[en] Steady state flow rate and friction factor of superfluid helium (HeII) were measured under controlled experimental conditions. The driving pressure difference was due to the saturated vapour pressure difference and a small hydrostatic pressure head; it ranged from 1 to 35 mm Hg (0.13 to 4.7 kPa). Previous studies were restricted primarily to isothermal flow and small He II column height difference. In this study the temperature ranged from 1.5 K to T lambda. The stainless steel transfer tubes with 0.87 mm and 1.18 mm internal diameters were under an adiabatic condition. Several tube lengths were studied, the results were universal. For comparison, the transfer of He I was also investigated with the same apparatus. Characteristics on the flow rate and friction factor are presented and discussed. (author)