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RV-3 ? Avionics Wiring has begun!

Ironflight

Ironflight

VAF Moderator / Line Boy
Mentor
No one can build an entire avionics harness for an airplane ? it just can?t be done! Of course, no one can build an airplane either - it is an absurd proposition that anyone could build something so complex! But you CAN build a lot of airplane parts, and then assemble them into an airplane?.and in the same fashion, you can build wiring harness components for a number of different boxes, eventually joining them together to find yourself with a working panel!

Such are the thoughts one has as they haul out the tools, wires and connector kits to begin building the central nervous system of an EFIS-equipped, IFR machine. Our dual-screen G3X system will be joined by a GNS 430W, SL40, GTX330, and GMA 240 audio panel ? not to mention the Tru Trak GX Pilot and ADI. Almost all of these boxes have to talk to one another in some way, shape, or fashion; understanding how they are going to do this takes a lot of study, sketching, and note-taking. We?ve had the boxes here now for several months, and the manuals before that ? but I am just now reaching the point where it is time to take tools in hand and start building components.

I have been doing my own avionics installations for literally decades ? under the supervision of A&P?s and Avionics techs when I had certified machines, and working closely with the companies that provide today?s experimental EFIS?s when I moved in to the homebuilding world. My RV8 was my first real foray into all-digital equipment, and the panel went together quite well with the harness furnished with the units, plus those I built for the rest of the avionics. When we rebuilt the panel on Louise?s RV-6 we likewise started with Steinair harnesses for the EFIS and autopilots, plus the older radio harnesses for the equipment being re-used. Joining the bits and pieces together was lots of fun, but it did take time to get it right.

For the RV-3 project, we are doing the harness work from the ground up. Partly, this is because harnesses are just now becoming available for the G3X line, and partly it is more interesting to do it myself and share the experience with everyone else. There is no better way to understand how your system works than to build it yourself! With installation manuals for all the equipment, lots of conversations with Stein (and the gang) in Minneapolis, and some integrated drawings from the Garmin guys, it is doable ? with the right tools and an organized approach. Garmin technical standards are very high, and this forces one to work to a higher level of precision and quality. Nothing wrong with that approach! Besides, it?s a good excuse to buy better and more expensive crimping, stripping, and cutting tools?.;)

I will try to update this thread as the harness work progresses but to get started, tonight?s project was building the ?stubs? for the PFD and MFD ? the two G3X display units. When you first look at the connectors for these units, it is easy to panic and run screaming in to the night ? they have 50 pin D-Subs! Fortunately, only a very few of the pins are actually used. Power, Ground, Signal Ground, and Lighting are all very straightforward. Add to that the CAN bus (two wires), a jumper on the PFD to tell it that it is the PFD and a four-wire EEPROM module that stores the configuration for the PFD ? and that?s it! The data lines use shielded twisted pairs, so knowing how to properly terminate the shields to a ground wire using heat-shrink solder rings is important to make a neat and electronically sound assembly.

Probably the toughest part of getting started on the harness was figuring out the lengths of wire to leave on each ?pigtail? as I got going. Since the fuselage is an open book right now, I used a small piece of parachute cord to simulate the harness components and give me an idea how much wire to leave for each part of the system to give me room to play with yet not waste wire. I hate having to stop in the middle of a job to wait for more wire to arrive from Stein! We?ll see how well I do in a few more days of work?. Fortunately , there are really only three (major) components to the G3X system ? the two displays and the GSU (ADAHRS and Engine Monitor in a box). The magnetometer is a peripheral to the GSU that only takes a few more conductors ? not a big issue. So now that I have the two display connectors done, I only have the GSU to go! Of course it is way more complex, with two big connectors. Then there is the avionics stack of course. Looks I?ve got some fun shop time coming up?.

A couple of pictures:

Not many of the 50 positions on this D-Sub are actually used for the Display units ? thank heaven! There is some moderately advanced splicing and shield work involved to do it up right.
IMG_0464.JPG


The high quality connectors have tapped #8 holes for attaching ground straps ? nice and convenient!
IMG_0465.JPG


Two down, and I don?t want to count how many more to go?.
IMG_0466.JPG


Here is a link to a few more captioned pictures:

http://picasaweb.google.com/Ironflight/2011_01_26RV3AvionicsHarnessConstruction#

Paul
 
Color-coded wiring...

