I was thinking about something regarding the MiG-25's top-speed. There are some things about it that don't seem to add up...
For example the engines: The Tumansky R-15 -- It only has a pressure ratio of 4.75:1, and 5 compressor-stages and from what I remember a pretty high turbine temperature. I know the Russians didn't quite have the engine capability that we had, but I still find it hard to believe that with that kind of pressure ratio with most of their thrust no doubt coming off ram-compression and the engine's colossal afterburner that it would redline at only Mach 2.83, and burn out at Mach 3.2
The plane had a fuel that had a high-temperature flashpoint, which while not quite as high as the JP-7 used on the Blackbird, still higher than say JP-4. Other than the Blackbird, the only plane I can think of that utilized a high flashpoint fuel was the XB-70 Valkyrie, which used JP-6. It is officially stated to be a Mach 3 capable design, however they did wind-tunnel tests to Mach 4, and the chief-engineer of the project stated that the inlets could perform Mach 4 speed, and it's been acknowledged that the J-93 could achieve it as well.
Now I'm not necessarily saying the MiG-25 could do Mach 4. But I'm wondering if it's limit is 2.8/3.2 or a bit higher than that especially for quick bursts.
Of course I don't know why anyone would lie about it though. It's not like it's a new state of the art design and it's not even our design.
Kendra
