JayZ - I was actually the one that originally assumed about a 20% thrust vs. normal force. It seemed about right when taking a quick look at thrusts of several large aircraft. That said, I could be totally wrong.

I said what I needed to say and posted a FBD back on page 8, and was done, but came back to make sure to clarify that I said it was 20%, not JeffW. Jeff just happens to be using the FBD in his arquement as well.