The US, Britain, Russia, Germany and Japan all had ongoing projects throughout the war. Some reached fruition and some didn’t. Most were serious and projected as viable future ventures.
There were late-war aircraft of theis ilk like the Tachikawa Ki 94, the Mitsubishi Ki 83 or the Nakajima Ki 87 that represented the heavy fighter thinking of the era. More existed in various stages of completion including blueprints only.
The Ki 73 and Ki 78 died due to the lack of Ha 40 V-12s. They were real projects. The Kawanishi J6K1 Jinpu was coming along with the Mansyu Ki 98 heavy ground attack fighter. The J4M1 Senden was another. The Rikugun Ki 93 heavy interceptor was being tested. The Yokosuka R2Y Keiun flew under prop power as a test bed for a later jet design, the R2Y2. And the very real J8N1 Mitsubishi jet was a step toward the Ki 201 Karyu being assembles in caves at the end of the war capable of 530 MPH armed with 30 mm cannon.
Simply because the Allies won the war and completed planes in post-war times that were on the drawing board or conceived during the war doesn’t mean they were not real projects, does it? The Allies simply had the luxury of the victory to continue to develop them into actual planes.
The Axis defeat has direct bearing on the fact that their blueprints and mock-ups had no chance of seeing completion. It doesen’t automatically perclude that all their designs in various stages were not viable.
The above image is not an unreasonable design in concept or in aerodynamics. The fact that is is illustrated with V-12s would preclude its completion in that form simply because the Ha 40 derivitaves of the Daimler Benz DB 601A were in very short supply. This is how the superb Ki 100 came into existance, from the Ki 61 airframes using Mitsubishi radials. There is no reason to presume that the above design would not have been developed given time and replacing the V-12 with radials.
Looking at initial concept illustrations is a bankrupt perspective on deciding whether that concept would or wouldn’t work. EVERY aircraft once completed has gone through many phases of modification from initial concept to wind tunnel models to mock-ups through to several flight tested prototypes each evolving as they were test-flown.
