Originally Posted by
msbbarratt
I recall ages ago reading some work someone had done to calculate the top speed, came out at M3.4 so far as I can recall. The limiting factor is the compressor inlet air temperature, which increases with speed. Any faster than that and the air temperature profile throughout the compressor results in the latter stages getting hot enough to melt.
Of course, Reaction Engines’ helium cooled heat exchanger on their Sabre concept overcomes that general limitation. I wouldn’t be entirely surprised if that pitches up in something hypersonic in the US.
In my adoration for Her I neglected any Ram rise...3.4 is still excellent
Thanks