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Dynon compass module placement

carguy614

carguy614

Well Known Member
Installed the module in my 9A as many have done, behind the aft baggage bulkhead, hanging in free space under the canopy rail. After calibration, I had over 20 degrees of misalignment. A call to Mike at Dynon was very informative. Great support from this excellent company. We discussed the possible causes, and determined that it must be ferrous interference of some kind. Then...while getting ready to do the compass calibration...I thought about the canopy rail interfering with the calibration when it was slid open. Bottom line, make sure the canopy is closed when you swing the module if you have a similar installation as mine. You can watch the compass heading increase as you slide the canopy rearward, but by the time the lid is 2/3rds closed, there is no more deflection. I will most likely move the module 1 bulkhead rearward to minimize risk of ferrous items in the baggage bay from affecting the heading. Short flight last night showed headings where they should be in all directions.
Just some feedback I hope will help.

Regards,
Chris
 
I have mine mounted on the floor just behind the baggage bulkhead. Been working great for years. I have a "basket" containing oil, cleaning rags, water, etc. that always goes just in front of it so there's no danger of putting ferrous materials in that location.
 
carguy614 said:
Installed the module in my 9A as many have done, behind the aft baggage bulkhead, hanging in free space under the canopy rail. After calibration, I had over 20 degrees of misalignment. A call to Mike at Dynon was very informative. Great support from this excellent company. We discussed the possible causes, and determined that it must be ferrous interference of some kind. Then...while getting ready to do the compass calibration...I thought about the canopy rail interfering with the calibration when it was slid open. Bottom line, make sure the canopy is closed when you swing the module if you have a similar installation as mine. You can watch the compass heading increase as you slide the canopy rearward, but by the time the lid is 2/3rds closed, there is no more deflection. I will most likely move the module 1 bulkhead rearward to minimize risk of ferrous items in the baggage bay from affecting the heading. Short flight last night showed headings where they should be in all directions.
Just some feedback I hope will help.

Regards,
Chris
Click to expand...

It took me a while to figure this out as well. Makes it difficult to swing the compass module from outside the aircraft. I ended up using a paint stick to press the Dynon buttons during calibration, with the canopy cracked open about 1 inch.

Off thread. Our local airport repainted all of the lines on the field, including our compass rose... which hasn't been calibrated in 40 years. Absolute precision, total inaccuracy!

Vern
 
I mounted the Dynon module on a bracket designed for it and then located the assembly on the right outboard wing rib. My thinking was purely convenience.....I did not want to have to partially remove the interior and then (if need be) crawl back to access it in the regions behind the baggage compartment. If required, it should be simple enough to quickly remove the wingtip to make a minor adjustment in alignment.

​
 
I agree with Rick but my rationale was that I could never get mine to work accurately from the tail cone. I bought a mounting kit and moved it to the wing tip and now it works perfectly. Because of the much better access it is also orders of magnitude easier to install accurately. I bought the very nice mounting kit from these folks: http://www.safeair1.com/index.htm

Luis Luciani
RV8, 100+ hours
 
Rear Deck?

I put mine on the rear deck with the OAT probe under the outboard edge of the HS. This was as per suggestions in the Dynon installation manual.
I used aluminum rivets and screws to mount it and it's easy to get at under the empenage fairing.
Don't know if it works yet. I'll let you all know.
Only hunk of steel back there is the tail spring and mount and it's a couple of feet away.
Anyone else have experience of this installation?
magnetometer1xi0.jpg

Jim Sharkey
RV6 - At airport finishing up and getting ready to inspect and fly!
 
Last edited:
jsharkey said:
I put mine on the rear deck with the OAT probe under the outboard edge of the HS. This was as per suggestions in the Dynon installation manual.
I used aluminum rivets and screws to mount it and it's easy to get at under the empenage fairing.
Don't know if it works yet. I'll let you all know.
Only hunk of steel back there is the tail spring and mount and it's a couple of feet away.
Anyone else have experience of this installation?
Click to expand...

When I was building, I installed my EFIS and powered it up. Then I placed the compass module in various locations and moved the controls around. with the magnetometer on the rear deck, I was able to get the compass heading to change +/- 5 degrees just by moving the elevator - that was due to the steel elevator horns! That's why mine lives halfway between the tail and baggage compartment (on my -8). Just remember to calibrate it with the canopy closed - the in flight configuration of the steel canopy frame!

