Might have mentioned this previously, but with the new blades I inquired as to whether the 23mm ballistic tests were repeated and they were.Same test requirement since the A model. Also for instance had to build a drop test structure for the main fuel tank. Had to have all the structure surrounding the tank. Fill up the tank. Get a crane and lift the whole thing to 65 ft and drop it. No leaks allowed.
These design features are just two of a long list.