Didn't see any specs on mass or energy density.
But for 1/2A control line the electric power plant is very feasible.
I like to fly these for sport.

http://www.stevensaero.com/StevensAe...0-p-20279.html

With the larger prop disk area my disk loading is actually better than most of my slime power 1/2As. The consistent power flight after flight and with steady power through out the whole flight, actually make the electric C/L more desirable. I think there are now electric precision aerobatic C/L ships that are competitive in the FAI classes.

I will say that the set up shown in the link performs much like a Cox Black Widow on a 5.25 x 4 prop. A properly set up Tee Dee will out pull the shown set up but it is very difficult to get the kind of reliability, of the electric, with a Cox. There are good reasons that the Cox 1/2A is now relegated pretty much to just nostalgia.

All the best,

Sparky

FYI,
I don't use the GWS prop.