Mastering the Immelmann – from model aviation by Dave Scott

Lessons in proactive vs. reactive flying
The Immelmann is an aerobatic maneuver that allows you to do a 180° turnaround
Featured in the August 2014 issue of Model Aviation.

http://www.modelaviation.com/masteringtheimmelmann

If you did not see this in Model Aviation you can read it at the above link.