The skyfly wing is very weak. If it is already cracked, you can try some gorilla glue and use some 3M extreme packing tape to re-enforce the cracked area and also underneath the wing along its span. Don't use regular CA glue if CA is your adhesive of choice. It will attack the foam in that wing big time. The Skyfly tends to be sensitive to wing tip stalling as far as I remember. Site down from the front of the plane and make sure the stabilizer and rudder look striaght.

dave mc