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So the 850 is a fixed pitch prop? RPM change on prop usually changes prop pitch to maintain efficiency at different altitudes thus increasing torque, or so my King Air pilot neighbor tells me. The huge change in RPM has minimal or no effective change in prop torque. Just checking...
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@rbringh looking at a PIM/POH/whatever, it looks like RPM is only really changed during run-up to exercise the prop, and during cruise to reduce noise at mostly negligible impact on all other parameters. As long as you change Np slowly, it doesn't have a large impact on overall torque in the sim, but quick changes will do something. There's also a torque limiter at work when you aren't in 850 Mode that makes everything but torque regulate to remain safe, and in 850 Mode where the limiter is inactive, I really don't know what's even going on.
A footnote on Np in a performance table (all tables are made for 2000 RPM...):
Propeller RPM utilization between 1600 and 2000 RPM is possible without changing performance. Display the TRQ indicated in table with Np = 2000 RPM, then reduce Np without exceeding 121.4 % TRQ.
That pretty much looks a bit like leaning, but for noise, and some Socata Magic.
