SR71 was unique and had issues that wouldn't work for modern and especially low observable. For example it leaked I MEAN LEAKED. Because of its flight envelope the aircraft was built with loose tolerances so that as it flew and heated up the metal expanded. But this meant the fuel loaded in her on take off had leaked out in early flight she had to tank before mission because her on board fuel was gone.
Indeed although A12 did have a interceptor version concept. It would have suffered the same issues as SR71 mind you.
But the claims of the Mig41 are right out of sci-fi especially the time line.
It's supposed to be built by 2025. That means it should be in prototype form right now. And... Nodda.
It may one day be real but there timeline is bogus to say the least. My bet is Mig41 will be more of a Mig31 update than uber interceptor.
The Lockheed A12 was not the only proposal for that program. There was also the Convair Kingfish. Parallel to that, around the time of the Valkyrie bomber project, there was a corresponding program for an escort fighter/interceptor: the North American XF-108 Rapier. That was basically the aircraft the MiG-25 was made to compete with.
Other countries had similar programs contemporary to the Lockheed A12 including British, French, and Soviet programs.
Like I said today we have much better manufacturing technology and materials. For example friction-stir-welding was invented in the early 1990s and is widely used in the space industry. It is one reason why SpaceX's rockets are able to achieve a dry mass fraction as low as they can. They can make a two-stage to orbit vehicle which would otherwise have required a three-stage-vehicle or reduced the payload. A SpaceX Falcon 9 rocket first stage reaches like Mach 6+ speeds and is built of Al-Li alloys. It can get toasty so it needs some sort of thermal protection system (TPS). But if you could make the vehicle out of titanium, which isn't outside the realm of possibility (heck the SR-71 used that), then it shouldn't even need the TPS. For example the latest Falcon 9 first stages have titanium grid fins without a TPS and withstand those speeds just fine. There are also carbon fiber composites and ceramic matrix composites. The Soviets had high density hydrocarbon fuels like Sintin which is a kind of hydrocarbon which has more density than the fuel the SR-71 used.
Even if they did not have a combined turbofan/ramjet engine like that of the SR-71. If the Russians just wanted a quick hack of an aircraft which would have a limited range. They could simply stick an RD-193 rocket engine into it.
Any aircraft which that kind of speed would need to have a longer range radar than its competition. So, much like the MiG-31 it should have a huge radar. This would not be particularly hard to design, especially given how AESA radars are constructed with modules. It would just be more expensive than a regular radar.
I mean just look at SpaceShipTwo. It withstands similar speeds. If a small company like Scaled Composites could do it, do you think a nation state can't do something better than that?
