There are two things that normally cause what you described.
One is the c of g too far back or just flying too slow. If too slow maybe you were flying with the wind and your air speed was too slow even though you seemed to be flying quite fast..
Originally Posted by BD700
I have a Swift II in a typical config. I noticed the other day when doing some low fly bys that it was rocking back and forth on lateral axis like it was fighting yaw.
Has anyone else seen this and is there a reason and a fix or just typical of a wing.
This is my first wing and it does fly great and takes a lot of abuse.