Ken I have some drawings for a J.B.Root square piston engine. If you like I can send them on to you it looks like a fairly easy engine to build. I think I originally found them on Yahoo Groups but I can't remember which one. I have put a picture here. http://tinypic.com/view.php?pic=87itjy8&s=1 Lee ----- Original Message ----- From: "Ken Strauss" <ken.strauss@xxxxxxxxxxxx> To: <modeleng@xxxxxxxxxxxxx> Sent: Monday, December 10, 2007 4:51 AM Subject: [modeleng] Square pistons > Page 28 of "100 Great Models" shows a "Robertson Semi-Rotary Engine" which > is described in "Modern Steam Engines" by Joshua Rose (page 329-330). Have > plans for this engine for the modeller been published? 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.