On your Cub as on all planes your plane should go left on take-off requireing alot of right rudder until you rech sufficiante airspeed for the tail to work properly.It's called (p) factor air circleing the fuselage hits the tail fin pushing it right which makes you turn left.Ounce moving the vertical stabilizer holds your plane straight unless rudder is applied.As you gain airspeed right rudder can gradually be reduced. Good Luck