The article is devoted to the analysis of the process of loading plant mass into the assembly chamber, carried out due to the energy of the air flow generated by the fan and the kinetic energy imparted to it by the rotor blades. Theoretical calculations performed using experimental data from the literature devoted to the study of hay-straw material pneumatic transport are presented. These calculations made it possible to determine the approximate range of the air flow for the developed hay transportation method. To determine the air pressure loss, the balance of resistance to the movement of air and material in the air duct was considered according to the Bernoulli equation for an elementary section. As a result of aerodynamic studies, the following was revealed: the dependence of the air flow velocity along the section width on the distance to the loader at different fan rotor speeds. Curves of distribution of velocities having the form of a parabola with a vertex in the middle of the air duct and the dependence of the velocities on the rotor speed were experimentally established. The obtained experimental data made it possible to evaluate the theoretical prerequisites, the possibility of using the Bernoulli equation in the calculations of transportation through the air duct of the loader