What both of them said. The plastic that the gimbles are made from is very VERY difficult to glue. Any glue joint you make is pretty much doomed to fail. And as John said above, you don't want it to fail in such a way that you lose your plane. You were lucky that you were able to get your plane down the first time, don't tempt fate. It's very possible for that little piece to break off and then jam the entire gimble so you won't be able to fly the plane and you'll lose it. My advice is to send it to Radio South, or Futaba, and let them make the repairs properly.

Ken