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How much wire goes in to RV-7???

vluvelin

Well Known Member
Question to those with fully loaded electrically dependent setups.
could you guys post some numbers
Gage of wire and how many feet of wire you used
Thank you!!
 
I'm in the process of planning my wiring run for my 7 with a relatively full VFR Dynon panel, and I've been putting together a spreadsheet for the runs to various "stations" on the A/C (panel, mid fuse, tail, wings, etc)

My rough net numbers looks like:

22AWG 785'
20AWG 339'
18AWG 100'

I'll be using lots of different colors; these numbers are somewhat conservative (this is what I'll order)

If you like, PM me with an email address and I'll send a copy of my draft spreadsheet.
 
It would be helpful to know what sort of avionics you will be installing.
I used the VP-X wiring kit and that did the majority of the simple circuits in the airplane for lighting and various other things like fuel pump, seat heaters, power ports, ELT, etc.
The Dynon Skyview comes with various wiring kits for the EMS, EFIS, Network, Autopilot, ADS-B, XPNDR and radios. What's left is wiring the switches on the panel and sticks. I bought a bunch of smaller lengths in various colors from Stein Air, and you will need some shielded wiring for strobes, and coax for antennas.
I made a very detailed spreadsheet with all of the circuits and the various types of wires. A modern avionics system has hundreds of wires! Way more than you think until you start listing each one from where it originates to where it terminates.
 
You've got lot's of planning ahead...

I'm in the process of wiring up my RV-7. I'm thru about 60% of the wiring so far. I have quite a bit of avionics: Dual AFS 5600's, Dynon D10A, TruTrak Vizion 385 w/ auto trim, Garmin 240, 650, 255A, 330-ES, AeroLED wingtip lights, Nav/Strobes, Dynon regulated Pitot Heat, defog fans, seat heaters, panel and map lights, boost pump, P-Mags, Plane Power 30A backup alternator, ADS-B, ACK ELT, etc. Search the forums and you can see a CAD model I made of my instrument panel.

I've got 34 pages of wiring schematics. All of the wires are labeled with a code that matches the wire on the schematic and the wire "function" to make future troubleshooting/modifications easier. I broke the schematics down by sub system. I'm running all of my ground wires to a forest of tabs located on the inside of the firewall (P-mags and a few other engine related items have a local ground). To get a handle on how much wire I would need and how to route it I first ran string for all the wiring. It was cheaper and quicker than using actual wire. It was a good thing I did since I changed my mind 4 or 5 times during the string running due to figuring out better routing. I measured the length of every string and used this to purchase my wire. Of course I purchased a little bit more just in case. During my wiring process I've been measuring the actual length of the wires and updating a spreadsheet that has all of the wire lengths and other info I need to wire this thing up. The difference between the string lengths and the actual wire lengths have usually been within an inch or two. Most of the time, almost exactly the same. The nice thing is I'll have actual numbers on how much wire I installed.

So, to answer your question, how much wire is in a RV-7? Well, for me it's about 2,024 feet of wire. That's 497 individual wires, not including shield ground wires. The total wire weight is 17.3 lbm (this will change a little until I finish with all of the wiring as will the total wire length). The interesting thing is the heaviest sub system is the Landing/Nav/Strobe lights (2.36 lbm wire weight). It's not that the wires for this are all that beefy. It's that they are so long. The GTN 650 was next (1.95 lbm), mainly due to a lot of shielded wires and the RG-400 coax going out to the Archer wing tip antenna. The third heaviest sub system was the GNC 255A at 1.59 lbm (again, shielded wire and coax to the wing tip antenna). The fourth heaviest was the Auto Pilot (1.15 lbm). Again, a lot of small, really long wires. The fifth was the starter system (1.02 lbm). Not a surprise there given the large wires used for it. However, they are relatively short so that's why the starter is fifth on the list. My "gut" feel before running the numbers was that the starter system wiring would be the heaviest since the wires for it are huge. I was wrong however.

Once I get finished with this I plan to clean up my spreadsheet and post my results here on VAF. I see a lot of people talk about how much this or that adds to the weight of the aircraft. Lots of opinion without any numbers to back up their claims. I'll have actual data to back things up. Of course, any changes to this will affect the numbers but it should give people a good idea on how much wire weight they are adding to their planes.

Another thing that was interesting was that if you were to switch from a 14VDC system to 28VDC, you could reduce the wire size somewhat and save some weight. I ran the numbers for this, keeping AWG22 as the smallest wire size due to ease of use and robustness. The weight saved was about 3.5 lbm. Not a whole lot. Especially when you consider that you're going to have to use a 24VDC battery and would most likely want to add something so you had 12VDC for things like charging Ipads, etc. Those extra items you will need by switching to 28VDC quickly cut into your 3.5 lbm weight savings. For me, it wasn't worth the added complexity to go to 28VDC so I've got a 14VDC system.

