Counterclockwise Yaw During Takeoff

GlassKNees

I've been experiencing an intermittent yaw tendency during takeoff that required me to apply considerable right rudder trim to correct. When I got home, I discovered that the #2 motor was loose - could jiggle the can slightly (like a loose tooth)... At first I thought the four screws securing the motor to the moun were lose but they felt tight, but I replaced them anyway. The motor was still loose, so I replaced it with spare I had hanging around. There was no play in it after I mounted it and put the aircraft back together. This morning, I flew it several times and it seems to work fine now. I don't know if the motor simply had worn bearings or if it suffered some damage in a hard landing - at any rate, it seems to fly okay now.