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HELP ! Wire routing over spar in a 6

NYTOM

Well Known Member
Has anyone run conduit along the sides of the cockpit under the armrests to get the wiring over the giant spar in the 6. :confused:
I'm trying to get as much done as possible before going to the airport and it would be great if I can get all of my wiring done without going through that little hole they provide in the spar. If I do it will I weaken the structure and fall out of the sky someday? :eek:
I was thinking 1/2" aluminum tube along both sides through the bulkheads from under the panel back to a spot behind the seat backs. About 6 inches above where the rudder cable's run. If this sounds really dumb to you please feel free express your opinion. :eek:
 
I was thinking 1/2" aluminum tube along both sides through the bulkheads from under the panel back to a spot behind the seat backs. About 6 inches above where the rudder cable's run. If this sounds really dumb to you please feel free express your opinion. :eek:

Tom,

It is permissible to cut the web in the spar to a larger size for wiring pass thru, etc. I don't know anyone who has ever run a conduit the route you are considering. Sounds like you are contemplating passing the conduit thru the F-604 bulkhead and I think that would be a major no-no. That's a major structural part.

Here is a photo of what I did in the web. The photo was taken to show the spar chamfer but you can see the web "slot" pass thru. The second photo kind of shows the resulting wiring pass thru. You have to look hard but it's there. The photo is taken from in front of the spar area.

c4acn.jpg


2hx0fog.jpg
 
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wire run

Its ok per Vans to make like hole in other spar giving twice the space thur center run they said its ok to trim as in picture giving more room and not having to cut wire if you ever take wings off.
 
Can go around instead of through

Has anyone run conduit along the sides of the cockpit under the armrests to get the wiring over the giant spar in the 6. :confused:
I'm trying to get as much done as possible before going to the airport and it would be great if I can get all of my wiring done without going through that little hole they provide in the spar. If I do it will I weaken the structure and fall out of the sky someday? :eek:
I was thinking 1/2" aluminum tube along both sides through the bulkheads from under the panel back to a spot behind the seat backs. About 6 inches above where the rudder cable's run. If this sounds really dumb to you please feel free express your opinion. :eek:

Just another option; I went around the main spar carry through bulkhead instead of through it. I put a small number of wires through a very small hole in the rear spar bulkhead, smaller than the rudder cable hole.
This method is not completely invisible but done neatly it looks fine and is easy to get at if ever need to change wires out or add to the run.
Some of my routing during the build phase, before completely cleaned up and covered up, is shown at:

http://rv6aproject.ckhand.com/panelAndElectrical/electrical/electricalPg4.htm

and

http://rv6aproject.ckhand.com/panelAndElectrical/electrical/electricalPg6.htm

wingtip nav antenna and ptt wires running to under seat pan, and strobe power supply wires running aft to power supply behind baggage compartment:

electrical015.JPG


This bundle runs under seat floor for nav light power distribution to wing tips and has wing leveler servo wires that run under seat floor out to wing. Also has ELT wires. The visible part of the wire bundle here is actually hidden by the seat back and cushions so don't ever see this unless pull the seat back forward:

electrical016.JPG


Dynon EDC wires running back to tail mount location for my Dynon D100 digital compass mount:

electrical018.JPG
 
I have had bad luck with those 'sticky-backs' holding wire.. eventually they un-stick and leave a un-stickable area on the surface. Have used hundereds of them in my line of work.

Sheldon
 
I ran my pitot/static lines under the armrest and through the vertical portion of the F-604 bulkhead. I called Vans first to ask if it was ok to put a hole in the F-604 vertical and they said it was, just to keep it to a minimum and that my one 3/8" holes was fine. The 3/8" hole fit a 1/4" ID snap grommet. If you do decide to run wires under the armrest I would run them as high as possible and then just use a cushion clamp on the underside to support the wires. The wires can then continue aft behind the baggage side panels and forward just under the section of angle between the F-604, through the former and to the firewall. The only place the wires would be visable is by your knee where they exit F-604.
 
