I've done some more work on the combination crank slider / belt drive mechanism that I started yesterday and I must say its looking good!

The pulley wheels in the model that I made yesterday where a little bit too far apart, (above left) so I started off by remaking the top of the shaft with the wheels closer together. (Above right) 

To fit the pulley wheel in place I had to taper the top of the shaft. Then it was just a case of making a narrower shaft.

To tidy up the belts I've made a simple guide to hold them up against the shaft. This picture is from yesterday's prototype where I was trying the guide out.

I've also changed the diameter of the pulleys. The originals were 14mm, these are reduced to 12mm. For the same belt movement the wheel turns a few extra degrees. The result works really well, the movement has a different feel compared with push rod driven wings, much brisker and more positive.

Here's what it looks like with a body and head 🙂