Quad copters are one of the most used configurations to develop Unmanned Aerial Vehicles for civil and military applications. The flow dynamics developed by four rotors of a quadc opteris complex due to interaction between the rotor wakes and the quad copter fuselage. In the present study, the flow simulations of three cases were conducted: a single operating rotor, four operating rotors (no fuselage), and a simplified quad copter operating at hover, in order to better understand the flow dynamics and to estimate the qua copter aerodynamic performance. The simulations were based on the Unsteady Vortex Lattice Method (UVLM) with a viscous correction. In particular, an asymmetrical pressure coefficient distribution on the rotor blades was observed in the simulation of the simplified quad copter, with the Cp distribution depending on the blade position with respect to the fuselage. Computational results of the quad copter aero dynamics performance were compared with experimental measurements from the bench(single rotor) and flight tests (complete quad copter). A good agreement was observed between the numerical and experimental results for the thrust, whereas the torque was underestimated.
