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Where to mount Dynon AHARS

BobCollins(AA) said:
Where is a good location to mount a dual AHARS System on the RV-7A
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You need a spot away from magnetic fields (created by electrical currents in wiring, or magnetized metal, especially magnetized metal that MOVES in flight). The tail section is one of the preferred locations, I put my Dynon and MGL boxes back there.

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I am in the prosess of mounting mine right now, I built a shelf with a par of .063 angle riveted to the longerons in front of the aft deck. away from AP servo motor and seat belt cables.
 
BobCollins(AA) said:
Thanks for the info Greg.
How do you access the AHARS after the fuse is closed ?
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Valid point - I made sure that I could reach the units through the holes in the tailcone bulkhead to remove the units before I put the aft skin on, actually doing it once. I removed some skin from one hand but I was able to remove units with access only through that bulkhead under the tail fairing. I would suggest making up your mount plate and finding its final location using this same method. Notice in the photo the screw heads are on the bottom side of the mount plate, that's the only way you can make it work and still be able to pull them and replace them through those bulkhead holes. I used a small dab of epoxy on the nuts to hold them in place on the body of the ADAHRS boxes, a poor substitute for a nutplate but it works and it's not steel!
 
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It's going to depend upon where you have some other electronics mounted at. In my case I have an autopilot servo right behind the baggage bulkhead, and I mounted my strobe power pack there as well as the transponder and ELT, and I'm using an aft-mounted battery on the backside of the baggage bulkhead, so there was enough wiring in that area that I wanted to get away from it. If that area of your plane is electrically quiet then larry has a good location with decent access as well.
 
larrynew said:
This is a popular location.

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+1 this location, I have all my other items eg servo, strobe pack etc here with no problems.

Note, when you need to do your transponder test, you need to be able to get to the 3 ports on the ADAHARS.

The only problem I had, is that i have a slider and the compass moves when you slider the canopy open, so do your Cal with it closed. This shouldnt be a problem as I dont intend to open it in flight :p
 
Keep in mind that working thru those holes after the skin is on is pretty easy up until one mounts the empennage...once it is on, you can't get into the same positions you can prior to its mounting.
 
I installed mine in the same spot and had the same problem with the canopy .
You just need to make the brackets a little longer.
 
What's wrong with mounting them aft of the last bulk head just behind the large holes instead of building a mounting bracket A lot easier to service.
 
Some folks have raised the issue of the steel bolts/nuts used in elevator and rudder causing problems with the magnetic fields as they move in flight. I don't know of any confirmed problems associated with that, just lots of questions and cautious people. The theory is valid, we just don't know if it's serious enough to be worth acting on. "Better safe than sorry" seems to be the most well-beaten path so far.
 
On the top of the fuselage there is one VHF antena, one GPS antena and you have to locate the AHARS at least 2 feet away from each other. When you have a sliding canopy the real estate does not add up
 
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I have done some experiments back in that area and found no interference from stay magnetic fields. I originally thought that the elevator horn would present the most problem but it appears that it is far enough away that any field generated by it is not strong enough to cause interference. The magnetic fields generated by the strobe light and nav light in the rudder and the trim motor and associated wiring don't seem to produce enough electrical field to cause any interference either.
 
So far I am having great success with my Dynon ADHARS mounted in the left wing of my RV-9A. It is just aft of the inboard access. It sits pretty much over the tire. I made a bracket to mount the ADHARS on so it can be disconnected and removed if need be. I really like that my AOA line does not come into the fuselage. I hear tell that the RV-14 uses this location.
 
DYNON AHARS has to be within the footprint of the fuselage inside the CG envelope
I am installing the AHARS in the back just in front of the rear bulkhead
 
My setup

This is in my RV9A just behind the baggage compartment for easy access in the future. Those are dual ADAHRS on the right. The orange/black/gray wiring going up are to the GPS antennas. The red box on the left is the GADAHRS unit for my Vertical Power VP-400.

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I mounted mine very similar to Larry New but a little forward closer to the baggage bulkhead. I connstructed the mounting bracket a year ago after reviewing all posts at that time and just finished the dual adahrs mounting and plumbing last week. Good location, none better.

Hope to make first flight in June. (Is that God laughing I hear?)
 
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I too mounted mine on my tipper behind the bulkhead similar to Jamie's but instead mounted mine fore and aft. Picture 647 of the second builders log.

Smilin' Jack
 
This is half way between the baggage rib bulkhead ( F706) and the next rearward rib( F707) looking aft.
( yes that rivet on the left side was re-set :cool:) )

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Some measurements for you. Note the 9 pin connector faces rearward once installed. Also you have to put a slight down ward angle on the verticals, as the aft deck runs downward to the tail.
The base is 6 12/32 inch long. On the left side vertical near the 9pin, its height is 2 10/32 ( rear ) and the front is 2 30/32 ( forward side ) I made the width the same size as the ADAHRS. It was made out of 032.
 
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