There is a bit of confusion possible (from reading some of the above posts). Remember there are three things at the back of the aeroplane:
- the tailplane (or horizontal stabiliser)
- the elevator - a movable control surface usually attached to the rear edge of the tailplane
- the trimmer - which can mechanically work in a numbr of ways, but effectively biases the elevator
All three of these can be at different angles to the airflow and exert different forces as a result.