hval
I think the simple answer to all your questions is no. In the early days engine reilability was seen as vital to the future of jet VSTOL. Usually reliability gets better as you avoid complexity. In 1964 the Pegasus I flew had a 1 hour life with the nozzles deflected (25 hrs nozzles aft). Whenever it was pulled after the hour was up and went back for a strip overhaul there was always one blade missing in the hot end so the life allowance was hardly ultra-conservative. I don't know what thrust that engine would have produced at 50 deg C but I would guess about 8,000lb. Today's donk offers over 24,000 plus goodness knows what life - I lost interest once it passed 1000 hrs years ago.
There was continued development of the front end blade shapes and much more importantly big improvements to the hot end. In the end the Pegaus was FLAT RATED to 50deg C ambient. Or if you are not familiar with the significance of that in plain English it translates to the pilot only had RPM limits and could turn his back on JPT instead of checking that with evey third breath as was the case in earlier times.
With a powered lift aircraft you must control the thrust centre in the hover in the same way as the CG in normal flight. (sorry if I am teaching granny to suck eggs)
Last edited by John Farley; 22nd Mar 2012 at 16:22.