Yup, they supply a 7.2 motor, but they also supply a 8-cell pack - not a 7 cell. I tried a MPX 6v motor this morning and it does give a little more authority but not a whole lot. I've found some folks over on RCgroups that are successfully using low ratio gearboxes. I might look into that.

BTW - The NASA yaw vanes work, but they aren't as powerfull as I thought. I can keep the nose straight in a deep stall though.