Some 16 or 17 years ago when I was building my RV-6, I found out that I could run the wires past the SPAR just under the main longeron. There is not a lot of room but there was enough room for tail strobe, tail light, ELT remote phone cable wire, PTT, and headset jack wires. I use a piece of heat sleaving over the wires where it came in contact with the metal.

There is at least 1/8" space above F604E at the top where it meets the main longeron and holds F604B and F604C apart. Ref RV-6 DWG 31 detail A in the upper left hand part of the drawing.

Hope this is helpful and easy to understand.
 
Running wires anywhere there is a moving part is a receipe for a problem. I guarantee that the sticky holders that are holding the bundles or even a single wire will come loose and either short out or get chafed by a moving cable such as a rudder cable. (Don't ask how I learned this) If you have to route wiring past a control surface use an Adel clamp or find another route. We have found that drilling an appropriate sized "lightening hole" is OK to route small bundles through without weakening a structure. Good luck and I think you are really smart to post photos and ask advice.
Woodman
 
Why I love this site and always " DONATE "

Thanks to all for your help. I got a lot of momentum going from all these travel stories and videos and I'm going to move on this right away. Love Colin's routing of the pitot/static lines and going to copy it. Gary's slotting of the spar makes the most sense to me for my project. I'm trying to complete as much as possible and hoping to just plug in the wings in when I get to the airport to complete my project. Hangars are real expensive and real hard to get around here and although I've been on a waiting list for a while I may have to complete my project in a open tie-down area. :eek:
Thanks again to my RV family. :)
 
don't rely on the "sticky backs"

I have had bad luck with those 'sticky-backs' holding wire.. eventually they un-stick and leave a un-stickable area on the surface. Have used hundereds of them in my line of work.

Sheldon

Should have added, if you want to use the "sticky backs" and have them work long term, remove the sticky pad, scuff skin and plastic with sandpaper, wipe surfaces with denatured alchohol or similar, and use small dab of adhesive (E6000 or similar) to attach.

There were a few in other locations that I could get at easily that I didn't do that to initially, and yes I've had to go back and glue some of those in place eventually. But they've worked for me and others, and I've had A&P/IA use them similarly with success in the Cessna 140 I used to own (for 337 approved installation of replacement strobe). Clamps are better where you can use them, but for areas you don't want to rivet/bolt/screw a clamp through the skin, these are an option that worked for me.

I wouldn't expect to not inspect the wires during regular inspections and things are pretty visible for checking on things fairly often, so if anything came loose and got close to moving parts, that should be found before chaffing is an issue. The bundle near the canopy latch in my pictures isn't actually touching or close enough to vibrate near those moving parts - angle of shot may be misleading.
 
More paths

One path exists, similar to the one mentioned earlier by RV-6 Flyer but more hidden.

Shamelessly stolen from another builder.

You can come up the side panel under the forward seat pan and run over the top of the spar to the fuel selector area and then down the center tunnel.

side-1.jpg


All concealed when the seat pan is added -

side-2.jpg


This might be a little easier because I shimmed up the undersized outermost fore-aft seat supports an 1/8 inch to keep the seat pan flat.

----------------------------------------

The center spar slot already mentioned can take quite a bundle of wires, and can be secured easily out of the way of the controls. The hole used for the clamp is an existing one for the removable section of the seat support in the center area.

spar-2.jpg


The bundle needs to be well protected in the slot area. A good job for the expensive Mil-Spec edge protector with a good metal tooth for grip. You don't want the cheap ones falling off here when you install the wings....:mad:

spar-1.jpg


Only one edge is protected in this shot. Another will be added for the second slot edge.

I think it's this one "M22529/2-1R" - good for 0.25 to 0.034 thickness - from Spruce, but their new web pages suck. It will bend in the tight radius needed.

