sentences:  Prompted by Charles Gibbs-Smith, when analysed by aerodynamic experts at the Royal Aeronautical Society in the late 1950s, it was found that the rocking wing had a significant disadvantage; it had the effect of a single combined aileron and rudder.To execute a banked turn from flying straight and level, the rocking wing worked moderately effectively, but when the aeroplane's lateral equilibrium had been compromised, tipping the rocking wing in the opposite direction to the down-going wing to right itself had a tendency to yaw the aircraft in that direction.In effect, the rocking wing did not fully assist in correcting conditions of instability since the pilot had no means with which to induce or correct a yawing motion.