Birk Petersen built this miniature Comber rotary engine. His initial design didn’t run very well, so Birk altered the plans. This second version worked much better. Birk noted in his blog, “After working on it since the first part of September, on the 16th I completed a model of a Comber rotary engine using plans taken from the book ‘Elmer’s Engines.’ Although it would spin free and easy when turned by hand, it refused to even try to run when air pressure was applied—even up to 120 psi. Needless to say I was quite disappointed.” His friend Mike Nay did some research, along with some other peers who had experienced the same problem. Birk ended up rebuilding part of the engine to increase the cylinder bore by 1/16”, and reduce the rotary valve by 3/16” diameter. That change made all the difference. It ran on almost no air pressure at all.

Mr. Petersen created a vast array of projects over his lifetime, ranging from miniature engines to hand-cranked animations and more. He built functional miniatures like a 1/3 scale Gatling gun or a 1/4 scale Case steam tractor, but he also built mechanical creations for the fun and enjoyment of his family. When Birk passed away in 2015, his family graciously donated over 150 items from his collection for display at the Miniature Engineering Craftsmanship Museum, where they are currently on display. We thank the Petersen family for sharing his extensive collection, which demonstrates the broad interests and many talents of Birk Petersen.

Exhibit added: May 7, 2016 - Last modified: January 19, 2024

Presented by The Joe Martin Foundation for Exceptional Craftsmanship