"More firepower" is a subjective claim. The 5 flexible 20mm mounts were drum fed with cans of up to 45 rounds (less than one second of fire), and used the same low-velocity gun as the A6M2. They weren't known to be highly accurate in that configuration. The H8K did not have armor, and "partial self-sealing tanks." Does that mean it had some lined fuel tanks and some unlined ones?
In any case, F4Fs seem to have had no difficulty shooting them down.
Only the crew had some armor in H8K2, the fuel tank arrangement was a bit bizarre with 8 small tanks in the wings, and 6 partial-self-sealing carbon dioxide extinguisher system tanks deeper inside the hull. If the fuel was crossed fed to the wing tanks first then the engines, then it would have negated the effect of having 6 well protected tanks. And your right more firepower is subjective, their armament (and high speed) would seem better suited to chasing down large allied transports and patrol planes, not nimble fighters. Very few were built, so its hard to generalize but in some cases it survived long enough to ditch at home, and I couldn't find any combustible reports about it. Actually I agree now with the initial assessment, with the exception that torpedo/bomb carrying capacity should have been sacrificed (maybe some small depth charges as only offensive armament) and guns and armor should have been added (2000kgs of weight altogether) . It did need the fuel for its huge range at high speed.
So hard to find exact specs for this, this is the best description of the fuel system I found at http://www.aer.ita.br/~bmattos/mundo/ww2/kwkh8k.htm
These hull tanks were protected by partial self sealing and a carbon dioxide fire extinguisher system, and they were arranged so that if any were punctured, the fuel would drain into a bilge where a pump would transfer it to an undamaged tank. Total fuel capacity was an amazing 3,749 gallons, and the weight of the fuel represented about 29 percent of the aircraft’s total take-off weight. Armor protection for the crew was also provided for, and the proposed defensive armament was immense by the standards of those days. No less than five 20mm cannon were to be carried, one each in powered nose, dorsal, and tail turrets, and one apiece in the port and starboard beam blisters. Three flexible 7.7mm machine guns were also available, one each in port and starboard beam hatches to supplement the fire of the beam cannon, and one in a ventral position.
< Message edited by icepharmy -- 12/1/2011 10:11:19 PM >