...was a Military standard when I taught Avionics in the Army. When I got into civil stuff, all the white wires didn't make sense, and surpised me. I suppose it had to do with budgets and such...who knows.

Regards,
 
No, thanks!

Better you than I, Paul. I've had an issue with my Dynons not getting info from my GPS since Day One. No big deal, but irritating that I don't have full capability of my panel. So, I decided to tackle that oversight last week.

After discussions about various setup options in the Dynon and Garmin menus with the various tech support guys, it was finally decided that my 496 was NOT connected to anything but the autopilot.

After tearing into various connectors to tap ONE stinkin' wire from Point A to Point B, it *should* work now. Unfortunately, it doesn't. I need to have enough snow melt out there so that I can push Smokey out into the open and let the GPS update. Maybe that's the problem.

I don't envy you, buddy. Keep us apprised of your progress.
 
Paul,
Thanks for posting this and for paving the way. I'm going with almost the exact same avionics suite in my RV-10 that you are in your -3 (the only differences are I'm going with a PS Engineering audio panel vs. the Garmin and the TT Gemini as my backup EFIS).
 
As an ex-avionics Tech on Army helicopters and a current Director of Maintenance on Gulfstreams, I have to say that wiring my RV has been the most satisfying aspect of the project so far. So true, there is no better way to know how it all works than to put it together yourself.....oh, and having all the right tools is a must.

img0806qt.jpg
 
One of the nice things about using good quality components is that they are designed to add and subtract pins, sockets, and wires. For instance, while reviewing drawings at breakfast this morning, I realized that these two connectors aren't really complete, because I forgot the audio lines (in and out) - but it's a simple matter to unscrew the cover and strain relief, add the appropriate connections, and re-assemble.

I find that adding things in to a harness is a constant in this type of construction - so stop complaining Don! ;)
 
Ironflight said:
One of the nice things about using good quality components is that they are designed to add and subtract pins, sockets, and wires. For instance, while reviewing drawings at breakfast this morning, I realized that these two connectors aren't really complete, because I forgot the audio lines (in and out) - but it's a simple matter to unscrew the cover and strain relief, add the appropriate connections, and re-assemble.

I find that adding things in to a harness is a constant in this type of construction - so stop complaining Don! ;)
Click to expand...

Paul,

That's the advantage of drawing a schematic first, before you start the wiring process. It identifies all the connections, and gives you a sheet to markup as you make those connections. It also results in a good documentation package of how you actually wired the plane, and more insight of that wiring when you start making equipment changes down the road....
 
Fred.Stucklen said:
Paul,

That's the advantage of drawing a schematic first, before you start the wiring process. It identifies all the connections, and gives you a sheet to markup as you make those connections. It also results in a good documentation package of how you actually wired the plane, and more insight of that wiring when you start making equipment changes down the road....
Click to expand...


You're right, of course Fred - but what I generally find is that changes do occur, often for the better, during construction, and then during flight...so it is good to be open to change, even when you have things written down. As I go through the manuals and drawings for the various components, it often-times isn't until I get in the middle of the project that I'll have an "Ah-Ha!" moment and realize that there is a capability that I didn't plan for that I want to add. In fact, that is one of the more enjoyable parts of the process for me.

In this case, I am working from some preliminary drawings, and some crib sheets from another G3X builder who is a little farther along than I am. His drawings are organized by "function" (data connections, audio conneciton, pwer connections) on different sheets, which is one good way to do things. But that means there are differnet parts of the same "box" on different pages. I need to rememrb to flip through all the pages each time I do a connector this way. Final drawings of our "as built" configuration are being done in parallel.

I have yet to see a complex air/space craft that didn't have upgrades in it's future....;)
 
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Schematics

Ironflight said:
You're right, of course Fred - but what I generally find is that changes do occur, often for the better, during construction, and then during flight...so it is good to be open to change, even when you have things written down. As I go through the manuals and drawings for the various components, it often-times isn't until I get in the middle of the project that I'll have an "Ah-Ha!" moment and realize that there is a capability that I didn't plan for that I want to add. In fact, that is one of the more enjoyable parts of the process for me.

