Determination of optimal azimuth for mounting ultralight coaxial helicopter blades

The possibility of reducing vibration of the ultralight coaxial helicopter blades on the through harmonic wave by mounting blades on the optimal azimuth is shown. The methods of the aerodynamic calculation of rotors and the calculation results for the horizontal flight of Rotorfly helicopter are offered. The optimal azimuth of blades intersection is defined as 37.5 degrees angle along the direction of the upper rotor rotation.