RE: Park Zone's Icon A5
The Icon tail wiggle is caused by turbulence from the large fuse pod impinging on the vertical tail, plus some prop effects.
A number of folks have solved the tail wag issue on the Parkzone Icon by using an inexpensive peizio rate gyro on the rudder.
My 6 foot Icon does some of the same same thing, but oddly enough, my little tiny one (the small one from Hobby King, not the Guanli one) barely does it at all.
I plan on eventually trying a rate gyro on my large Icon.