In electric aircraft, the propellers are turned by a motor powered by a rechargeable battery pack. An electronic speed control (ESC) regulates the motor's output for throttle control. The motor, battery, and ESC are all installed on-board the model. The first electric R/C models were equipped with brushed motors — in which brushes carry current and spin the rotor — and nickel-cadmium (NiCd) rechargeable battery packs. They provided flight times of around 5-10 minutes.
A glow engine plane of similar weight and power, however, would allow nearly double that flight time when fully fueled. Electric systems have now been developed that take advantage of brushless motor technology for much better results.
In a brushless system the ESC energizes the motor's electro-magnetic field, and that causes the motor to turn. Compared to brushed motors, there's less friction, waste heat, and wear. Brushed motors are only about 35-40% power-efficient...brushless motors improve that to 80-90%! And the recent improvements in motor technology are only part of the story behind electric models' surging popularity.
Rechargeable battery technology has made enormous forward leaps, too. First, the higher-capacity nickel-metal hydride (NiMH) battery chemistry appeared as an alternative to NiCds. Flight times improved. NiMH performance was soon surpassed by lithium batteries. With lithium batteries and brushless motors, electric flight times and power can approach — even exceed — that of glow engines!
Choosing an electric motor.
You'll find electric options for everything from trainer planes to park flyers to scale giants. Today's brushless electric power systems even provide enough pinpoint control and instantaneous, all-out power for jaw-dropping 3D aerobatics! Of course, the Tower Hobbies web site gives very thorough and specific completion item recommendations on every aircraft product page. That's an excellent resource for anyone new to R/C flying, period. If you decide to select a motor on your own, you'll notice that the motor requirement is indicated by a "kV" number, such as "800kV". That number indicates the power output, expressed as rpm per volt of input. Running an 800kV motor using 6V of input means that the motor will turn at 4800 rpm.
Brushless motors by ElectriFly include that kV number in their product names, preceded by two other numbers — for example, "42-50-800kV". The first is the motor's can diameter in millimeters; the second, its length in millimeters. Match the motor size that your model will accept with the power output required, and you've made an appropriate choice for your plane.
Depending on the airplane, you may be advised to buy an inrunner or an outrunner brushless motor. What's the difference?
Motor Systems take the guesswork out of matching the right motor with the right ESC – because the work’s already been done for you! Available for a wide variety of aircraft, Motor Systems also usually include a propeller and other required hardware. For maximum convenience and incredible savings, look for Motor Systems
on Tower Hobbies.com!
Inrunner Brushless Motors:
"Inrunner" motors are the standard type in which the motor can is stationary and the shaft spins inside. The motor can is longer and thinner, allowing higher rpm and making them better for ducted fan planes, racing planes, and planes with thin noses. Some applications might require pairing the inrunner motor with a gear drive, which adds to the cost and installation effort.
Outrunner Brushless Motors:
As the name implies, "outrunners" work the opposite of inrunners — in this case, the shaft is fixed and the can spins around it. An immediate benefit of this style in R/C use is that they can turn larger, more efficient propellers without needing gearboxes. That makes them a simpler, lighter weight, less expensive power option suitable for all sizes and styles of aircraft.
The rest of the electric power system.
- Rechargeable battery (NiMH or Lithium)
- Electronic speed control
- Motor mount
- Prop adapter
Once your aircraft is chosen, built and covered, there's only one thing left to do...fly it! To do that, you'll need what we refer to as "flight line equipment"—such as fuel, a fuel pump, engine starting equipment and a few other basic tools. Except for the fuel, most flight line supplies are one-time purchases. You can use them throughout your modeling career, with as many different models as you fly.
Most modelers go to the field equipped with the following, all stored in a "flight box" for easy transport:
— the centralized power source for electrical field equipment.
12V Field Battery
— to supply power to the power panel.
— to recharge starter, motor or radio batteries.
Charger Shopping Tips & More
Glow Plug Clip
— an electric device that gives your engine's glow plug the initial heat it needs to burn fuel.
— to move fuel from your gallon can or jug to the plane's fuel tank, available in hand-crank or electric-powered styles.
Fuel Line, Filters & Cap Fittings
— to connect your fuel to the pump, and the pump to the plane's fuel tank.
12V Electric Starter
— a device for quick, easy engine starting, powered from the power panel (a small wooden dowel or "chicken stick" can also be used).
— including a 4-way glow plug/prop wrench.
Glow Plugs and Propellers
— it's always a good idea to carry extras...without a spare, you might be forced to stop flying early.
The glow fuel
used for a model engines carries a percent rating, which indicates its nitromethane content. For trainer aircraft, 10% or 15% is recommended. Use a good quality fuel with a blend of castor oil and synthetic lubricants to protect your engine. Avoid "cheap" fuels, which sometimes attract moisture and cause engine parts to rust.
