fired this volley in
:

Clare Snyder,
technical director
Recrational Aircraft Association of Canada (RAA)

Ok, so, talking to a pilot, now -- you're claiming that the engine mass
has no significant effect on an aircraft's magnetic compass. That only
steel tube welded fuse frames are to fault. Right?

And, you're saying that aluminum fuselages with iron-bearing engines
don't suffer from that, because they're not 'magnetic' in character?

And, that any of this has anything whatsoever to do with using a magnetic
compass in a semi truck-trailer combo?

Right?

Are you sure you don't work for the US FAA? G

(I know of a Super Viking owner who might argue your points, unless
spruce and mahogany have become magnetic during my inattention)

Lloyd

On Thu, 26 Feb 2015 21:42:34 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

fired this volley in
:

Clare Snyder,
technical director
Recrational Aircraft Association of Canada (RAA)

Ok, so, talking to a pilot, now -- you're claiming that the engine mass
has no significant effect on an aircraft's magnetic compass. That only
steel tube welded fuse frames are to fault. Right?

That is not what I said. I said the the attraction of the iron in the
nose mounted engine - if not magnetized, is insignificant compared to
the effect of magnetized metal in the fuselage.

And, you're saying that aluminum fuselages with iron-bearing engines
don't suffer from that, because they're not 'magnetic' in character?

I didn't say that.

You remind me of the story of two brothers.Bill and Bob. Bill was a
scoundrel. He had been in just about any kind of trouble you could
imagine, leaving bedlam in his wake - ex wives and illigitamate
offspring and a criminal record as long as your arm.
He died.
His brother Bob went to the pastor who was in charge of the funeral
service and offered him $1000 extra if he told everyone his brother
was a saint.
Small-town pastors are not terribly well paid - he figured he could
really use the money.
At the funeral service, the pastor said "As you all know, Bill was a
scoundrel, a theif, and a womanizer,There really isn't a whole lot of
good I can say about him, but compared to his brother Bob, Bill was a
saint!"

And, that any of this has anything whatsoever to do with using a magnetic
compass in a semi truck-trailer combo?

We don't know what kind of Semi he's talking about installing it in.
Aluminum cab, steel cab, or mostly fiberglass. A set of non-sheilded
stereo speakers in the dash of an aluminm cabbed Pete are going to
cause more havoc than a 400 Hp Paccar up front, compass-wise

Right?

Are you sure you don't work for the US FAA? G

(I know of a Super Viking owner who might argue your points, unless
spruce and mahogany have become magnetic during my inattention)

Emeraude and Jodel too. The compass can be compensated to within a
degree or two with no problem Starter current can spin the compass on
the jodel.

Can't compensate for a magnetized loop. Particularly if the compass is
mounted to one side or other of the panel.
Lloyd

On Thu, 26 Feb 2015 19:19:07 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

fired this volley in
:

A magnetized fuselage is more likely with a mig welded
fuselage than with a gas welded one. (particularly if welded with a DC
welder)


Eh... magnetization has little to do with it. This method was perfected
in the day of riveted iron vessels, not welded.

The simple matter is that the compass pointer itself is THE magnet,
attracted to whatever iron masses may be near enough.

Make those _apparent_ masses equal in all directions, and the pointer
would be equally attracted in all directions, leaving only the earth's
magnetic pole to control its pointing.

And... where have you found a _powered_ aluminum aircraft that did not
have sizable masses of ferrous metal inside and around the engine(s)
(aluminum blocks/heads nothwithstanding)? And, at least in single-engine
planes, that those masses weren't pretty close (relatively) to the
dashboard, console, or windshield where the compass was mounted?

LLoyd

At one point I worked as a mechanic for a comp[any that had contracted
to provide primary flight training for the Air force and had been
supplied a fleet of about a hundred T-6 aircraft - recep engine,
retracting gear and all maneuvers rated.
see: http://tinyurl.com/psccosl for a picha

Anyway, I changed the magnetic compass of one of my planes and had to
swing the compass and fill out a deviation card.

As no one else seemed to know how to do it I had to read up on the
procedure... the Air Force has maintenance books that tell you how to
do this, and I became sort of the air base unofficial compass swinger
:-)

The point is every one of the airplanes I swung the compass on had
some deviation and a different deviation from any other airplane
although they were all the same aluminum airframes and wings and had
an identical engine installed.

Being made of aluminum and having the engine mounted way out there
does not result in zero deviation.
--
Cheers,

John B.

On Friday, February 27, 2015 at 6:05:02 AM UTC-5, John B. Slocomb wrote:
On Thu, 26 Feb 2015 19:19:07 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

fired this volley in
:

A magnetized fuselage is more likely with a mig welded
fuselage than with a gas welded one. (particularly if welded with a DC
welder)


Eh... magnetization has little to do with it. This method was perfected
in the day of riveted iron vessels, not welded.

The simple matter is that the compass pointer itself is THE magnet,
attracted to whatever iron masses may be near enough.

Make those _apparent_ masses equal in all directions, and the pointer
would be equally attracted in all directions, leaving only the earth's
magnetic pole to control its pointing.

And... where have you found a _powered_ aluminum aircraft that did not
have sizable masses of ferrous metal inside and around the engine(s)
(aluminum blocks/heads nothwithstanding)? And, at least in single-engine
planes, that those masses weren't pretty close (relatively) to the
dashboard, console, or windshield where the compass was mounted?

LLoyd

At one point I worked as a mechanic for a comp[any that had contracted
to provide primary flight training for the Air force and had been
supplied a fleet of about a hundred T-6 aircraft - recep engine,
retracting gear and all maneuvers rated.
see: http://tinyurl.com/psccosl for a picha

Anyway, I changed the magnetic compass of one of my planes and had to
swing the compass and fill out a deviation card.

As no one else seemed to know how to do it I had to read up on the
procedure... the Air Force has maintenance books that tell you how to
do this, and I became sort of the air base unofficial compass swinger
:-)

The point is every one of the airplanes I swung the compass on had
some deviation and a different deviation from any other airplane
although they were all the same aluminum airframes and wings and had
an identical engine installed.

Being made of aluminum and having the engine mounted way out there
does not result in zero deviation.
--
Cheers,

John B.

That is an accurate representation of every compass swing I did with Boeing, Airbus, Fokker, and MD equipment. The company did finally wise up and start keeping scans of compass cards. Don't know why it took them so long to figure that out. If one was lost, they sent the scan from maintenance control.