The gyrodyne includes an inertial wheel mounted, via a wheel support, on the moving part or rotor of a cardan assembly. The clamp includes a body member and latch members integrally formed with the body member. The second end section has an atmosphere-opened port. The control circuit further includes an integrator circuit responsive to an output of the summing circuit. Fastening means of the other bearing device are released and the other bearing device is pivoted.