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Wing harness and manufacturer recommendations

Rteem

Member
Lurker here, but hoping to be more active on the forums.

I've been reading other posts and manufacturer information that leads me to believe it's superior to use shielded and grounded lighting wires.

It seems that the Vans harness contradicts Aeroled's recommended practice to reduce noise by specifically using shielded wires and using the shield as return ground:
http://aeroleds.com/how-to-minimize-strobe-noise-2/

Garmin agrees with this practice and states in section 8.4.1:
"A dedicated power ground should be used and returned as a twisted pair [for the lighting] with the power source back into the fuselage"

Furthermore, for what it's worth Garmin recommends that all conductors near the magnetometer be twisted and shielded (section 8-4):
http://www.aeroelectric.com/Installation_Data/Garmin/G3X_IM.pdf

I'm sure the other manufacturers recommend the same, and am curious about other builders thoughts - why is the Vans harness (Stein air I think makes them) still using outdated wiring? Is there some drawback to using twisted and shielded pairs beyond the small amount of extra weight and resistance?
 
Lurker here, but hoping to be more active on the forums.

I've been reading other posts and manufacturer information that leads me to believe it's superior to use shielded and grounded lighting wires.

It seems that the Vans harness contradicts Aeroled's recommended practice to reduce noise by specifically using shielded wires and using the shield as return ground:
http://aeroleds.com/how-to-minimize-strobe-noise-2/

Garmin agrees with this practice and states in section 8.4.1:
"A dedicated power ground should be used and returned as a twisted pair [for the lighting] with the power source back into the fuselage"
Furthermore, for what it's worth Garmin recommends that all conductors near the magnetometer be twisted and shielded (section 8-4):
http://www.aeroelectric.com/Installation_Data/Garmin/G3X_IM.pdf

I'm sure the other manufacturers recommend the same, and am curious about other builders thoughts - why is the Vans harness (Stein air I think makes them) still using outdated wiring? Is there some drawback to using twisted and shielded pairs beyond the small amount of extra weight and resistance?

Look at my previous posts on this subject. The best thing to do, in my opinion, is to not use any of the Van's RV-14 wire harnesses. I wasted a couple of weeks helping a friend "fix stuff" on his RV-14A that used all the Van's harnesses.

Wire is about the easiest thing to do in an RV - why go with someone else's idea?

Carl
 
Tom,

Canopy and panel are done, so I'm trying to get this wiring figured out - I still owe you a picture of the beautiful brake lines you did :)

Will let you know before the engine is going on!
 
Look at my previous posts on this subject. The best thing to do, in my opinion, is to not use any of the Van's RV-14 wire harnesses. I wasted a couple of weeks helping a friend "fix stuff" on his RV-14A that used all the Van's harnesses.

Wire is about the easiest thing to do in an RV - why go with someone else's idea?

Carl

Would you possibly elaborate on this Carl? Is it the quality of the harnesses that you found insufficient, or the type of harness used? Do you, as per the OP's original enquiry, feel the supplied wire is also not suited?

I'm just about to get going on the wings on my 14, so I've been thinking a lot about wiring recently.
 
I am about to put the bottom skins on my second wing. What do you recommend in place of the stuff Van's gives?
 
Would you possibly elaborate on this Carl? Is it the quality of the harnesses that you found insufficient, or the type of harness used?

I've read many of Carl's posts regarding the wire harness and while he has made some interesting points, I believe, for most builders the supplied harnesses are more than acceptable and in fact the best choice. Consider this a friendly rebuttal to Carl's well thought out posts.

First, all of my supplied harnesses from Van's were built by Stein. I believe that is still the case. Stein does first rate work and I have never had a material or major quality issue with any of their harnesses.

Second, Carl has mentioned the fuselage to aft fuselage joint as being unneeded. While a connector free run is always better, the practicality of the connector is beyond question a good thing. You can build the tail cone and have it wired up without having to worry about running wires after the fact.

Third, some people object to the larger molex connectors that are used to join the harness sections together. These connectors are more than adequate for the job they have. Builders should understand that these connectors have a limited number of on off cycles - so don't be connecting and removing them willy nilly, only connect them at the appropriate time and leave them alone.

I object to some uses of the mini molex connectors and replaced the ones in the sticks and the one to the flap motor. These connectors can be troublesome for field installation of small wires. I replaced the stick connectors because I was not able to isolate the joint from motion and in my experience they will separate or pins will come loose unless they are secured from any cable strain or joint flexing.

