why use a tailrotor to begin with? i just use a double top rotor with opposite rotations.

if done properly, there will be no residual torque on the body of the machine generated by the rotor. in contrary to real life, it is in besiege possible to neglect all counter torques by using a unpowered wheel/swivel/balljoint/unpowered cog/(spinning block set to 0?). however, those components will function themselves as the countertorque absorbing object. thus better increase teh inertia of that object to make sure the rotor still spins enough