added damage when friction is set below 0.97

lib_planes/custom_physics.lua

@@ -1,5 +1,5 @@
 function airutils.physics(self)
-    local friction = 0.99
+    local friction = self._ground_friction or 0.99
 	local vel=self.object:get_velocity()
     local new_velocity = vel
 
@@ -72,6 +72,15 @@ function airutils.physics(self)
             end
             new_velocity = vnew
         end
+
+        --damage if the friction is below .97
+        if self._last_longit_speed then
+            if friction <= 0.97 and self._last_longit_speed > 0 then
+                self.hp_max = self.hp_max - 0.001
+                airutils.setText(self, self._vehicle_name)
+            end --damage the plane if it have hard friction
+        end
+
         self.object:set_velocity(new_velocity)
     end
 

lib_planes/utilities.lua

@@ -344,14 +344,27 @@ function airutils.testImpact(self, velocity, position)
         local noded = airutils.nodeatpos(airutils.pos_shift(p,{y=touch_point}))
 	    if (noded and noded.drawtype ~= 'airlike') and (noded.drawtype ~= 'liquid') then
             self._last_touch = 0
-            minetest.sound_play("airutils_touch", {
+            if not self._ground_friction then self._ground_friction = 0.99 end
-                --to_player = self.driver_name,
+
-                object = self.object,
+            if self._ground_friction > 0.97 then
-                max_hear_distance = 15,
+                minetest.sound_play("airutils_touch", {
-                gain = 1.0,
+                    --to_player = self.driver_name,
-                fade = 0.0,
+                    object = self.object,
-                pitch = 1.0,
+                    max_hear_distance = 15,
-            }, true)
+                    gain = 1.0,
+                    fade = 0.0,
+                    pitch = 1.0,
+                }, true)
+            else
+                minetest.sound_play("airutils_collision", {
+                    --to_player = self.driver_name,
+                    object = self.object,
+                    max_hear_distance = 15,
+                    gain = 1.0,
+                    fade = 0.0,
+                    pitch = 1.0,
+                }, true)
+            end
 	    end
     end