The bundle through the spar has -

Skyview AHRS cable (8)
Skyview Servo cable (6)
Skyview GPS leads (4)
Skyview UAT leads (4)
Elev. trim leads (3)
16 g flap motor leads (2)
PTT leads (4)
16 g wires for nav lts, strobe pwr and landing light (3)
Power to overhead light
AP disconnect
Comm Freq Swap
GPS leads to ELT (3)

You can fit a lot of wires through the standard hole.
 
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Gil I'm impressed with all the wires you got through that spar hole. I have about the same total so I think I'm going to be good on this one. :)
Are the lines you have going over the spar your pitot and static lines? :confused: Kind of like that route.
And thanks for the heads up on the edge protector. I found some on line but it didn't have the metal clips, just plane plastic. :eek: Going to look that one up. ;)
Thanks
 
Gil I'm impressed with all the wires you got through that spar hole. I have about the same total so I think I'm going to be good on this one. :)
Are the lines you have going over the spar your pitot and static lines? :confused: Kind of like that route.
And thanks for the heads up on the edge protector. I found some on line but it didn't have the metal clips, just plane plastic. :eek: Going to look that one up. ;)
Thanks

Yes... I was sort of surprised at the number of wires I got through. Some of mine were 20 g, if you go 22 g for all of the non-power stuff it will be easier.

The two "lines" over the spar are RG-400 and RG-58 co-ax cables for comm antennae. However, the pitot line will go in the same location on the pilots side. The static line is under the left cockpit rail.

The Mil-Spec edge protector is expensive, but just a foot or two should do it for critical locations. The regular plastic stuff that looks like a centipede works for the usual big holes in stuff.
 
I just had to run two new shielded autopilot servo wires via the same hole in the middle crammed with wires. This is on a flying RV-6. Boy was that a PITA especially with the controls in the way.
 
One path exists, similar to the one mentioned earlier by RV-6 Flyer but more hidden.

Shamelessly stolen from another builder.

You can come up the side panel under the forward seat pan and run over the top of the spar to the fuel selector area and then down the center tunnel.

side-1.jpg

I fixed a shorted wire at that exact location where the spiral wrap is, the floor pan had pushed the wire into the edge of the vertical reinforcement. When you set on the seat the autopilot stopped working, when you got up is worked ok.
 
Since it hasn't been mentioned....
It is acceptable to make a second hole in the right side spar stub, mirror image of the one on the left side originally intended for the manual pitch trim cable.
 
I have had bad luck with those 'sticky-backs' holding wire.. eventually they un-stick and leave a un-stickable area on the surface. Have used hundereds of them in my line of work.

Sheldon

Just remove the sticky pads and use Goop Automotive Trim Adhesive, available at any auto parts store. Just make sure to put your zip-tie in the pad before adding adhesive as it tends to fill in the holes.
 
I fixed a shorted wire at that exact location where the spiral wrap is, the floor pan had pushed the wire into the edge of the vertical reinforcement. When you set on the seat the autopilot stopped working, when you got up is worked ok.

Yes, I thought of that, hence the spiral wrap. Since they are co-ax cables there is a little more "meat" involved in the insulation.

If they were part of a wire bundle, I would have used a section of vinyl hose to protect the wires.

I also rounded off the sharp edges with a file.

Did you have the top edge of the outer F-615 bulkheads shimmed? That could make the "sit on the seat and short" problem a bit worse.
 
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With the second hole through the web, the coax cables can go through that and need not run along the spar. Much better protection. Also, by not opening the spar hole "extension" width to the hole diameter all the way to the center, a round section is left at the original hole location and a standard (slit) plastic insert can be used for edge protection. Much more stable and simpler.
 
With the second hole through the web, the coax cables can go through that and need not run along the spar. Much better protection. Also, by not opening the spar hole "extension" width to the hole diameter all the way to the center, a round section is left at the original hole location and a standard (slit) plastic insert can be used for edge protection. Much more stable and simpler.

The reason for the slit is so that the wiring can be done before the wings are installed.

