BASIC RULES OF FLIGHT
  Some of the pioneers of electric flight have set forth basic rules to help the rest of us get started and succeed with our electric models.  Keep just a few things in mind, and you will be successful. 
  How much power is required for electric flight?
 It takes approximately 30 watts per pound of aircraft to stay in the air.  About 40 to 50 watts per pound are needed to take off from a grass field  or rise-off ground (ROG).  With 60 watts per pound, you will be aerobatic if your airframe is capable.  At 100+ watts per pound full aerobatic performance is possible.  These critical values were determined for brushed motors, therefore these numbers can be adjusted down for brushless flight.  These numbers are all relevant to the many aspects of your plane.  At MEGA Motor USA we have tested a GWS E-Starter and taken off from a smooth surface (not grass) with 23 watts per pound. Larger models like 1/4 scale and up run on 200 watts per pound.  Smaller 3D planes such as the MEGA Freedom 3D have amazing performance at 100 to 120 watts per pound.
  How should the weight be distributed? 
The motor, speed control (ESC), and battery pack should equal approximately half of all the planes weight.  For example, the airframe should be able to lift its own weight and drive train components while maintaining structural integrity.  The electric model must balance on it's airframe (CG) similar to other non-electric models. The battery is usually moved accordingly to achieve balance because it is one of the heaviest components and placement throughout the airplane is not critical.
  How does wing loading differ in electric flight? 
Wing loading is nearly the same as any other radio controlled airplane.  Roughly 15oz/sf  (ounces per square foot) is considered a floater, 15-20 oz/sf is recommended for high wing and trainers, and 20-28 oz/sf is suggested for low wing aerobatic planes.  If you are converting a glow plane to electric your wing loading will probably increase because of the battery weight.
  What is the best airplane for electric flight?
The "best" airplane is based on what you personally enjoy in a radio controlled aircraft.  We can suggest things that make a good electric airplane, but keep in mind it is only an opinion. Slow Sticks, Terry's and other 2-channel planes are great fun but MEGA Motor USA suggests a plane with at least 4 channels (elevator, ruder, ailerons, and throttle). Additionally, electric technology has advanced so quickly that you can get any type of electric plane with a performance level at par or above that of glow and gas powered aircraft.
  How accurate are these "Rules Of Thumb"?
There are hundreds of factors that play into the flight of a radio controlled airplane, this makes it difficult for us to say that the "Rules of Thumb" are 100% accurate.  For example:  You have a Cermark Glider with the following stats:  60 oz, 12 volts, 20 amps (from a factory brushed motor.  The first rule of power tells us that at 58 watts/pound this plane will have good power and climb rate, well above the 30 watts/pound needed to stay airborne.   Replacing the motor with a MEGA ACn 22/30/3 Brushless Motor will provide the same power of 58 watts per pound, however, due to the increased efficiency, power to the prop will increase from 160 to 190 watts causing the plane to perform significantly better.