EntityQ889636· pop 10· linked from 65 articlesground resonanceSign in to saveimbalance helicopter rotation when the blades become bunched in the rotational plane, typically on the ground when the landing gear is prevented from freely movingConnectionshelicopter rotorEntityhelicopter flight controlsEntityhelicopterEntitywashing machineEntitymomentumEntityrotationEntityaerospace engineeringEntitycenter of massEntityautogyroEntityIngenuityEntitysearch and rescueEntityattack helicopterEntityrotorcraftEntityJuan de la CiervaEntitygyrodyneEntityutility helicopterEntityairframeEntitymilitary helicopterEntityautorotationEntitylist of aircraftEntityCategoriesAviation risksHelicopter aerodynamicsWaves