Radial fans are used to transport gases with non-excessive pressure differences. The apparatus provides the basic experiments to get to know the operating behaviour and the important characteristic variables of radial fans. The optional software for data acquisition and Visualization makes the experiments especially clear and enables fast execution of experiments with reliable results. The radial fan with motor features free speed adjustment. The long and transparent intake and delivery pipes enable stable stationary flow conditions. The air flow is set by a throttle valve at the end of the pressure pipe. To demonstrate the effect of different blade shapes two impellers are included in the scope of delivery: one impeller with forward curved blades and one with rear curved blades. The impellers are easy to replace. The experimental unit is equipped with measuring transducers for pressure, differential pressure, temperature and speed. Using the software the measurements are represented graphically and characteristics recorded. The air flow is calculated.