Mxsmanic wrote:
When I change the prop setting on my (simulated) Baron 58, lowering
the prop RPM, my airspeed drops. I thought that for a given throttle
setting, the actual thrust produced by the powerplant was supposed to
remain the same for a wide range of prop settings, because of
automatic pitch changes made when I change the prop RPM. However,
that doesn't seem to be the case. A lowering of the prop RPM also
lowers airspeed, which implies a change in thrust. The fuel flow also
diminishes, which implies a change in power (?).

So, exactly what do I gain or lose by adjusting prop RPM when I'm
cruising along? Why would I want to change it? Some sources I've
read say that the prop makes less noise, which is surely true, but it
seems that I can't lower the RPM without losing airspeed (and thus I
must be losing power, right?).



Of course you are loosing power. All other things being equal, the
slower an engine spins the less power it can put out, as you have also
noticed, the less fuel it needs. The reason you lower your rpm is to
reduce stress on the engine. In general, engines aren't rated to run
continuously at take off rpm.

--
Chris W
KE5GIX

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