----[Please read http://ercoupers.com/disclaimer.htm before following any
advice in this forum.]----
I agree that many/most airport compass roses are well out of date, that God
invented the GPS in HER infinite wisdom to preclude need for accurate
whiskey compasses, and that a GPS can be used to adjust the compass with the
tiny brass screws while taxiing in a straight line with NLG tire directly on
the yellow/black line. I've done one heading taxiing out, another upon
return, plus two more in the compass rose area or on intersecting taxiways.
No need to do them all on the same flight. I recorded my findings and filled
out/signed/dated a tiny card - which I never look at! It is my humble
opinion that this is "good enough", but am not able to recommend it since I
am not a compass "guru".
I, too, have a panel mounted LOWRANCE 2000c GPS MAP - it is a magnificent
device!
Don Bowen
[EMAIL PROTECTED]
----Original Message Follows----
From: "Bob Branch" <[EMAIL PROTECTED]>
Reply-To: "Bob Branch" <[EMAIL PROTECTED]>
To: <[email protected]>
Subject: Re: [COUPERS-TECH] Deviation chart - engine on or off?
Date: Wed, 28 Dec 2005 20:12:12 -0500
----[Please read http://ercoupers.com/disclaimer.htm before following any
advice in this forum.]----
Jason
A very good point indeed. Here in the midwest (Michigan) the change has been
over 2 1/2 degrees in the years I have been doing navigation of one form or
another. The other question is however, can anyone fly an aircraft compass
to withing 2 1/2 degrees of error. Not me. If anyone can, I bow to ya. Even
in a boat with a 5 or 7 inch diameter compass, that is pretty good driving.
That kind of navigational accuracy used to be expected in sailing before the
advent of electronic navigation systems. Now with those we can really
navigate with that level of accuracy quite easily. I haven't measured the
diameter of the compass rose on my Lowrance 2000C but I'll bet it is out in
the 10 or 12 inch range when its extended.
bob branch
N99891
----- Original Message -----
From: "Jason J Ellingson" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, December 28, 2005 6:25 PM
Subject: RE: [COUPERS-TECH] Deviation chart - engine on or off?
> ----[Please read http://ercoupers.com/disclaimer.htm before following any
advice in this forum.]----
>
>
> <humor mode = "ON">
>
> Take the prop off. Then you can leave it running while using the tow bar
to
> move it around.
>
> <humor mode = "OFF">
>
> On a serious note... I wonder how many airports repaint their compass
rose
> to keep with magnetic drift? A local airport here has one, but it hasn't
> been repainted for a long time... Yet the runways have been renumbered
due
> to magnetic drift.
> ------------------------------------------------------------
> Jason J Ellingson
> NC2273H
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, December 28, 2005 5:17 PM
> To: [email protected]
> Subject: [COUPERS-TECH] Deviation chart - engine on or off?
>
> ----[Please read http://ercoupers.com/disclaimer.htm before following any
> advice in this forum.]----
>
>
> Okay, on to esoteric technical problems...
>
> I found an airport with a compass rose and proceeded to align my airplane
> over the rose, to get data to make a compass deviation card.
>
> Found it hard to assure good alignment with the rose, with the plane's
> engine on and myself inside the plane.
>
> It would be more precise to have the plane off and to position it over
the
> compass rose by handling it from the outside. I could have the radios on
> while doing this, however, I think that I would be missing significant
> mangnetic fields from all those moving metallic parts in the motor, the
> firing magnetos and spark plugs, and the turning generator, which's not
that
> far from the compass.
>
> IMHO you need the engine on in order to take every magnetic field into
> account while gathering data for your compass deviation card.
>
> Am I right?
>
> Of course, I could position the plane while turned off, then start it and
> take the reading, turn it off, reposition it, take another reading, and
go
> on...
> However, I don't think turning the plane's engine on and off 12 times in
a
> short span of time is healthy for the engine, and worth it.
>
> So I either have the plane off and miss all those magnetic fields, or
have
> it on and miss accuracy in positioning it over the compass rose.
>
> So which one is it? How is it done in real life??
>
> Eliacim Cortes
> N87071
>
>
============================================================================
> ==
> To leave this forum go to: http://ercoupers.com/lists.htm Search the
> archives on http://escribe.com/aviation/coupers-tech/
>
>
>
>
>
============================================================================
==
> To leave this forum go to: http://ercoupers.com/lists.htm
> Search the archives on http://escribe.com/aviation/coupers-tech/
>
>
>
==============================================================================
To leave this forum go to: http://ercoupers.com/lists.htm
Search the archives on http://escribe.com/aviation/coupers-tech/
==============================================================================
To leave this forum go to: http://ercoupers.com/lists.htm
Search the archives on http://escribe.com/aviation/coupers-tech/
