The Craftmans Shop > Model Engineering

Block port size. Bogstandard’s Paddle Duck Engine

(1/1)

Knock-wood:
I’m 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 Ø 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? I’ve a funny feeling it’s not that simple.

awemawson:
Can't help you with the port sizing, but welcome aboard the forum

SwarfnStuff:
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

Navigation

[0] Message Index