I've had my quadcopter for a while now, and I have noticed that when I throttle up, either fast, or im using lots of throttle on a low battery, the quad yaws left quite substantially. This makes LOS fairly difficult and makes learning FPV nearly impossible because it's hard o go straight. I put on fresh props and it still occured. I am running it on a Hovership MHQ2 that I printed. Everything else about it works well, and at a low throttle it doesn't yaw much if at all.