I notice a couple of pages back, discussion about roll drift starting to occur after a few minutes flight (you should also get tilt drift but less pronounced). This is due to vibrations, and basically PL losing its reference of where "down" is. Pls check post #783 and 785 on page 79.
Different platforms will generate different frequencies, so the settings will have to be adjusted for each case, you'll also have to experiment w/ different thickness of tape.
Also, if your PL has been calibrated at an ambient temperature of say 20°, and you then fly w/ a temperature substantially different from this, your PL will exhibit the same issue w/ roll drift. The solution here is to calibrate it at the temperature you'll be flying at (make sure it's level when you calibrate it).
E