Green Arc Red Zone

Jack Allison's discussion of the Hartzell AD for his Arrow has gotten me
to thinking.
What aircraft do you fly/have you flown/do you have first hand knowledge
of which have a red zone somewhere in the green arc of the tachometer?

For example, I know there are/were certain models of Cessna 210's that
had such markings, but I cannot remember the specific models/engine/prop
combinations.

Jack Allison's discussion of the Hartzell AD for his Arrow has gotten me to thinking.
What aircraft do you fly/have you flown/do you have first hand knowledge of which have a red zone somewhere in the green arc of the tachometer?

There was one aircraft I flew (C172? Arrow?) which had a placard to
avoid operations between (I think) 2000 and 2200, or something like
that. It was not marked as a red zone on the tach though.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

john smith wrote:
Jack Allison's discussion of the Hartzell AD for his Arrow has gotten me
to thinking.
What aircraft do you fly/have you flown/do you have first hand knowledge
of which have a red zone somewhere in the green arc of the tachometer?

My club used to have an Arrow-II which had a red arc from (IIRC 2150 - 2300
RPM). Green above and below that. The POH listed only two allowable
cruise RPMs: 2100 or 2400, nothing in between.

I may be off a little on the actual numeric values.

Several reasons for a restricted RPM, due to harmonic
vibration...some say not to have prolonged operation in
certain RPM ranges, some have a red range in the green arc.
I think Lycomng has a FAQ on their engines.


"Roy Smith" wrote in message
...
| john smith wrote:
| Jack Allison's discussion of the Hartzell AD for his
Arrow has gotten me
| to thinking.
| What aircraft do you fly/have you flown/do you have
first hand knowledge
| of which have a red zone somewhere in the green arc of
the tachometer?
|
| My club used to have an Arrow-II which had a red arc from
(IIRC 2150 - 2300
| RPM). Green above and below that. The POH listed only
two allowable
| cruise RPMs: 2100 or 2400, nothing in between.
|
| I may be off a little on the actual numeric values.

C-177B models also had a red zone range
you could feel the vibration in the floor if you were in the "red zone",
neat trick for instructors..
Instructor to student: "you feel that vibration"
Student: "yes"...
Instructor: "Then do something about it"
Student: "What should I do? I'm not flying to fast.."
Instructor: "You think maybe the engine or prop are trying to tell you
something?"
Student: "Oh yah.. That red arc"

BT

"john smith" wrote in message
...
Jack Allison's discussion of the Hartzell AD for his Arrow has gotten me
to thinking.
What aircraft do you fly/have you flown/do you have first hand knowledge
of which have a red zone somewhere in the green arc of the tachometer?

For example, I know there are/were certain models of Cessna 210's that had
such markings, but I cannot remember the specific models/engine/prop
combinations.

"john smith" wrote in message
...
Jack Allison's discussion of the Hartzell AD for his Arrow has gotten me
to thinking.
What aircraft do you fly/have you flown/do you have first hand knowledge
of which have a red zone somewhere in the green arc of the tachometer?

For example, I know there are/were certain models of Cessna 210's that had
such markings, but I cannot remember the specific models/engine/prop
combinations.

Jose wrote:
There was one aircraft I flew (C172? Arrow?) which had a placard to
avoid operations between (I think) 2000 and 2200, or something like
that. It was not marked as a red zone on the tach though.



I'll bet it was the Arrow. I recall seeing the same sort of placard but nothing
on the tach, either.



--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com

"Jim Macklin" wrote in message
...
Several reasons for a restricted RPM, due to harmonic
vibration...some say not to have prolonged operation in
certain RPM ranges, some have a red range in the green arc.
I think Lycomng has a FAQ on their engines.

The Lockheed Electra sure could have used a prop AD for this one!
Dudley Henriques




"Roy Smith" wrote in message
...
| john smith wrote:
| Jack Allison's discussion of the Hartzell AD for his
Arrow has gotten me
| to thinking.
| What aircraft do you fly/have you flown/do you have
first hand knowledge
| of which have a red zone somewhere in the green arc of
the tachometer?
|
| My club used to have an Arrow-II which had a red arc from
(IIRC 2150 - 2300
| RPM). Green above and below that. The POH listed only
two allowable
| cruise RPMs: 2100 or 2400, nothing in between.
|
| I may be off a little on the actual numeric values.

"Dudley Henriques" wrote

The Lockheed Electra sure could have used a prop AD for this one!

So there was a RPM restriction on the Electra?

What do you recall? Didn't a constant speed prop pretty much bypass it?
--
Jim in NC

"Morgans" wrote in message
...

"Dudley Henriques" wrote

The Lockheed Electra sure could have used a prop AD for this one!

So there was a RPM restriction on the Electra?

What do you recall? Didn't a constant speed prop pretty much bypass it?
--
Jim in NC

I only have a vague recall on this. It came up during a safety meeting at
the Naval Test Pilots School many years ago.
If I remember right, it involved a harmonic mode (whirl I believe) not
transmitting correctly through the outboard engine mounts on the airplane.
They specified certain conditions that caused this to happen but I don't
remember what they were. I seem to recall that after the issue was addressed
by Lockheed and the mounts were redesigned, there was a further wing issue
as well that had to be dealt with.
I think Macklin will probably be the guy who can best deal with exactly what
was going on.
Dudley Henriques