This study aims to quantify the aerodynamic behaviour of fixed pitch rotors with a diameter of 12.7 cm in axial descent, and its contribution to the attitude oscillations found for quadcopters under similar flight conditions. Wind tunnel tests are performed with an isolated rotor, as well as a complete quadcopter mounted inside a gimbal that allows for roll and pitch motions. Isolated rotor wind tunnel tests show that thrust and torque fluctuations manifest in the pre-vortex ring state, but peak in the vortex ring state. The derivatives of thrust and torque with respect to airspeed remain positive in ranges from 0 mps to 25 mps and 3000 rpm to 20000 rpm. Comparison of these results with measured quadcopter motions reveal that isolated rotor characteristics only partly explain the attitude oscillations found for quadcopters in axial descent.