Archer Tach Red Arc

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 *
************************************************** ***********************

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)

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

"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?