The Propeller Lever DOES have a use!
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I was thumbing through a TBM 850 POH that I shamelessly pillaged off of the internet, and I came across a lone footnote that other pilots might be interested in.
Per the Black Square manual and the performance charts I'd looked at before, the propeller lever looked to have been added as a joke by TBM, as it had only two positions: full and feather. In the bowels of the POH cruise charts, I found a note stating that cruise RPMs of 1600-2000 were possible with no loss in performance. Apply the desired cruise setting using 2000 RPM, then lower the RPM without exceeding 121% TRQ.
I know what I'm trying tomorrow!
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Unfortunately, constant-speed props aren't simulated accurately in MSFS so you do actually lose substantial airspeed when lowering the Prop RPM for a given power setting. Compared to other complex aircraft, the prop lever isn't used as extensively on the TBM. Whereas on most complex aircraft you adjust the prop RPM for each phase of flight, in the TBM you leave the prop at 2000 the entire time except for maybe cruise. Some pilots bring the prop back to 1900 RPM for a "quiet" cruise, and some just leave it at 2000. The new TBMs don't even have a prop lever and are just kept at 2000 for all operations.
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@jheidebrecht I confirmed this tonight. Dropping to 1800 RPM cost me 20KIAS at FL260.
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I've been thinking about this; Nick, are you aware of this? Granted, I'm no expert, but I don't believe I have seen this in other planes.
It's not a turboprop (maybe that's the issue, I know MSFS isn't great at those), but I adjust RPM in the DC-6 constantly, and I'm always getting the speeds given in the power charts, but I am adjusting both speed and power, unlike the TBM where the TQ increases as I reduce RPM.
I haven't flown the Arrows in too long to comment on how the constant speed prop works there.