Dave, Don't assume that battery has to go in the back with a 914, unless you
absolutely insist on such a heavy battery. My monoXS/914/Kremen CS/Hawker
Energy Odyssey RG battery combination weighed in at 836lbs with CG at
58.5''. I felt this was slightly too far forward for the CG and put 3lbs in
front of the sternpost to bring the CG back to what I thing is the ideal
position of 59''- which is compatible with pretty much any combination of
fat passenger/no luggage or no pax/max luggage and max fuel. I thought that
the 3lb penalty in lead was well worth while for the convenience and
efficiency of siting the battery in the engine compartment on top of the
passenger footwell, which also saves a fair bit of weight by avoiding long
runs of heavy duty cable and the need to build a strong retaining box for
the battery, (as opposed to sitting it in a small light tray and simply
strapping it to the firewall). The battery, an Odyssey 680 weighs only 6kg,
is rated 19ah and has the enormous cranking power of 245amps. It has coped
without a moment's hesitation with starting the engine in all weathers even
after a gap of 6weeks (or more in a Falke motorglider that I have with the
same battery). Although I have the greatest respect for Nigel Charles'
ingenuity I haven't found any need for a jump lead access system. Happy New
Year, David Joyce, 402
----- Original Message -----
From: <DJA727@aol.com>
Subject: Re: Battery in Front or Back?
> In a message dated 1/3/2003 5:27:54 AM Pacific Standard Time,
ScramIt@aol.com
> writes:
>
> > That's it that's the question. Monowheel, 912S, AirMaster prop.
> > I have the long cable set. Then I was thinking two people, fuel,
baggage,
> > maybe its better up front.
> >
>
> Steve,
>
> I just finished my CG check. I have a 914 engine and I have 2 batteries. I
> installed them in the back -- long wings too. My CG is forward in the
> envelope, but well inside. I ended up at 58.8 empty. If I remove a 20
pound
> weight from there and install it at the firewall, the CG would
be.......57.4.
> That represents the shift of moving a 20 pound weight that far forward --
> basically 1.4 inches. I have the airmaster prop also, which is a heavy
weight
> forward. You could compare the difference between the engine weights
compared
> to the battery shift and make your decision. Make sure you get this right,
> because I can tell you that once you do this CG check, you feel pretty set
in
> concrete and hoping it will work out OK. For sure, the batt goes in the
back
> for a 914. For a 912 with airmaster???
> Dave
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