You can download this file by clicking the Download button on the viewer control frame, or find it on the Tutorials page. I hope you find these helpful.
Alternative download link:
Youtube.com video versions of these files by Nivesh and Nisheeth:
Update:In addition to these drawings you can find several "projects" at these links.
An entire page devoted to model engine plans from Inventor Wizards:
You can use this link for an English translation:
A Few Engine Plans From Dave Archer Of Andover, England.
(Thanks again Dave!)
The first link for each plan set, shows the overall model as well as each part, and included video of the engine in action. The second link for each plan set it to the zip file which contains detailed part drawings in PDF format.
A simple twin cylinder model engine:
A small two stroke radial engine:
A twin cylinder slide valve flash steam engine: