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Old January 16th 07, 12:04 PM posted to rec.aviation.piloting,rec.aviation.student
Jim Macklin
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Posts: 2,070
Default Why does airspeed change when I adjust the prop?

Horsepower depends on rpm and MAP. Lowering rpm without
increasing MAP [throttle] will reduce horsepower and that
causes a reduction in speed.



"C J Campbell" wrote in
message
e.com...
| On Tue, 16 Jan 2007 00:14:47 -0800, Mxsmanic wrote
| (in article ):
|
| 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 (?).
|
| Think about it. What happens to thrust and airspeed if you
reduce RPM to 0?
|