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Hose and wire routing

sbalmos

Well Known Member
I've been looking over good old DWG 36A, thinking through where everything should be routed. Not just brake, fuel, etc, but electrical back to the tail. My overall feeling is there is going to be way too much to fit in the center tunnel from the center bulkhead forward to the panel. I'd be looking at two fuel lines, brake lines, pitot, static, AOA, and *gobs* of wiring, no? And I'm not feeling too thrilled at the two conduits of wiring in the baggage area tunnel, possibly interfering with the elevator pushrod. So here's my thoughts, comments or corrections appreciated:

Brake lines: Run along the sidewalls, probably through a grommet in the forward bulkhead, to the bottom skin port. This would be behind the Classic Aero side wall, and beneath the gear leg weldment cover. I'm using the Beringer flexible steel-braid-covered hose.

Fuel lines: Can't really do anything here. Intake and return lines still going through forward center tunnel.

Static line: Pretty sure this is still standard. Reading through other posts, everyone drills a random hole through the seatback brace bulkhead. I might use the covered-up tooling hole that is just slightly below where I've seen everyone usually putting the static hole. I'm assuming there would be similar holes near the top of each of the center bulkhead's left legs, under the longeron, and possibly also in the forward bulkhead (somewhere underneath the three rivets for the subpanel?).

Pitot/AOA: I read elsewhere this gets routed through the outboard-most set of bushings in the center bulkhead, then run parallel to the forward center bulkhead, and forward in the center tunnel with the fuel lines? What about running them along the sidewall like I'll be doing with the left brake line?

Wiring conduits: This is what really gets me. Is there really enough space for two wiring conduits, amidst everything else in the center tunnel? Also going back, in the baggage tunnel without interfering with the elevator pushrod or bellcrank. Working back to front, I've already drilled both the manual trim cable and optional mirror wiring holes in F-708 & F-707 bulkheads as per spec. I've got the mirror static line hole in the upper right side of F-706 and forward bulkheads (but I read somewhere from Mel that the ELT wire shouldn't go here, as bulkheads could cut the ELT line?). What I'm thinking is to cut two wiring conduit holes in the F-706 bulkhead in the next bay outboard from the center tunnel (I don't like the plan's idea of drilling the hole through both the bulkhead and baggage rib flange, and making the conduit run right up against the two bellcrank / tailcone support ribs). The conduit would run forward, diagonally, through holes I'd cut in the two inner baggage ribs' webs, and then run forward through the tunnel. This would also help with wiring the two COM antennas, which I'd be placing in those baggage bays where the conduit crosses through the ribs.

I'm still stuck in my head whether two conduits are going to fit in the center tunnel without interference, much less still be enough for all the wiring (4 antennas, lights, magnetometer, servos, etc etc etc).

Sorry for the long stream of consciousness post. Am I overthinking the wiring runs? Where else would you run wiring conduit, so they're under the carpet / feet going from the center bulkhead forward to the panel?
 
Thanks Scott

To Scott and all,

Thanks for asking these questions since I am in same boat (airplane?!).

Also any referral to a good source for bus blocks would be appreciated! Can't seem to find any....

Thanks guys!
 
Some clarifying pictures, after playing around in the garage tonight.

Wiring conduit on either side of baggage tunnel, through baggage ribs, to pass-through holes in F-706 that are more outboard than what the plans show, so we're not trying to jam so much right next to the elevator bellcrank.

FA3KSL3RplCBpkNdkGuZe3nHpllfUetZLmsKhr7bs2U=w538-h950-no


Static line hole through seatback bulkhead. Most people I've seen drill a hole either immediately to the right, or immediately below, the upper-left-most rivet. I'm thinking the tooling hole, near the center of the pic, is a better idea.

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Center bulkhead forward, I'm still mulling over. I'm thinking of the right side outboard-most pass-through in the center bulkhead to be dedicated to wiring going out to the right wing (CAN bus, etc to the roll servo, lighting, NAV antenna coax, etc). I think I might try to draw a pseudo-schematic tomorrow.
 
Hey Scott,

My build is pretty simple (AHRS integrated into the PFD, no autopilot) so I'm not dealing with the amount of wiring you are, but here's what I did. Wiring along the right of the center tunnel, static tube along the left. For the latter, I used a 90-degree quick-disconnect fitting so I could run most of the tubing beneath the riveted-in-place baggage floor. Big blue section of conduit carries only magnetometer wiring, so plenty of space for future wiring upgrades.

Forward of the spar carrier, I ran all tubing and wiring up the center tunnel too...it seemed like a neat and clean way to do it.

Click on any photo and it'll take you to my Photobucket page where there are a bunch more assorted images.





 
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Hi Doug,

Yeah, you did what I was planning, on the right side, running the wiring through the baggage rib next to the tunnel instead of in the tunnel, then through the bulkhead on the outside. Where does the magnetometer wiring hose penetrate the spar box? Did you drill separate holes through the spar box for it?

And looking at your other pics... Did you *really* paint your elevator pushrod tubes blue? :p
 
I just slogged through this last year. Several tips and Oops I hit. I bought a project, so some decisions I was given, some I made.

