landing_gear_design_documentation: - update section nacelle clearance

docs/documentation/sizing/landing_gear_design/design_method.md

@@ -322,28 +322,10 @@ With the known values, the landing gear placement and dimensions are estimated m
 Ground clearance angles for nacelles and wing tips are calculated and verified in accordance to Torenbeek<sup>[6]</sup> and CS-25<sup>[2]</sup>.
 
 ### Nacelle clearance
-The ground clearance $c_{\text{nacelle}}$ for each nacelle is given as:
-$$
-  c_{\text{nacelle}} = d_{\text{GND to FCL}} - |z_{\text{nacelle}}| - |h_{\text{nacelle}}|
-$$
-
-In which
-
-- $d_{\text{GND to FCL}}$ - vertical distance between ground and fuselage center line
-- $z_{\text{nacelle}}$ - z position of nacelle
-- $h_{\text{nacelle}}$ - height of nacelle
-
-The nacelle clearance angle can then be determined:
-$$
-  \theta_{\text{nacelle}} = \arctan\left(\frac{c_{\text{nacelle}}}{|y_{\text{nacelle}}| - y_{\text{MLG outer strut}}}\right) \cdot \frac{180}{\pi}
-$$
-
-In which:
-
-- $y_{\text{nacelle}}$ - y position of nacelle
-- $y_{\text{MLG outer strut}}$ - y position of outer main landing gear strut
+The ground clearance $c_{nacelle}$ for each nacelle can be specified via the module configuration file. A value of 0.45 meters is set by default. 
+This value is usually used by the manufacturers as the nacelle safety clearance; a specification by certification regulations is not given.
 
-This value is then checked regarding the minimum required clearance angle of 5 degree, defined by CS 25.149, and the user-specified nacelle clearance angle.
+The implemented method checks for each existing propulsor whether it is mounted on the wing and if the nacelle used complies with the required safety distance. If the check fails, the necessary delta length of the main landing gear struts is calculated and the dimensioning of these is restarted. The repositioning in the direction of the span resulting due to the change in length is also performed. If there is a collision with the innermost propulsor mounted on to the wing, an error message is displayed and repositioning is terminated.
 
 ### Wing tip clearance
 The wing tip ground clearance $c_{\text{wing tip}}$ is known from the positions of the wing tip section.