Sketch of the double-cone geometry used for the modelling of MWC349A. The ionized gas is contained in a double cone with its revolution axis perpendicular to the plane of the neutral disk. Each cone has a semi-opening angle of θ_a and is made up of two ionized regions with different kinematics: i) a rotating and expanding ionized wind contained within the double-cone with semi-opening angle θ_a − θ_d; and ii) a Keplerian rotating ionized layer comprised between the ionized wind and the neutral disk with an opening angle relative to the conical surface of the double cone of θ_d. The observer is located toward the negative z-axis. The derived inclination angle θ_i is such that the source is tipped up in front.