In this case, I am working from some preliminary drawings, and some crib sheets from another G3X builder who is a little farther along than I am. His drawings are organized by "function" (data connections, audio conneciton, pwer connections) on different sheets, which is one good way to do things. But that means there are differnet parts of the same "box" on different pages. I need to rememrb to flip through all the pages each time I do a connector this way. Final drawings of our "as built" configuration are being done in parallel.

I have yet to see a complex air/space craft that didn't have upgrades in it's future....;)
Click to expand...

Each to his/her own... I'm from the camp of design first, them implement. The design phase is suppose to identify all the posibilities and choices. Changes can easily be made during the implemetation phase, and are red-lined onto the implementation schematic so that those changes aren't lost in the final documentation phase....
And of coarse your panel won't be as complicated as mine was due to the limited space. My RV-7A electrical & avionics took up seven "D" size sheets to document......
 
Electrical Tools

I'm still pounding rivets but thinking ahead to the electrical system. There have been a couple of references to the "right tools" for doing electrical harnesses already in this thread. For all that's published on the web and in the Aeroelectric Connection, I'd like to hear what electrical tools you have, which ones you still lust for, and which ones are your favorites.

Paul, Jeff, anyone...?
 
Here you go.:D

http://www.bandc.biz/d-submachinedpincrimptool.aspx

http://www.bandc.biz/pidgstylecrimptool.aspx

http://www.bandc.biz/openbarrelcrimptool.aspx

http://www.bandc.biz/bnccoaxconnectorcrimptool.aspx

http://www.bandc.biz/idealstripmaster45-097.aspx

http://www.bandc.biz/insertionextractiontoold-subpins.aspx

http://www.bandc.biz/heavydutycablecutter.aspx

The above are just lifted from the B and C site-----I have bought tools from them, as well as from Stein, and have been happy with both suppliers.

The above is a good start in what you need for wiring a plane.
 
Sorry Paul if we are hijacking....

terrye said:
I'm still pounding rivets but thinking ahead to the electrical system. There have been a couple of references to the "right tools" for doing electrical harnesses already in this thread. For all that's published on the web and in the Aeroelectric Connection, I'd like to hear what electrical tools you have, which ones you still lust for, and which ones are your favorites.

Paul, Jeff, anyone...?
Click to expand...

Mike certainly covered quite a few. Having been in the aviation business for a while, I have accumulated all kinds of avionics/electrical tools, cheap and EXPENSIVE. Ebay is typically a good source, but you never really know the condition of what you're buying. For me, new is usually best. Again, being in the business I can "justify" the expense....knowing I'll use them for quite some time.

Daniels Manufacturing has all types of tools and info. Depending on the complexity of your system, you may want to invest in an AF8 or AFM8 and the appropriate turret heads or positioners.

You can find a lot at these sites:
http://www.cms-tools.com/mm5/merchant.mvc?
http://www.dmctools.com/

Of course, I always would want you to give Doug's advertisers the first chance at your business. :D
 
Jeff A said:
Mike certainly covered quite a few. Having been in the aviation business for a while, I have accumulated all kinds of avionics/electrical tools, cheap and EXPENSIVE. Ebay is typically a good source, but you never really know the condition of what you're buying. For me, new is usually best. Again, being in the business I can "justify" the expense....knowing I'll use them for quite some time.

Daniels Manufacturing has all types of tools and info. Depending on the complexity of your system, you may want to invest in an AF8 or AFM8 and the appropriate turret heads or positioners.
Click to expand...

Yup - the first airplane did fine with the red-handled D-Sub crimpers, but when you get started on your second, it becomes apparent that this might be a habit, and going for the Daniel's becomes much easier....

I didn't buy all my crimpers and strippers at once either - I've collected them over the years. Good ones last forever.

LeeM_2000 said:
This has to be the best G3X installation action shot I have seen yet. :D

IMG_0468.JPG
Click to expand...

You should see the messy part of the table....;)

That's a four-inch binder, and it is basically full - of JUST the avionics and EFIS installation manuals. The G3X manual is a work of art, and includes some GREAT pictures of how to do shield terminations perfectly. I have had fairly good training in aerospace connections through my day job, and still, I've learned some new stuff from this job already.
 
