Tip: Done with Disconnects!

I have always been a big fan of wing root disconnects for electrical lines because, well?..I like being able to disconnect everything if I am going to disconnect something. I have never really encouraged anyone else to put disconnects at the wing root, staying out of the advice game ? but it just seems cool that if you are going to pull a wing, you can disconnect the wires right there with a dedicated D-Sub, Amp, or Canon Plug. Many have just said ?put an extra service loop of wire in there, and if you have to pull a wing, cut it and splice the wires back together later.? Well,?.that just seems so messy ? and if the disconnect doesn?t do any harm, well, why not trick it out?

Well, I am done with that. I hung the wings on the RV-8 ten years ago ? they have never had to come off. The RV-3 wings went on in 2011 ? same thing. Mikey, the RV-6?.I think the last person to see it with the wings off was Mike Seager when he built it, and that was over 25 years ago. The wings just don?t have to come off on these things. And on the side of ?disconnects don?t do any harm?, we spent the better part of a day tracing a flaky OAT signal on the RV-3 last week ? and much of that was trying to work on the disconnect through the wing root fairing. Sure enough, there was the problem, a pin/socket that had built up a little schmutz (or something). There is no room on an RV-3 to get your hand in there without pulling a wing ? and we sure weren?t going to do that! Louise finally got her smaller hands in that way, and I went under the seat pan (which is riveted in, so it was actually back under the inspection covers and then under the pan) to get it working. If I?d just had a loop of wire ? there wouldn?t have been a problem in the first place.

So yup ? I am done with wing root disconnects. Well, except for the motorglider, we might want those wings to come off. And then the Tundra we?re working on?.not sure how our partner did those when he hung the wings?.but from now on, for me it?s just a loop of wire, no extra connections to fail, and if the wings come off, out come the cutters and the splices when they go back on.

Sort of like nutplates and the rear floors on the RV-8 ? its? quicker to drill out the pop rivets if it ever needs to come out than to unscrew all the screws and mount all those nutplates?..
Paul

Sometimes it just takes time and experiences. Part of the issue in a public forum is how people ask the question. "what should I use...." Then good hearted folk do their best to answer that question and next thing you know, you have a mil spec $100 cannon plug buried in there.
If you try to say "don't do it" you can be viewed as not answering the question and not helping, or worse, being critical of others decisions.
Your experience is invaluable and can not be argued. It also follows my own philosophy, and in a public forum, makes it easy for me to pile on
Another common public forum thing, we like people and ideas that are like minded....

The last 2 planes I wired up, did the same thing. I simply left enough slack in the wires in the wing root areas that if the wings ever have to come off, the wires can simply be cut and add on connectors to reconnect them when it's time to bolt the wings back on.

Well, considering that I did the wiring in the wings way before they were mounted on the fuse, and ditto the fuse wiring before mounting the wings, I had to use a connector of some kind. I never even considered running the wing wires after mounting the wings.

I used knife splices------also heard them called "gladhands: and put shrink wrap over the splice and onto the wire insulation too. Should be water tight, and so far has not been a problem.

One thing in my favor, the 10 has a nice large gap at the wing root if I even need to work on them.

http://www.vansairforce.com/community/showpost.php?p=927843&postcount=5

And for the other side of the coin, I would never build a plane without them.
1. Ive removed my wings several times over the years.
2. Makes back-probing of wiring easier for troubleshooting
3. Makes assembly at the hanger faster. I was flight ready 48 hours from arrival at the airport with parts. I could not have done that if everything wasn't ready, tested, and in order. That includes quick connections of everything, pretested at home.
4. Makes the addition of wires over time easier.

Just another mans opinion.

Welcome to the other side Paul, and thanks much for the post. I've had that conversation so many times...

Clearly Mike is a "unique" case .

scard said:

Clearly Mike is a "unique" case .

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Not at all. I built my plane at home and had to trailer it to the airport. No way I could have done that with the wings on and wired up and there was no way I was going to run the wires at the airport. I used Molex connectors for all my connections in the wing root. A little dielectric on all the pins and a quick zip tie to ensure the connectors will not come apart accidentally. So far so good.

