With a standard drop tank (Ii don't know its capacity) the Zeke had a combat radius of about 650 miles. this is a far cry from the 'thousands of miles" recorded for it in its specifications, but it is still a very good endurance. You would know better than me, but I have read its long legs were the result of it small capacity engine and ultra light construction. Even so, to get from Formosa to Luzon and back, the Japanese had to develop new flying techniques and engine mixture settings to do it.
Don't know if this helps. most of what you are saying I agree with, but Zekes on these long range escort missions were not just puttering along at training speeds. they were, to an extent at least, combat missions comparable in their ardor to anything in the ETO or the MTO.
In reverse, I would not say that long over water flights in single engine aircraft were not difficult or nerve wracking, especially considering the state of Japanese air/sea rescue service. However the time, percentage wise, of the mission spent in 'hot zones' (AA fire or likely enemy aircraft action) was less than most European missions. Time spent in action (hot zone) could be every bit as bad as in Europe.
we do have conflicting statements.
"Even so, to get from Formosa to Luzon and back, the Japanese had to develop new flying techniques and engine mixture settings to do it."
"Zekes on these long range escort missions were not just puttering along at training speeds"
Aircraft range comes down to 3 things.
1. Drag= power needed to fly at desired speed
2. efficiency of the engine= pounds of fuel per HP hour.
3. amount of fuel carried.
There is no way to get extra long ranges without "new flying techniques and engine mixture settings" unless they include "puttering along at training speeds"
Max range or endurance ( They are not quite the same) will be rather close to the max climb speed as that is the lowest drag speed. However the engine may or may not be at it's most efficient at that speed. Most of these engines are going to be within 10-15% of each other in fuel consumption (lbs per HP/HR) in lean cruise conditions. The Zero is probably on the low end or even a bit of an outlier. The Merlin was a bit on the high side. Allison's were about 5-8% more economical than Merlins when cruising. Nobody really figured that close most of the time.
A P-47 burned about 0.45lbs per HP hour at most economical. However for a P-47 that meant 60 gallons an hour to make 800hp at 5000ft. You don't fly 12,000 planes of that size with the same fuel as planes less than half the weight. A P-38L burned 33 gallons an our (per engine) to make 425hp at 5000ft for 0.465lbs per hp hour. most economical. Very few engines get below around 0.42 and very few got above 0.50lbhp/hr. in lean cruise. Rich mixture is a whole different story.
The British were teaching their pilots to use low revs and high boost to squeeze the most fuel economy out of their engines by 1941 or 42. The whole "lean into France" fiasco taught them that "cruising" in the low 200mph range was near suicidal over occupied territory. Almost anywhere of occupied Europe.
You could keep a Spitfire in the air for almost 3 hours on the normal internal fuel, You just couldn't fight very long or go very fast.
The Zero was light, (less induced drag) but it's form, while good, wasn't great, not in the sense of a quantum change great. You need a certain amount of power so the small engine was help ( a bit less internal friction and less weight) compared to using a very large engine at very low rpm. and the Zero, especially with large drop tank (Zero was within a few gallons of the P-40 for internal fuel) carried the most fuel on combat operations (not ferry) of any early war fighters (not recon aircraft).
The Zero was a very good solution to the Japanese Navy's needs but take it out of it's element and plunk it into Europe in 1941/42 and things might turn out a lot different. Zero pilots with the same training as British pilots of 1941 vs German pilots of 1941? Zeros having to keep cruising speeds closer to 300mph rather than 200mph to minimize the disadvantage of being bounced? Ability to keep the drop tank or have to jettison to keep up performance vs Bf 109? Yes the allied fighters dropped their tanks and turned back after engaging interceptors and had a relief escort group take over.