Magnatometer location in Cherokee 140

Timbeck2

Timbeck2

Final Approach
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Timbeck2
Those who have installed one or know, what's the best place for it? I understand it has to be in the wing or fuselage and not within 2' of the cabin. Wing is most likely out due to lack of access.
 
Timbeck2 said:
Those who have installed one or know, what's the best place for it? I understand it has to be in the wing or fuselage and not within 2' of the cabin. Wing is most likely out due to lack of access.
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Don’t know but I was looking into an installation on a Grumman Tiger once. The Avionics dude said they put them in the fuselage behind the rear seat. Similar plane, I’d guess it would be the same.
 
You can mount it on or adjacent to a wing panel. Keep as far away from wing lighting wires as possible. In the tail/fuse should be fine too. Use a magnetic compass to test for magnetic field changes while turning lights on and off and transmitting on radios.
 
Timbeck2 said:
Those who have installed one or know, what's the best place for it? I understand it has to be in the wing or fuselage and not within 2' of the cabin. Wing is most likely out due to lack of access.
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I chewed on that a long time when doing Dad's 182. The reality is there are crap tons of aircraft out there with the units installed in the wingtips, only inches away from nav lights and strobes. With that in mind I ran the interference test then installed it there, it worked out great.

Adding, this has no wingtip strobes and has regular incandescent nav lights. The only "special" thing I did was run the power & ground wires in a shielded twisted pair cable the whole way out to the GMU in the wing. (Also installed the heavy metal overbraid per STC since it's a non-metallic wingtip)

Cherokee wingtip is much closer to the ground and whatnot like steel rebar in concrete.
 

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Mine's in the wing. Had an issue where nav lights caused the magnetometer to fail. I replaced them with LED's and also gave the MX a grounding bulletin from Garmin - has been flawless since. Not sure if ground or LED was the fix. I did not do the Magnetometer install, was done by the prior owner.
 
Mine's in the aft fuselage belly about halfway between the passenger cabin bulkhead and the tail cone. There's nothing ferrous within ~36 inches.
 
Pardon my ignorance, but why install a magnetometer? What is it's use?
I'm not trying to troll anyone here. I just want to know the purpose of a magnetometer in an aircraft. is it for navigation, or are you looking for something like minerals?
 
KRyan said:
Pardon my ignorance, but why install a magnetometer? What is it's use?
I'm not trying to troll anyone here. I just want to know the purpose of a magnetometer in an aircraft. is it for navigation, or are you looking for something like minerals?
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In order to display magnetic heading on these electronic doo dads, you need a magnetic heading source. Apparently Garmin couldn't get it built into the G5 box for mag interference reasons or potato, so they need an isolated box, which adds to the labor costs.
 
hindsight2020 said:
In order to display magnetic heading on these electronic doo dads, you need a magnetic heading source. Apparently Garmin couldn't get it built into the G5 box for mag interference reasons or potato, so they need an isolated box, which adds to the labor costs.
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And quite possibly increases accuracy (if install correctly).
 
Thanks, I just didn't understand why one would be needed.
 
My G3X magnetometer is in the right wing outboard of the aileron bell crank and brackets. It's accuracy is incredible. Way better than conventional instruments I'm used to.
 
Stewartb said:
My G3X magnetometer is in the right wing outboard of the aileron bell crank and brackets. It's accuracy is incredible. Way better than conventional instruments I'm used to.
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I put it in the on wing also since I knew of an Aspen system that would get messed up when loading metal objects in the baggage compartment. That airplane had the RSM mounted on top of the tailcone about a foot behind the window on a high wing Cessna.

The G5 compass rose is dead on, the whiskey compass not so much.
 
hindsight2020 said:
In order to display magnetic heading on these electronic doo dads, you need a magnetic heading source. Apparently Garmin couldn't get it built into the G5 box for mag interference reasons or potato, so they need an isolated box, which adds to the labor costs.
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Labor costs to me are nil since I'm going to be the one building the platform and installing it in the fuselage behind the cabin. I'm working on my A&P and I need the sheet metal experience.
 
I'm going to put it right next to the dual overhead gonkulators. Seems like a good place.
 
No, that's where the vacuum pump used to be. Sterilizing chemicals finally arrived.
 
I installed the MGL SP-6 remote magnetometer and AV-1 display because I was having issues with my panel mounted PAI-700 vertical card compass. It had been installed by a previous owner, and the A&P who installed it noted in the log that he couldn't get it compensated satisfactorily. Huh? o_OSoon after I bought the airplane the PAI-700, with less than 100 hours on it, went belly-up.

The MGL SP-6/AV-1 replaced the PAI-700 and has proven to be very reliable and is dead-on accurate.

The compass compensation adjustment holes are still there.
AV-1%20Compass%20Display_zpsvynn4cwd.jpg


Bench testing before installation.
MGL%20AV-1%20and%20SP-6%20Bench%20Test%20sm_zpsxnuhkmhm.jpg
 
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Did the location survey last night. There is an existing tray in the back where the ELT lives with plenty of space for the magnetometer. The test was successful. However and I have to talk to Garmin about this, there is ONE pixel that is displayed in red on the new Garmin G5 HSI. A small thing but once it is seen, it cannot be unseen.
 
My Dynon magnetometer is in a position that sounds similar to Tim's. About 1' behind the rear baggage panel.
 
Well THAT was certainly a chore. The magnetometer has to be within 1/2 degree from the aircraft flight centerline and within 3 degrees of pitch and roll. Centerline was easy, just a square against the rear bulkhead but the pitch and roll was another issue. I used a digital level placed on the spar and zeroed it out as a reference point. The shelf I installed the mag on wasn't exactly perpendicular to the spar so I had to use shims. The pitch was determined by placing the level on the two screws located just below the pilot's window and zeroing it out for the reference point. I had to install more shims to match the pitch but now I've got it almost dead nuts on. My replacement G5 should arrive today so all will be buttoned up by this weekend.


Then my annual can begin.
 
I used precisely cut spacers between the shelf and the bottom of the magnetometer on the front mounting screws to get mine level. I used brass (non-ferrous) screws.
 
I have the G5 for the attitude only right now.. I don't have a magnetometer yet but have planned on it.. I actually kinda like the GPS ground track displayed.. for the "heading bug" at the top of the G5 AI.. Are you able to display magnetic and GPS track on the G5 at the same time?
 
Stan Cooper said:
I used precisely cut spacers between the shelf and the bottom of the magnetometer on the front mounting screws to get mine level. I used brass (non-ferrous) screws.
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I bought a kit which included spacers of aluminum in 32nd" increments up to 3/4" with a hole for a #6 screw in each one. I used stainless steel and made sure it was the non ferrous type.
 
Indiana_Pilot said:
I have the G5 for the attitude only right now.. I don't have a magnetometer yet but have planned on it.. I actually kinda like the GPS ground track displayed.. for the "heading bug" at the top of the G5 AI.. Are you able to display magnetic and GPS track on the G5 at the same time?
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Not sure but I think the GPS ground track is displayed when it is connected to another device such as a 430. I don't have a 430.
 
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