MGL SP-6 & SP-7

[pilotyoung]

I bought a Onex recently with an MGL Xtreme. It does not have a AHRS or magnetrometer. I just bought a used SP-6 & SP-7, AHRS and magnetrometer. I am planning on installing them under the seat. As I was getting out of the aircraft yesterday I was thinking about this installation. I noticed that the push-pull rods and stick are right in front of the spar. The instructions for the SP-6 and SP-7 say not to mount them near metals that may interfere with the magnetic properties.

Has anyone mounted these modules under the seat in a Onex? If so, are they working properly? Has anyone mounted them in another location?

Thanks.

John

[MichaelFarley56]

John,

For what it’s worth, I don’t believe there is a “perfect” location for the sensors but most people have reported good luck (no issues) by mounting them in the tailcone just behind the baggage area. There are several cross members at the top of the “box” where the curved upper fuselage meets the upper longerons. Pick one as close to the baggage area as possible, find the center, and mount them there (or at least the AHRS; you may be able to mount the magnetometer close by as well but you want the AHRS as close to the C.G. As possible.)

On RV’s it’s common for people to mount the magnetometer out in a wingtip under the fiberglass wingtip itself to help prevent interference. That could be an option for you as well.

Just out of curiosity, where did you find the sensors? I’ve been keeping an eye out for used ones and never see ones available.

Good luck on the install!

[pilotyoung]

I found them on the Van's forum under Classifieds. I also own an RV-12 so I am on the Vans forum as well as this one. When I saw them, I jumped on them. Since my Onex has the Xtreme EFIS, and the RDAC, these will be an easy install. Thanks for the information.

[sonex1566]

I mounted mine under the seat, which has proved to be a bone headed idea. I've been meaning to try them on the glare shield to see how that works without having to modify the wiring while I experiment. My std compass up on the canopy frame is fine, but the moving control rods cause havoc with the electronic compass.

[XenosN42]

I bought a Onex recently with an MGL Xtreme. It does not have a AHRS or magnetrometer. I just bought a used SP-6 & SP-7, AHRS and magnetrometer. I am planning on installing them under the seat. As I was getting out of the aircraft yesterday I was thinking about this installation. I noticed that the push-pull rods and stick are right in front of the spar. The instructions for the SP-6 and SP-7 say not to mount them near metals that may interfere with the magnetic properties.

Has anyone mounted these modules under the seat in a Onex? If so, are they working properly? Has anyone mounted them in another location?

Thanks.

John

Hello John,

Congratulations on your new OneX!

I built a OneX which I’ve been flying for about 5-1/2 years. It has a MGL Discovery with a AHRS and magnetometer.

First for the SonexBuilders readers that don’t know the MGL product line:

MGL SP-6 === magnetometer
MGL SP 7 === AHRS= attitude, heading referencing system

I installed my SP7 under the seat. IMO, that’s the best place for it. It should be as near the plane’s center of rotation as possible. It has been very accurate.

I installed my SP6 in the left horizontal stabilizer. I picked that location so that it would be as far from any ferrous metals as possible. Another option would be one of the wing tips. You would need to figure out how to run the wires across the folding wing gap. There are a few solutions for that problem. And finally the top of the glare shield might work.

Installing the SP6 under the seat isn’t a good idea, IMO. You have the control stick, as you mentioned. Also consider what you might have in your pockets: car keys, cell phone, etc.

Where ever you install the SP6 remember that you’ll need to calibrate it using an inflight procedure. Check the EFIS manual, each MGL model has a different method. This is easy to forget and without it the compass will be inaccurate no matter where you install it. I re run the procedure on an annual basis to account for north pole drift and any additions to the airframe.

I also installed a two axis auto pilot. If that is in your future read this thread: http://www.sonexbuilders.net/viewtopic.php?f=5&t=5844&hilit=onex+auto+pilot
Here is a video of the auto pilot in action: https://www.youtube.com/watch?v=QEDbQCNe08Y&t=102s

Hope you have fun with your OneX.

[GraemeSmith]

SP-7 centered under the seat on a foam vibration insulating block seems to work fine. My SP-6 is down aft on one of the cross beams.

[Onex107]

Mine are both under the seat. Velcro mounted. The SP7 eventually needed vibration protection. 300 hours, No problems.

[Fastcapy]

I had nothing but issues with the sp6 under the seat. Moved it into the tailcone and I actually get accurate, steady headings now. It was not even close to accurate under the seat.

My sp7 is still under the seat without issue.

Sent from my LM-G710 using Tapatalk

[pilotyoung]

Mike,

Can you be more specific on where you mounted it in the tail? Maybe even show a picture?

Thanks.

John

[NWade]

The SP-6 and -7 do best when they are far away from ferrous metals (especially the magnetometer). This means keeping them away from other avionics, welded parts such as the rudder pedals and pushrods, and other areas where there are lots of bolts and fasteners.

The logical place then to put these is just behind the baggage compartment, at the top of the fuselage frames (as others have mentioned). This sites them close to the CG and the center of rotation for the airplane, it also makes it easy to mount them parallel with the longitudinal axis of the aircraft, and keeps them reasonably far from all ferrous metal (excluding the elevator pushrod which is still at least a foot away from the unit if you mount it in the right spot).

Here are photos of my installation, utilizing the fuselage cross-tie behind the baggage compartment and a couple of small brackets I quickly folded up out of spare aluminum sheet:

https://1drv.ms/u/s!ApMKXiyfUEPR0DNrtKnTvA8t6-QU?e=dg7LOB

https://1drv.ms/u/s!ApMKXiyfUEPR0DTfcu3_zUkn0xZF?e=exIOy3

Enjoy!

--Noel Wade
Sonex #1339