Welcome to the forums, aramis09.
Yes, you'll need to modify some values in the [contact_points] section of the aircraft.cfg. The first three points (0 to 2) define the ground contact points for the undercarriage. Count along to the 4th value in each of these, and you will see a negative value, e.g. -7.40. Increasing this negative number (e.g. to -7.70) will drop the plane further into the ground, raising it (e.g. to -7.20) will raise it. Adjust the numbers until the plane is where you need it. You 'll also need to adjust the static_cg_height figure to match what you've done with the contact points.
Don't forget to make a backup of the .cfg file first!
