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  #1  
Old 02-20-2012, 02:12 PM
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Space Cadet Space Cadet is offline
 
Join Date: Mar 2007
Location: Denver, CO
Posts: 211
Default Battery on firewall out there?

Think I remember someone in RV-10-land who had to move their battery up to the front of the firewall. If so, where did you end up putting it? My c.g. is too far aft and moving the battery appears to be about perfect swap to fix. Will not do it until first annual, at the earliest if ever, but still pondering it.

Thanks,
Dwight
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  #2  
Old 02-20-2012, 03:46 PM
Tom Martin Tom Martin is offline
 
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Location: Ontario, Canada
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We did a RV10 with a firewall mounted 680 odyssey last year. The installation saved quite a bit of weight and complexity. The main mission for the plane was to be a cross country family airplane thus moving the weight forward meant that it was virtually impossible to exceed the aft centre of gravity and stay within Van's gross weight for the aircraft. Solo, the aircraft was placarded for a requirement of 50 pounds in the baggage compartment.
I flew the plane solo and fully loaded and it handled well in both configurations.
It had a six pack IFR panel and came in, I think, at 1625 empty weight. I would recommend this installation to others that have a similar mission.
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  #3  
Old 02-20-2012, 04:23 PM
Ron B. Ron B. is offline
 
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Location: Yarmouth, Nova Scotia
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It was probably us you are refering to. Transport Canada would not issue a C of A without correcting our aft c of g. We , like you had planned in moving our batteries forward during the next winter and wanted our C of A approved with the aft c of g, but that did not fly. We lost flying weather as I believe it was June when this took place. I have no regrets with the two 680 batteries mounted in their mounting trays, mounted directly on the firewall. We reinforced the firewall to accept the trays. Like Tom Martin says it reduced the total install weight by a bit, can't rember exactly but I could look up the ammendments. Our C of G is within limites solo with a 150lb pilot and no additional ballast and with all fuel levels. We still don't know why ours turned out so much different than most others. Our ac was complete and painted when we were doing our weight and balance.
Very pleased with the results.
Ron
PS Top cowling is off now I could take a photo and try and post it if needed.
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  #4  
Old 02-21-2012, 06:41 AM
rvdave rvdave is offline
 
Join Date: Jun 2005
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Would like to see photos of this install, I am thinking about a 925 in plans location and a 680 on the firewall for dual elect ignition, anyone ever done this before?

Dave Ford
Cadillac, mi
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  #5  
Old 02-21-2012, 11:44 AM
bcondrey bcondrey is offline
 
Join Date: Jan 2005
Location: Bellevue, NE
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Dave,

It's been done multiple times. Use the PC-680 battery box kit from Van's, add a couple of angles to the aft side of the firewall for the mount bolts and you're good to go. There are at least a half dozen that I'm aware of with a PC-925 in back and PC-680 up front (including my first RV-10 and the one I'm currently building).

For those considering this, the "normal", perfectly stock RV-10 will have a CG near the forward limit. Passengers and baggage will move the CG aft. Front passengers and fuel are close to the empty CG. Because of this, many people put a few pounds on the baggage compartment so there's isn't a heavy stick feel in the flair because of the forward CG.

Now, if you're swapping out mags for electronic ignition, have something lighter weight than the alternator and/or starter, have an O2 cylinder in the back, have a lighter prop than the Hartzell, etc. you'll have a CG that is aft of the forward limit. Since it really isn't possible to load "stuff" into the plane and move the CG forward, having the empty CG at or near the forward limit is desireable.

Bob
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  #6  
Old 02-21-2012, 01:08 PM
tfarrell839 tfarrell839 is offline
 
Join Date: Oct 2009
Location: Canby, OR
Posts: 53
Default Battery Box for Firewall Forward

I have a battery box for an Odyessey PC680 that is designed to mount to the firewall. I personally would drill this out significantly with lightening holes. This is what I would use to mount it. I'll try to find some pics of an install on an RV-10, or at least of the space where you could install it and post those later.



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  #7  
Old 02-22-2012, 05:57 AM
paul330 paul330 is offline
 
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Location: Mpumalanga, South Africa
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I'm a bit confused - easily done

I thought the whole point of fitting the battery at the rear ( and having the subsequent extra weight of the #2 wire all the way for the starter) was because there was an issue of the CG being too far forward.......
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  #8  
Old 02-22-2012, 07:42 AM
Wayne Gillispie Wayne Gillispie is offline
 
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Location: USA
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This will give you an example Paul.

I built per plans...no A/C, no lightweight prop, no electronic ign, no heavy interior, cloth seats, elt just behind baggage bulkhead.

The extra heavy items added aft of cg are: pc680 aux beside 925, 10 ga wire to front, 6 space hot bat fuse block, extra contactor/#2 wire to interconnect to main bat, baggage led's/switch, two cig lighter accy ports, 6 spare 18 ga wires from panel to rear for future use(ads-b, etc).

My ewcg is 1/2" aft of Van's fwd limit. When loaded with family and 100 lbs of baggage I am at full gross with cg 1 1/4" fwd of aft limit. As the kids grow up a little more we will have to leave some baggage off. If I want to haul two normal people in the back then no baggage.

My thoughts on the firewall mounted pc680 battery. If you are going to have lightweight prop/starter/ignition then I would install aux bat up front. If you are going to have A/C then install it up front. Otherwise as you can see I would be over gross before I went past my aft limit and will never go past my fwd limit. If one decides to go with all of the heavy stuff up front incl pc680 and A/C, plus heavy interior then you will probably be fine with cg but will just be limiting your useful load. Plan accordingly.
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  #9  
Old 02-22-2012, 08:50 AM
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ppilotmike ppilotmike is offline
 
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Default What about 2 people??

Quote:
Originally Posted by Wayne Gillispie View Post
This will give you an example Paul.

I built per plans...no A/C, no lightweight prop, no electronic ign, no heavy interior, cloth seats, elt just behind baggage bulkhead.
Wayne,

What about when you carry only 2 adults up front? Do you have to carry ballast? If so, how much and where?
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  #10  
Old 02-22-2012, 09:18 AM
BobTurner BobTurner is online now
 
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Wayne's approach is a good one.
The cg range of the -10 is not as generous as, say, a 182.
If you can start out with the cg a little forward at light weights, just front seats occupied, you can always add ballast in the back. Then when the cg wants to go aft with heavy loadings in the back of the plane, you've got some room on the cg chart.
But you do have to be careful. For some configurations it may be necessary to place the bags at the passengers' feet.
Also, note that with aft cg loadings, the cg will move further aft as you burn fuel. Be sure to check the cg with the minimum fuel, too.
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