I replaced the flap motor mini connector for reasons unrelated to the mini connector.

Fourth, the materials used in the harnesses are aircraft grade Tefzel wires and I found all the wire size choices to be acceptable. I've already mentioned that I believe the connectors are entirely suitable.

Fifth, although touched on earlier in this post, the ability to have the wiring done while building the sections is not to be underestimated. If you are a new builder and starting on the wings, you will have to start worrying about how to wire the plane right at the start. That is not a trivial task, as you will have to make many decisions about what size wire and how many you will need.

With the 14, at most, if you know you are going to have something not provided for in the basic wiring, you will only have to add it to the supplied bundle. I don't know how the wing wiring has changed, but I added two wires for pitot heat at build time. I was surprised to find that they are in the fuselage wiring so maybe they are now in the wing wiring.

Van's has also made a change to suggest running wing grounds all the way to the fuselage for magnetometer issues. I had added a wire to the wing bundles for this purpose so I was able to make that change easily.

Sixth, the wiring is already very complete for a very robust list of gadgets. It supports three servos, including a yaw servo, all typical lighting options, wing mounted ADAHRS or Magnetometer, OAT, old style stall warning, both pitch and roll trim, flaps, headphones - including the fancy new plug for powered headphones, all typical stick functions, aux power jack and audio input and at least partially - pitot heat.

Now, some have nits with some of the basic choices, for example the aux power jack being just the old cigarette lighter type, but these are trivial to fix later in the build when you are knee deep in wiring up the panel. These are no reasons to toss a perfectly good set of wires.

I have now built two airplanes. I did all the wiring on the first one and enjoyed it immensely, but it was a lot of work even though I was basically following a Bob Nuckells Z drawing. I had to route it all, decide on wire sizing, buy all the wires, run out and buy more wire and then end up with way too much of a wrong size - and that was for an airplane without AP servos, electric trim or electric flaps.

I found all that work done for me by Van's to a very acceptable level. There are several things I might have changed or done differently had I designed the wire bundles myself but I was more than satisfied that, on the whole, Van's had done a credible job.

I also had Stein build me a harness that interfaced with the fuselage wiring and the Garmin units, but I had them just leave long unterminated leads for all the power and switches that I then routed to my own panel layout and power distribution system. Their work matched the quality level of all the other wiring and was almost fault free.

For my last point, I have now flown my airplane with Van's standard wiring and have had no issues with any of the wiring. No noise in the headphones or radio transmissions, or interference with the magnetometer. All the Garmin tests on the ground passed easily and no issues have presented themselves in the air.

I am still early in my flight testing so I report any issues that may come up further along. So far however it's a totally wonderful airplane, including the electrical system.

I'm very satisfied with my aircrafts wiring from Van's and do not recommend tossing out the valuable wiring supplied with the kit.
 
Wire is about the easiest thing to do in an RV - why go with someone else's idea?

Carl

Maybe for some people, but a large majority it is the most intimidating part of the whole build process

I've read many of Carl's posts regarding the wire harness and while he has made some interesting points, I believe, for most builders the supplied harnesses are more than acceptable and in fact the best choice.

I agree.... for the reason posted above.....
 
Maybe for some people, but a large majority it is the most intimidating part of the whole build process...

If you can build an airplane, you can wire it as well. If you wire it you might build the neccessary skill set to maintain and modify it along the way. Same goes for building your own panel.

It seems I'm outnumbered on this so I'll back out.

Carl
 
This is great feedback and discourse. Thanks everyone.

Bob makes an undisputable and compelling argument:
For my last point, I have now flown my airplane with Van's standard wiring and have had no issues with any of the wiring.

However, I can't just go against all manufacturer recommendations I can find and sleep at night, so Carl most closely aligns with my personal plans. Based on posts, quite a few people are getting warnings or outright failures of the GMU when mounted in the wing with stock wiring harnesses. I would rather be proactive.

Running the ground wire through the wing as pointed out by Bob was an afterthough by Stein / Vans, and I'm still really confused why they would run shielded for the nav/strobe to the tail but NOT when going past their recommended location for the magnetometer. It's such a trivial change.

Additionally, it appears that a heated pitot (which I am installing) has the potential to cause conflict when placed in the left wing.

