Are you looking for a few dimensioned drawings to practice your Inventor modeling with? I've put together 24 sheets of detailed part drawings for practice in a PDF.
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 DropBox download link:
Youtube.com video versions of these files by Nivesh and Nisheeth:
http://www.youtube.com/watch?v=FXyopiUEp40&feature=share&list=PLKWX3xUP3pPogJ-snxl4NP18CEi-I82dU
Update:
In addition to these drawings you can find several "projects" at this link:Inventor Wizards
An entire page devoted to model engine plans from Inventor Wizards:
http://www.inventorwizard.be/blueprints/index.html