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INDOORS OR OUT, ELECTRIC HELICOPTERS WILL GIVE YOU A CHARGE!Electric Helicopters are experiencing the strongest growth segment in the RC helicopter hobby right now. This of course is due to better battery and motor technology that was not available even a few years ago. For all the reasons outlined in the Best RC Helicopter Power section, growing popularity will continue. Don't think electric RC helicopters have caught up to nitro in terms of performance? Watch Bobby wring out Miniature Aircraft's MA 450 - amazing! My personal favorite thing about electric helicopters is the noise they produce. The quiet electric motor allows you to hear the rotor blades interacting with the air much more. You can even hear when the rotor blades change pitch angles as they beat the air molecules into submission – what an amazing sound! This is a transitional time in the RC aircraft hobby right now. RC electric helicopters and planes are getting better and better. Flight times are equal to or even longer than on nitro and gas models. Some electric RC Helis and planes are getting 15 - 20 minuet flight times on a single battery charge. To say the future looks bright for electric RC aircraft is an understatement. As we discussed in the Best Helicopter Size page, electric helicopters are currently limited in size to having rotor diameters of less than 1500mm (60 inches). On the other end of the size spectrum however, they keep getting smaller with rotor diameters down to about 150mm (6 inches). Miniature Aircraft's Ion... One of the largest and highest quality electric RC helis on the market with a rotor diameter of over 1580mm. If you fly in windy conditions and want a powerful 3D aerobatic electric heli - the Ion is in a class of its own. 
The Air Hogs Havoc Toy RC Helicopter is on the other end of the electric heli size scale with a rotor diameter of only 150mm. 
Obviously as technology advances, electric RC helicopters will continue to push both those size boundaries further – this is really exciting. Imagine small electric RC helis the size of small dragon flies or large ¼ scale electric helicopters with rotor diameters of over 2500mm. The overall design of hobby grade electric helicopters is no different than that of nitro or gas. The controls and construction are exactly the same. In fact, several manufactures offer the same model helicopter kit in both electric versions and nitro versions, or supply electric conversion kits. The only differences of course are having an electric motor instead of a nitro engine, a battery pack in place of a gas tank, and an electronic speed controller in place of a throttle servo. As I indicated earlier there are three reasons electric RC helicopters have caught up to the performance of nitro helis and are poised to surpass them in some areas: Without these three technologies, electric RC helicopters would remain small with poor performance. BATTERIES Lithium battery packs are generally not supplied with the helicopter kit. This is because the helicopter manufactures recognize that everyone has different needs when it comes to flight times, performance, and budget. I should mention that some micro electric helicopters use Nickel-Metal-Hydride (NiMH) batteries. They cost less than Li-Po or Li-Ion batteries, but don’t provide enough battery capacity for larger electric rc helis. As Li-Po batteries continue to come down in cost – Ni-MH will most likely become obsolete for use in electric RC helis. My advice when you are learning is to get the largest capacity battery you can afford. Stick time when you are learning is more important than saving weight with a smaller battery. There is nothing more frustrating than just being on the verge of controlling a hover and the battery dies out every 5 minuets. Get a battery that will give you at least a 10 min flight per charge with your specific heli. It is a proven fact that hand eye coordination will improve much quicker with longer practice sessions. This also means it is beneficial to have one or more spare battery packs if your budget allows. BRUSHLESS ELECTRIC MOTORS Most electric RC helicopters will be supplied with the motor and matched speed controller. In most cases these motors are very sufficient for learning how to fly or general sport flying. You may want to upgrade to a stronger and more efficient motor as you progress or when your motor wears out. Brushless motors if looked after will last a long time however. The motor selection out there right now is vast and confusing. The fact that there is really no standardized method of rating motors clouds the issue even more. I could probably create an entire web site on brushless DC motors and speed controllers for the RC hobby industry. The only advice I can give you is talk to your local hobby shop or other RC heli pilots, and see what they recommend and have experience with. Just remember, in the electric motor world, more costly doesn’t always mean better. If you upgrade or have to replace your electric motor, you will need to get a motor with the same or similar Kv rating and physical size to fit your specific electric helicopter. Remember – you have to keep your rotor head speed at the correct RPM. If you change the motor Kv rating much, you will have to play around with changing pinion gear sizes to maintain the correct rotor speed. For most people efficiency is going to be more important than power and, good cooling is more important than weight savings. Long motor life is probably the number one criteria for most people so stay away from inexpensive motors that claim very high power output. These types of electric motors tend to run hot and lose their core magnetic fields – this translates to power loss and eventual motor failure. Electric helicopters are a compromise between size, power/performance, and flight times - in the years to come, those compromises will fade substantially. Miniature Aircrafts Ion helicopter is living proof of this.
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