Bryan- excuse me for feeling like I am sitting in court with you cross examining me. I am not making this stuff up just to be blabbing here! Its a real small lithium ion battery about the size of a cigarette pack. from a golf cart shop. Heres the kicker, my main Odyssey 680 batteries weigh 30 pounds together and are back behind my turbine. I could replace them with lithium ion batteries that together weigh 7.5 pounds. That would be around a 22.5 pound savings..........but I need the weight of those heavy batteries for my weight and balance. I would have to have those super light batteries clear back on the tail and with more ballast also. My 30 pounds of batteries are on a moment arm of 48 inches. Their weght is aproximately 1/30 of my flying weight of 900 pounds. The batteries can slide for and aft on my tail boom. Since they are 1/30th of my average weight, every inch I move them forward causes my CG to shift 1/30th of an inch as well. But lets drop those 30 pound batteries and replace them with the 7.5 pound total that the lithium ion batteries weigh. The 30 pounds of batteries are on a 4 foot moment arm. The 7.5 pound batteries are 1/4th the weight and would need to have a moment arm 4 times farther back - or 16 feet back. I am not near my calculator, but it would be slightly less than 12 feet since my total flying weight is 22.5 pounds less. Stan
