There was an original Atkinson cycle engine at the Paducah, KY steam and gas show about 10-15 years ago. I did not see it as I was not there, but a good friend told me he saw the thing running. If you think that Atkinson engine was weird, you need to go to Lindsaybks.com (I may have that addy a bit off) and see the Atkins engine that Dave Gingery made. It is totally different in action from the one that was at Paducah and has two pistons in the same cylinder. I believe Lindsay has a video of the thing in operation or at least an animation of the principle. Jesse the crazed Tennessee Machinist. There are two known full size Atkinson Cycle engines. One is (or was) in the Ford Dearborn museum, but is not on public display. The other is at he Anson Engine Museum, Poynton, Lancs. It has been run on several occasions. When I aw it, the speed was down to about 60rpm! Fascinating to watch, as you say Alan. Anson Engine Museum: http://www.enginemuseum.org Well worth a visit. Dave Saudi-Arabia-On-Sea 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.