© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Micro Air Vehicles (MAVs) operate in highly unsteady and often separated flow conditions which are well outside the usual design space of conventional lifting surfaces. This paper aims to coalesce theory and simply explain the physical mechanisms behind force production for such unsteady and separated flows with regards to added mass and circulatory (vortex dynamics) effects. Particle Image Velocimetry (PIV) and flow visualisation are additionally used to show that the ’non-circulatory’ added mass forces are responsible for production of vorticity bound to the wing surface, thus can be confused with free vortices in the flow field. Changes to the ’added mass vorticity’ and thus forces derived from this are shown to be independent of flow topology and perhaps viscous effects in general with exception to edge conditions. A technique to simply quantify the distribution of the bound vorticity from PIV measurements is additionally described and utilised.