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Connectors vs. Straight Wire

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Dennis Johnson

Joined: 10 Jan 2006
Posts: 89
Location: N. Calif.

Posted: Mon Oct 02, 2006 7:34 am Post subject: Connectors vs. Straight Wire

Greetings,

  

 The entire instrument panel on my Lancair Legacy I'm building is attached  to the airframe with only four bolts and is therefore relatively easy to  remove in one large piece.  That is, mechanically easy to remove, if  it weren't for a bazillion wires connecting it to the  airframe.  On the other hand, the Legacy has a front hinged canopy and  a removable glare shield, which provide reasonably good access to the rear of  the instrument panel while it is in place. 

  

 I can either run the wires from the airframe directly to the various  components on the panel or I can insert D-Sub connectors between  all the wires and the instrument panel.  If I use connectors, it will make  removing the instrument panel easier for repairs or  upgrades.  Running the wires directly to the panel, without  connectors, will reduce the parts count but make future service more  difficult.  

  

 I'm torn between the two alternatives.  My first thought was to  add connectors to every wire in the expectation that I'll almost  certainly want to remove the instrument panel at some point in the future  for troubleshooting, repairs, or upgrades.  Working on the panel while it's  on my workbench is soooooo convenient.  But there are tons of wires, many  of them shielded, and running every single one of them through a connector  is a big project.  Considering that I have reasonable access to  the rear of the panel with the canopy open and the glareshield removed, should I  just plan to service the panel with it in place?  Anybody who's "been  there, done that" have any advice?

  

 Thanks,

 Dennis Johnson

 Lancair Legacy; painting done, still wiring the  panel        

    [quote][b]

aadamson(at)highrf.com
Guest

Posted: Mon Oct 02, 2006 1:09 pm Post subject: Connectors vs. Straight Wire

Dennis.

  

 I might be late with this comment.... But Cannon Plugs,  Cannon Plugs, Cannon Plugs..... Did I say Cannon Plugs?

  

 You can get them in various densities.  I'd try to  keep it to 3 or 4 and group things together in logical  sense.

  

 I know you can get them Lancair, or there are probably  other sources as well.  I've not gone there yet, but when I do, it will be  Deutch connectors and Cannon plugs you can be assured.

  

 Also, heat-shrink labelers are pretty cheap and are  available on ebay to help keep things grouped and sorted and  labeled.

  

 Alan



   From:  owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dennis  Johnson

Sent: Monday, October 02, 2006 11:34 AM

To:  aeroelectric-list(at)matronics.com

Subject: Connectors  vs. Straight Wire

 

 Greetings,

  

 The entire instrument panel on my Lancair Legacy I'm building is attached  to the airframe with only four bolts and is therefore relatively easy to  remove in one large piece.  That is, mechanically easy to remove, if  it weren't for a bazillion wires connecting it to the  airframe.  On the other hand, the Legacy has a front hinged canopy and  a removable glare shield, which provide reasonably good access to the rear of  the instrument panel while it is in place. 

  

 I can either run the wires from the airframe directly to the various  components on the panel or I can insert D-Sub connectors between  all the wires and the instrument panel.  If I use connectors, it will make  removing the instrument panel easier for repairs or  upgrades.  Running the wires directly to the panel, without  connectors, will reduce the parts count but make future service more  difficult.  

  

 I'm torn between the two alternatives.  My first thought was to  add connectors to every wire in the expectation that I'll almost  certainly want to remove the instrument panel at some point in the future  for troubleshooting, repairs, or upgrades.  Working on the panel while it's  on my workbench is soooooo convenient.  But there are tons of wires, many  of them shielded, and running every single one of them through a connector  is a big project.  Considering that I have reasonable access to  the rear of the panel with the canopy open and the glareshield removed, should I  just plan to service the panel with it in place?  Anybody who's "been  there, done that" have any advice?

  

 Thanks,

 Dennis Johnson

 Lancair Legacy; painting done, still wiring the  panel        

[quote]



matronics.com/Navigator?AeroElectric-List



[b]

Dennis Johnson

Joined: 10 Jan 2006
Posts: 89
Location: N. Calif.

Posted: Mon Oct 02, 2006 4:26 pm Post subject: Re: Connectors vs. Straight Wire

Hi Alan,



Thanks for the reply to my question about connectors to allow removing the instrument panel.  You suggested Cannon plugs.  It seems to me that Cannon plugs are more expensive and less convenient to install than D-Sub connectors.  I hope there's not a fundamental problem with D-Subs because nearly every electronic component I installed came with D-Subs on the back.