In the case of the RV-6s the hole only approach is not "much simpler", but YMMV.
 
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The reason for the slit is so that the wiring can be done before the wings are installed.

In the case of the RV-6s the hole only approach is not "much simpler", but YMMV.

Maybe I wasn't clear in my post Gill... the second hole can be an exact mirror image of the first (in the wing and the bulkhead), with the slot cut to the hole in the right wing spar also. It will then work the same way for both holes... wings can be installed after the wiring.

Also, Jays comment is valid when just dealing with a couple or three coax cables. You still make the slit/slot, you just don't make it quite as wide as the full hole diameter. It will still be wide enough to slip the spar past the coax cables, but a snap bushing will snap in place on the aft and fwd sides, after the wing is installed (as long as you remember to put snap bushings on the wires as you route them through the bulkhead).
 
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Maybe I wasn't clear in my post Gill... the second hole can be an exact mirror image of the first (in the wing and the bulkhead), with the slot cut to the hole in the right wing spar also. It will then work the same way for both holes... wings can be installed after the wiring.

Also, Jays comment is valid when just dealing with a couple or three coax cables. You still make the slit/slot, you just don't make it quite as wide as the full hole diameter. It will still be wide enough to slip the spar past the coax cables, but a snap bushing will snap in place on the aft and fwd sides, after the wing is installed (as long as you remember to put snap bushings on the wires as you route them through the bulkhead).

Thanks for the clarification.

I certainly understood your previous comment on the mirror image slot. I was prepared to make one but managed to get my bundle through the single hole.

I also mis-typed when I said "slit" and not "slot"....:)

It was Jay's description of "standard (slit) plastic insert can be used for edge protection" that confused me.

The snap bushing you mention certainly makes sense.

But, if I was mirror imaging the hole and slot, I think I would make it the full size that is recommended. I see no real advantage to a smaller bushing hole in that location.

As a generic comment, I wish I had put larger bushings everywhere. The number of wires needed always seems to increase, never decrease...:)
 
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But, if I was mirror imaging the hole and slot, I think I would make it the full size that is recommended. I see no real advantage to a smaller bushing hole in that location.

Probably the only advantage is in being able to use a couple of .10 cent bushings instead of the expensive cat. track.
 
Keyhole slot

Now I understand what you guys are talking about. ;). I actually like the idea of running my coax that way as long as I remember to put the snap bushings on while wiring. :rolleyes: As far as the main bundle goes a full slot will be necessary if using all the available space in the existing hole which I think will be required in my case.
 
To expand upon Scott's comments (RVBuilder2002), I put a slit from front to back in the snap bushing using a hacksaw blade. It will still snap in that way. The advantage is that the snap bushing can then be put around the wires afterward and there is nothing to worry about in the original wiring. Try it once with a simple hole in a piece of sheet metal. The key is to have the snap bushing pull apart slightly along the cut. The opening will be enough for one or more of the wires to slip in. Then you can feed them in one at a time if necessary. Also, the spiral wrap typically used around wires can be fed through the snap bushing if there is space. Actually, with a hole of 1/2 inch or more, the snap bushing will open quite a bit
I can take some pictures if I can have an email. I haven't figured how to put pictures in the responses.

Also, it is good to have extra space to feed wires through. There will be one you add for something up front later or one you forgot. Things shouldn't be so tight that you need to fight it for a later addition.
 
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Slot in spar web details

Resurrecting this thread because some of the original pictures are no longer there.

Does anyone have details please of the permissible slotting of the inner ends of where the two main wing spars meet for a RV-6? I want to be able to run wiring and manual elevator trim cable through the spar and then under the seats/baggage floor prior to installing the wings. And also to be able to take the wings off without cutting any wiring.

Thanks,
Paul.
 
I ran most wires above the spar / below the armrests (both sides) along with the static tube. Belly antenna wires went through the center of the spar. I think you can go either way but do be careful about that spar bulkhead, you don't want to compromise it either by putting too big a hole(s) in it.

