Abstract This work focuses on the flow past fixed and flapping flat-plane wings of Micro-Air-Vehicles. The aerodynamics of these small unmanned flyers within the typical Reynolds number range between 104 and 105 is characterized by large separations consisting of complex vortex systems. Thus, aerodynamic forces are mainly created by the pressure distribution on the wing induced by these vortices. The rise of Micro-Air-Vehicles opened up a new field of research for determining e.g. the causal relations between wing design and flapping kinematics and the resulting flow topology and the associated force production. Funded by Deutsche Forschungsgemeinschaft, the research project Instationäre Aerodynamik von Tragflügeln bei kleinen Reynolds-Zahlen comprises, amongst other means, wind tunnel force measurements and numerical analysis featuring an unorthodox approach. In this work, both practices will be evaluated against analytical solutions and existing published results. Furthermore, the acquired aerodynamic findings will be shared. The wind tunnel experiments were conducted in the MAV-Lab, a specially designed measurement setup of Technische Universität Braunschweig. The quality of both, the carried out flapping motions as well as the force measurements was evaluated utilizing error analysis based on the Monte Carlo-Method and highly accurate optical measurements. For force measurement under static conditions as well as flapping motion creation, the setup delivers high accuracy and precision on par with other established high-end MAV-facilities. The force acquisition during flapping motions is stressed between the scaling effects of aerodynamic forces dropping overproportionally with the Reynolds number on the one hand and inertial forces growing progressively with the flapping frequency on the other hand. The presented numerical approach is equivalent to the Direct Numerical Solution of the Navier Stokes-Equations but with subsampling resolutions after having proven that turbulence has a negligible meaning to the dominant vortex structures in the given Reynolds number domain, wherein the approach delivers throughout results in good agreement to experimental results as well as to analytical theory. It is therefore a suited tool to investigate the mentioned flow topology and influential quantities as it offers more physical insight than classical simplified approaches, whilst on the other hand it is already applicable with current computational power. With this methodology, this work elaborates the essential flow structures featuring primary and secondary vortex phenomena depending on wing planform and aspect ratio as well as on the different parameters of flapping kinematics towards the deliberate, effective and efficient production of aerodynamic forces over time.weiterlesen