Yeah that's a AA pack. I don't like using AA on my 50cc planes. You need a beefier cell for this stuff.

4/5A FAUP 1950 5-cell about 1/3 of the way down this web page:
http://www.hangtimes.com/giantrxpacks.html

4/5A Elite 2000 5-cell near the bottom of this web page. You can get a heavy duty bars soldered on these packs for just a few bucks. Don't let their name fool you. The pack is awesome quality and well built.
http://www.cheapbatterypacks.com/?si...ells&chem=NIMH
http://www.cheapbatterypacks.com/cel...nvid=ELITE2000