Hi Aeromariner, long time no talk.
I am just back home after another 60 Airvan hours in the last couple of weeks amd ar$e is just fine, though i was certainly not responsible for the enduro foam substitution for the bus cusion. That original was excellent and i wish it was the one that was used. I believe they may also be used in some of the more comfortable train seats as well.
I agree that the vibes that the three blade turbo makes are a little more noticeable than the two blade normally aspirated version. And internal noise level seems (subjectively) a little more intrusive, though making the extra MAP is a likely conributer. I really prefer the NA two blader overall, ecxept for when the extra altitude performance of the TC allows cruise at FL180 when a big tailwind is available, 180 kt GS is nice and i regularly cruise the TC in the flight levels where the power can still be made, the TAS adds up and i can hunt for favourable winds. I still like the NA better all the same, it is nicer to fly and a bit smoother engine/prop combination i think. It also has a better useful load. It is only really when climb or altitude (above 10,000) performance is needed that the TC romps away.
I cruise the 2 blade NA at 25"MAP 2300 RPM 61 l/hr but this limits it to about 6000 ft. The TC likes to run at 30" and 2250 for 63 l/hr for a similar speed of about 128 TAS at the 6000 - 8000 ft mark and 131 at 10,000 ft