Abstract
We analyzed a small coaxial helicopter developed for entertainment in 2002. The upper and lower rotors are rigid rotors. The upper rotor is connected to a stabilizer bar. The cyclic pitch of the upper rotor is controlled by the stabilizer bar when the attitude of the helicopter is varied. The angle between the upper rotor and the stabilizer bar is 41°. The cyclic pitch of the lower rotor is controlled by servo motors and the inputs of the cyclic pitch from the servo motors are at the azimuth angles of 45°, 225° and 135°, 315°. This paper clarifies how the angle between the upper rotor and its stabilizer bar and the azimuth angles of the inputs of the cyclic pitch to the lower rotor are determined.
