to the nearest 1/2mm.
I was wondering how this size is calculated? Is there a formula that uses boar and stroke to work this out?
Can I simply double this 1.6mm diameter for my engine? Iíve a funny feeling itís not that simple.
Title: Re: Block port size. Bogstandardís Paddle Duck Engine
Post by: awemawson on November 30, 2015, 03:10:46 PM
Can't help you with the port sizing, but welcome aboard the forum
Title: Re: Block port size. Bogstandardís Paddle Duck Engine
Post by: SwarfnStuff on December 01, 2015, 01:02:19 AM
Hi, just did a search on "port sizing in steam engines" and ended up here.

 http://www.steamautomobile.com/ForuM/read.php?1,24667

Have a look and see if it helps or confuses. I did notice some three or four posts down someone had attached a spread sheet you may wish to check.

John B