To: Imabell
What I was implying is that the engineering philosophies in presenting POF are different. I said this many posts ago that if a UK or OZ helicopter instructor were to conduct a course in POF to students in the USA that had previously learned this subject from their instructors they would think the UK or OZ instructor to be daft. It has nothing to do with language it has everything to do with philosophy and concepts. Now, your understanding of the subject may be spot on but it doesn’t fly in the USA at least, in technical and service schools for pilots and mechanics as they for the most part teach gyroscopic precession and phase angles of 90-degrees. The concept is very easy to present when you look at the lead angle of the Bell rotor system of 90-degrees relative to the displacement of the swashplate of 90-degrees ahead in rotation. On all Sikorsky helicopters but with the possible exception it seems of the S-76 the servo positions are displaced at 45-degrees ahead of the desired disc displacement and the pitch horn is placed 45-degrees ahead of the blade. It all adds up to 90-degrees of phase angle.
The blades may move exactly the way that Nick Lappos indicated and for all of the technical reasons he indicated. However to try to teach this engineering concept to pilots and mechanics you would lose your audience at least in the USA.