Archer Tach Red Arc

[Greg Esres]

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?

[Steven Barnes]

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.

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

"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?

[BTIZ]

does this archer have the standard engine installed?? then I would not think
that there was an RPM limitation.. if there was an STC for a larger or
different engine prop combination, then that may require the red arc area...
and I agree.. this sounds like something from an Arrow with 3 prop blades..
if there is no documentation of the requirement in the aircraft logs.. then
it is an improper marking on the glass face..

BT

"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?

[Roger]

On Mon, 17 Jan 2005 19:04:04 -0800, "BTIZ" >
wrote:

>does this archer have the standard engine installed?? then I would not think
>that there was an RPM limitation.. if there was an STC for a larger or
>different engine prop combination, then that may require the red arc area...
>and I agree.. this sounds like something from an Arrow with 3 prop blades..

I thought you went to the 3-blade to get rid of the red arc, at least
that's what they said in an article on the conversion a few years
back.

OTOH I've never seen a Cherokee or Archer with the RPM range
limitation. Only an Arrow, but are at least two or three of them I've
probably missed<:-))


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com.

[Greg Esres]

<<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?

[Greg Esres]

<<does this archer have the standard engine installed?? >>

I think so.

<<if there was an STC for a larger or different engine prop
combination, then that may require the red arc area... >>

I'll have to check the logs.

<<this sounds like something from an Arrow with 3 prop blades.. >>

I believe that it's the Arrow 2-blade that has the limitation. We
have one with 3 blades that the mechanic says doesn't need the red
arc, but they left it on anyway.

Thanks

[[email protected]]

Check the FAA Type Certificate Data Sheets for the Pipers.
You will probably find the prop combination liisted with a note
about the tach marking.

If the prop was a result of an STC, it may not be listed. But
I think I've seen new Pipers with tachs like this.

Probably depends on what dampers are on the engine which
would be indicatded by the engine dash number.

Bill Hale A&P

[Steven Barnes]

I can't remember. 2 blades, though. :-)
I found a digital pic of our logbook from 1968 for an engine overhaul that
says it had a Sensenich. Not sure if that's what's still on it or not. A
friend of mine has an '65 or '66 180. He has the red arc, too.

"Greg Esres" > wrote in message
...
> <<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?
>

[[email protected]]

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

The reason is for resonance issues with the Sensenich 76" (EMS8 or whatever)
prop and a Lycoming O-360-A3A (hollow-crank) engine. Our 140 has the Avcon engine
upgrade to 180 HP and has the limitation specified in the STC and the supplemental POH
that came with the STC.... but *only* if the engine is a -A3A. If it's a -A4A, it's
got a solid crank and doesn't require the limitation.

I'd say check the logbooks for propeller model and engine model suffix. I
believe the wording is, "Avoid prolonged cruise power within the 2150-2350 rpm range"

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

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[Nathan Young]

On Tue, 18 Jan 2005 02:40:13 GMT, Greg Esres >
wrote:

>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?

The older Cherokee 180s had the O-360-A3A engine with the hollow crank
shaft. There was a prohibited RPM range at approx 2150-2350.

I would bet the tach is out of one of these 180s.

-Nathan

[[email protected]]

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)

[[email protected]]

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)

[John Kunkel]

"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.

[[email protected]]

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)

[Jerry]

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?

[nuke]

<< 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. >><BR><BR>

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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Spam forgeries have resulted in thousands of faked bounces to my address.