Best,

Dennis

aadamson(at)highrf.com
Guest

Posted: Mon Oct 02, 2006 5:05 pm Post subject: Connectors vs. Straight Wire

Oh, I think they would work ok... Except, I had one bad experience.  I had a

monitor with a 15pin D-Sub on it.  It worked for a couple of years and then

all of a sudden it started to flake out... I found that the "tension" on the

female pins started to fail.  I would have to "cock" the connector in order

that the colors on the monitor appeared correct.  Finally, it just wouldn't

take any jiggling to get the colors right and I had to buy a new monitor.



YMMV, but there are lots of kinds of Cannon plugs, and it's a one time

investment.  For something like interconnects that have to survive in

"hostile" environments, its just my preference, but I'll use cannon plugs.

Good luck btw, can't wait to see yours sometime ...



Alan 



--

stein(at)steinair.com
Guest

Posted: Mon Oct 02, 2006 5:26 pm Post subject: Connectors vs. Straight Wire

My  comment will probably be a little different from the typical..but, I'd push  you to do as much straight wiring as possible.  On my 1st plane I did the  Canon Plug thing all over the place.....have you ever tried to troubleshoot an  electrical gremlin through a bunch of canon plugs or D-Subs?  It's a pain  in the rear. Once you add hundreds of pins, that's hundreds of new joints that  are potential future problem areas.

  

 Next,  why do you really need them?  Sure, it sounds like a great idea, but  really....how many times do you actually take a panel in and out of   plane?  As far as individual components, it only takes a couple screws to  drop out any of the EFIS's out there, radios slide out of trays, etc..., so you  don't get much advantage there.  Next, even if you wanted you shouldn't run  everything through canon plugs. Audio Wires specifically can get really touchy  running them through connectors...all the headset, mic, aux leads are/should be  shielded and breaking that shield just creates another area for noise and more  gremlins to move in.  You can't shouldn't split EGT/CHT wires, nor some  other sensor wires along with the heavy wires.  Basically, it looks good at  airshows and in magazines, but the truth of the matter is it's almost impossible  to get by NOT hooking some things directly to your panel anyway and then there  you are with a bunch of nice looking canon plugs, then you Still have to remove  things from the panel anyway....point is no matter what your intentions you'll  still probably have a bunch of stuff hooked directly to the panel anyway (pitot  tubing, static tubing, maybe some antennas, fat battery wires, 02 lines if you  have them, "P" leads which shouldn't be broke, air vents lines, push/pull  cables, so on and so forth).

  

 I  guess I'm trying to say that anytime you added un-needed connections to a  particular system you are just asking for longer term troubles and an overall  reduction in reliability.  Keep It Simple!  Most of today's major  components come out of the panels so easily that I can't see a huge benefit of  just adding connectors in case someday you might want to yank the whole panel  out?

  

 The  point is you should wire and build your airplane for the 99th percentile of it's  functionality and reliability, not the 1% "whatifs".  I don't know if this  all makes sense or not, but if it were me (and it is dozens of times we discuss  panels with customers), I really try to put function ahead of form and convince  people to do what makes sense from a functional, reliable and simplicity  standpoint.  You can't beat it!

  

 Cheers,

 Stein.

 [quote]   --

Jim Baker

Joined: 30 Mar 2006
Posts: 181
Location: Sayre, PA

Posted: Mon Oct 02, 2006 5:57 pm Post subject: Connectors vs. Straight Wire

 	  Quote: 	
		   I guess I'm trying to say that anytime you added un-needed connections to a particular system 

 you are just asking for longer term troubles and an overall reduction in reliability. 

____________________________________________
	




Spot on! Besides, you'll have a lot of the panel terminated in 

connectors of one sort or another anyway....how hard to remove 

those.....



Tho I kinda wish the D-sub folks would go back to the old 

Centronics wire bail form of shell attachment. No trying to get 

the screw driver on the screw head in a spot you can't easily see. 

Jim Baker

580.788.2779

Elmore City, OK

nuckollsr(at)cox.net
Guest

Posted: Mon Oct 02, 2006 8:07 pm Post subject: Connectors vs. Straight Wire

At 08:56 PM 10/2/2006 -0500, you wrote:



 	  Quote: 	
		  



 > I guess I'm trying to say that anytime you added un-needed connections 

 to a particular system

 > you are just asking for longer term troubles and an overall reduction 

 in reliability.

