TURNINGAlthough turning is only a horizontal change of direction, airplanes can only perform flat (unbanked) turns at low speeds. Normally, the rudders cannot be used simply to turn the airplane's nose toward a different heading. Airplanes have much more control in pitching (up-down rotation), and so turns are made by changing a yawing (sideways turning) motion into one involving pitch. This is done by banking the aircraft, that is, by raising one wing and lowering the other.
To make a turn, you must bank the aircraft so that your desired direction is above your nose. So, push the joystick (or mouse) sideways for a second (or press either the 'left arrow' or 'right arrow' key), then release it. The aircraft will bank and your nose should slowly begin to edge below the horizon as you yaw into the turn. Now, pull back on the joystick (or mouse), or tap the 'down arrow' key, so as to keep your nose level. You are now executing a level turn. The more you bank, the faster you will be able to turn with a level nose.
While turning, you are now using only part of your lift to keep the aircraft up. The rest of your lift is changing the direction of your aircraft's movement. Aerodynamic stability makes sure that your aircraft's nose does not stray too far from this direction at any time. Obviously, as only part of your lift is balancing out your weight, you need more lift in total to stay up. When lift is different to weight, you begin to feel the effect of the resulting acceleration. This is called g-force. "
From the manual