At the moment I only have one program, as that is all that is needed at this point in time.
This little program
will calculate the top speed, engine rpms or ratio needed depending
on what information you know.
All you do is put in the rpms you expect the motor to do, what gearing
you want to use, and your wheel diameter and press calculate to
find out the speed.
What you then do is change values particularly the ratio until you
get the right speed that you want.
Most brushcutters and similar engines will go up to near 9000rpm
flat out. Some will go more, some less.
Work on that as being the top speed you expect, and you shouldn't
have any problems.
Download ratiocalc172.zip (~200kb)