Originally Posted by AlexF
James - trust me, I teach this stuff for a living!
draw a diagram of a crank with a 2cm throw and a 10 cm conrod
then move the crank 90 dgrees and measure the difference from where the top of the conrod was to where it is now!!
it will have move 2.2cm NOT 2.5!!!!
Alex
Where the hell do you get 2.5cm from?
He is saying it will be halfway, thats 2cm.
He is of course wrong though, at 90 degrees the piston will NOT have moved halfway it will have moved more than half way, then in the second 90 degrees it moves less than half way.
The longer the rod, the smaller the distance between these two distances (ie the closer it gets to having moved halfway).