A my day job (airliners) wing/component disconnects are part of the big plane design, and usually the culprit of wiring/electrical problems..hate them. My RV is hard wired with a service loop in the event I need to chop them. A splice takes about a minute to make if I ever need. Mike has a point about troubleshooting, but I don't have anything that complicated on my -4 so I just used splices with a heatshrink seal over it.

9GT said:

Not at all. I built my plane at home and had to trailer it to the airport. No way I could have done that with the wings on and wired up and there was no way I was going to run the wires at the airport. I used Molex connectors for all my connections in the wing root. A little dielectric on all the pins and a quick zip tie to ensure the connectors will not come apart accidentally. So far so good.

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Ok. Yep, the majority of us trailer it to the airport and run the necessary wires out to the wing tips in a couple of hours. No biggie. I'm on my second airplane (never touched the one that is at 1500hrs), Paul is on his third, Mike is on his xxxx due to his OP. It is a good conversation for those trying to figure out what to do for the first time.

I've ever only built one airplane but I couldn't see the benefit of disconnects for the wings. There just aren't that many wires. All of my wires have little service loops on the ends in case I ever need to cut off the connectors and pull the wiring back into the fuselage for wing removal.

scard said:

I'm on my second airplane (never touched the one that is at 1500hrs), Paul is on his third, Mike is on his xxxx due to his OP. It is a good conversation for those trying to figure out what to do for the first time.

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It's not my first rodeo either cowboy. To each his own. You say that the majority do it your way. Where did you come up with that?

Pretty close

We are pretty close on this one. I'm going with Kahuna. I used a high quality Military cannon plug at the root. For me it made the initial wiring easier and I could 'ring out' each section and make it easier to hook up.

I put the wings on to set up the lead/lag and incidence, rig the controls, hook up the fuel system, rig the flaps and do the fairings. After that, I took them off again for FWF work. They went back on when all that was done. Later, they were pulled for painting. The connectors make things much easier and they have worked flawlessly.

For those that have said, "I can add connectors later," it is much easier on the front end!!!

Fun thread!!

Adding a connector or terminal block means 3 or 4, respectively, additional points of failure for each wire. For me, the possible convenience in the rare case of needing to remove a wing was outweighed by reliability desires.

I had the wires hanging out the sides of the fuse when I hauled the fuse to the airport. It maybe took a couple hours to run the wires at the airport. Probably would have taken more time to wire at home, but with connectors.

For those not sure, do one wing with connectors and the other without. Check back in 20 years.

scard said:

Welcome to the other side Paul, and thanks much for the post. I've had that conversation so many times...

Clearly Mike is a "unique" case .

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Then there is more than one, because I agree with his logic.

Building an airplane is a huge undertaking.
When it gets near the end, people usually are getting anxious to finally fly their creation.
In that context, most people with the life experience of having completed at least one airplane, will usually agree that completing as much work in your shop at home as possible, before moving the airplane to the airport is a smart thing to do for a lot of reasons that I wont bother repeating.

Being able to just join a (previously function tested) connector while attaching each wing to the fuselage can be a big time saver. No need to get re familiar with electrical circuits that may have been installed years ago and long forgotten.

I have done this on all airplanes that I have been involved with (at least a dozen builds... lost count of an exact number), and I will continue to in the future.

The new RV-14 kit has this concept integrated into the design. While the builder is constructing the wings and aft fuselage, they install wiring harnesses that terminate at specifically designed brackets to hold the connectors. When these assemblies eventually join the fwd fuselage, a couple of molex plugs will be inserted for each assembly, and the wiring is finished.

Now don't get me wrong folks - I still like to fully wire and test the wings before they go on - and I'll continue to do so. I'll just leave a few feet of extra wire at the wing root and make simple connections once they get into the fuselage.

Quite a few ways to skin this cat - I've done both.

And I maintain that I don't give folks advice - just relating my experience......

I was glad to see you post this thread, Paul. I have a bundle of wires loosely tied in a loop on each side of my fuselage, and I plan on just pulling them through the wings when I install them for good at the airport. No connectors to wire up, no trying to decide which model or type of connector to use, no additional money spent, and less possible failure points. I can still test each item at home, using the ends of the wires, so I know everything works. I can't imagine my wings will ever come off, but if they do, I don't see it as a big deal to pull the small number of wires back into the fuse and pull the wings.

