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praterdj

Well Known Member
I am currently working on the empennage for my RV-8 and during the time when I am unable to build I find that I am constantly planning for later phases.

My question revolves around battery location. As mentioned I am building the 8 (tandem seating) and C.G. is an issue. I am not a small person (6?5? and 250#), I am looking at either the new IO-390 or an IO-360, and a constant speed propeller.

I know this is not an uncommon situation but I would like to build the plane as light as possible. The question is that since I?m going to use one of the light batteries (12 pounds?) and a sky tech starter, do I need to put the battery in the back?

Another location I am considering is in the front baggage compartment. My only reluctance for a rear battery location would be running the battery cables through so many structures as well as the additional weight of the longer cables.

Any suggestions?

Thanks,

Donald
 
Donald,

I had the same decision to make. It is very tempting to put the battery, especially the light one, in the front baggage compartment. I used the w&B spreadsheet that another 8 builder shared with me to determine the differnence.

I did the numbers with the battery in the back, and with it in the front baggage compartment. There was more of a difference that I would have thought given the light weight of the battery. With the battery in the front, I was within about 4% of the forward CG with me in the pilot seat. I weight about 200 lbs. I am planning for the catto prop (18 lbs.). With the C/S prop, there is no question that I would put the battery in the rear even with the longer cable runs.

I wish that I had a different answer for you. I would love to put the battery in the front baggage compartment for simplicity of wiring.

Tony
 
praterdj said:
My question revolves around battery location. As mentioned I am building the 8 (tandem seating) and C.G. is an issue. I am not a small person (6?5? and 250#), I am looking at either the new IO-390 or an IO-360, and a constant speed propeller.

Donald
Click to expand...

You MUST put it in the back with this config.
Maybe further back than design given its light weight

Kahuna
 
Thanks

Thanks guys for the input. I've pretty much come to the same conclusion but it helps to hear it from someone else.

I might even decide not to go with the lighter battery so that I can use the additional ballast to my advantage.

I'm trying to diet as well but considering how that's going I might need to use a big truck battery for balance. :p
 
praterdj said:
Thanks guys for the input. I've pretty much come to the same conclusion but it helps to hear it from someone else.

I might even decide not to go with the lighter battery so that I can use the additional ballast to my advantage.

I'm trying to diet as well but considering how that's going I might need to use a big truck battery for balance. :p
Click to expand...

Gill G-35's are pretty heavy :)
 
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