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Old August 20th 03, 01:06 PM
David Megginson
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"Marty Ross" writes:

OK now I have another problem with this. Shouldn't this depend on
the propeller? For example, I believe the limitation on static rpm
(for maximum throttle setting) on the plane I fly is less than the
2480 number you mention, so I would guess all of the numbers will be
different for me. However, my POH seems to show the power curves up
to 2700 rpm, and does not mention the type of propeller (maybe it's
the "standard" prop?).


If you have a PA-28-161 (or any other plane recent enough to have a
standard POH), look at section 1 "General" to see what propeller the
POH uses for the performance tables. Under subsection 1.5
"Propellers", I have this information:

(a) Number of Propellers 1
(b) Propeller Manufacturer Sensenich
(c) Model 74DM6-0-60
(d) Number of Blades 2
(e) Propeller Diameter (inches()
(1) Maximum 74
(2) Minimum 72
(f) Propeller Type Fixed Pitch

If you don't have that propeller, I'll hope that you got revised
performance tables with your STC or field approval, but I don't know
enough about the regs.

What's with your maximum static rpms? Can you really spin your prop
up much higher than 2480 (e.g., without damaging it)?


Yes -- it's rated up to 2700 rpm in the type certficate, but obviously
it cannot get up there in a static run. At sea level ISA, with the
60-inch-pitch propeller, minimum static RPM (i.e. sitting still on the
ground) is 2330 and maximum static RPM is 2430 -- for the propeller to
spin any faster, the plane has to be moving.

With a 58-inch-pitch propeller (also in the type certificate), the
static RPM range at sea level ISA is 2365-2465.

In my Warrior II (or a 172 from the same period), you have to spin the
propeller faster to get rated performance at higher altitudes -- at
8000 ft density, 75% power is 2665 rpm, for example.


All the best,


David

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David Megginson, , http://www.megginson.com/