Effect of Number of Engines and Payload Weight on Static Stability of an Unmanned Aerial Vehicle

The goal of this work is to study the effect of number of engines and payload weight on the static stability of an unmanned aerial vehicle (uav) after the pre-sizing phase of its design. The aim is to answer the designer’s question, at this early stage, what will happen to the uav’s static stability if we increase these two parameters? After pre-sizing an uav that satisfies our requirements, we start by using the semi-empirical method known as Data Compendium to calculate and quantify their effect on static stability derivatives coefficients. In the next step, we develop a model using the vortex lattice method of the XFLR5 software to characterize these effects. Both methods give similar qualitative results. Using these results, we show that increasing the number of engines of this uav induces a non-monotonic change in its static stability with respect to the three axes. We also show that increasing the payload weight increases its static stability. However, this increase is non-monotonic with the increase of the number of engines. These conclusions show uav designers, focused on increasing static stability with respect to specific axis, how to choose the right number of engines and to manage payload’s weight during operations.