This is the blog of John Dulaney, a hacker of Fedora, SCAdian, player of Music, blacksmith, sailor, and consumer of Bacon.
Monthly Archives: August 2017
While the traditional way to design steam engines seems to have been to draw out diagrams representing the relationship between the piston, crank, and valve, I prefer to do the math directly.
First, you need to find the angle of the crank at cutoff
Ac is the angle of the crank, 0 being top dead center
rc is the radius of the crank, equal to one half piston travel
p is the piston’s position at cutoff
lr is the length of the connecting rod
To find the steam lap:
L is the angle of lead
Vt is the valve travel
SL is the steam lap
Finally, the maximum port opening is simply:
Po is the port opening