The receiver in your airplane would typically is powered by 4.8 volt NiCd or NiMh battery. But this can be accomplished in two ways. 1) separate receiver battery (4, 1.2 volt NiCd or NiMh cells in series with a plug that matches the receiver, or 2) via a battery eliminator circuit (BEC) from the electronic speed control unit used to control the speed of the electric motor. Not knowing what the motor specs are, what the ESC is, how big the airplane is, etc, it is hard to tell what you need for a battery. A 500 - 850 mha 7-8 cell battery does not have very much capacity so your Aspire must be a very small foam type airplane. A 7 - 8 cell battery (NiCd or NiMh) is either 8.4 or 9.6 volts so I suspect the motor is a brushed in-runner. But if it has speed control there must be a speed control in the airplane. Whether or not that unit provides a 4.8 volt source for the receiver is what you need to determine. I'm not familiar with the airplane so unless you provide more detail I'm done here.