Starting to Wire - How to Route?

Just starting to wire her up (finally).

Wires from the engine compartment and panel itself are pretty well self defining as to routing, but from the tail and wings not quite so easy. So the question is how to get from here to there?

Obviously there are requirements, ease of access, short runs, hidden, protected etc.

How did some of you folks route the wires from the wings and tail up to the panel? Conduit, under the side panel covers, up the fire wall etc?

Thanks, Larry

conduit

Hi Larry,
We used the flexible conduit down the wings. We put everything in the conduit except for the strobe power supply which we ran down the gromets. We put the conduit up one hole in the wing rib to keep it away from the aileron push/pull tube. We drilled a small hole in each rib and place a tie wrap around the conduit. The final adjustment on the conduit is to place a large glob of goop at each rib junction and let it dry. Then we pulled the tie wraps snug against the goop and rib. We have not gotten to the fuselage yet, but we plan on using PVC there too. Here are some pictures.

Stuff here, stuff there, stuff everywhere

In the right wing conduit we have the Nav light, Marker bcn, Nav antenna, Angle of attack tubing, and auto pilot servo with the storbe power running seperately (the gray wire).

The way it looks inside the right wing

The left wing conduit has the Nav light, landing light, and heated pitot tubing and wiring.

Heated pitot runs in the left wing conduit

The right wing is stuffed so tight we cant get another wire in, the left wing is not so full.

Hi Larry:

Which model are you building? Wiring routing can vary greatly from model to model.

Jamie said:

Hi Larry:

Which model are you building? Wiring routing can vary greatly from model to model.

Click to expand...

OOP's, I should have said it's a 7A.
Larry

Claude,
I see you went with the Gretz heated pitot w/ chrome base - so did I. Are you planning on painting this, or chroming it? When I got mine I realized it was some composite material, and wondered if it could be chromed.

Thoughts?

Not to hijack the thread, but I'm in the same pickle with the chrome mount/black pitot. I'm pretty sure you can't chrome plate something unless it's metallic. You could paint it with some silver paint, though. I'll either try that, or paint the pitot and mount to match. Wish I hadn't sprung for the chrome mount way back when.

gretz pitot

The Gretz people say not to paint it because of the heat. We are going to just let it fade and weather as is. Maybe it can be painted with some chrome heat resistant engine enamel. I dont know how hot it will get, but I bet pretty hot. Its one of those little surprises we expected to see a chrome probe too when we opened the box.. oh well at least the mast looks pretty.

Back to our Program...

Can we get back to the question on the wire routing? I'm at that point now and am sure interested on aft to forward routing.

Jim

Ok, ok, back to the original question. A lot of the wiring runs depend on where you put the strobe power supply, trim switches, antennas, etc.

From the tail, my nav light wire runs up the floor of the tail w/o conduit. I used some of the sticky tie-wrap mounts. It then goes up the left side of the tunnel, through F-704 to the firewall and up alongside the firewall recess. I used tie-wrap mounts with screws everywhere except on exterior skins.


I have the strobe power supply under the baggage floor, so that wire branches off in the baggage compartment. Elev trim wire follows a similar route to the pilot stick.

I drilled some holes going side-to-side just aft of the control sticks. The strobe wires for the wings run straight forward under the baggage floor/pilot seat and then out to the wings using those holes.


I located stuff in the left vs. right wing to balance the fill in the conduits. I also made a diagram of the tight wiring spots (mainly the F-704 wiring holes) and made a list of every wire passing through each spot. That enabled me to balance the wires. I didn't need any extra holes in the F-704 (so far).

In a nutshell, the main wiring runs are the central tunnel, the transverse run just aft of the control sticks, along the front of the central spar, and up both sides of the firewall recess.

Trying to find pictures on my site, I realize I haven't taken many pictures of the wiring process. I'll try to snap a few more of where all the wires are at.

