Joe, there is one more consideration regarding aircraft grade wire.  Aircraft grade wire has a layer of tin coating each strand of the copper wire to prevent/reduce corrosion.  Older automobile electrical systems used to start giving problems around the 10 year mark (depending where you lived) due to the oxygen oxidizing the copper wiring.

 

A lot of the PVC insulation wire does not have the tin coating and are therefore more susceptible to corrosion/oxidation.  So use care in the PVC wire you select.  Also if there is sufficient heat to ignite the PVC insulation, it gives off toxic gases which in an enclosed cockpit might be a bit much to deal with.

 

FWIW

 

Ed.

 

 

----- Original Message -----

From: Jeff Luckey

To: Rotary motors in aircraft

Sent: Friday, December 04, 2009 11:20 PM

Subject: [FlyRotary] Re: Primer in AC/DC Electricity - Wire Types

 

I read thru Greg’s paper and found it very interesting.  He recommends Teflon wire as opposed to Tefzel wire.

 

I’m wondering: what are the main differences between the two types of insulation. I remember reading something about Teflon being softer or less durable – but I don’t remember the details. 

 

Are there any A&P/EE’s out there who want to tackle this question? (mere mortals can also feel free to respond as well ;)

 

 

 

 

---

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bill Bradburry
Sent: Friday, December 04, 2009 14:57
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Primer in AC/DC Electricity

 

George,

He is probably not talking to folks who install an electrically dependant alternative engine.  If you just forget the problems that might arise getting Tracy’s controllers, etc, and the 12V auto starter to work on 24V, you still have to accept the fact that that “big 24V battery” can fail.  If is does and you don’t have a second battery, it will get very quiet in the cockpit until the screaming starts.  Also don’t forget that the only way you can get a 24V battery is to tie two 12V batteries together.  If you go with one 24V battery, you have the same battery weight plus the weight of redundant busses.  If you go with two batteries, you now have 4 times the weight of one 12V battery.  If you try to mix the systems so you have 24V and 12V, you have a nightmare.

The only real advantage seems to me to be wire weight (smaller wire for 24V).  I am pretty sure that I ate more weight for last nights dinner than the entire wireing system in my plane  :>)

 

If you really want to save weight in your plane, go on a diet!  (I don’t want to hear that you are 7 feet tall and weigh 120 lbs!  :>))

 

Bill B 

 

---

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of George Lendich
Sent: Friday, December 04, 2009 3:45 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Primer in AC/DC Electricity

Kelly,

Being electronically challenged I had a quick look. It says 24 volts is better for aircraft use eliminating the need for extra batteries and alternator, I'm wondering why builders collectively don't already go that way. Are there complications or additional expenses to be considered or are auto conversions typically locked in to a 12 volt system for one reason or another - perhaps just the alternator.

George ( down under)

Group,

         Some of you may have already seen this and to others this may be knowledge that you carry

around in your head and use everyday but to someone like me whose schooling in AC/DC (Navy) 

electricity was 50 plus years ago and also something I do not use everyday the following link has

refreshed my old brain..............Hope some of the group finds it useful..............

 

      http://www.eaa.org/experimenter/articles/0903_aircraft_wiring.pdf

--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold

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