In-service is very true.
However the interest in the type of aircraft started in 1934. France, Germany and Poland were formulating the requirements that lead to the Bf 110, the Potez 630 and the PZL .38 Wilk
There were competitors in France and Germany but the theory gained considerable traction and Fokker in Holland and Bell in the US joined the 2-engine fighter movement. This was also the start of things for Italy and Japan. In March of 1937 the Japanese had 3 companies submit bids (or were requested to) that lead to the Ki 45.
There was no practical experience before Sept 1939 even Poland offered little any practical experience.
Point of this is that aircraft programs were not in a vacuum. A number of Air Forces planned to use 2 engine fighters for long range/long endurance missions. Other planned programs could leave the shorter missions to the single engine fighters (which were cheaper). Seeing as how it took around 4 years to go from start to getting planes in service in any sort of quantity there were a lot of twists and turns from start to finish.
Twin engine single seat fighters were a much smaller group and some of them were rather specialized. The Whirlwind for instance was not a long range fighter. It was, for it's time, a heavily armed interceptor.
Whirlwind was 'medium ranged' by the standards of it's day- it had a range of ~ 800 miles, almost twice the earlier Bf 109, Yaks, LaGG 3 and La 5, Spitfire, Hurricane, MC 202 etc. Because of this it ended up being used over the channel and North Sea quite a bit later in it's sadly all-too-short career.
In fact, and
more to the point, this is also true of the Dewoitine D.520 (strait line range 810-930 miles - with self-sealing fuel tanks and armor mind you), and the MS 406 had a range of 680 miles.
I would say that this represented the French already thinking about extending the range of their small fighters. If, in 1940, they are already reaching 800 mile range, it's reasonable to assume they could improve that especially with external fuel tanks.
This was an interesting engine. A problem was how to use it. Sticking a 900-1000kg engine into a fighter with about the same wing size as a fighter using a 600kg engine.
Mig-3 also used about 650L fuel supply instead of the 400-500L of the M-105 powered planes. One result was the rather poor armament of the M-3.
MiG-3, at least the later versions, had exceptionally heavy armament by Soviet standards, 3 x 12.7mm and 2 x 7.62 mm machine guns, which was one of it's problems (heavy weight). I they took off the gun pods on the wings it became lightly armed in that it lacked a hub cannon, which I guess was due to the Mikulin not having a
motorkanone mount. Which was one of the quite nice advantages of the HS 12Y.
Bf 109E was not that good. They did have better trained pilots, better tactics (Finger 4 beats 3 plane vics just about all the time), a much high sortie rate. A German squadron could equal 3-4 French squadrons in missions per day, at least is a short campaign.
If BF 109E is 'not that good' in 1940, I think the problem here is that the standard for 'good' is against a theoretical ideal, rather than the equivalent forces that the French would be facing. You have a point about the lack of French fighter bombers, though the French did of course have fast bomber / strafer types, as well as a possibly improved version of their heavy fighter, and the French Navy had
a weird dive bomber which probably wasn't viable but could have been improved upon. They had already figured out the dive-bombing part, they just needed to improve speed (it only had a 690 hp engine so there was room for improvement there). The Germans actually turned the Bf 109 into a fairly effective
Jabo, more than most people realize, and the Soviets did the same with the I-16 and I-153 (in part with the help of rockets). And of course the French had American types like the A-20 and SBD was on the way too as well (in theory).
Say what you want about that Br 693, but it's design principle matches strafer roles later adapted by the US, British and Soviets, with varying degrees of success, and it could carry a 1,000 lb bomb load.
But nobody's fighters were close to being perfect at the time.
This the key point. Fighter design was always a system of tradeoffs.
In general, you need a lot more planes for offence then defense. Germans were also taken surprise by their success in France. Bf 109s were too short ranged for the BoB. And it turns out the 110 didn't work as advertised. It worked in reverse when the Spits didn't have the range needed for the "lean into France" campaign.
The Bf 110 worked pretty well in France, it was the BoB where the limitations for daylight combat were revealed. And this had largely to do with speed. For a heavy / twin engined fighter to have a shot in air combat against single engined types, it needed to be at least a little bit faster. Bf 110Cs were considerably faster than MS.406s and Bloch 152s which made up the bulk of the French fighter force in May 1940. They were also (slightly less) faster than the Hawk 75A3 and
slightly faster than the Hurricane 1.
But notably slower than a Spitfire, which spelled doom. And the speed of the D.520 would have as well if they hadn't had such a hasty and chaotic introduction.
When planning purchases/acquisitions it was often 1-2 years before combat use. A-20s were fairly successful but somewhat short supply. P-40s and Hurricanes still needed top cover.
A-20s were successful but really needed more fuel which they got (a little bit at a time) in successive waves, and improved armament helped a lot.
That notion of P-40s relying on top cover is largely a myth. P-40s were
not flying with top cover really anywhere in the world in 1941 through mid 1942 (because there was nothing available to play that role), and top cover from planes other than
more advanced P-40s was still very rare in the Pacific and MTO well into 1943 (in part because of limited range of planes like the Spitfire, and for other reasons with the P-38). It was never used with top cover in China and Burma as far as I know. Not sure about Russia.
Hurricanes were fine in 1940 during the BoB, especially once they switched to finger-four formations etc. Unfortunately that vital change in tactics was not communicated to the forces in North Africa and Burma for another year or more.
A nation with several fighter programs could have used different specifications. Building 3 or more different fighters that were all small means the nation actually has restricted options for future developments or needs.
Debatable. It's always a trade off between various pros and cons.
And yet in 1941-42 the P-40 could do both. It wasn't the best fighter, but it was good enough. 109 had a small wing but it had power. Hurricane had big wing and power.
P-40s didn't have bomb carrying capacity until the Hawk 87 / P-40D / E Kittyhawk which first arrived in combat units very late in 1941.
Hurricanes were already seriously struggling against Axis fighters everywhere they were used by 1942.
Soviet fighters could only carry a small load. French fighters in 1940 lacked power. In 1941-42 they have better power but the French were going for even smaller wings, 150 sq ft instead of 170-180sqft aside from the Bloch series.
The VG 33 was a specialized design for fighter supremacy, but there is no reason they couldn't have built a larger wing for it in subsequent iterations.
Having good fighters helps, but if you don't have good mud movers (either fighter bombers or light bombers) and light bombers designed to hold eight-ten 50kg bombs are not really good mud movers in 1942, then the good fighters only go so far, more defense than offensive.
They had the Bloch 693, the excellent LeO 451, plus various American types (Maryland and Boston). I don't think it's likely that they couldn't put bombs on any of their fighter types.
I would also note that the Japanese air forces proved surprisingly effective in China with planes like the Ki-21 and Ki-48 as bombers, and (specially against shipping) G3M and G4M, despite their light bomb loads and 50kg bombs (and torpedoes of course, in the case of the IJN types), and notably various dive bombers like the Ki-30, Ki-32, and Ki-51 for the Army and D3A for the Navy.