As a result, for anyone curious, I plan to use the stock Vans harness in the tailcone on the left side only. I'll place the OAT in the left wing, with all high-power active equipment (pitot, ap servo, trim) in the right wing away from the magnetometer. Wing lighting will be shielded (at least on the L side), and unfortunately fuselage wiring will have to be custom because I've now departed too far from the Vans plans.
 
I can agree with Carl too that I think many people who build the plane can also wire it just fine. Not 100% of them, but a large portion. People just chicken out. There's a lot to be learned and gained from obtaining that skill that will help with future upgrades. And if you do use the factory harness, fine, but you will still need to get a nearly full understanding of what everything does, because you're going to find things that require modification along the way for your needs. Considering that you really need to understand what all of these signals are that run up and down the wires, it's not THAT much additional work to just lay it all out and pull the wires. I guess I'd say that if you're going to go with a stock panel where everything is done 100% per plans, you should probably get the stock harness, and then be prepared to make some minor mods along the way. If you're going to deviate on the panel a lot, you may as well scrap the factory harness idea and just build your own. You'll spend more time analyzing the harness and determining what you should do to modify it than if you simply chose your wires and laid them out. And if you build it yourself you can buy the wire fairly inexpensively and have plenty on hand for changes along the way.
It was my most fun part of the build. Plus I got to run the ground wires wherever I wanted them and don't have any noise in anything to speak of, so there was that bonus.
 
I note that it seems to be a given that a magnetometer be fitted when a Garmin system is being installed but seems like an optional extra with the Dynon system.
I can't get a definitive answer reading through the Dynon system requirements. Dynon has the ADHRS box which I'm assuming does all the remote sensing required.
The question is should I accommodate for a magnetometer with the Dynon system and if this is the case run an independent earth lead through the wing back to the fuselage. Thanks.
 
because you're going to find things that require modification along the way for your needs.

I fully understand this is the case for you Tim because you have specific ideas of what you want and you are fully capable of implementing them.

Being able to look at this from a different angle because of all of the tech assistance help time we spend helping people through electrical problems, I can tell you with certainty this is not the case with a large percentage of builders (or all of the effort to design and produce it would not have been invested because of little return). The RV-12 has proven this. A large percentage of the RV-12 builders have said that it is a primary reason they chose it as a kit to build.
 
I note that it seems to be a given that a magnetometer be fitted when a Garmin system is being installed but seems like an optional extra with the Dynon system.
I can't get a definitive answer reading through the Dynon system requirements. Dynon has the ADHRS box which I'm assuming does all the remote sensing required.
The question is should I accommodate for a magnetometer with the Dynon system and if this is the case run an independent earth lead through the wing back to the fuselage. Thanks.

The ADAHRS for Skyview has the magnetometer inside it.
 
I note that it seems to be a given that a magnetometer be fitted when a Garmin system is being installed but seems like an optional extra with the Dynon system.
I can't get a definitive answer reading through the Dynon system requirements. Dynon has the ADHRS box which I'm assuming does all the remote sensing required.
The question is should I accommodate for a magnetometer with the Dynon system and if this is the case run an independent earth lead through the wing back to the fuselage. Thanks.

No. What you do need to do is get the Dynon ADHARS backing plate that lets you stack one module on top of the other. That way the single mount you get for the left wing with the RV-14 kit works for the dual ADHARS install you want to do with the Dynon SkyView.

Then of course throw away the Van's wiring as it is useless for his application.

Carl
 
unfortunately fuselage wiring will have to be custom because I've now departed too far from the Vans plans.

From what you list, I'm not so sure. The AP servo and roll trim are already in the right wing so no interference there. If the left wing strobe wiring bothers you, just add the twisted/shielded wiring you prefer to the left bundle.

As to the heated pitot, just twist up some 14 gauge wire - about 6 or 8 twists per foot and add it to the left wing wiring also. Everything will merge with the fuselage harness fine.

I'm not opposed to rolling your own wiring, I just think a blanket statement that you are better off without the kit wiring is too strong for most builders. I enjoy the challenge of designing and installing wiring, that's why I didn't just have Stein build the panel complete for me. Even though I like wiring I also liked the idea of having all the wiring harnesses in the structure done for me.

I've met many builders who think that is nuts and don't even want to understand how all the wiring works. While that's not the way I think about wiring, don't get me started on my thoughts about fiberglass.
 
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