____________________________________________



Spot on! Besides, you'll have a lot of the panel terminated in

connectors of one sort or another anyway....how hard to remove

those.....



Tho I kinda wish the D-sub folks would go back to the old

Centronics wire bail form of shell attachment. No trying to get

the screw driver on the screw head in a spot you can't easily see.


	


   There ARE wire bails for keeping d-subs together. My favorite for

   cable-to-cable d-subs is remove the jack-screw hardware and use

   tye-wraps to keep them together.



   Also, I'd ALWAYS use the machined d-sub pins. They're of the

   same pedigree as the older and larger 'Cannon' plugs, etc.

   I'm REALLY disappointed that folks who sell really expensive

   avionics ship those sheet-metal, b-crimp pins with their

   radios.



   Bob . . .



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

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

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

Jim Baker

Joined: 30 Mar 2006
Posts: 181
Location: Sayre, PA

Posted: Tue Oct 03, 2006 6:42 am Post subject: Connectors vs. Straight Wire

 	  Quote: 	
		      There ARE wire bails for keeping d-subs together. My favorite for

    cable-to-cable d-subs is remove the jack-screw hardware and use

    tye-wraps to keep them together.


	


Must be rarer than hens teeth....all I can find is the IDC D-sub 

w/bail locks. Did find a bail lock kit...going price was $7 a pop 

with one vendor down to $3. Your Ty Wraps look better all the 

time.



Jim Baker

580.788.2779

Elmore City, OK

nuckollsr(at)cox.net
Guest

Posted: Tue Oct 03, 2006 9:28 am Post subject: Connectors vs. Straight Wire

At 09:40 AM 10/3/2006 -0500, you wrote:



 	  Quote: 	
		  



 >    There ARE wire bails for keeping d-subs together. My favorite for

 >    cable-to-cable d-subs is remove the jack-screw hardware and use

 >    tye-wraps to keep them together.



Must be rarer than hens teeth....all I can find is the IDC D-sub

w/bail locks. Did find a bail lock kit...going price was $7 a pop

with one vendor down to $3. Your Ty Wraps look better all the

time.


	


   Take a look at page 17 of:



http://www.aeroelectric.com/Mfgr_Data/Connectors/ITT_Cannon/dsub_accessories.pdf



   The next greatest thing are Positronic's V series spring

   loaded slide latches. See page 10 of:



http://www.connectpositronic.com/pdf/SubDAccess_C007RevB1.pdf



   Bob . . .

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

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

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

Dennis Johnson

Joined: 10 Jan 2006
Posts: 89
Location: N. Calif.

Posted: Wed Oct 04, 2006 6:42 am Post subject: Connectors vs. Straight Wire

Hi Stein,

  

 Thanks so much for your very thoughtful reply to my question about the  trade-offs between straight-wiring my instrument panel to the airframe wiring  and the alternative of putting connectors in every wire so that I can remove the  panel for service.  

  

 I think I'll take your advice and go with the straight-wire concept,  without connectors in every wire.  The airplane I'm building has better  than average access to the panel in-place and most of the stuff in the  panel are relatively easy to remove.  

  

 Thanks again,

 Dennis Johnson

  

 Do not archive

    [quote][b]

nuckollsr(at)cox.net
Guest

Posted: Wed Oct 04, 2006 7:36 am Post subject: Connectors vs. Straight Wire

At 07:37 AM 10/4/2006 -0700, you wrote:



 	  Quote: 	
		  Hi Stein,



Thanks so much for your very thoughtful reply to my question about the 

trade-offs between straight-wiring my instrument panel to the airframe 

wiring and the alternative of putting connectors in every wire so that I 

can remove the panel for service.



I think I'll take your advice and go with the straight-wire concept, 

without connectors in every wire.  The airplane I'm building has better 

than average access to the panel in-place and most of the stuff in the 

panel are relatively easy to remove.


	


    From a servicing perspective, consider making your

    panel from "modules" of flat sheet, each removable

    for servicing. Make wire bundles to each module

    long enough to allow pulling the module out for access

    while extending a bundle. When mounted for operation,

    coil the bundles behind the panel and secure with

    tye-wraps. If your bundles are not too populace, this

    is a good way to maintain both serviceability =AND=

    wire integrity.



    Bob . . .

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

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

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

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