I am trying to understand the frequency spectrum of a co-axial rotor system. Form now i have a RC helicopter with two sets of three gear systems arranged in parallel, The number of teeth are 7,23,27) respectively. The 2 input dc motors are running at 35K RPM which runs the rotors at approximately 2800 RPM because of the total gear ratio 12.47.
What I understand the frequency spectrum should have -6 peaks of individual gears at there respective rpm's. -2 peaks of Gear Mesh Frequency -2 peaks of blade pass frequencies (rotor have 2 blades each total 4 blades in the RC helicopter.
Is there anything I am missing in this?