In the mean time, this does therefore prove that the Italians did in fact have access to swept wing technologies, which in turn means that the Re.2007 having swept wings is a tad bit more likely now.
Swept wings may look cool but they only offer a good reduction of drag as the aircraft approaches transonic speeds (around Mach 0.75–1.0). If the plane isn't powerful enough to reach those speeds then swept wings become pointless, as the Germans themselves found out:
"Calculations showed that the use of modern aerodynamics did not promise any appreciable speed advantage. In addition, further investigation and wind tunnel tests indicated the distinct disadvantages inherent in a swept (leading edge) wing in terms of construction and, above all, in low speed flight performance." -Luftwaffe Secret Projects Fighters 1939-1945 by Walter Schick & Ingolf Meyer
And this was about Focke-Wulf proposals for a jet fighter! Not even for a common prop fighter.
The authors are also referring to the fact that swept wings actually reduce lift at low speeds, making takeoff and landing performance worse. They also shift the center of mass rearward and introduce stronger bending and torsional loads, which were hard to handle with the aluminum and wood structures of the time.
So yea, while Italy and Germany and other big powers had experimented with swept wings and other new aerodynamics (since ww1 biplanes in fact...), they didn't mass-adopt them immediately because A) they were harder to construct, B) unstable, C) did not offer better performance but introduced new problems.
Anybody could draw swept wings on paper and promise incredible performance, but then you had to face constraints. Many engineers preferred the simplicity and proven reliability of straight wings and conventional aerodynamics. You could also reuse the same designs that worked already on previous planes for new ones. The most effective planes and the ones that were produced the most during WW2 have their roots in the mid 30s, and were simply upgraded with better engines and things like that, not different aerodynamics.
This is why even after WW2 and well into the 50s and 60s you still had planes with conventional wings (especially naval ones). If swept wings were so revolutionary why didn't everybody simply mass adopt them on all planes? The same can be said for stealth and other technologies today, there are technologies that only make sense for some aircraft and not all.
The Jona J.10 had slightly swept wings in it's first design, and also the tail was different, but the later re-designs changed them for conventional aerodynamics, probably for the same reasons stated above.
The need for radically new designs came at the end of the war when the Axis was losing and needed something to counter the Allies.
It was called "emergency fighter programme" for a reason, they needed fast interceptors to take on allied bombers that were crossing the skies of Europe at will day and night, and so they came up with many interceptor designs, even rocket powered and VTOL as you know. Nobody was thinking that rocket planes and VTOL would replace ordinary planes forever, it was an extreme measure.
Years earlier, under normal circumstances, a rocket powered plane that can only fly a few minutes would have been laughed at, but during the last phases of WW2 it was a serious idea.
Most people today (especially people who don't know history) are under the false assumption that because Germany developed these rocket powered aircraft and other things, they must have been "years ahead" in technology or something. In reality they only developed them because their technology had been SURPASSED by the Allies. The Germans didn't have aircraft carriers or good strategic bombers for instance. They lost air superiority, and after their land based radars were also destroyed the Allies were free to bomb them day and night. This is why they suddenly came up with all kinds of new designs for interceptors, night fighters, etc. and old projects that had been proposed many years earlier were suddenly resurrected because now they were necessary...
But what do I know, I'm just a guy on the internet...
