or it is because the primary wing of the plane is used.down makes more lift so you go up down make more drag so you go down.I hope thats correct.

@AgDynamics OK thanks :)

Check out the troubleshooting section of the Wiki over on the reddit site.

Specifically:

Your elevators are inverted (pitching down will pitch you up and vice versa) even if they move in a regular way. Your wing must be delta with a really long chord. The force produced by elevators is applied at 25% of the chord of the wing (front), so if you have a delta wing it's likely that this point is in front of your COM, this is why it's inverted. Try to move your elevators on the tip of the wing where the chord is usually shorter.