Home > VansAirForceForums

- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

Go Back   VAF Forums > Model Specific > RV-14
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Thread Tools Search this Thread Display Modes
Old 04-18-2019, 03:09 PM
Reflex Reflex is offline
Join Date: Jan 2015
Location: Kansas
Posts: 153
Default Garmin Magnetometer Placement (Again!)

I know this has been covered and there are about as many answers as there are posts on this subject, but I have to ask. Given that Garmin has very specific recommendations on where not to place the magnetometer, where did you put it and why?

Based on the table below, it appears that there's really no place on an RV that truly meets all the requirements. My guess is that the best place may be on the right outside rib as far back from the strobes as possible (should be able to do 3+ feet).

I'm working on the -14 and the ADHARS shelf appears to be in violation of several of these recommendations; specifically, the landing gear and the heated pitot are too close.

In addition, a shelf behind the bulkheads is too close to the rudder cables, the stabilizer deck is too close to the tailwheel, etc.

See the table below from page 8-3 in the installation manual.


Dues Paid for 2020
Empennage Complete (including fiberglass)
Wings complete (including fiberglass)
Front half of fuse complete

Last edited by Reflex : 04-18-2019 at 03:26 PM.
Reply With Quote
Old 04-18-2019, 03:27 PM
JTJones's Avatar
JTJones JTJones is offline
Join Date: Jun 2015
Location: Haleiwa, HI
Posts: 101
Default I put in in the tailcone

We made a bracket and mounted it in the Tailcone on the top of the F-01407 bulkhead. I've had no issues with it mounted there.
Jeffrey T Jones
RV-14 N588TJ Completed
First Flight July 10, 2018
Flight testing completed August 14, 2018
2019 VAF dues paid plus beer money😜
Reply With Quote
Old 04-18-2019, 03:28 PM
Av8rRob's Avatar
Av8rRob Av8rRob is offline
Join Date: May 2005
Location: Rescue, CA. KROB
Posts: 337

I put my pitot on the right side to avoid this situation.
Rob Lasater
Rv-14 still workin, but getting close
Paid Dec 2019
Reply With Quote
Old 04-18-2019, 04:26 PM
snoop9erdog snoop9erdog is offline
Join Date: Oct 2005
Posts: 259

I'm planning on Pitot in the left wing, Magnetometer right wing (don't want it in the bag because I'm going tailwheel and don't want unnecessary weight aft CG).

But even then.....My magnetometer will be relatively close to the right wing roll servo....

So you are right...numerous ways to skin the cat and they are not perfect per Garmin's letter of the law.
Ed Avila
St. Johns, AZ (SJN)
N646A RV9
Worlds longest RV build...but getting there
Reply With Quote
Old 04-18-2019, 05:11 PM
Nova RV Nova RV is offline
Join Date: Aug 2015
Location: Leesburg, VA
Posts: 444

I used the kit mounting bracket and location for a GMU 22 in the left wing. No issues and passed all testing.
Chris Moon
Leesburg, VA

CFI-I ASMEL, ATP, B-1900, A319/320, B-757/767, B-737, Flight Engineer-Turbojet

RV-14A kit # 140243 (flying as of 11/18)
VAF 2018 and 2019 paid
Reply With Quote
Old 04-18-2019, 07:45 PM
Don E Don E is online now
Join Date: Aug 2016
Location: West Chester, PA
Posts: 107
Default Same as Chris in my RV-14.

Originally Posted by Nova RV View Post
I used the kit mounting bracket and location for a GMU 22 in the left wing. No issues and passed all testing.
No issues at all.
RV-14 Built
Can’t believe I built an airplane!
First flight October 22, 2018
Kit #140329
If I had a nickel for every time I didn’t know what was going on, I’d be, like, “Why am I always getting all these nickels?”
Reply With Quote
Old 04-18-2019, 10:08 PM
JDA_BTR JDA_BTR is offline
Join Date: Dec 2013
Location: Baton Rouge, LA
Posts: 998

I put the GMU22 in the left wing on the shelf. I had a pitot heat controller that made the magnetometer crazy. When I went to a pitot heater that was just "on" and not with a controller, the magnetometer was good with it. My strobes and lights don't affect it at all, nor anything else inboard.

When I had the heat controlled pitot it didn't matter how I ran the power, or the ground, or anything; I tried quite a few cabling options. The only thing that mattered was if that controller was present. No controller no problem with simple twisted wire power to the pitot and ground at the wing root fuselage ground point.

The reason is that the dynon controller I had wasn't doing proportional control of current to keep the temp. It was On/Off and every on/off transition made a big flux change at the magnetometer. Having a simply switched heater has gotten rid of this big flux at every on/off of the controller transistor. Also, the controller was by design grounded at the base of the transistor to the case and thus to the airframe. I don't think this was the problem though because the flux effect at the magnetometer didn't go away with the controller hanging in space off the plane.

It should be possible to put a better control loop in the heat controller to get away from the simple on/off and make the control proportional (and more steady with less magnetic flux); but that is a manufacturer thing....
Ser 104142, RV-14A flying - N1463
Ser 83825, RV-8 building - N8638?
USN Ret, Urologist, AME, Repeat Offender
Reply With Quote
Old 04-19-2019, 06:21 AM
JHartline JHartline is offline
Join Date: Dec 2012
Location: Carrollton, GA 5GA2
Posts: 242

Mine is in the left wing location. I used the factory harness, G3X touch panel and everything that goes with it, unregulated pitot, LED lights, everything done pretty much per the plans. I ran the interference test several times because the results were so low I thought I might be doing it wrong.
James Hartline
Carrollton, GA 5GA2
RV-14 - First flight 4/7/2019. Phase I complete as of 9/11/2019!!
Reply With Quote
Old 04-19-2019, 07:08 AM
kbalch's Avatar
kbalch kbalch is offline
Join Date: Jan 2005
Location: Clermont, FL
Posts: 524

Originally Posted by Nova RV View Post
I used the kit mounting bracket and location for a GMU 22 in the left wing. No issues and passed all testing.
Exactly what I'm doing, too. No need to overthink this...

RV-8 N118KB (#81125) - Sold
RV-14A N114KB (#140494) - Flying!
N114KB Build Site

RV-14(A) Fuel Tanks
RV Builder Assistance
RV First Flights
Reply With Quote
Old 04-30-2019, 09:37 AM
pentoli pentoli is offline
Join Date: Oct 2016
Location: Riehen, Switzerland
Posts: 2

I am just about to order the Garmin instruments. Why did you chose the GMU 22 over the GMU 11?
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -6. The time now is 03:27 PM.

The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.