Green Arc Red Zone

it is constant speed props on the Arrow and Cardinal..
and there is still a harmonic vibration range

BT

"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

"Dudley Henriques" wrote

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.


Yeah, I remember that coming up once before, now that the whirl mode is
mentioned. I don't recall the details, either.
--
Jim in NC

Thanks, but I'm not really an expert on the Electra. But I
also read that they harmonic was such that a whirl-mode
began [as you also said] and this caused several complete
airframe failures.

The NTSB probably has a file.


"Dudley Henriques" wrote in message
...
|
| "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
|
|

Google found this
http://www.cs.clemson.edu/~steve/Spiro/electra1.html


"Dudley Henriques" wrote in message
...
|
| "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
|
|

Google found this
http://www.cs.clemson.edu/~steve/Spiro/electra1.html

And here is part 2.
http://www.cs.clemson.edu/~steve/Spiro/electra2.html
--
Jim in NC

"Jim Macklin" wrote in message
...
Google found this
http://www.cs.clemson.edu/~steve/Spiro/electra1.html

The second page of the above story is located at:
http://www.cs.clemson.edu/~steve/Spiro/electra2.html
(The link embedded at the end of the first page is obsolete)
Peter



"Dudley Henriques" wrote in message
...
|
| "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
|
|

I saw part two is linked at the bottom of the page, so
didn't bother to put both there.
Didn't know the link was bad when I posted. Thanks.


What did you think of the article? It seems to be a an
aviation history students
paper.


"Morgans" wrote in message
...
| Google found this
| http://www.cs.clemson.edu/~steve/Spiro/electra1.html
|
| And here is part 2.
| http://www.cs.clemson.edu/~steve/Spiro/electra2.html
| --
| Jim in NC
|
|

Morgans wrote
So there was a RPM restriction on the Electra?
What do you recall? Didn't a constant speed prop pretty much bypass it?

The Electra (L-188) engine (Allison) always turned at 1061 RPM except at
ground idle. It had no Prop Control.

Bob Moore
ATP L-188
Combat Aircrew Commander P-3B

"Jim Macklin" wrote in message
...
I saw part two is linked at the bottom of the page, so
didn't bother to put both there.
Didn't know the link was bad when I posted. Thanks.


What did you think of the article? It seems to be a an
aviation history students
paper.

Perhaps more like a journalist student who is interested in aviation. I
noticed the poetic license, and the big buzz words, like "tube of death."

Some technical items not quite right, but if this is a journalist, it is
better accident reporting, than most! g
--
Jim in NC

"Bob Moore" wrote in message
46.128...
Morgans wrote
So there was a RPM restriction on the Electra?
What do you recall? Didn't a constant speed prop pretty much bypass it?

The Electra (L-188) engine (Allison) always turned at 1061 RPM except at
ground idle. It had no Prop Control.

So, fixing the mounts and stiffening the wings was the only thing that was
changed; no different operating procedures?
--
Jim in NC