& Lamers 2000, Hamann & Koesterke 2000). The predicted value is thus representative for the lower range of observed mass loss (i.e corresponding to weak lined WN stars).

As we have adopted a wind velocity law, and only obtained a globally consistent mass-loss rate, the system is not necessarily dynamically consistent. Although we do not aim to derive a model that is locally consistent in the transfer of bulk momentum from the photons to the gas, we may still test the quality of our velocity law by comparing the radiative acceleration that we compute to that implied by the adopted velocity law via the equation of motion. Figure \[f\_gradcomp\_wnl\] shows the computed radiative acceleration by the dashed line, and the one imposed by the velocity law by the solid line. Both show a similar qualitative behaviour with radius, but there are systematic differences. Our models underpredict the line force in the inner wind, and overpredict it in the outer wind. This is similar to what was found by Lucy & Abbott (1993) and Schmutz (1997). The likely reasons for these discrepancies have been listed in Sect. \[sec:winddynamics\] (i.e. no back-warming due to Fe; no iron ionization stages above [ix]{}, no 