this is due to what is called the inertia head that increases as the fluctuation of the total flow rate increases and as we know the flow out of each piston is a sine wave function which is shifted by the angle between them according to their number. this shifting angle will cause minimum fluctuations in the total flow rate when using an odd number of pistons while the even number of pistons won't lead to minimum fluctuations in the total flow rate
why swash plate piston number 7;9/11, why not 6/8/10
this is due to what is called the inertia head that increases as the fluctuation of the total flow rate increases and as we know the flow out of each piston is a sine wave function which is shifted by the angle between them according to their number.
this shifting angle will cause minimum fluctuations in the total flow rate when using an odd number of pistons
while the even number of pistons won't lead to minimum fluctuations in the total flow rate