Axial piston pumps with constant pressure and variable flow have extraordinary possibilities for controlling the flow by change of pressure. Owing to pressure feedback, volumetric control of the pump provides a wide application of these pumps in complex hydraulic systems, particularly in aeronautics and space engineering. Mathematical modeling is the first phase in defining the conception of a design and it has been carried out at the beginning of the project. Next very important phase is the check-out of the characteristics at the physical model when the pump has been produced. Optimal solution to the hydropump design has been reached by thorough analysis of the parameters obtained at the physical model by means of the simulation results of the mathematical model. The paper presents the possibilities for selecting the most influential parameters, their correction for certain values, and eventually the simulation at the mathematical model which shows the change of hydropump performances. After all these analyses, appropriate changes are made in design documentation which will serve for prototype production. Finally, when all kinds of tests are done at the prototypes along with fine adjustment of design solution, the series production of hydropump will be organized.