REFLECTOR: 24 volts vs. 12 volts

[dandemitchell at earthlink.net]

Thats a pretty long Velocity!  Based on your calculations and going say 20 feet then you will save ~1.505 Lbs.  Spread this along the length of the aircraft for proper W&B and it equals about three Big Mac's w/ fries (how many passengers are you carrying?) or 1/4 gallon of AVgas. Doesn't seem like a reasonable trade-off. As far as voltage drop, most of the drop is at the connectors so keep them clean and you should never see less than ~9-10 VDC  at the starter unless it is really cold. Then watch the oil pressure!

Ed


----- Original Message ----- 
From: Douglas Holub 
To: Velocity Aircraft Owners and Builders list
Sent: 1/16/2005 9:11:08 PM 
Subject: Re: REFLECTOR: 24 volts vs. 12 volts


If anyone is interested, I did some calculations: 30 feet of 2 AWG wire weighs 6 lbs, and will drop .468 volts with a 100 amp load; 30 feet of 4 AWG wire weighs 3.78 lbs and will drop .373 volts with a 50 amp load.

Doug
----- Original Message ----- 
From: Joe 
To: Velocity Aircraft Owners and Builders list 
Sent: Sunday, January 16, 2005 10:13 PM
Subject: Re: REFLECTOR: 24 volts vs. 12 volts


Doug,
No real downside if all the components you use are rated for 24v (radios etc.)  You will need speed brake and trim actuators for 24v or build a voltage divider into those circuits.  I was going to go 24v myself, but since I am doing an auto conversion finding a 24v starter and/or 24v ECU made it easier to stay 12v.

Be careful with your statement about wires being smaller by 1/2, wire size to current capability is not linear.  The wire length also has to be included into wire sizing so that there is no more than a 0.5v drop on 12v circuits and 1.0v on 24v circuits.  AC 43-13 is a good source for sizing wire in aircraft applications.

One possible downside, if you want 110 vac power for say a laptop computer, you might have a hard time finding a 24V inverter.

Joe
----- Original Message ----- 
From: Douglas Holub 
To: reflector at tvbf.org 
Sent: Sunday, January 16, 2005 10:37 PM
Subject: REFLECTOR: 24 volts vs. 12 volts


If I have a 24 volt system I'll use half the current so my wires can be smaller by 1/2 and I'll save a pound or two. What's the downside?

Doug



_______________________________________________
To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html



_______________________________________________
To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20050119/7ba43c5a/attachment.htm