BjC: Reliability: I am confident that the electrical propulsion systems are more reliable mechanically. This is just a byproduct of electric. The cost of these systems is low..Ishmael and will probably get cheaper in time whereas petrol power, while being beautifully well understood and made by so many...is complex and prone to many kinds of possible failure modes. I also see the cost climbing...and while it does the public will gradually point "enviro-fingers" at even the classic warbirds who kept us safe in the past. I'm going to give electric a try...but hedge by bets with a radial. I may want to make very long flights. Time will tell. A radial is a perfect a compact attractive choice...except for low rpm vibration. The mount will have to be more substantial than electric. Infact...I have considered making the entire wing swappable (electric and gas). All gas related controls like throttle and mixture and carb heat...and fuel quantity could be electronically controlled/monitored in the cockpit. It's more a conversation of could over should. Weight would be comparable electric or gas...except gas gets lighter as you fly. Riggerrob CG for flouting with wings folded. I think the wings will have to be extended..or at least one wing. I think trying to add buoyancy for stable folded wing water use is a little too much of a challenge if the wings folded over the top it might be possible...and upright at 90 deg. may turn into a "sail-plane"...is that name already in use??? Wing sweep like an f14 would keep cg in place while swept...???