What makes you say that, WH? Loyalty or analysis? I hope the latter as I can't directly recall any encounters with Franks so I would love to hear of some.
I always find it hard to compare aircraft although, obviously, some have distinct advantages over others. Many people have gone round and round about what's the best and what's the worst but, to me, there is never any definitive answer. For example, you can say quite easily that the Spitfire is a better aircraft than the Hurricane but, at the same time, you're comparing two aircraft built entirely differently. On top of that, the Hurri could absorb more punishment and was a more stable gun platform. Swings and roundabouts. The perrenial favourites for "worst" are always the Buffalo and the Airacobra but look at how the Finns used the former (and give kudos to the Commonwealth guys in the Far East as well) and how the Russians used the latter. We had a discussion on here a while ago regarding what makes a good pilot and this can be extended to the aircraft as well. No matter how inferior an aircraft like the Buffalo appeared to be, there was always a group of pilots who could make it work. In that sense, I reckon, without looking into it further, a Frank would be a worthy match for a Corsair or Mustang on even terms. Sure, it might be not as well built or whatever but I bet it could out-turn its opponents. In the latter stages of the war when the Mustang and Corsair were more prevalent in the Frank's "world", it's also quite likely the Japanese pilots were, for the most part, nowhere near as experienced or well-trained as their predecessors.
There is some comment in the link above that it could also out-climb seriously powerful and/or lightweight aircraft like the P-47N and P-51H.
Just my thoughts in a rare moment of clarity!

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