Archer Tach Red Arc

Greg Esres wrote:
Perhaps in a tach from a plane that had this prop, or the Archer
actually has it.

The owner is unaware of any such installation for this airplane, and
there is no supplement in the POH.

What prop do you have?

It's not just the prop. It's the prop/engine combination. The
Cherokee "C" model 180s and earlier had a hollow crankshaft that caused
some harmonic vibrations between 2150 and 2350. The Archer may have
inherited an airspeed indicator from one of those earlier planes.
Beginning with the '68 "D" model, the 180 hp PA28s were equipped with
the Lyc. O-360-A4x engine, which had a solid crankshaft. This removed
the rpm restriction. The Archer in question should not have any rpm
restrictions (except at 2700), if it is equipped with the factory model
engine and prop.

John Galban=====N4BQ (PA28-180)

wrote:


I think they discovered this issue shortly after the -180's came
out, so I'm
surprised that an Archer POH doesn't mention it.


Cory,

All of the Archers have either an O-360-A4A, or O-360-A4M. Both have
solid cranks. That's why there's no mention of it in an Archer POH.
John Galban=====N4BQ (PA28-180)

"Greg Esres" wrote in message
...
A student has an Archer II that has a red arc painted on the glass of
the tach between 2150 and 2350 RPM. The POH makes no mention of a red
arc.

I'm thinking that either the tach came out of an Arrow (which has a
red arc in this range) or some A&P confused the Archer with an Arrow
and painted it on.

I'm surprised the arc is red (prohibited), it should be yellow (caution) to
warn against continuous operation in that rpm range.

It's pretty hard to accelerate from idle to max rpm, without passing through
the range that is red arced on the tach.

John Kunkel wrote:

I'm surprised the arc is red (prohibited), it should be yellow
(caution) to
warn against continuous operation in that rpm range.

On most of the original planes with this marking, I remember that it
was a yellow marking. Over the last several years, I've noticed the
red arc popping up in the same range. I just figured that either
someone got the color wrong, or the spec. was changed by Piper.


It's pretty hard to accelerate from idle to max rpm, without passing
through
the range that is red arced on the tach.

That's correct. The only reason I could figure they'd change it to
red would be to emphasize that you really don't want to spend time with
your engine running in this range. I could see pilots confusing it
with the yellow arc on the airspeed indicator. In smooth conditions
it just fine to operate in the yellow arc.
John Galban=====N4BQ (PA28-180)

There was an AD in effect for a few years that applied the RPM restriction
even to solid-cranshaft Archers. It was rescinded later. I think our Archer
had ugly red paint on the tach for a year or so in the early 90's.

Jflyer

"Greg Esres" wrote in message
...
A student has an Archer II that has a red arc painted on the glass of
the tach between 2150 and 2350 RPM. The POH makes no mention of a red
arc.

I'm thinking that either the tach came out of an Arrow (which has a
red arc in this range) or some A&P confused the Archer with an Arrow
and painted it on.

Does anyone know of any legitimate reason for an Archer to have a red
arc, other than max RPM?

Our Cherokee 180C has a similar red arc due to the type of prop we have on
it (can't remember type) for vibration issues. We could put a different prop
on and have the red arc removed. $$$$$$$$$$ Ugh. BRBR

The red arc on the Cherokee is from the Sensenich prop on any hollow crankshaft
Lycoming, namely the O360-A3A engines.

The solution, which was around 1967 and up was a switch on the Cherokee 180's
to an O360-A4A, which has a solid crank and is green arc all the way.

It sounds very suspiciously like the tach from a Cherokee was installed in the
Archer.
--
Dr. Nuketopia
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