Combat trim automatically trims your plane level for the speed your flying. In most cases it's not a problem, but when you get slow it has a tendency to trim you nose up. In a 38 I can get it "stuck" in the air, and you are fighting it like crazy when slow.
A good trick is to set a button to turn on/off auto trim. Level, flick it on, then off and it will trim you for that speed.
As everyone else said, give trackIR time, you'll get it in a few weeks.