Today's Message Index:
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1. 04:31 AM - Aft Battery (Nic)
2. 10:58 AM - Re: Aft Battery (Paul Schattauer)
Message 1
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--> RV8-List message posted by: "Nic" <Nic@skyhi.flyer.co.uk>
> Is this worth the extra weight? What are other builders doing?=20
Hi, A forward battery goes against current thinking, but for what its
worth, here is my experience.
Even with the rear placement of your battery the CofG issue is not
satisfactorily resolved and you will still usually require rearward ballast
to counter the problems with heavy stick forces and handling, particularly
if you have a C/s prop.
In deciding on the battery location I used electronic car rally scales and
Kevin's great Excel spreadsheet, we tried all the different options and
looked at the change in CofG. In the end I decided to install the battery in
the recess in the front baggage bay. One great advantage is that the cable
runs are short and no problems with earthling through the longerons, and
this allows for a lightweight, compact battery, and probably saved several
pounds.
Being close to the engine, but rear of the firewall seems a great
compromise.
As for Cof G, If I am flying alone I use two sail bags in the rear luggage
locker which fill the space and cant move when doing aeros.
If I have a passenger then I remove the sail bags and my Cof G is perfect.
Compare this with a long cable run, which adds weight particularly when
used in conjunction with a big battery. My build came out at 1112 lbs with
a full Christen inverted system and MT C/s prop which is not the lightest,
but reasonable.
Best Rgds, Nic
Message 2
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--> RV8-List message posted by: "Paul Schattauer" <chasm711@msn.com>
I agree with Nic
My setup is with the battery aft, MT prop heavy engine, extensive avionics,
grove gear and otherwise standard airplane. My weight came out at 1170 lbs
and CG slightly aft. I can carry a 220 lb person in the back but no more
and no aft baggage if that person is on board. Works ok for me and my wife
(she doesn't weigh near 220 but makes up for it with luggage :) I would
have been happier with the battery forward in the well in the forward
baggage compartment. Shorter wire runs, less wire weight and better
balance. I am considering using a smaller battery aft but so far the
current setup works ok. It's hard to change things that work when flying is
more fun.
Paul Schattauer
RV8 808PS
>From: "Nic" <Nic@skyhi.flyer.co.uk>
>To: <rv8-list@matronics.com>
>Subject: RV8-List: Aft Battery
>Date: Sun, 28 May 2006 12:24:05 +0100
>
>--> RV8-List message posted by: "Nic" <Nic@skyhi.flyer.co.uk>
>
> > Is this worth the extra weight? What are other builders doing?=20
>
>Hi, A forward battery goes against current thinking, but for what its
>worth, here is my experience.
>
>Even with the rear placement of your battery the CofG issue is not
>satisfactorily resolved and you will still usually require rearward ballast
>to counter the problems with heavy stick forces and handling, particularly
>if you have a C/s prop.
>
>In deciding on the battery location I used electronic car rally scales and
>Kevin's great Excel spreadsheet, we tried all the different options and
>looked at the change in CofG. In the end I decided to install the battery
>in
>the recess in the front baggage bay. One great advantage is that the cable
>runs are short and no problems with earthling through the longerons, and
>this allows for a lightweight, compact battery, and probably saved several
>pounds.
>
>Being close to the engine, but rear of the firewall seems a great
>compromise.
>
>As for Cof G, If I am flying alone I use two sail bags in the rear luggage
>locker which fill the space and cant move when doing aeros.
>
>If I have a passenger then I remove the sail bags and my Cof G is perfect.
>Compare this with a long cable run, which adds weight particularly when
>used in conjunction with a big battery. My build came out at 1112 lbs with
>a full Christen inverted system and MT C/s prop which is not the lightest,
>but reasonable.
>
>Best Rgds, Nic
>
>
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