The latest Apollos use a brushless motor and a motor timer/height limiter,but they do retain the seven cell NiMh battery as part of the competition specification. If you aren't going to fly in competitions, the battery and power train aren't important. Enough power to climb to a decent height with enough left over for an emergency power-up,and enough weight to enable the glider to penetrate and get up-wind, with the C of G in the right place, the Apollo will more or less take care of everything else. Component Shop is a good source of 7 cell NiMh packs.