Every aircraft will have different trim settings for each phase of flight. There’s too situations, after calibrating your device, that you may find yourself fighting the aircraft. Trim is the solution.
If you are pulling back on your device from where you calibrated it use positive trim. Using positive trim will bring the nose up and slow the aircraft down.
If you are pushing forward on your device from where you calibrated it use negative trim. Negative trim is going to bring the nose down and it will increase the speed.
Trim must be applied in the opposite direction.
You can learn how to change trim in Infinite Flight’s Getting Started Guide.