In what context are we telling people that "flapping to equality" (a passable descriptive term of harmonic flapping) doesn't occur in forward flight?
FDR, my science degree with majors in physics and mathematics was 55 years ago, so you lost me with your way-too-deep equations.
My comment was that a lot of people think that the advancing blade is flapping up in forward flight and the retreating blade is flapping down , when in fact they are doing the exact opposite.
Regarding Shawn, I had a delightful lunch with him in LA back in 2003, and got a signed copy of his book as well. I found quite a few things that could have been clarified better, and lots of spelling and grammatical errors, and I sent him a list of the suggested amendments. But when the next edition came out, the same errors were there - perhaps he didn't like the critique, or maybe the 2nd edition was already in the hands of the printers, will never know. But a lovely guy.