Oxygen breathing engines particularly designed for the upper atmosphere find it tough going without lots of intake and compression.
The gas turbine is gasping at much above 90,000 ft - doesn't have much thrust up there either.
Some one else will no doubt come up with the numbers.
Aviation lost an accomplished test pilot recently with the passage of Pete KNIGHT to the big hangar in the sky. For more years than I can remember he holds the world speed and altitude records in an X15.
I believe 3954 Kts or 6.7 Mach
354,200 feet where he would have been seeing all the stars against a black sky.
In a full pressure suit of course.
Last edited by Milt; 5th September 2004 at 01:30.