No, SR-71s are still limited by engine temperature. They measure the Compressor Inlet Temperature, but I suspect that actual limitation is the turbine inlet tem

No, SR-71s are still limited by engine temperature. They measure the Compressor Inlet Temperature, but I suspect that actual limitation is the turbine inlet temp. That said, it'll merrily try to go above that without issue if you don't throttle back. Additionally, there's the Mach Cone. The shock wave off the nose forms a cone shape, with the angle determined by the speed of the aircraft. From the nose to the wingtip forms an angle of about 17.5 degrees, which corresponds well with the max speed from the CIT of Mach 3.3. That both methods of determining max speed agree shouldn't be surprising. Skunk Works was filled with good engineers.