Hey I also have several 4s packs. Like 4 4s 4000 mah 20 c packs. And another 4 5000 mah 20c packs. I usually run a 4s 2p set up in my boats. And also as u noted I have the 2 2s packs that I use in series all the time anyhow. What kind of kv would be good for direct drive? Over in the boat world we like to work with a prop speed around 30000 k so around 1800-2200 kv is a typical motor selection.
I'm thinking I want a mid wing for my next plane. What would be some options to build a plane around the 4s cells I have and I don't see why I couldn't utilize my 120 amp speedo. Only thing is I'm more interested in the parkflyer size and it seems too keep cost down. Is it possible to get a plane servos and a motor for 200 give or take? how big a plane are we talking to use 4 s in? Wing span? And would it be foam? Not good enough to want to get away from foam. Stuff is surprisingly tough and easy to repair. I have a truck but I prefer to have the plane in the back seat vs in the bed.