imagine your plane with no propellor.... in KE it would push to the belly slightly both left and right rudder....
now.. superimpose on this tendency the effect of "P" factor... this is the tendency of a prop, with its axis at some significant AOA
having more "Bite" on one side than the other....

With right rudder.... the "P" factor is towards the canopy... nulling the belly pitch inherent in the design...

with left rudder.. the two effects combine to create a pitch toward the landing gear...

try the following test with no mixing.....

get the plane really high, pull the power to idle, push it straight down and apply rudder... see what happens....
repeat again applying rudder the other direction.... I bet there is a very slight trendency to push towards the gear both ways....
(This test is designed to reduce the influence of the motor/prop)