I wouldn't waste time worrying about wires with respect to taking the wings off at some future time. Once you get those seventy-odd bolts in, you will just hope you never have to take them off again. If you do, having to cut and splice a few wires will be minor compared to the rest of it.
EDIT: Well, except for antenna wires that is :)
 
Wires along sides

Thanks Randall for the tip about running the wires under the arm rest. How did you then get them to go under the seating area for connections to stick switches and autopilot roll servo (if fitted)? I believe that the whole of bulkhead F604 including the spar area and the side uprights is structural, so what size holes were permissible through the upright box channel sections?

Apart from being able to remove the wings for painting after running the wiring, I was also hoping to be able to prepare all of the wiring harnesses on the bench before installation.
 
All of my wiring (no AP) and static line run in conduits attached below the top longerons. Both sticks PTT and trim wires run inside the F-604 bulkheads.
Re size of the holes/conduits, not sure anymore, but the conduits are the black corrugated that was sold by Vans.
 
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Pictures that PaulvS requested

Paul,

Here are a couple of pictures that I have of the slot that I cut on either side of the center section of the main spar. They are 3/4" tall and I believe that they go about 1 1/2" horizontally into each spar. The pictures do not show the final product with the anti-chafing installed. One side had signal wires and the other had coax.

FP18012018A0001C.jpg

The last photo is the slot made in F-604A bulkhead.

Sorry I did not take pictures of the finished product.
 

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F604 Bulkhead Holes

Better check with Vans if you are considering slotting the actual F604 bulkhead. When I was doing mine, Vans told me it was ok to slot each side of the wing spar web which allows insert and removal of wings without moving wiring. They did not say it was ok to slot the actual F604 bulkhead. You can drill an identical hole in both sides. Check on slotting the bulkhead.
 
Thanks for the pics. I wouldn't need to slot the actual F604 bulkhead, only the internal end of the spar web so that some wiring runs can be done independently of wings on or off.
I also contacted Vans support to check and the advice is that another hole is allowed in the RH spar web, up to 3/4" dia, mirroring the existing hole for the manual elevator trim cable in the LH spar web. I did not get any factory blessing (or not) to slot the spar.
 
Thanks Randall for the tip about running the wires under the arm rest. How did you then get them to go under the seating area for connections to stick switches and autopilot roll servo (if fitted)? I believe that the whole of bulkhead F604 including the spar area and the side uprights is structural, so what size holes were permissible through the upright box channel sections?
To be honest all that is a little vague, having been done over 20 years ago :D And I can't speak with any authority on the structural part of it, just saying what I did. I may have consulted Vans' on it but I don't remember for sure. Seems worth doing anyway. In the meantime I can go today or tomorrow and re-familiarize myself and take some pics at any rate.

Apart from being able to remove the wings for painting after running the wiring, I was also hoping to be able to prepare all of the wiring harnesses on the bench before installation.
Yeah good point, though I didn't remove the wings for painting. In your case I would say just use connectors. Best to not add any more potential points of failure than you have to, but sometimes you have to. For single wires I like the knife disconnects - cover with heat shrink at final assembly and they're about as robust as you can get.
 
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I would recommend against slotting the F-604 bulkhead.

No offense, but it is frustrating every time I see someone post a justification statement to defend a modification they have made, by saying "I haven't had any problems in XX years or hours".

Lets say just for the sake of conversation, that someone does a mod. that unknowingly reduces the limit load strength of the wing spar from 6 G's to 5.5 G's.
Now lets say they fly their airplane for many years (even doing aerobatics) but never exceed 5 G's.
Does all of that time prove that there is no negative effect caused by the modification?
No, because the modification has never been fully tested, and if the airplane was ever exposed to 6 G's, structural damage would occur.

My point isn't to say that a slot installed as depicted in the previous photo will cause a negative reduction in strength.... it is to say that until fully tested, there is know way to know for sure.
 
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