Sorry,

Additonally,  Bob you say "the rotary (uses it's displacement ) in 3 revolutions of the E-shaft or one revolution of the rotors."     While all of the displacement of all the rotors is disturbed during one revolution of all of the rotors, Ed's work attempts to determine how much combustion charge is consumed (factoring in displacement and other factors) per revolution of the rotors and then determine CFM based on consumed combustion charges and rpm. Apparently it isn't as simple as what you said about 'uses it's displacement'  Or so I think.

Tom