Model planes can use several different types of power sources. Electric models carry battery-powered motors to turn the propeller. Gliders or sailplanes ride on thermal air currents (some also have electric motors for quick launching to great heights). Most R/C models, however, are powered by Glow Engines
The most economical are basic 2-stroke engines with brass bushings supporting the crankshaft. For a little more power, you might choose a 2-stroke that uses ball bearings to support the crankshaft. The ball bearings also extend the life of the engine, so you can continue using it to power future models. The cost, however, is nearly twice that of a bushing-equipped engine.
Finally, there's the 4-stroke glow engine—slightly less powerful than 2-strokes of the same size and higher priced, but offering more torque, swinging bigger props, using less fuel and sounding much more realistic.
Another popular power option for pilots is gasoline engines. There are many advantages to gasoline power. First off, fuel is not only more affordable, it’s also as close as your nearest local station. Gasoline engines offer low-rpm, low-noise operation, which makes them ideal for noise-sensitive flying fields. In addition, they’re easy to tune, exceptionally economical, cleaner-burning and longer-lasting!
R/C planes are controlled by a Radio System
that consists of a transmitter—which stays with you on the ground—plus a receiver, servos, and receiver battery (all of which are "on-board" components, mounted inside your model). Most aircraft radio systems come with everything you need, including a rechargeable battery pack.
As mentioned earlier, first-time pilots should always seek the help of an instructor. And an important part of working with an instructor is making sure that both of you use radios with "trainer box" or "buddy box" capability. The trainer system allows you to connect your radio to your instructor's, using a cable. You'll still be the one controlling your model, so long as your instructor holds down the trainer switch on his transmitter. But if you start having trouble, all the instructor has to do is release the switch to take over full control.
Most trainer planes require a radio with at least four channels of control, to operate the throttle, elevator, rudder and ailerons. But not all 4-channel radio systems come equipped with the necessary four servos. Make sure your system has as many as your plane requires.
One "ideal" first 4-channel radio is the Futaba 4YF 4-Channel 2.4GHz Sport FHSS
. Futaba quality, FHSS technology and an economical price make the 4YF 2.4GHz Radio an excellent choice for cost-conscious modelers wanting an interference-free spread spectrum system for sport flying. The 4YF has always been a great value – and now it's enhanced with cutting-edge 2.4GHz performance and security!
When you buy a model airplane, you'll probably also need to buy a number of additional, inexpensive accessory items to make it flight-ready (those items are listed under the Accessories Required links for the plane you choose). These parts are traditionally left out of kits because the appropriate sizes depend on your choice of engine; also, experienced hobbyists may have a brand preference or already keep those parts in their workshop. Required accessories often include the following:
— The adhesive-backed, plastic or fabric "skin" that surrounds a model airplane's structure, applied by a process of heating and stretching.
— Rods that link your radio system's servos to the parts of the model that those servos move. They're often made of wire or a firm piece of balsa, fiberglass, or plastic, with a clevis fastener at the end.
— A bracket, mounted on a part of the model, where the pushrods are attached.
— Connect the moveable surfaces of a model to the main, static structure.
— Used to cushion the on-board radio equipment to protect it from engine vibration.
Wing Seating Tape
—Applied where the wing fits onto the fuselage, to cushion the wing and prevent exhaust oils from entering the fuselage.
— Small metal collars which keep the plane's wheels positioned correctly on the axle.
— Available in several styles, such as treaded, non-treaded, scale, and air-filled.
— Plastic or aluminum cone mounted at the "nose" of the plane to improve looks and aerodynamics.
— Reinforced structure, often made of nylon or aluminum, that allows your engine to be attached securely to the plane.
Fuel Tank, Tubing & Filters
— The size used depends on the engine you select; therefore, these often are not included with the model.
— Propellers are usually not included with the engine or the plane; also, your engine may or may not come with a muffler
and glow plug
Tools & Building Equipment
Regardless of whether a model comes in kit form or prebuilt, some Building Tools and Workshop Accessories
will be needed to make it flight-ready. These include such common items as a hobby knife, T-pins, screwdrivers, pliers, sandpaper, masking tape, and perhaps a drill. Building a kit also takes some specialized equipment like covering tools. Follow the Accessories Required links for the plane you choose to see a list of the tools needed.
R/C model building adhesives are also required, and differ from the white glue and model airplane cement you may have worked with in the past. Cyanoacrylates are commonly used. These are glues specially formulated for working with wood, which provide a range of curing speeds—giving you as little or as much time as each assembly step requires. "Thick" cyanoacrylates also help to fill slight gaps between parts.
Modeling Epoxies are two-part adhesives, consisting of a resin and a hardener. At steps where very strong bonds are critical, a plane's manual will often recommend epoxy. The resin and hardener must first be mixed, then applied to the surface—so mixing cups, mixing sticks and inexpensive, disposable epoxy