For a half-A size electric, I wanted something that would fly on at least 35' or more of .008 cable and would fly through the pattern maneuvers, not great maybe, but well enough that I'd enjoy flying it. I found that it took more power than I thought it would, had to go to larger motors and batteries, that was heavier so needed more wing area. After a number of designs I ended up with about 250 sq ins wing area and about 12 to 15 ozs ready to fly weight. Lighter without landing gear, I fly over grass, put landing gear on for indoor flying in sports domes etc. When Bob Hunt flies it, he does things like Cotter Pins and Point-Down Triangles, lays down on the grass while flying, he has a lot of fun and we get a lot of laughs with it.
I'm using 3-cell LiPo packs, 1500, 1800, up to 2000mah ratings. Different motors drawing 12 to 16 amps. So about 150 watts to get the performance I wanted. Haven't got to sophisticated timers, I use the Zigras timer, run wide open till cutoff, hey this is simply a small size aircraft, flying for fun. My latest electric C/L was in the April 2006 issue of FM, plans and details in there.
Outrunner motors with 8 or 9" props, inrunner motors with geared setups turning 11" props much slower, both approaches work, outrunner setup is easier. I went with sheet foam construction for simplicity. For years I flew half-A sheet balsa profiles and enjoyed them, now I enjoy the electric foam sheet profiles. With enough power I've flown an electric on 45' lines, it handles well. One of the planes pictured has an airfoiled foam core cut by Phil C., his half-A combat wing, and it works well, but it could use some more area.
I'm sure electric C/L could be, is being done with smaller motors and batteries, lighter airplanes and shorter lines. I've seen the indoor small electric C/L slow flying videos, they're neat, I just wanted something larger for outdoor flying, the stuff I prefer.
Next step for better performance would be to make a light weight built-up balsa airplane, something like Larry Renger's latest Sky Sport in FM with a little more area, for this electric power setup. When I get around to it.