drifting

Hello, im having some problem with my quadcopter. its my first cheap quadcopter called JJRC H29W my quadcopter keeps drifting to the top right (north east?). so lets say i calibrate it(both sticks down to the right) to the north and it will drift to the north east, calibrate it to the South ...

I am having an issue where the tricopter drifts in one direction. I trim that out and it flies ok for about 5 secs. Then it will start to drift again that direction. Again trim it out and the same happens. Until full trim is reached. Also, it will be one direction one time a different direction...