One other thing you may want to do to make it fly better is change the lines if you are using the Dacron lines / plastic handle.
Get a set of .008 lines and an adjustable handle, ( the Cox one doesn't fit my hand right). Another option is Spyder wire fishing line, it is stronger and has less drag than the supplied Dacron lines.
Using 25% nitro is also helpful for increased power and better runs from 1/2A engines.