Thank you! I feel much better about my decision.

All in for continuous wing wires

Yep, I have a coil of wire hanging for the wing. I considered the Detusch DT connectors that I have personal knowledge of at (former) work and they have excellent reliability in high vibration, wet and dirty environments. But . . . I think I can remove pins and snake the wires back through the wing faster than the time used installing the connectors. Also different amperage requirements mean different pins. Just too much trouble and even if there were no failures -too much trouble, not to mention cost.

Yep, I am "all in" for continuous wires.

Funny, I had a plan to use these connectors for many connections, but each time made this same evaluation and walked away. Don't even consider an open connector style of any make.

An unbroken wire is certainly the most reliable but not always the most convenient.
These may not be as "elegant" as the more expensive connectors but for ease of use, reliability, current carrying ability, troubleshooting, etc. it's hard to beat these simple terminal blocks for about 5 bucks.
Inside the fuselage in not what I would consider a harsh enviironment, but if it makes you feel better you can spray them with LPS every now and then to prevent oxidation.

I'd question the "reliability" aspect of the terminal blocks shown. They are quite often the source of electrical gremlins due to bad crimps or dirty connections. And each of them weighs a whole lot more than a service loop of wire. They certainly have their place, but I'm not a fan of routine use.

fixnflyguy said:

A my day job (airliners) wing/component disconnects are part of the big plane design, and usually the culprit of wiring/electrical problems..hate them.

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My day job involves a lot of troubleshooting in cars and trucks...same deal.

Had one just the other day, a lighting problem on an International 4300 box truck. It was the multi-pin connector on the firewall.

Toobuilder said:

I'd question the "reliability" aspect of the terminal blocks shown. They are quite often the source of electrical gremlins due to bad crimps or dirty connections. And each of them weighs a whole lot more than a service loop of wire. They certainly have their place, but I'm not a fan of routine use.

Click to expand...

The blocks themselves with screw connections are just about bullet proof, but obviously, if you can't make a good crimp then you're screwed no matter what you do (hard to build an airplane without terminating wires). Dirty connections, well dirt cannot get into a connection unless its loose. Extra weight.. thats a stretch, extra wire has weight too.

I'll aslo add that these are fine for "high current" wires like lights, heated probes etc. but I would not recommend them for "signal" wires like RS232 and such, for those connections a solid length of wire is absolutely superior to any connector, but if I have to make an RS232 signal wire splice I prefer a solder connection (smart AP servos come to mind).

Connections

One can wire their bird point-to-point but that means running the wiring once the wings are on. This eliminates the need for a connector at the wing root. This approach is the most reliable. However there is great value in having a connector or terminal block in the wiring for the wings. As some have mentioned it allows for debugging of the connections at times. But this less reliable then the point-to-point approach.

I think the confusion in some of the posts is not that a connector shouldn?t be used but where to put it. If the connector is mounted to the side of the fuselage at the wing root it could be subjected to rain if the root seal leaked. This wouldn?t be good for a connector (corrosion).

A free hanging connection that is not hard mounted to the fuselage side and had a generous service loop it a great option. If you need to debug the wiring you can disconnect it and the service loop allows better access to the connector while debugging the system. This approach can also be used with a terminal block (mounted to a seat floor rib). Yes, this may means that the wing wiring isn?t fully completed until final assembly but it only took me about 1-2 hours to terminate the connections.

The only time I ever expect to take the wings off is if I have accident with the plane. If that were to occur I would have much more to worry about then cutting the connectors off.

I used terminal blocks under the seat pans to connect my wing wiring.

No problems after over 21 years of flying. Like Walt said, if you can't make good crimps, you're in trouble no matter what method you use.

Bottom line, do it as you prefer. It's not a deal breaker however you want to do it.

Failure points

I knew it would only a take a few posts for someone to mention the "failure point," argument. On my first 7 I had connectors at the tip,at the fuselage and all wiring from the wings and tail was strung to a Terminal strip. All those failure points built in and in nearly 1000 hours, no failures. I wired the new one in a very similar manner.

I guess the thing is you have to do what makes you feel good. I don't think there is right or wrong. Both planes were build with serviceability in mind.

Here's a photo of the connector used at the fuselage and the tip.
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