In this paper we present identification results of an internal combustion engine propulsion system. We aim to use this system in a large quadrotor designed to lift heavy objects with flight autonomy up to 60 minutes. In this paper we describe the testbed which we have built to perform the experiments. We present the static and dynamical characteristic of the propulsion system and discuss its dependence on the fuel-air mixture. In particular, we determine the static throttle-speed and speed-thrust curves. For dynamics analysis, we assume that the rotor dynamics can be represented by a PT 1 term and present its parameters for different engine regimes. Using the overall system transfer function we design a simple PI control of the rotor speed which assures setpoint tracking. Finally, we discuss if the achieved closed loop dynamics is suitable for attitude control of a large quadrotor.
