Servo in wing
Something to point out here is that the Citabria is not a beginners plane (Citabria is "Airbatic" spelled backwards). Find your local club and get instruction! They do not charge for this service and it is worth a fortune. It is MUCH more difficult than it looks to learn to fly, and starting out with an advanced plane like the Citabria will make it that much more difficult. DO NOT ATTEMPT TO FLY THIS WITHOUT HELP!!!