Happy to hear that you are getting along with the Wingo. If the motor is rated 6.0V it will need 4 1.5 V alkaline batteries or 5 nicads. Alkalines have 1.5 V per cell and nicads 1.2 V per cell. The smallest motors are usually 7.2V which reqires 6 nicads. 8.4 V requires 1 more nicad, and so on up the scale 9.6 V, 10.8 V and so on. Some of the larger scale electrics use 20 to 30 cells. mAh is miliamperehours and is a measure of the expected endurance of a battery pack. 1,000 mAh is one amp. If your motor requires 1/2 amp to run 5 minutes you need a 500 mAh battery pack. Usually with electrics your ESC (electronic speed control) should have a BEC (battery eliminator circuit) if the receiver and the motor run on the same pack. The BEC will shut down the motor when a certain voltage is reached and leave enough power to run the receiver. Typical shutoff is 4.8 V. Most electric flyers prefer nicads because they are rechargable. Some can be recharged up to 700 times. Compared to the cost of alkalines you can save the cost of a charger quite soon. Please note the above figures are general. I have a GWS Slow Stick with a 7.2 V, 400 mAh battery pack that will run full throttle for 7 minutes static. That's on the ground without moving. In the air it is not necessary to fly full throttle at all times. Slow the motor down and the airplane will fly about 11 or 12 minutes. A gear box allows you to turn a larger prop when needed and is usually necessary for two meter sailplanes that typically fly with 10 or 12 X 8.4 props. If you want your electric to resemble a real life airplane Sig makes an ARF (almost ready to fly) that includes the motor and ESC. It is a lovely little plane. If you have mastered the Wingo you should handle the Rascal quite well. The Hobby Lobby catalog has a listing of many airplanes and you can get as large and complicated as you wish.