(I still like the fuselage mount, because you can set it up and do all systems integration and checkout in the shop, without the wings attached. Wingtip is a good operational spot though!)
 
wingtip mount and other locations

I opted out of the wingtip mount idea for 2 reasons. First, some have said that the strobes would interfere with the compass accuracy, but I have not experimented with placement there. The other reason was to stabilize the heading in rough air. In rough air the wing tip deflection is much greater than at the centerline of the aircraft, but again this is armchair engineering. I did try the module on the rear deck, a very convenient location, but the elevator horns and trim cable were an issue, and just wouldn't work for me. Seems that the fuse mount behind the baggage bulkhead seems to be working real well, and subsequent flights have so far proven it to be good in terms of heading. Dynon held guy mike said that they shoot for 3 feet of clearance to any ferrous object. That's a tough one in our little planes.

Observations...That's all....

Chris
 
jsharkey said:
I put mine on the rear deck with the OAT probe under the outboard edge of the HS. This was as per suggestions in the Dynon installation manual.
I used aluminum rivets and screws to mount it and it's easy to get at under the empenage fairing.
Don't know if it works yet. I'll let you all know.
Only hunk of steel back there is the tail spring and mount and it's a couple of feet away.
Anyone else have experience of this installation?

Jim Sharkey
RV6 - At airport finishing up and getting ready to inspect and fly!
Click to expand...

Jim, I've had three different magnetometers on the rear deck at various times over the past several years and all of them have worked flawlessly with no problems from the tail spring or elevator horns. Mine is mounted about six inches farther forward than yours, between the two small holes. I wrapped the mag in a plastic zip-lock back before mounting to eliminate the possibility of water running down the vertical stab onto the mag.
 
same place as Sam

I mounted mine in the same place as Sam (based on earlier threads on this issue) i.e between the two forward holes. After Paul's post I checked out if there was any change induced by moving the elevator and there was no perceptible impact that I could see. I am not flying yet.
 
I have mounted the compass module in all three locations in various RV's--behind the baggage bulkhead suspended from the top, out in the wing tip, and on the aft tail cone. All three locations worked fine. I didn't noticed the mag deflections on the tail install that Paul did (mine was on the RV-10 so it may have a little more distance). I did swing it in flight and on the ground with the elevator in the normal flight condition, and they were the same. I wouldn't worry about the impact on full flight control throw, as you probably aren't looking at the compass when at either extremes of the control if in flight. :)

Vic
 
Trutrak Auto Trim Module Location

Can anyone point me to a picture of where you guys have mounted a Trutrak Auto Trim Module box?

I'm thinking about mounting it near the elevator servo, but would like some suggestions.

Haven't been active on the list in a while, so I don't know what's been discussed. I did a search, and came up with nothing.

Ant suggestions?
 
I mounted my Dynon magnetometer on the inside of the inboard right wing inspection plate. It works fine there but I do notice that landing lights will make it move a few degrees. It is not a big problem and I never noticed it until I activated the Vertical Power Wig-Wag function.
Does anybody know if I could somehow shield the Dynon magnetometer, or the landing light wires to minimize the interference? The landing light wires are in the Van's black conduit and are a few inches above the magnetometer.

My Chelton (Pinpoint) magnetometer is on the rear deck and works great. No fluctuation with elevator movement.
 
I put mine just FWD the aft deck. We'll see how it works. I haven't leveled it yet, the long attaching hardware will give me the ability to adjust the pitch as necessary.
2gtnn2u.jpg
 
dmaib said:
I mounted my Dynon magnetometer on the inside of the inboard right wing inspection plate. It works fine there but I do notice that landing lights will make it move a few degrees. It is not a big problem and I never noticed it until I activated the Vertical Power Wig-Wag function.
Does anybody know if I could somehow shield the Dynon magnetometer, or the landing light wires to minimize the interference? The landing light wires are in the Van's black conduit and are a few inches above the magnetometer.

My Chelton (Pinpoint) magnetometer is on the rear deck and works great. No fluctuation with elevator movement.
Click to expand...

If you've got a spare wire in the conduit, or can snake one in there, use that for the ground of the landing lights instead of locally grounding them to the frame at the light location. This will cancel out the magnetic field component created by the one-way current flow in the landing wires at the magnetometer location.
 
airguy said:
If you've got a spare wire in the conduit, or can snake one in there, use that for the ground of the landing lights instead of locally grounding them to the frame at the light location. This will cancel out the magnetic field component created by the one-way current flow in the landing wires at the magnetometer location.
Click to expand...
Thanks Greg! I will give that a shot.
 
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