This article describes the findings of a experimental study of the effect of the profile and angle of attack of the propeller blades on the operational parameters of the 3W 275 B2 CS piston engine of air. Forces, the head's temperature and the crank's speed were recorded during real time on a special test vehicle. The investigation involved different configurations of propellers (2 and 3 blades) and different speeds. This made it possible to evaluate the influence of the propeller geometry on the engine efficiency. The results have shown that the right selection of the angle of attack and the profile of the blades and their number significantly affects the reached parameters - especially the string and temperature distribution, which is important for the safety and durability of components of the propeller system. The developed research stand enables further research on the selection of flour propellers. The novelty of the work is the use of a new type of research stand to determine the changes in the value of the force obtained during tests for wide range of rotation speeds of the internal combustion engine shaft. The selection of propellers depending on the number of blades and their profile is very difficult to predict and you should always do it individually for each engine after testing. The profile and the number of propeller blades so much allows you to get high flexibility of the engine and a good propeller continuing depending on the speed of the shaft.