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  #1  
Old 05-12-2018, 09:36 PM
sjhurlbut sjhurlbut is offline
 
Join Date: Jan 2005
Posts: 578
Default Batt cables through gear towers?

I'm almost done wiring my 8. Basic VFR with a few extra wiring items (still tight). My goal is to have all the wiring hidden so going forward into the baggage area is no go.

Question is for guys who have the solenoids behind the firewall (want those hidden as well) I'm running out of room to run the alternator and starter wires (both 4 AWG welding wire from B&C). Don't really want to drill another wiring hole through the left gear tower. Could run it along the floor and cover it somehow.

Any other solutions to this?
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Steve H
Cold Lake, Alberta
RV7A #70015 - C-FZQX - built - sold
RV7A #71629 - C-FSIS - built - sold across Atlantic
RV7 #70215 - C-GOJU - flying - sold
RV7 #70703 - C-GMIY - flying - sold
RV6 #60119 - C-FHBZ - built - Airventure 2016 Bronze Lindy - sold
RV10 #41779 - built emp - sold
RV8 #82842 - C-FSBG - Fastback with big hp IO-360-A1B6 10:1
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  #2  
Old 05-12-2018, 09:50 PM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 623
Default Alternator wire size

Quote:
Originally Posted by sjhurlbut View Post
I'm almost done wiring my 8. Basic VFR with a few extra wiring items (still tight). My goal is to have all the wiring hidden so going forward into the baggage area is no go.

Question is for guys who have the solenoids behind the firewall (want those hidden as well) I'm running out of room to run the alternator and starter wires (both 4 AWG welding wire from B&C). Don't really want to drill another wiring hole through the left gear tower. Could run it along the floor and cover it somehow.

Any other solutions to this?
4 AWG is overkill for the alternator wire. 6 or 8 should be more than adequate. At any rate, my alternator wire doesn’t go through the gear tower. It runs right underneath the sub panel (baggage compartment bulkhead) to my main bus which is located on the aft lower left side of the baggage compartment bulkhead.

Skylor
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  #3  
Old 05-12-2018, 11:51 PM
rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGG
Posts: 2,301
Default lifepo4 battery?

Apologies for the thread drift. I also started with a battery in the tail for weight and balance, but changed to the lifepo4 from VAF sponsor EarthX and mounted it up front. This keeps all the fat wires FWF, and saves a lot of weight. All the cable going to the tail is gone, as is the heavy battery.


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  #4  
Old 05-13-2018, 11:18 AM
sjhurlbut sjhurlbut is offline
 
Join Date: Jan 2005
Posts: 578
Default Bat

I have earthx as well but goal is clean firewall so I'll stick with it behind seats. Think I'll mount solenoid on forward part of gear tower requiring only 1 fat wire to pass through tower
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"Aerodynamics is for people who can't build engines"
Enzo Ferrari

Steve H
Cold Lake, Alberta
RV7A #70015 - C-FZQX - built - sold
RV7A #71629 - C-FSIS - built - sold across Atlantic
RV7 #70215 - C-GOJU - flying - sold
RV7 #70703 - C-GMIY - flying - sold
RV6 #60119 - C-FHBZ - built - Airventure 2016 Bronze Lindy - sold
RV10 #41779 - built emp - sold
RV8 #82842 - C-FSBG - Fastback with big hp IO-360-A1B6 10:1
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  #5  
Old 05-13-2018, 12:18 PM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is offline
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 1,538
Default

As you consider battery mounting locations for the RV-8, I recommend you do the math to estimate W&B for each option.

The best way I found to do this is to find a similarly equipped RV-8, then correct for whatever prop is used to reflect your prop. Correct for the planes battery location so you can have a baseline to estimate your W&B for each battery mount you consider.

I did this for my RV-8 (IO-360-M1B, Hartzell BA prop and Grove airfoil gear) and quickly determined that one PC-625 in the forward baggage well and one in the aft battery location yielded the best W&B.

Side note - the first RV-8A (parallel valve IO-360 and Hartzell BA prop) had both PC-625s on the forward floor just aft of the firewall. Solo was ok, but it was easier to land with a 25 pound shot bag in the rear luggage compartment.

So sharpen those pencils, dust off the calculator and as Sheldon would say, do the math.

Carl
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  #6  
Old 06-18-2018, 03:32 PM
raisbeck raisbeck is offline
 
Join Date: Mar 2013
Location: Laramie, WY
Posts: 6
Default Planning w&b

Does anyone have w&b dara for a bare (no interior, avionics, etc.) RV8?

I'm trying to keep track of the weight as we build to avoid any unpleasant surprises.
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  #7  
Old 06-18-2018, 10:30 PM
rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGG
Posts: 2,301
Default W&B info

A few possibly useful resources:

https://www.vansaircraft.com/public/downloads.htm

http://www.vansairforce.com/communit...ad.php?t=74046
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  #8  
Old 06-18-2018, 11:02 PM
SHIPCHIEF SHIPCHIEF is offline
 
Join Date: Mar 2008
Location: Seattle
Posts: 1,366
Default

I'm completely opposed to your idea, here is why:
I'm an operating engineer, and I have to troubleshoot and repair 40 year old stuff as well as operate it.
Things Fail. Obsolete stuff must be replaced. Neat new stuff is too cool to ignore.
Hidden stuff is hard to get to, hard to troubleshoot and hard to replace.
I like your idea of a simple VFR ship, I built an RV-8 with that as my goal.
BUT, I ran wires from the right console, thru the gear tower and thru the baggage well, and mounted the battery on the firewall, with the filter capacitor, battery contactor, gauge manifold, fuel filter and fuel return regulator on the firewall where I can easily access them. (Battery and electric system back and up the right side, Fuel system up and back the left side)
I put the electric fuel pumps in front of the left gear tower, and dread replacing a fuel pump when the time comes, heck, it's hard enough to clean this area.
My RV-8 is no show plane, it's rather plain, unpainted dull aluminum and DP-40 on fiberglass, but it only weighs 1034 lbs empty and flies great! (I didn't even convert to aluminum gear legs!)
You could run the wires below the longeron and drill holes in the center of the longeron flange for zip ties or lacing cord to hold the wire bundle up out of sight.
The Glory of an Experimental Aircraft is the freedom to change it. I'm in the process of removing engine gauges and installing an EMS, so my accessible wiring is going to be butchered again.
Hey; I'm adding 'lightness'!
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http://gallery.eaa326.org/v/members/semery/
EAA 668340, chapter 326 & IAC chapter 67
RV-8 N89SE first flight 12/26/2013
Yak55M, and the wife has an RV-4
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