Central Tunnel Wiring Runs

Dave,

Did you have room for all the wires (strobe, nav power, trim power, A/P and antenna coax) to fit through the existing wire holes in the spar? I assume that we take the bundle, run it under the center floor cover then up the side of the forward/ heat cover? I have the strobe power under baggage floor and hope to keep the a/p, strobe, and antenna coax seperate.

Jim

how I did it

I took most all my wires through the two pre-punched holes near the center of the spar. The bundle runs in the center fuselage under the cover for the fuel pump... used some of the 3/4" corrugated conduit for that. Towards the end pulling wires through the conduit got pretty interesting - leave some pull string or wire in there for future upgrades.

What I didn't do was run my wires down in the center where the elevator pushrod is... I branched them out left/right as needed. Therefore they are completely out of the way of the control stick and pushrod. I ran some conduit under each of the seat pans.

I also used a hole near the gear weldment for the antennas. Let's see - I think I have three lines running through that hole (marker beacon, transponder, comm). The only other hole I had to punch myself was for the wing servo wire harness.

Does that all make sense?

Jim P said:

Did you have room for all the wires (strobe, nav power, trim power, A/P and antenna coax) to fit through the existing wire holes in the spar? I assume that we take the bundle, run it under the center floor cover then up the side of the forward/ heat cover? I have the strobe power under baggage floor and hope to keep the a/p, strobe, and antenna coax seperate.

Click to expand...

I used the outboard and inboard holes in the spar:

• strobe - didn't need to go thru the spar
• nav - inboard hole
• trim - inboard
• A/P - routes along the front of the spar to an outboard hole
• VOR/MB - also front of spar/outboard hole

I mainly used the outboard holes in the spar for the wing stuff with just a few exceptions. Tail stuff used the inboard holes.

I ran two bundles under the cover forward of the AFP pump. They will pop out in the gaps at the side of the cover right under the cabin heat and up each side of the recess. I'll use some split conduit or spiral wrap to protect the wires as they go up the firewall.

Trying to keep the noisy/sensitive wires separate is a good idea, but difficult. I was able to keep A/P & strobe separate other than about 4 feet in the wing. Comm antennas and strobe are separate except for maybe 1 foot. MB/VOR and strobe share the length of the wing.

There are two approaches to routing wires. a) Just go for it--might lead to re-doing/changing some wire routes mid-stream. b) Try to plan every wire route, and still might have to make changes mid-stream.

Larry,

1st rule you can never have enough conduit.

2nd rule put in extras for the future.

3rd keep the runs out of the elevator tunnel, the void in the main spar and the area behind the main spar (the stick mechanism area)

If I had to do it over again here is the plan that I would follow:

Wire runs

I ran conduit on the right and left side along the floor from the gear weldment to the corner where the floor meets the firewall then up the the corner.

I can email you photos if you wish. Let me know

N797RV said:

3rd keep the runs out of the elevator tunnel, the void in the main spar and the area behind the main spar (the stick mechanism area)

Click to expand...

Out of curiosity, Dick, why keep wires out of the elevator tunnel? Van's runs the manual trim cable down one side. Why not use the other side to run wires as Van's suggests. After all, like the trim cable, they'd almost certainly be secured to the ribs with adel clamps or something. There's really no way for them to interfere with the pushrod if they are secured. I'm genuinely curious here because this has been my intention all along and I'm close to getting ready to do some of these runs. Thanks.

Larry,

Your diagram shows five penetrations of the main spar. Did you add an additions hole beyond the four that Van's provides and was Vans's ok with it.

Thanks,

Joel
Finishing wireing and having trouble with wires through the main spar

Xtra holes in Spar

I added one extra hole per side of the spar with the blessings of Vans. They provided guidance as to where not to put them.

Holes in the rear spar

Jeff,
I recently sent an email to Vans about this, no reply just yet, could you show me their response on this issue?

Davepar said:

I have the strobe power supply under the baggage floor, so that wire branches off in the baggage compartment. Elev trim wire follows a similar route to the pilot stick.

Click to expand...

Is that what's under those hinged panels in the baggage area? That's not stock, is it?