Thanks for the help on the way to say Reuleaux, I was not even close as I knew that he was German and that made me think the x was not silent.

I will get back to the diagram in

__The Constructor__ it is a more complex version that uses the connecting rod length.

This is the simple version. I took a look at

__Model Engineers Handbook__ by Tubal Cain and I modified that diagram to match the rotation shown with the Zeuner diagram.

The hard bit for me to figure was the angle of advance if it was not given in a drawing set. Well thanks to this thread I have finally worked that out in my head. The angle of advance is the angle the the eccentric is ahead of the crank plus 900.

Looking at the Zeuner diagram it can be seen that the sine of the angle of advance is the opposite divided by the hypotenuse or the

(lap + lead)/(1/2 valve travel) = sine of the angle of advance.

This was the part I was hanging up on but it is the calculation required with the start information we have for all the diagrams.

Now you will notice that the simple Reuleaux diagram is exactly the same as a Zeuner diagram it is just a quicker way to draw it.

I imported the Dockstader Zeuner diagram into my cad program. Then I made a

red mirror image the Reuleaux diagram in the last post and centered it on the image.

Now it should be clear how the graphics work in Dockstader Zeuner module. I still have to explain some of the output numbers and the port width line.

Dan