So I was thinking, hmm, the 1300mAh 2S batteries have the same footprint as the 1300mAh 3S batteries from my Glasair, so I bet I can get one in there.
I still had the wrecked canopy from the ill-fated maiden flight, so I taped up the cracked top and cut a recess in the bottom of it to allow for the extra height of the 3S pack. Mr. Pilot is still there, but I think he was cutting washers out of his seat cushion.
The CG remained the same because the battery is positioned over it. The stock prop is an 8.25 x 5.5, but I went ahead and put an 8 x 6 APC prop on just for grins.
I went to the field this morning and put her in the air. Wow! The scale purists won't like it because of the speed, but this little bird can fly!
I set the timer for 6 minutes. The battery voltage was 3.7V, so I could have flown a while longer, but the wind was kicking up so I decided to pack it in for the day.
There were two downsides. First, adverse yaw really shows up in a turn. I use an aileron/rudder mix set at 100%, and that wasn't enough. I had to add rudder to keep the nose in line.
Second, it came in very hot, and it was really difficult to get it to slow down enough to land. Our field is 600' long x 200' wide, and I used every bit of it to land. I need to set the battery back a bit, and maybe try the flaps mod.
Anyways, it was an easy mod and completely reversible. Just install the stock canopy, prop, and battery and fly lazily around the field. What ever suits your mood!