Solution: 1.The helicopter is shaking when it is flying.
Answer:Firstly, using the trim of the controller to adjust the best flying condition of helicopter.Then check whether the blades of helicopter are loose.Avoid flying it in air-condition or windy place.
2.The tail blades can't spin.
Answer:Firstly,remove the tail baldes of helicopter to see whether it is pasted by the glue .Then check whether the motor of the tail blade fall off.
3The helicopter can't fly high enough.
Answer:Firstly,please check whether the battery of helicopter is more than 4.0V.Secondly ,please check whether the blades break or not.If it does, replace the blades then it can fly normally.