Anyway, I hope this helps. Please let me know if you have any questions.

Jeff
 
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I'm in the process of planning my wiring run for my 7 with a relatively full VFR Dynon panel, and I've been putting together a spreadsheet for the runs to various "stations" on the A/C (panel, mid fuse, tail, wings, etc)

My rough net numbers looks like:

22AWG 785'
20AWG 339'
18AWG 100'

I'll be using lots of different colors; these numbers are somewhat conservative (this is what I'll order)

If you like, PM me with an email address and I'll send a copy of my draft spreadsheet.

Thank you I am very far from my wiring but if a deal on wire will come up I will have proximate numbers to grab it
 
I've got 34 pages of wiring schematics. All of the wires are labeled with a code that matches the wire on the schematic and the wire "function" to make future troubleshooting/modifications easier.
Jeff

What software you used to make you schematic?



So, to answer your question, how much wire is in a RV-7? Well, for me it's about 2,024 feet of wire.
Jeff

could you please proximate each gage of wire and feet






Once I get finished with this I plan to clean up my spreadsheet and post my results here on VAF. I see a lot of people talk about how much this or that adds to the weight of the aircraft. Lots of opinion without any numbers to back up their claims. I'll have actual data to back things up. Of course, any changes to this will affect the numbers but it should give people a good idea on how much wire weight they are adding to their planes.
Jeff

What software you use for spreadsheet??
This is exactly the info I was hopping to find in one of the posts but was unable

Another thing that was interesting was that if you were to switch from a 14VDC system to 28VDC, you could reduce the wire size somewhat and save some weight. I ran the numbers for this, keeping AWG22 as the smallest wire size due to ease of use and robustness. The weight saved was about 3.5 lbm. Not a whole lot. Especially when you consider that you're going to have to use a 24VDC battery and would most likely want to add something so you had 12VDC for things like charging Ipads, etc. Those extra items you will need by switching to 28VDC quickly cut into your 3.5 lbm weight savings.
Jeff

I would stay with 12V system for its practicality

Anyway, I hope this helps. Please let me know if you have any questions.
Jeff

Yes Jeff this was a lot of statistical info that is hard to find
I am just tooling up for a build and I am sure I will see your full info on wiring before I will get to my wiring
Thank you
Julian
 
It would be helpful to know what sort of avionics you will be installing.

That is the real problem I am far away from wiring just getting an idea how much wire to buy in case i get good deal.
In 5 years a lot of new products will be released and wiring demand will be reduced a little due to increasing use of CAN and other serial data networks.

in any case i am just getting approximate numbers each bird is different
Thank you
Julian
 
Part of the discussion needs to include shielded wire. I installed G3X. Garmin's wiring calls for a lot of shielded wire. I followed their requirements. I have no idea how much wire I used. I do know I had to reorder wire more than once.
 
I'm in the process of planning my wiring run for my 7 with a relatively full VFR Dynon panel, and I've been putting together a spreadsheet for the runs to various "stations" on the A/C (panel, mid fuse, tail, wings, etc)

My rough net numbers looks like:

22AWG 785'
20AWG 339'
18AWG 100'

I'll be using lots of different colors; these numbers are somewhat conservative (this is what I'll order)

If you like, PM me with an email address and I'll send a copy of my draft spreadsheet.
I'd like a copy of your spreadsheet if available. We're about to dive into avionics and electrical on our RV-7A.
 
That is the real problem I am far away from wiring just getting an idea how much wire to buy in case i get good deal.

Julian

I wouldn't spend too much time trying to figure this out so far in advance, because it really depends a whole lot on what avionics you choose and if/what they have for pre-made leads/harnesses,what antennas you use, etc.. For example, if you use a pre-made Skyview cable from your panel to the ADAHRS (lets say 20'), that can be 180' of AWG22 wire right there....and the cost of the premade harness isn't a whole lot more than the raw cost of the components (not counting your time).

As others have mentioned, it can vary DRASTICALLY depending on a whole host of things (even what lights you use, etc..).

In the end, it's likely the entirety of wire in your plane is hundreds of dollars so it's not like you can save thousands on that no matter what you do. I'd say spend your time on the things that CAN save you the real money like a Prop, Engine and even Avionics themselves. Heck, both Garmin and Dynon occasionally have had deals worth more than the entire bulk of your wire purchase for the entire airplane...and it takes no spreadsheets that will most likely end up being inaccurate anyway (because what you 'think' you might use/buy now will likely change in the years before you actually buy it).

Not trying to dissuade you from doing your due diligence - that's a good thing. Just trying to make sure you don't forget the forest for the trees, or end up stepping over a dollar to pick up a dime. :)

Just my 2 cents as usual.

Cheers,
Stein
 
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