PURPOSE: To obtain a stable helicopter by interlocking a seesaw rod having an auxiliary wing at one end with the flap of a rotary wing, causing the lift of the auxiliary wing to act on the flap, and making the lift of each rotary wing uniform via an available seesaw effect.

CONSTITUTION: Rotary wings 3 and 4 located above a helicopter body 1 are fixed to the outer edge of a rotary wing head 5 at a constant pitch angle, and supplied with torque from the rotary shaft of a prime mover installed in the body 1. Flaps 6 and 7 are connected to the leading edges of the rotary wings 3 and 4, and a support frame 8 is extended upright from the root of the rotary wins 3 and 4. A bulbous seesaw head 9 is mounted on top of the frame 8 and a seesaw rod 10 is provided on the top as a support point. Also, auxiliary wings 11 and 12 are fitted to both ends of the rod 10 at a constant pitch angle. A part of right and left sections of the seesaw rod 10 is jointed to the flaps 6 and 7 via connection rods 13 and 14, thereby interlocking the auxiliary wings 11 and 12 with the flaps 6 and 7. According to the aforesaid construction, a seesaw effect due to the lift of the auxiliary wings 11 and 12 can reduce a flap effect, and enlarge the flap effect of the rotary wings 3 and 4 generating small lift. Furthermore, a difference in pitch angle of each rotary wing, or a difference in rotary wing lift can be made uniform.