T

TShort

Well Known Member
I've looked thru all the posts here and reviewed the Matronics lists and the Van's .pdf file on conduit location ... still have a question:

It seems to me that it might be better to put the conduit near the top of the rib - that way, I could pull it thru after riveting the top skin and before putting on the bottoms. It seems like putting it on the bottom would cause trouble with bucking the lower wing skins since it would have to be pulled thru before they're bucked.

Am I missing something? Is there an interference issue at the wing root or would it be bad to have the conduit coming out higher?

Thanks
Thomas
 
Conduit

TShort said:
I've looked thru all the posts here and reviewed the Matronics lists and the Van's .pdf file on conduit location ... still have a question:

It seems to me that it might be better to put the conduit near the top of the rib - that way, I could pull it thru after riveting the top skin and before putting on the bottoms. It seems like putting it on the bottom would cause trouble with bucking the lower wing skins since it would have to be pulled thru before they're bucked.

Am I missing something? Is there an interference issue at the wing root or would it be bad to have the conduit coming out higher?

Thanks
Thomas
Click to expand...

You have the general idea. If you attach the top skins first, then put the conduit at the top of the ribs. Same-same if you choose to attach the bottom skins first.
 
it's really not an issue.. you just need the right bucking bar..

my suggestion -- follow Van's recommendation.
 
I ran the conduit before attaching any of the skins and used a little pro seal to boot. It's really not a problem....I just used a bucking bar with a little lip on it.
 
I'm piggy backing on this question instead of starting another thread.

I bought the black conduit from Van's and downloaded the Wing Wiring FAQ from their website. They tell you to drill a 3/4" hole to run the conduit. It will fit, but it takes a lot of effort to get it through. I am worried that I may end up warping the ribs with all that pulling. I'm curious as to what others have done with the Van's conduit. Is a 13/16" hole too large?
 
I went with a larger, 7/8" hole and am using a class 1 wiring method called Electrical Non Metallic Conduit (ENT) which can be found in the Aviation Department at Home Depot or Lowes.

As a professional electrician I recognize the flame retardency and high thermal properties of this material as well as the non deliterious nature of this product to be superior to the Vans conduit. It also has rounded interior "ribs" if you will. This facilitates easier installation of conductors, as it is made as a wireway!

Buuuuuut, it IS BIGGER! Soooooo, I called Van. The answer was the usual. Well, we never tested it... you know the rest. Come to find out, they never tested the 3/4" hole either! They know it works because thousands of RV's haven't crashed! They expect that another 1/8" added to that hole shouldn't be a factor. If it makes you feel any more comfortable, the wings haven't collapsed in my jig yet!

;)

Hope this helps!

:D CJ
 
"You can do it"

I did follow Van?s instructions to the letter (on this issue) and didn?t have a problem. It does take some work to pull the conduit through the holes and it makes an awful noise but there is enough play in the conduit that it will not warp the ribs. Once the conduit was in place I prosealed, as recommended.

To get the holes lined up, I made a small rectangular template with a #40 hole in it. I then placed the template on the rib with one corner of the template just touching the big lightening hole and the edge resting on the bottom of the rib, I then used a punch in the #40 hole to mark the center of where the conduit hole should go for ?Right? ribs and flipped it over for ?Left? ribs. If this isn?t clear, let me know and I?ll post a picture of my template.

One other thing to consider, if you are going to use Dynon?s AOA pitot tube you will want to drill a 2nd set of holes next to the pitot tube holes for the AOA line before you assemble the left wing. You can do this after the top skin is on (I did) but it is a PITA! There is a picture of the two lines running down the wing on the wing page of my web site. Also, don't drill the hole for the Van's pitot tube if you are going to use something else, like the Dynon pitot.
 
Wing Conduit

I pretty much used Dan Checkoway's idea and put the holes for the conduit in the top forward corner of the main ribs. See his site :
http://www.rvproject.com/20020522.html

I drilled all the holes 13/16" except for the ribs on each end of the wing. I drilled these holes 3/4". That way you can get the conduit through the inner ribs fairly easy and the ribs on the end will hold it snug. It's a little tough to get it into the 3/4" holes, but once it's there it's not going anywhere. I plan to put a dab of tank sealant at each of the inner ribs to keep the conduit from moving any in the 13/16" holes.
 
I didn't do this, but I heard if you heat up the black flex conduit in the oven a bit, it becomes much more pliable and thus easier to thread through the wing rib holes. I used 3/4" and just muscled it through.

Dave
 
Why not use the litening holes/

I don't get it.

Pardon my ignorance, but why not put the conduit through the great big hole already provided? Seems like a lot of work to drill new ones.

Someone please set me straight on this.

Duane Wilson
RV9 QB. ready to start wings
 
dwilson said:
I don't get it.

Pardon my ignorance, but why not put the conduit through the great big hole already provided? Seems like a lot of work to drill new ones.

Someone please set me straight on this.

Duane Wilson
RV9 QB. ready to start wings
Click to expand...

Hi Duane--

At least two reasons:
1. The aileron push tubes go through at least one of the big holes and you'd have to keep the conduit away from it.
2. You'd still have to find someway to tie the conduit to the rib so that it did n't float around and eventually chafe through the conduit. You can buy clips to do this, but I haven't seen the necessity yet.

I did exactly what Bill Repucci did above and am finding no problems. My thoughts are to definitely go through the lower portion of the rib because it should provide greater clearance for the aileron bellcrank/small pushrod that attaches to aileron. Ditto on drilling a second hole for AOA if possibly going with a Dynon at any time in the future.

