I have been flying the Mayhem around for a couple months now and im having a ball with it. I find now that i want to move the cg back a bit for some things and forward for others. I would like to be able to do it in flite for hovering etc.... Got me thinking why couldnt you make a battery mount on a track with a servo or gear motor on it so you could just position a switch or slider to move the cg back and forth for different manovers? Might be overkill but I like some flight caracteristics of the forward positions and some of the more aft positions. Sounds like a good enough system but probably a reason i have not seen such a device yet. Guess im just to lazy to keep taking the wing off an moving the weight around.