Daniels crimper - get one

I'm doing my internship on my first airplane and I sprung for the Daniels AFM8 crimper. If you are going to make harnesses on your own you most definitely want one of these and the associated positioners when working with the various pins. It does a fantastic job. I picked mine up with the positioners off Ebay. Sorry Stein. Buying the crimper did delay me in buying the nice air vents you sale.

Paul I just wish I lived closer so I could absorb all the build knowledge you possess first hand. I have learned quite a bit from you postings over the years. I can't wait to see the RV3 up close when it makes it to OSH.
 
Daniels, Astro, Balmar

Fearless said:
I'm doing my internship on my first airplane and I sprung for the Daniels AFM8 crimper. If you are going to make harnesses on your own you most definitely want one of these and the associated positioners when working with the various pins.
Click to expand...

If you are looking for a high-quality crimper for D-sub pins keep in mind that the Daniels AFM8 is a mil-spec tool. The mil number is M22520/2-01 and there are other brands of crimpers that are manufactured to the same spec. For example, Astro and Balmar also make M22520/2-01 crimpers that are widely available used. These other brands and their positioners tend to be cheaper than the Daniels/DMC, but IMHO they are as good, and because they are made to the same spec the positioners are interchangeable.

Here's a little cross-reference for D-sub pin and socket positioners that fit the M22520/2-01 crimpers:

Positioner for standard D-sub pins and sockets:
mil M22520/2-08, Daniels K13-1, Astro 615724

Positioner for subminiature D-sub female sockets:
mil M22520/2-06, Daniels K41, Astro 615722

Positioner for subminiature D-sub male pins:
mil M22520/2-09, Daniels K42, Astro 615725

Happy hunting!

--Paul
 
Strain Relief Protection

I had a couple of questions via PM from folks about protecting the wires where they pas through the strain relief on the Garmin plugs. In truth, in the original photos I posted, I hadn’t installed any, but knew that I had to – as soon as I found some “Silicone Fusion Tape”. After talking with the guys at Steinair, they said that they used a thin rubber tape produced by 3M, and that while the manual calls to wrap it around each wire, another way of doing it is to pad the “jaws” of the strain relief bar – this seemed like a much easier way to do it, and keeps the metal from bearing on the wire insulation (the whole point), so that’s what I did. I used a leather punch to clear a hole for the screw, and a little PlioBond held the strips in place.

IMG_0472.JPG


Paul
 
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G3X EIS Harness

If you equate the words ?Challenging? and ?fun?, then I guess you?ll love building the EIS harness for the G3X system. I spent about a week of evenings in our ?sorta-clean-room? cutting and crimping High Density D-Sub pins on to 24 gauge wires and building up the most complex harness I have ever built. Yes, it was fun ? in the sense that you really have to be on your game to get it all correct. There are lots of tricky shields and jumpers to configure, and different types of sensors are tied together in different ways. For instance, the pressure sensors have their power and signal grounds tied together, along with their shields (which are tied to common drain lines, but not the grounds?).

This is what it looks like on the drawing:
IMG_0489.JPG


And this is what it looks like when it is complete:
IMG_0491.JPG



Simple, huh? ;)

This is all inserted into a 78-pin High Density, four-row connector body ? and it is almost full by the time you are done:
IMG_0496.JPG


Most of the wiring is either shielded twisted pairs (or three-wire) or tiny (24 gauge) thermocouple wire. The Thermocouple wire (for the CHT and EGT sensors) is two bucks a foot BTW ? not cheap. On the other hand, it is so much nicer than the bulky stuff I have used on other harnesses. You get what you pay for! Louise prepped and pinned all of the Thermocouple wires, and some of the shielded twisted pairs. We both really like the solder sleeves for finishing the shields ? very classy, high quality results done easily with a heat gun. Stein sells ?em ? I don?t think I ever want to be without them again!

