Abstract
This paper considers the dynamic simulation of an Unmanned Hybrid Flying Robot (UHFR) with main fuel engine in the middle to carry most of the weight and promises long flights. This configuration will increase the flight time of the unmanned copter for a given payload size as opposed to the traditional quad-copters, where only DC motors are used. A parametric study to investigate the effect of the propellers ratio (main rotor propeller diameter to secondary rotor propeller diameter), the angle of incidence of the main rotor and the twist angle of the main rotor blades on selected performance criteria of the UHFR is presented.