  The classic Weber-Davis model of the solar wind is reconsidered by
incorporating alpha particles and by allowing the solar wind to flow out of the
equatorial plane in an axisymmetrical configuration. In the ion momentum
equations of the solar wind, the ion gyro-frequency is many orders of magnitude
higher than any other frequency. This requires that the difference between
proton and alpha velocity vectors be aligned with the background magnetic
field. With the aid of this alignment condition, the governing equations of the
multi-fluid solar wind are derived from the standard transport equations. The
governing equations are numerically solved along a prescribed meridional
magnetic field line located at colatitude $70^\circ$ at 1AU and a steady state
fast solar wind solution is found. A general analysis concludes, in agreement
with the Weber-Davis model, that the magnetic field helps the coronal plasma to
achieve an effective corotation out to the Alfv\'enic radius, where the
poloidal Alfv\'enic Mach number $M_T$ equals unity ($M_T$ is defined by
equation (\ref{eq:mach})). The model computations show that, magnetic stresses
predominate the angular momentum loss of the Sun. For the fast wind considered,
the proton contribution to the angular momentum loss, which can be larger than
the magnetic one, is almost completely canceled by the alpha particles that
develop an azimuthal speed in the direction opposite to the solar rotation. The
Poynting flux associated with the azimuthal components is negligible in the
energy budget. However, the solar rotation can play some role in reducing the
relative speed between alpha particles and protons for low latitude fast solar
wind streams in interplanetary space.