1. Take the Vans three view drawing and copy it several times. Sketch your known electronics locations, sensor locations, light locations, AP locations, trim locations, ELT location, antennas ... etc. Add the existing penetrations in the wing spar to the drawing and start to bundle wires and plan where they would pass through the wing spar. Where they penetrate controls the routing.
If I was starting today I would call Vans and discuss increasing the dia. of the wing penetrations. Mine were packed.

2. Your Avionics choices can change all of the above. As an example, with Dynon the static, AOA and Pitot lines all run to aft of the baggage bulkhead to the AHARS.

3. In my case Dynon (MY Choice of EFIS), has added an SV AP panel, SV Knob panel, SV ADSB -470 receiver, SC Com and the SV Hub after my panel layout. All added well after I did most of the initial wiring installations .
Adding a few missed wires not planned for is a PITA.

4. My floor were in as received. I now wish I had removed them and added three conduits two on the pilot's side and one on the co-pilot's side of the tunnel. One is needed to route the AOA and Pitot tubes aft the others for wiring.

5. You will find items missed in planning. In my case, I missed the cap to voltage converters, the flap position indicator and the GPS signal to the ELT.
 
I just slogged through this last year. Several tips and Oops I hit. I bought a project, so some decisions I was given, some I made.

1. Take the Vans three view drawing and copy it several times. Sketch your known electronics locations, sensor locations, light locations, AP locations, trim locations, ELT location, antennas ... etc. Add the existing penetrations in the wing spar to the drawing and start to bundle wires and plan where they would pass through the wing spar. Where they penetrate controls the routing.
If I was starting today I would call Vans and discuss increasing the dia. of the wing penetrations. Mine were packed.

2. Your Avionics choices can change all of the above. As an example, with Dynon the static, AOA and Pitot lines all run to aft of the baggage bulkhead to the AHARS.

3. In my case Dynon (MY Choice of EFIS), has added an SV AP panel, SV Knob panel, SV ADSB -470 receiver, SC Com and the SV Hub after my panel layout. All added well after I did most of the initial wiring installations .
Adding a few missed wires not planned for is a PITA.

4. My floor were in as received. I now wish I had removed them and added three conduits two on the pilot's side and one on the co-pilot's side of the tunnel. One is needed to route the AOA and Pitot tubes aft the others for wiring.

5. You will find items missed in planning. In my case, I missed the cap to voltage converters, the flap position indicator and the GPS signal to the ELT.

Very Good Advice!

I might add, if you want to run wires, tubes under the side rails, plan well ahead and put in conduit. It is a knuckle buster job, a rotisserie would greatly help the old stiff guys.
 
I forgot the rotisserie .

I put my fuselage on a rotisserie, lowered to allow rotation about 45 degrees each way. The steps limit how much you can lower it and still rotate it.

I ran all the wires, brake and fuel lines, control linkage and anything else on the firewall from the stool.

My goal was to finish as much as possible in the garage, then to hangar for assembly.
 
Hey Scott,

What's wrong with blue? :):) There was a sale on Rustoleum, so I thought I'd make my pushrods purdy. :D

The big blue conduit ends right underneath the crotch strap attachment ( I shortened it a bit since the photo was taken), so there's no penetration of the spar carrier. From the blue conduit, the magnetometer wires run forward, then outboard through the seat pan ribs, into the spar carrier via the outboard aft hole, then up the cap strip (yet another reason to not close these up too early in the build), and forward to the IP beneath the canopy deck rail.



 
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Nothing at all Doug. Quite unique, making the primary light linkages bright blue. :D

And the wire routing is definitely interesting. Brings up some more ideas for where I can route stuff. Yeah, the center caps and everything are still off. I was wondering for a bit whether people thought it was okay to run wiring in the valley between the two spar box bulkheads and behind the center cap. You don't think you'll have any problem with any of those wires ever rubbing on the rudder cable? If I did that, I might slide on some heat-shrink sleeve or something.

Thanks Doug! Back to drawing...
 
the wiring daze

zip on, zip off, then do it again and again...... then somehow you're done.

try to remain calm while you whip this wiring thing out in a couple of weeks.....

100_4906.jpg


100_5011.jpg


100_5207.jpg
 
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Though it adds to the wiring that goes to through the spar, consider putting your headset jacks where the wires won't be dangling between you and the panel. I have a ADAHRS with pitot going to the left wing and AOA going to the right wing. Where you see my headset jack wiring going through the seat floor, the tubing goes through about 6 inches fwd, just behind the seat back bottoms so they won't be in the way of anything (I hope). To get there, they each go through the seat back support above the rear spar parallel to the rudder cables to avoid interference. Don't have a picture of the tubing yet but will tomorrow.

The third jack that may be unfamiliar is LEMO, for connecting and powering ANR headsets.

cLaGg5Ol.jpg
 
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You don't think you'll have any problem with any of those wires ever rubbing on the rudder cable? If I did that, I might slide on some heat-shrink sleeve or something.

Yeah, I'll have some anti-chafe protection at the very least, and figure out a method to secure the wiring away from the rudder cable.
 
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