At 08:46 PM 4/17/07 +0100, you wrote: >Several books described a way of analysing steam engine valve events by drawing a circle and dividing it up and dropping perpendiculars etc. >Can anyone help me out please? Cheers, Roger Roger, As I recall it's the Zeuner Diagram Regards, Harry Wade Nashville Tennessee MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.