S-T,
First flew the SA341-01 in Feb `71, when it was all civvie, ie low-back seats, different control set-up, so in jack-stall it would always roll-out, away from the turn.It was a much more rigid a/c than present models. Think I`ve seen about 350 kph on one test session.Then the extra doors got put in, tail-boom cranked down a bit, etc so it`s character changed, but it`s still a bit of a Ferrari, even if it has Citroen door handles !!
Regarding fixed shaft- vs free-turbine; a lot of f/s turbines have a centrifugal stage after the axial compressor and if you do manage to surge one , the centrifugal bit usually keeps pulling the air in and a momentary pause will clear it; with an axial f/t, it usually just goes, and the JPT/TIT/ is gone around the clock, leaving little silver bits in the jet-pipe; however, you usually have to be really trying, and an HP dump switch is advisable, a la Wessex/ S-K...