Good luck.

Steve
 
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I did most of the wing riveting myself. There's no way I could have done it had I put the bottom skins on first.

Otherwise, you don't have the access holes to reach into in order to buck the rivets. You'd need a partner.
 
Top skin first,then the bottom...

Bob Collins said:
I did most of the wing riveting myself. There's no way I could have done it had I put the bottom skins on first.

Otherwise, you don't have the access holes to reach into in order to buck the rivets. You'd need a partner.
Click to expand...

Bob,

I'm not sure which RV you built, I suspect a -4 or -6, but the -7's & -9's (I don't know about the -8's but I thnik they are the same.) wing's are supposed to have the top skin riveted on first, then the bottom skins. It is my understanding this is the reverse of how the -4's and -6's are done.

There is plenty of room to get to the rivets via the lightening holes and inspection holes. Of course, you will need help but isn't that what your wife and EAA chapter friends are for? Of course, it might cost you some pizza and beer, when you are finished of course.

If I'm wrong on which RV you built, I would like to see how you did the bottom skin first, I just can't picture it.
 
Picture Please...

N941WR said:
...To get the holes lined up, I made a small rectangular template with a #40 hole in it. I then placed the template on the rib with one corner of the template just touching the big lightening hole and the edge resting on the bottom of the rib, I then used a punch in the #40 hole to mark the center of where the conduit hole should go for ?Right? ribs and flipped it over for ?Left? ribs. If this isn?t clear, let me know and I?ll post a picture of my template.
Click to expand...
Yes please post a pic of template.

Thanx
 
Will do...

greylingr said:
Yes please post a pic of template.

Thanx
Click to expand...

It might be late tonight as I'm going for my biannual flight review in a Decathlon after work. I can?t wait, that should be a blast!
 
I am ordering the Duckworks landing light from Van's. What is the best way to get the wires to it? Can you just install a T off the wingtip conduit run conduit?
 
Bill, great question. I didn't think about it until you mentioned it!

You can pop out of the side of the conduit and run it fore, but that could hamper getting additional wires in later.

I am thinking of doing the Duckworks, but running the wire out to the tips and back inboard.

Reason: Not much more wire and no center tap in the conduit.

YMMV

:) CJ
 
No need for a "T"

bmurrish said:
I am ordering the Duckworks landing light from Van's. What is the best way to get the wires to it? Can you just install a T off the wingtip conduit run conduit?
Click to expand...

Run the wires out the end and loop them around to the light through the wing tip. This is also a good place for a "quick connect" so you can remove the light.

Otherwise you will need to cut a hole through the spar and I don't think you want to do that. Besides, the lights are in the last bay so the loop works well.
 
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I noticed nobody seems to use the method in the ornoff tapes which I have been following (i.e I drilled the 5/8 holes where suggested below the rib lightening holes). As I will probably be installing the pvc tube and riveting the bottom skin of my left wing this weekend I am interested in why and whether I should change approach. I have the Duckworth landing light installed and plan to add a wing mounted aileron servo later so my plan was the wing tip loop for the lights and a T in the aileron bracket bay for the servo
 
You will be installing the Duck Works light in the last bay of the wing, so take your wires all the way through the conduit into the wingtip and than just run it back into the bay from there.
If you use a T on the conduit, you won't be able to easily repull any wires in case you ever need to. Additionally, you will have access to everything in the wingtip.
 
conduit question

How do most people get the wires to the aileron servo that is normally mounted in the bellcrank bay??
 
Wiring to AP Servo

Here's how I'm going to do it. I used epoxy to hold the tee in place. Got the idea from my tech counselor Richard DeWitt.
teeforapharness3sb.jpg
 
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conduit

Looks good to me, I am using 5/8 O.D pvc tube a la the ornoff tapes and had planned a T in the same place. Pretty easy to reach through the access holes also.
 
Now easier not to use a conduit?

There are several builder I have talked to who have just used grommets. With the additional inspection holes on the -7 (& -8?) it is now much easier to pull wires down the wing and to breakout to servos, heated pitot tubes, mag flux sensors etc. Using 2 or 3 sets of grommets means you don't have to bundle the wingtip antenna coax with the strobe power supply wires etc. Any comments from anyone who has used that method?

Pete
 
No Conduit

Yeah, Penquin,

I was toying with posting a sarcastic post about page two this a.m., and you beat me to my intended suggestion:

Skip the conduit. It isn't necessary and complicates matters. Three pages of posts! Don't make a mountain out of a mole hill and save your wiring neurons for the panel and FWF.

Instead, install snap bushings. Reach through the access holes to pull wire bundles (probably easier than pushing or fishing wires through a conduit), and break-outs are a no-brainer. Lace the bundles before installation, or use those hideous, blood-draining nylon ties, a few places between the most widely spaced ribs if you're so inclined. The wires aren't going to touch anything they shouldn't if you use the tooling hole, except, perhaps having to Adel clamp them away from the aileron bellcrank. Drill other holes for different sized bushings for pitot line, coax, whatever. Worked great on my -7.

John Siebold
Boise, ID
 
Lacing in conduit

Should I lace the wire bundle that goes inside the conduit before pulling them through? Does lacing/not lacing make a difference in getting wires pulled through in the furure should the need arise? Should I run one two extra wires while pulling them through the first time? If so, what gauge?
Thanks.
Johan
 
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