Are you joking? The P-47 was one of the most if not the most rugged fighter in the conflict.
"The pilot is protected from enemy gun fire by face hardened 3/8" armor plate located in the forward and aft ends of the cockpit. The area above the front armor plate is protected by 1½" bullet resistant glass."
(Image removed from quote.)
in addition:
"Normal fuel load is carried in two self-sealing fuel tanks fitted with baffles to minimize surge; a main tank is installed between the wing hinge supporting bulkheads and an auxiliary tank is installed directly aft of the rear wing hinge supporting bulkhead."
The main tank being protected by the massive R-2800 radial... Your uninformed contrary answer for everything is getting really tiresome.
No, I am not joking. Most of a P-47 is unarmored. Seriously. I did not pick the P-47 at random to make my point either. People think of the P-47 as a big, tough, armored fighter, so I picked it to make a point. The armor it has covers a few vital points leaving the vast majority of the aircraft completely unprotected, hence the P-47 is mostly unarmored. Even the Il-2 is mostly unarmored.
The entire tail, aft fuselage, wings and engine on the P-47 is unarmored. It obtains its durability in those areas through structural strength, mass of aluminum and a very tough engine, not armor. Hence my point that the D3A would likely be much tougher than the Fi156, as it likewise has more mass of aluminum than the Fi156. The lack of armor for the cockpit and fuel system on the D3A does not magically make the rest of it weak.
