[comfortcat]

I have seen lots of special mounting brackets for the ADAHARS but why not just mount it at the back of the fuse? I made two Longeron cross braces, and put it close to the last bulkhead so I can reach it if required. I'm installing one, but can add a second if I decide later.

Any issues in installing here?

advTHANKSance

Dkb

 

[AJ85WA]

Tail mounting

Hi Dkb

I dont have much expierence in this so dont take my thoughts as being correct.

But I would think the tail would be the part moving around the most in turbulance and in general, also might be a bit delayed in the movement compared to mounting it towards the front.


Again just what I would think, could be wrong

 

[N941WR]

Having just mounted my dual ADHARS in my completed -9, I feel your pain.

Since you are building a -9A I would move them forward. The NG RV's tend to be a bit on the tail heavy side due the main gear being aft of the CG.

In my case, I put them just forward of the first bulkhead aft of the baggage compartment. It is accessible, barely, for future maintenance.

One other advantage to this location is that you can install the Dynon hub and plug your pitch servo in next to the ADHARS. Then you only need a wire running from the hub forward, along with the power and disconnect wires for the servo. That is, if you are installing an AP.

Also, while plate nuts are great, I bolted mine in place with brass bolts, washers, and locknuts from McMaster-Carr.

 

[airguy]

You mean like this?

You might want to remove the nutplates though, and use brass screws/nuts. The nutplates are steel and will affect the magnetometer.

 

[whd721]

N941WR,

How did you get back there?

With the top skin and the rear window in place, I am concerned that I will never be able to access the ADHARS again.

As I remember you are retrofiting a finished fusalage.

I am somewhat old and stiff. How did you do that?

 

[N941WR]

N941WR,

How did you get back there?

With the top skin and the rear window in place, I am concerned that I will never be able to access the ADHARS again.

As I remember you are retrofiting a finished fusalage.

I am somewhat old and stiff. How did you do that?

Like you, I am old and stiff and it wasn't easy.

I use three backpacker's Z-rest bed rolls to protect myself and the plane. That and I had a chapter member who is much smaller than I crawled back there to fit and drill the cross braces. However, he wasn't around when it came time to rivet them in place or do any of the other work required.

I found I can sit in the baggage compartment with my feet sticking in the tail cone "fairly" comfortably. I need to get someone to take a picture of me in there. Talk about 10 pounds of sh!t in a five pound bag!

There is access but it isn't easy. Remember, that if you put the ADHARS way back there, you will still need to access the tail cone to run the wires, pitot, static, and AoA lines. Let's face it, this stuff is somewhat like computers, you will replace it at some time.

 

[Walt]

I would make sure there are no leaks in your P-S system while you have access, getting back there to fix a leak won't make some poor avionics guy very happy

 

[gorbak]

Just behind the baggage compartment

Here is where I placed mine.

[/IMG]

Pat Garboden
RV9A
N942PT reserved

 

[airguy]

I thought real hard about Pat's installation as well, but discarded it for two reasons.

First, I put my battery right behind the baggage compartment bulkhead, which means large currents are flowing (and creating magnetic fields) in that area. This would only impact those who also have rear-mounted batteries.

Second, I didn't want my magnetometer affected by any type of magnetized metal that I might happen to throw in my baggage compartment for a trip.

 

[scrollF4]

Rudder Cables

I have seen lots of special mounting brackets for the ADAHARS but why not just mount it at the back of the fuse? I made two Longeron cross braces, and put it close to the last bulkhead so I can reach it if required. I'm installing one, but can add a second if I decide later.

Any issues in installing here?

advTHANKSance

Dkb

Right up front, I'm concerned about your rudder cables...they're made of a magnetically-attractive metal, which can throw off your magnetic compass sensors in the ADAHRS. I didn't read it in your post, but if it's a Dynon SkyView ADAHRS, you've got to keep it at least 2 feet from ferrous materials. "Ferrous" implies two things: Iron, and/or magnetically-attractive metals. I called Dynon to clarify, and they said they meant the latter. Thus, they want no metals that would pull the compass needle astray (thus, use brass nuts/bolts to attach).

I designed/fabricated a shelf that I hung from the roof of the fuselage from the j-stringers just aft of my 7A's aft baggage wall:

http://www.mykitlog.com/users/display_log.php?user=scrollf4&project=879&category=0&log=147364&row=5

 

[whd721]

I measured distances in my tail cone today.

Just Aft of baggage bulkhead (high)
Pitch servo distance ~24?
Seat Belt cable distance ~9?
Rudder cable distance ~26?

Just Aft of baggage bulkhead (low on longeron)
Pitch servo distance ~18?
Seat Belt cable distance ~6?
Rudder cable distance ~20?

Just forward of F-707 bulkhead (high)
Pitch servo distance ~24?
Seat Belt cable distance ~6?
Rudder cable distance ~26?

Just forward of F-707 bulkhead (low on longeron)
Pitch servo distance ~21?
Seat Belt cable distance ~7?
Rudder cable distance ~20?

Note: I measured from a servo (not there) to a ADAHARS (also not there) as best as I could. YMMV
I agree, as high as possible just aft of the baggage bulkhead is the best compromise.

Comments?

 

[gorbak]

Mangnetic shielding

I placed my ADHARS directly behind the baggage area on mounts across the longerons (see picture in previous page post) and came up with the following measurements:
Just Aft of baggage bulkhead (low on longeron with support from baggage center brace)
Pitch servo distance ~16?
Seat Belt cable distance ~8? at closest point
Rudder cable distance ~22?

I wanted the ADHARS to be as close as possible on all three axis of the plane and figured this is the closest I can get and keep it level. Meantime, I intend to use magnetic shielding from Aircraft Spruce, which comes by the inch in 4" width and 4 mil thickness. My intent is to attach a simple cover over the pitch servo (15" away) to shield any distraction. This will be attached by using heavy duty velcro and hook on two or three locations on the pitch servo with close attention paid to avoid any interference with performance/movement. I will then cut strips and wrap the seat belt cables from the baggage wall back towards the longeron attach point until I have 24inches from the ADHARS. The seat belt cables are stationary and hidden behind the baggage wall and are easier to attempt this instead of looking for a solution for rudder cables that move and must have free play. I ran this past an engineer and he thought it would work well. He also cautioned not to attach the magnetic shielding directly under the ADHARS unit itself to shield it (like bolting it on the support plate or longeron that holds the ADHARS).

Pat Garboden
RV9A
N942PT (reserved)