The finished harness looks like this: (well, almost finished - it will be cable tied and the tie-wraps removed as it is installed)
IMG_0506.JPG


And here are the top and bottom of the finished connector:
IMG_0507.JPG



IMG_0508.JPG


As I said ? lots of fun if you enjoy this sort of thing and have all of the right tools ? but there would be no shame in my mind to buy this one ready-made. Without the proper quality tools and some experience, this would be quite a job, with uncertain results. Marc Cook wrote this up in the latest issue of Kitplanes magazine, and I was able to learn a few things from his efforts ? I hope these pics and notes might help the next guy in line!

Paul
 
Solder sleeves??

Ironflight said:
We both really like the solder sleeves for finishing the shields ? very classy, high quality results done easily with a heat gun. Stein sells ?em ? I don?t think I ever want to be without them again!

Paul
Click to expand...

Details please.

Maybe a photo, and product link???

Thanks in advance,
 
Good timing...

Very timely. I'm about to embark on this section myself.

Ironflight said:
I spent about a week of evenings in our ?sorta-clean-room? cutting and crimping High Density D-Sub pins on to 24 gauge wires and building up the most complex harness I have ever built.
Click to expand...

What crimper did you use for the High Density D-Sub pins? I have the 4-way indent crimper from Stein, but I'm not sure if that's going to work on these pins.




Ironflight said:
Most of the wiring is either shielded twisted pairs (or three-wire) or tiny (24 gauge) thermocouple wire. The Thermocouple wire (for the CHT and EGT sensors) is two bucks a foot BTW ? not cheap.
Click to expand...

I never knew there was such a thing as thermocouple wire. What's the difference, and where did you source it?
 
Have fun! (And have a magnifier or reading glasses ready....)

GTWreck said:
What crimper did you use for the High Density D-Sub pins? I have the 4-way indent crimper from Stein, but I'm not sure if that's going to work on these pins.

I used the Daniels and bought the correct die - I don't think that you'd get very good results with the budget crimper on the high density pins.

I never knew there was such a thing as thermocouple wire. What's the difference, and where did you source it?

The usual source - Stein! You need the very small stuff (24 gauge) to fit in teh hi density pins.
Click to expand...
 
Only 22GA?

Sure enough... I never realized that was there before.

I only see the 22GA, not 24GA wire on Stein's webpage. http://steinair.com/wire.htm Part number DTT-K. Is that the one you used?

Of course, I could call Stein, but it's still early there.
 
Yor're right, I mis-typed - 22 gauge - much smaller than what you generally find on EFIS harnesses.
 
Glad to see you're using fabric to tie the wires properly. You are going to have the most outrageous RV-3 on the planet. I can't wait to see the finished product.
 
Saved!

Thank you Paul. You saved me from myself! I was seriously considering picking up an RV-8QB project that's on our field (52F), and finishing it. The firewall is polished but does not have a hole in it yet. There's no engine or prop! The instrument panel has not been started. Perfect! I could make this eight the way I want it.

Then last week, a builder posted a beautiful RV-8 panel with two G3X units, a 430,a Garmin 327 transponder etc. It was just what I would do for a new eight for me! Then I looked at the behind the panel shot and was reminded of all that work. Your article on making up the harness for twin G3X panels put me over the top. I think that I'll fly the wheels off the Doll and be happy!
 
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Hey Danny - don't feel safe yet....a pre-made harness is not going to be all that expensive, and once I've installed this unit, it would be easy to do another one....you're not going to get off the upgrade hook that easy!
 
Do I see a time/expertise swap brewing?

Ironflight said:
Hey Danny - don't feel safe yet....a pre-made harness is not going to be all that expensive, and once I've installed this unit, it would be easy to do another one....you're not going to get off the upgrade hook that easy!
Click to expand...

An offer of help with a panel upgrade for help with a canopy replacement?????
 
Looks familiar

I just got finished wiring my whole G3X panel. It has three screens with a GTS800, GTX330(es), GNS430W, SL30, PS9000 back up dynon. I had a great time wiring and really appreciated SteinAir for answering a lot of questions. It really comes down to research and reading the installation over and over. Literally every answer is in the Garmin installation manual. You just have to READ it. I finally figured this out. I am really happy with the system and had a lot of fun building it. The TCW back-up battery is really cool too and wires right in to the G3X system. Still need to configure boxes a little more. I will send pics soon. DAR scheduled for Monday the 28th!
 
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