PBY-5A
Edit: I'm sorry let me reiterate so people don't think me ignorant.
1) Ki-43 only has 2 12.7mm machine gun with 250 rpg. Bearly enough to kill someone unless a very good shot.
2) Even PBY has more guns and payload
3) Ki-43 would be even bigger hanger queen then PBY would ever be.
You are very wrong. You're comparing a free kill to the best turning fighter of WWII. Sure, two 12.7mm guns isn't much, but I assure you that you can kill with them. As I posted elsewhere, I have in a single sortie, killed a Hurricane IIc and C-47 with the same two 12.7mm guns on the Ki-84 after my 20mm had run dry. It would have been far easier to have killed that Hurri in a Ki-43 than it was in the Ki-84. In the 84 it took quite a few BnZ attacks to inflict fatal damage, whereas if I had been in a 43 I simply could have saddled up on the Hurri and killed it as there is nothing it could have done to escape me. I even would have gotten the C-47 that nearly escaped my 84 faster had I been in the 43, despite the 84's much higher top speed as I wouldn't have spent nearly as much time killing the Hurri.
Don't get me wrong, the Ki-84 is a vastly superior fighter to the Ki-43, but in that specific place, once my 20mm were dry and given my opponent's aircraft, the Ki-43 would have been superior.
Even in the LWA the Ki-43-II would see far more use than the PBY would after the PBY's "Its new and shiny" period had worn off. The PBY has no role in this game that isn't accomplished in a vastly superior way by other aircraft that already exist. Landing and taking off of water is not enough to make it useful given its massive shortcomings in all other areas.
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Yes, the Ki-27, Ki-43, Ki-44 and Ki-84 are all Nakajima products and yes, Subaru is one of Nakajima's decedent companies.