Address code review feedback

- Add comment explaining degrees to radians conversion in Flight.stability_margin
- Replace magic number 1e-10 with named constant epsilon in get_cp_position_from_alpha

Co-authored-by: Gui-FernandesBR <[email protected]>

Author: Copilot

rocketpy/rocket/rocket.py

@@ -689,8 +689,11 @@ def get_cp_position_from_alpha(self, alpha, mach):
         where CN(α) is the lift coefficient as a function of angle of attack
         and X_cp is the center of pressure position of each aerodynamic surface.
         """
+        # Threshold for numerical zero checks
+        epsilon = 1e-10
+
         # Handle edge case where alpha is effectively zero
-        if abs(alpha) < 1e-10:
+        if abs(alpha) < epsilon:
             return self.cp_position.get_value_opt(mach)
 
         total_cn = 0.0
@@ -707,7 +710,7 @@ def get_cp_position_from_alpha(self, alpha, mach):
             total_cn += cn
             weighted_cp += cn * surface_cp
 
-        if abs(total_cn) < 1e-10:
+        if abs(total_cn) < epsilon:
             return self.cp_position.get_value_opt(mach)
 
         return weighted_cp / total_cn

rocketpy/simulation/flight.py

@@ -3127,6 +3127,7 @@ def stability_margin(self):
 
         results = []
         for i, t in enumerate(time_values):
+            # Convert angle of attack from degrees to radians
             alpha_rad = np.deg2rad(aoa_values[i])
             mach = mach_values[i]
             sm = self.rocket.get_stability_margin_from_alpha(alpha_rad, mach, t)