A cyclocopter is a vertical takeoff and landing aircraft that has cycloidal blade systems that consist of several blades rotating about a horizontal axis. The cycloidal blade system allows changes in direction and magnitude of the generated thrust. This paper describes the design and experimental studies of a 110 kg cyclocopter having two cycloidal blade system rotors and one tail propeller rotor powered by a 300-cm 3 -class rotary engine. The tail rotor generates pitching motion and compensates for the torque generated by the front two rotors. The upward thrust direction of the tail rotor provides 10% of the lifting force. The design thrust of the cycloidal blade system rotor is estimated in analytical and numerical analyses. An accurate analytical aerodynamic model is developed. The analytically estimated results have a trend similar to that of computational fluid dynamics analysis. Both analysis results match well with the results of a ground test. The onboard flight control computer system has two embedded processors, and a proportional-integral-derivative algorithm is used as the flight control scheme. The gains of the proportional-integral-derivative algorithm are adjusted during tethered flight tests. Finally, the developed cyclocopter demonstrates hovering and maneuvering flight in a tethered test. Nomenclature C Lα= lift curve slope l = main shaft length p 0 = pressure at the free end of the main shaft T u , T d = thrust on upstream and downstream sides, respectively U R = resultant velocity U T , U P = tangential and perpendicular components of velocity, respectively λ u , λ d = inflow ratio on upstream and downstream sides, respectively ψ u = azimuth angles on the upstream side ψ d = azimuth angles on the downstream side Ω = rotational speed of main shaft Ω 0 = whirling speed of the shaft with zero external pressure [Eq. (24)]

No abstract