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RV8 Buss Bar Locations

dmatre

Member
I am building an RV8 and need input for placement of the main and avionics buss bars and grounding pins. Attached are a couple of photos where I think they could be mounted. Looks like the strut connecting the two gear towers could work - close to the breakers and the strut could support wire bundles. I do have the hinged avionics bay access door. Also attached is a photo of the panel so you can visualize avionics and back-up instruments protruding into the bay. Any critique or alternate ideas appreciated. Thanks.
 

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I mounted the busses on the inside of the door facing the avionics compartment. I made a tray across the crossmembers to mount the radio remote, EFIS BU battery, ground buss etc. Worked out ok.
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I did the avionics bay door to the baggage area, and found that it's much easier to access things by removing the instrument panel and putting it in your lap. When you need to get up, a couple of clecos puts it back in place temporarily. I also used the auto fuses similar to Al, and a pair of "forest of tabs" for grounds. On the panel, dedicated ground point. Bob Nuckolls (https://www.kitplanes.com/author/robert-l-nuckolls/) at AeroElectric Connection (http://www.aeroelectric.com/) makes a great case that auto fuses eliminate the need for "acres of breakers" and a "bus bar".

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I recommend his book - I learned a lot from it. It is an excellent foundation for aircraft electrical design and wiring, at least it was for me.
 
I did the avionics bay door to the baggage area, and found that it's much easier to access things by removing the instrument panel and putting it in your lap. When you need to get up, a couple of clecos puts it back in place temporarily. I also used the auto fuses similar to Al, and a pair of "forest of tabs" for grounds. On the panel, dedicated ground point. Bob Nuckolls (https://www.kitplanes.com/author/robert-l-nuckolls/) at AeroElectric Connection (http://www.aeroelectric.com/) makes a great case that auto fuses eliminate the need for "acres of breakers" and a "bus bar".

View attachment 77784

I recommend his book - I learned a lot from it. It is an excellent foundation for aircraft electrical design and wiring, at least it was for me.
Thanks Mickey. Yeh, I now get how fuses can reduce the massive area needed for breakers. However, I am building a relatively simple plane (VFR Day/Night) keeping some old school feel (mags and back-up analog gauges) with new tech (GRT Sport EFIS and their EIS). I do like the ability to see the status of a breaker in the cockpit for immediate identification of a problem. Another good book is Aircraft Wiring Guide by Marc Ausman.
 
I mounted the busses on the inside of the door facing the avionics compartment. I made a tray across the crossmembers to mount the radio remote, EFIS BU battery, ground buss etc. Worked out ok.
View attachment 77774

Thanks for the response and love the quick disconnect fasteners on the access door. Beautiful work on your plane. The shelf idea is great and will consider.
 
Not a fan of live bus bars facing up. Facing down means nothing can ever drop on them. And yes, using fuse blocks eliminates them entirely. Mine swing down.

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dmatre,

If you move your breakers and switches to the side wings and the arm rest, you greatly simplify maintenance, upgrades and modifications as removing the center panel to work it on the bench is a simple 15 minute task.

No need for shelves, access holes to the baggage compartment and such.

Side note. I never use copper buss bars. I know Cessnas and such use them but for me they just seem alike an accident waiting to happen.

Carl
 

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dmatre,

If you move your breakers and switches to the side wings and the arm rest, you greatly simplify maintenance, upgrades and modifications as removing the center panel to work it on the bench is a simple 15 minute task.

No need for shelves, access holes to the baggage compartment and such.

Side note. I never use copper buss bars. I know Cessnas and such use them but for me they just seem alike an accident waiting to happen.

Carl
Thanks Carl. Another RV owner mentioned that removing the EFIS unit also provides access. I am trying to keep the plane simple, so I suspect I will not need a shelf.
 
Thanks Carl. Another RV owner mentioned that removing the EFIS unit also provides access. I am trying to keep the plane simple, so I suspect I will not need a shelf.
Yep - but not as much access as you would think. Assuming you have other stuff in the panel (GPS navigator, comm, audio panel and such) this access does little to help with trays. The trays tend to be the biggest issue.

As I’ve posted in the past, the rule is “never on your back with your head under the panel”.

Carl
 
Photos of the center panel in and out of the plane.
Carl
 

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