Here is the start of my Strling engine by Coolegem. I got the plans from a Google search and found an online translator from the Dutch to English. After seeing the plans, I just had to make that linkage to see how it works. Like a lot of my builds, I now wait to find materials to finish it. Thin wall tubing in the needed sizes is my biggest obstacle.
Really beautiful and hardly any vibration at all! Using that sewing machine flywheel also gives you a round belt pulley to run an accessory if you so desire. Congratulations on a well executed and beautiful engine!