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Here's a link to a 'discussion' several years ago between the author of the article (Greg Richter) and Bob Nuckolls, who manages the Aeroelectric Connection here in the USA for homebuilders.
http://www.aeroelectric.com/articles/richter/richter.html
Like Bill says, the only real advantage to 24V is lower wire weight (negligible in a small homebuilt, since almost everything is very low power consumption these days anyway). Note that on pg 10, Richter negates even that advantage by recommending 18gauge wire everywhere even on 24 V. (??) The idea that devices will stay 'online' longer with 24v instead of 12v is highly suspect; the energy density in 12 or 24v batteries is the same, given the same (physical) size battery.
It's worth pointing out that Richter is the guy who made the Blue Mountain series of glass panels. His customers had years of nightmares getting the gear to work correctly and he's now abandoned them completely. You can buy the stuff now for about 15 cents on the dollar, if you're willing to gamble.
There are some useful ideas in the article, but if you're at the learning stage, how do you know which are useful & which are garbage?
Charlie
Bill Bradburry wrote:
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
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*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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