Nick,
I can only answer on my personal experience here which is limited to the 902, BO 105, AS355 and EC135.
I’m not sure how much you know about the Notar fan itself but it is pretty much an identical configuration to the Fenestron with the exception that the blades are a lot wider. The pitch change mechanism is similar to the Fenestron thus so far we have equal parts’ish to the 135
Here the control splits off to the tail via a flexible cable the same as a 135. At the tail you have 2 bellcranks which convert linier movement to rotating movement to the thruster cone. Now take into account you have 2 less driveshafts with couplings and no additional tail gearbox on the Notar I would say it’s about even stevens.
PAN, you implied the Grand Canyon crash was a Notar failure or else why would you have put it on this thread. You think you understand helicopter control systems although you are just an ex plod, not a pilot and defo not an engineer. You state in your first post that the aircraft suffered a Notar failure and crashed. In your second post you state that the NTSB said it was an anti torque control failure. You then worked out (must have engaged both brain cells) that any anti-torque failure on a 902 must also be a Notar failure. No pilot or engineer would think like that. Any pilot will back me up when I say an anti torque control failure has nothing to do with the type of fan, whether it be Fenestron, tail rotor, Notar or contra rotating! The result will always be the same, bad.
I am stating now that there are issues with the Notar. These issues arise from lack of development, something that I hope Ms Tilton and her merry team will address. I’m not so arrogant to think the 902 is perfect, far from it. But I think it has loads of potential if someone has the guts to plough in the cash to develop it. The thruster extension is just the beginning I’m sure. There’s lots of new blood at MDHI and they all have their sights on clawing back the US market from Eurocopter( come on PAN, take the bait).
Dr A