Hey Duncan, are you on the ARCN discord server? seen your name here and there.I did some experimenting with where I can put the battery and receiver to make it balance. If I put them here, it balances round about on the spar (maybe slightly forward).
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That's about as far back as I can get this battery with this hatch. I'm considering making some sort of tray so the battery can be velcroed to that, and then the tray can velcro to the fuse. That way I can get the battery further down inside the plane and still get it in and out! I'm not sure the hatch is big enough to do that and get the tray and the battery in at the same time, (and there's not really enough space for a sliding tray). I had similar battery placement issues with the last foamboard -> depron build I did (flite test mini scout) - think I need to learn my lesson and make the tail from something a bit more heavy duty next time!