A model of quadrocopter is created and its flight is visualized. The forces and torques in the Body subsystem are created by four rotors, each driven by a DC motor. The lift and drag of each rotor are computed from the angular speed. A controller subsystem is used to maintain the altitude of the quadrocopter at a reference point. In the attached Maple worksheet all the steps to design a LQG controller are demonstrated. Download the Physical Modeling Information Kit, a free resource demonstrating the speed, simplicity and power of physical modeling.