You may need to perform a "RC calibration" via the OSD. Use the 3 buttons located on core at the back of the TBS Vendetta. You can open the frame or use a pin (screw driver, etc.) to push the button through the opening of the frame. Push/hold the center button to open the OSD menu, then navigate with the side buttons to the RC calibration sub-menu. Make sure to position your flight mode switch button on your radio to the center position before doing a RC calibration.