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Electric RC AirplanesThere has never been a wider variety of affordable electric RC airplanes. Due to advancements in RC electric motors and battery technology, electric model airplanes have more power and longer flight times than ever before! Today’s electric model airplanes can do anything a nitro or gas powered airplane can do! In fact, many people have converted glow powered airplanes to electric model airplanes. The beauty of an electric RC plane is that there is never on oily mess to clean up when finished flying. There is no need for carrying a gallon of fuel or troubleshooting an engine for hours to discover that there is a pin hole in the fuel line! With an electric RC plane you simply charge the batteries and fly! Small electric RC airplanes are perfect for starting out in this hobby. I personally learned to fly with an electric park flyer. Park flyers are small electric airplanes that usually come with everything installed and ready to fly. Park flyers are cheaper and more durable than glow planes. RC electric airplanes are quieter, safer, and can be flown in fields, parks, and other places where glow powered airplanes can’t be flown. Electric RC Airplane Components.An electric RC plane needs batteries, a motor, sometimes a gearbox, and an electronic speed controller (ESC).Electric Motors The motor can be either a brushed or brushless motor. Brushless motors are more expensive but are much more powerful and efficient. To fully understand the difference between brushed and brushless motors you need to understand how motors work. "How Things Work” has a great article that does an excellent job of explaining how motors work. The graphics in the section were taken directly from that article. Standard "Canned" Brushless Motor
Brushless Motor
Electronic Speed ControllerAn ESC is what controls the speed of the RC electric motor. The ESC plugs into the receiver. Both the motor and battery plugs to the ESC. As you move the throttle stick, the receiver tells the ESC to change the speed of the motor. It is very important know that electronic speed controllers are made differently for brushed motors than they are for standard brushless motors. An ESC made for a brushed motor will not work with a brushless motor, and vice versa.GearboxMany electric RC airplanes have gearboxes between the motor and propeller. These are generally made from plastic. The speed at which an RC electric motor runs most efficiently is often much faster than we want the propeller to turn. Gearboxes reduce the speed and increase the torque in order to swing larger propellers. Some electric RC planes use gearboxes, others don’t.BatteriesThe batteries supply power to the motor. The three types of batteries most commonly used with electric RC airplanes are Nickel Cadmium(NiCd), Nickel Metal Hydride (NiMH), and Li-PO. Each type of battery needs to be charged differently and may require different chargers. Be sure to read the directions that come with your batteries carefully. Many park flyers come with only one battery. When flying electric RC airplanes you always want to have 2 or 3 batteries on hand. Nothing is worse than going out to fly and spend more time waiting for your batteries to charge than you do flying!NiCd batteries are commonly used for transmitters and receivers of both gas and electric RC airplanes. Many lower priced park flyers use this type of battery also. The main disadvantage of NiCd batteries is that they have a memory. In other words, the capacity diminishes if you do not fully discharge the battery after every use before recharging. NiHM are similar to NiCd batteries and have less issues with “memory” The capacity per weight is more than that of NiCd batteries. I replaced my receiver NiCd receiver batteries with NiHM batteries and they last about twice as long before having to be charged. LiPo batteries are a quantum leap from the other two types of batteries. These batteries pack an enormous amount of energy and are much lighter than the other two types. LiPo batteries combined with brushless motors have enabled electric RC airplanes to keep up with nitro powered airplanes. LiPo batteries keep a constant power output throughout the flight where as NiCd and NiHM batteries slowly loose power until the battery is dead. There is one major drawback to LiPo batteries. They are dangerous! Remember the Dell laptop computers that were blowing up? Those were LiPo batteries! There have been several fellow R/C’ers have their homes burned down because of these batteries exploding. I don’t mean to scare you away from LiPo batteries because quite frankly they are the best batteries. But if you do choose to get a LiPo battery, do NOT leave it charging unattended even for a second! It is also a good idea to store LiPo batteries in a fire proof box. Hooked on RC Airplanes Home Page
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Lets start with a standard brushed motor, also referred as a “canned” motor. Every brushed motor has an armature. This is the shaft of the motor that rotates. An armature has poles (usually 3 or more) and a commutator. The poles are nothing more than copper wire wrapped around a piece of metal to form an electromagnet. The copper wire of each pole (or each electromagnet) is attached to a terminal. Each terminal is wired to the commutator. A commutator consists of three plates (for a three pole motor). Electrical current flows from the battery to the commutator through the brushes of the motor.
The brushes (or tabs) in the motor cap are wired to the battery and make contact with the plates on the commutator as the armature rotates. When the brushes come in contact with the appropriate tabs of the commutator, a particular pole (electromagnet) is charged. The "can" is lined with two magnets of the opposite polarity. So when a pole is charged it is attracted to one of the magnets and repelled by the other. 
As the armature rotates the pole will pass a magnet and the brushes will come in contact with the next set of tabs on the commutator. This reverses the polarity of the pole, and it is now attracted to the next magnet in the "can". When the pole reaches the next magnet the brushes switch to the next tab on the commutator. Each pole switches polarity each time it passes a magnet and therefore is repelled by the magnet it just passed and is attracted by the next magnet. The process repeats as long as power is supplied to the motor.
Brushless motors work on the same principal as brushed motors, except the permanent magnets are on the armature and the electromagnets are on the outside. This eliminates the need for brushes! This is why brushless motors are so much more powerful and efficient. When dealing with electric RC airplanes, power to weight ratio makes all the difference in the world! The introduction of brushless motors has made it possible for electric motors to power large model airplanes that only could be flown with nitro-powered engines in the past. The significantly increased power to weight ratio of brushless motors has opened the door for an entire new category of electrical RC airplanes including indoor RC airplanes! 