Warbird Electrical Systems

[HarvardIV]

Hello Folks:

I know you all are good on your knowledge of warplanes, and somebodys question is always answered in this forum.

So here's the problem statement:

I am a book smart electrical college graduate, who knows the AC-4313 well. However, no practical experience with electrical work. Does anyone know any simple guidelines, (common practices) in wiring an electrical system? Maybe no one does , and I may have to go to the airport to look over some planes as examples.

Please excuse my lack of experience.

THanks,

Chris

[HELLDIVERS]

HI A GOOD PLACE TO START IS ON PAPER.BEGIN AT POINT A ,GIVE EACH WIRE A NUMBER,OR ITS DISCRIPTION ON A SMALL PIECE OF MASKING TAPE AT EACH END OF THE WIRE.CALCULATE THE GAUGE OF WIRE NEEDED TO POWER THE APPLIANCE,ROUTE,BULK HEADS, AND HOW LONG IT HAS TO BE (ALWAYS LEAVE PLENTY OF EXTRA)AVOID ROUTING HARNESSES TOO CLOSE TO CONTROL CABLES,MOVING PARTS,HIGH HEAT SOURCES,FUEL LINES AND TANKS.SECURITY IS A MUST!!LOTS OF ADEL CLAMPS AND TIE STRIPS OR CONDUITS.SHIELDING IS ALSO SOMETHING TO THINK ABOUT,STROBES,AVIONICS,ECT.CANNON PLUGS ARE A REAL LIFE SAVER IF THE A/C HAS TO BE DISASSEMBLED,SO THE MOST IMPORTANT PART IS TO PLAN AHEAD AS MUCH AS POSIBLE,THIS WILL SAVE YOU LOTS OF TIME MONEY AND FRUSTRATION IN THE FUTURE!!HOPE THIS IS A LITTLE BIT OF HELP ITS ONLY A SMALL PART OF A BIG JOB !!GOOD LUCK THANKS MIKE

[HarvardIV]

Hey thanks Mike:

It has been difficult to answer this question, but it looks like you have the answer I was thinking of. I had some help on the T-6 discussion board as well too.

I called my friend, and he had a similar answer to yours. He said to consider the power load of each system. SO treat the nav lights as one system, and then the landing lights as another. Like you said he mentioned to go liberal on the disign to overdesign it for more power/voltage than it needs.

Now I finally have a starting point, thanks a bunch!

Now next question: Why use a junction box like the one in the firewall on the T-6? Why not just direct connect all the wires w/o the junction box?


Thanks a lot Mike,

Chris

[Jeffrey]

I'm not an electrician but if I guess correctly it is so that you can gather together groups of wires all heading in same directions. like tail light and electrical confirmation of tail wheel extention, into the one conduit and run them together.

[HELLDIVERS]

HI :JUNCTION BOXES HAVE MANY FUNCTIONS,THEY CAN MAKE EASY WORK WHEN DISSASSEMBLY IS NEEDED.YOU CAN REMOVE THE COVER AND DISCONNECT THE HARNESS AT A TERMINAL STRIP THEN SEPARATE THE TWO COMPONENTS/WINGS TAIL ECT.THEY CAN ALSO HELP WHEN TROUBLE SHOOTING,OR ADDING NEW SYSTEMS.FIREWALL BOXES CONTAIN RELAYS, VOLTAGE REGULATORS,ECT.BUT ALSO PROVIDE A LOCAL ELECTRICAL DISCONNECT FOR THE Q.E.C.THE OLD RADIO GEAR REQUIRED LOTS OF WIRE BUNDLES,JUNCTION BOXES, RELAYS, INVERTERS, ECT.THE FOLKS THAT DESIGNED THEM PUT THEM IN FOR A REASON THAT BEING EASE OF MAINTANANCE.THANKS MIKE

[HarvardIV]

Thanks Helldivers and Jeffrey for your help.. The pieces of the electrical puzzle are fitting together. Now I can fill in the gaps with the existing T-6 electrical schematic.

Since I still know very little about electrical, I was wondering if electrical wires have an "in" wire and an "out" wire? I suppose the out wire is the ground? Please excuse the silly question.

Thanks,

Chris

[Broken-Wrench]

Just get a Cessna 172 Maintenance Manual as a rough guide and monkey see monkey do and fill in the gaps as needed with good advice.

[HarvardIV]

Broken Wrench,

Thanks for the input, I'll take a look. Again that T-6 schematic is pretty hard to read.

[HELLDIVERS]

HI:THE AIRFRAME IS THE GROUND,THE POSITIVE COMES FROM THE BUSS BAR TO THE CURCUIT BREAKER,THROUGH THE SWITCH,THEN TO THE APPLIANCE.DEPENDING ON THE AMP LOAD THIS MAY INCLUED A SOLINIOD,BUT MOST ALL COMPONANTS GROUND TO THE AIRFRAME.THANKS MIKE

[HELLDIVERS]

HI: ONE MORE HINT,MAKE A COPY OF YOUR SCHEMATIC,THEN USE DIFFERENT COLORS OF HIGHLIGHTERS TO DEFINE DIFFERENT SYSTEMS!THANKS MIKE

[HarvardIV]

Thanks for the help guys..