In the aircraft's  'aircraf.cfg'  file (main folder(use Wordpad or Notepad to open it)) there is a paragraph that will look like this:


[flight_tuning]
cruise_lift_scalar     = 1.0
parasite_drag_scalar   = 1.0
induced_drag_scalar    = 1.0
elevator_effectiveness = 1.0
aileron_effectiveness  = 1.0
rudder_effectiveness   = 1.0
pitch_stability        = 1.0
roll_stability         = 1.0
yaw_stability          = 1.0
elevator_trim_effectiveness = 1.0
aileron_trim_effectiveness  = 1.0
rudder_trim_effectiveness   = 1.0

Obviously you want to adjust the elevator_trim_effectiveness.  Reduce the 1.0 by 0.05 increments (first test being 0.95) until you get it where it feels right. Of course, make a backup of the file, just in case you really mess things up