I had the same problem. W37 sent me an article that helped me. If your rudder is mecanicly way of alignment, it will not work for you. He said I can post it, since it was a pdf file, I had to break it up. sorry. Change the extension of the last picture to (.txt) if you download it. This is the text file, or just click on it to show on your browser.
ORIGINAL: rweller
reply to Chrizz - Seems like you had the same problem I am having and I wondered if you solved it. I recently got a 37, and am having trouble with the rudder servo. When I first attach the battery, the rudder servo centers quickly, but then slowly creeps (ticks) forward so that it is not centered when I am ready for takeoff. Because of this, the heli keeps turning to the right. I adjusted the push rod as far as I could, but even with the control hard to the left I cannot keep the heli straight, let alone turn to the left. I hooked up another servo to the same plug and it acts exactly the same. Any advice you can give me would be great.