Radio:  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 system" 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.

Aerodynamics: To fly, an airplane's wing has to overcome gravity by developing lift greater than the weight of the plane. Since it can't do that standing still, airplanes use thrust...force directed backwards...to drive the wing forward through the air and generate lift. However, thrust has its own opposition to overcome in the form of drag—the resistance of the air to a body moving through it. If lift and thrust are greater than gravity and drag, you have the potential for flight...and fun.

Wing Location: Wing placement, for the most part, falls into two major categories—high wing design and low wing design. In a high wing design, the weight of the model is suspended below the wing. When the model tilts, the model's weight tries to return it to a level position. As a result, high-wing models tend to be more stable, easier to fly—and natural choices for trainers. A low-wing model is just the opposite. With its weight above the wing, it tends to be less stable—excellent for advanced fliers who want to perform rolls, loops and other aerobatic maneuvers.

Airfoil: If you face the wing tip of the plane and cut it from front to back, the cross section exposed would be the wing's airfoil. The Flat-Bottom Airfoil will develop the most lift at low speeds and helps return the model to upright when tilted. This is ideal for trainers and first-time pilots. A Symmetrical Airfoil's top and bottom have the same shape, allowing it to produce lift equally whether right side up or upside down and to transition between the two smoothly. This is recommended for advanced pilots. Lastly, a Semi-Symmetrical Airfoil is a combination of the other two and favored by intermediate and sport pilots.

Wing Area/Wing Loading: Wing area is the amount of wing surface available to create lift. Wing loading is the weight that a given area of the wing has to lift and is usually measured in ounces per square foot. Generally, a light wing loading is best for beginners. The plane will perform better and be easier to control.

Dihedral: Dihedral is the upward angle of the wings from the fuselage. Dihedral increases stability and decreases aerobatic ability.

Wing Thickness: Wing thickness — measured from top to bottom — determines how much drag is created. A thick wing creates more drag, causing slower speeds and gentler stalls and is ideal for beginners. A thin wing permits higher speeds and sudden stalls — desirable for racing and certain aerobatic maneuvers. Landing Gear Location: Tricycle gear includes a nose gear and two wing (main) gears, making takeoffs and landings easier—ideal for beginners.

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Kits vs. Prebuilt

Until recently, most R/C airplane models came in Kit form—consisting of a box full of parts, a set of plans, an instruction manual and some hardware. And kits remain very popular. Many modelers enjoy the challenge of putting them together as much as actually flying them. Depending on the kit, however, assembly can take weeks or even months to complete, and also requires a well-equipped hobby toolbox.

For a number of reasons—including a shortage of leisure time—hobbyists are now turning to "prebuilt" models as another way to enjoy R/C flight. Actually, prebuilt planes are great for first-time pilots. Because they come factory-assembled, you KNOW they're constructed well. Many are put together with materials as high in quality as any kit. Because you haven't put your heart and soul into building them, you're less likely to be nervous when flying them. And they let you focus on learning to fly, without also having to learn new model building skills.

You can choose from models with varying degrees of preassembly. The following acronyms are commonly used to identify types of prebuilt planes:

ARF: Stands for "Almost Ready-to-Fly." Most can be completed and flight-ready with as little as 16-20 hours of assembly. Major structures such as the wing halves, fuselage, and tail fins all come entirely built and covered. Average cost for a complete (but no frills) beginner package runs around $100-$150 You simply assemble those sections, install your power plant and radio gear is extra, attach the landing gear and a few other pieces of hardware...and you're done.

RTF: Stands for "Ready-to-Fly." Want a model that's ready for the air as little as 20 minutes after you open the box? Get an RTF. You'll still have to complete a few final assembly steps, but far less than even ARFs require. True RTFs include engine and radio gear already mounted inside the model. There's no easier way to get airborne! Average cost for a complete (but no frills) beginner package runs around $200-$350.

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Choosing the Size of Your Plane

The "size" of a model plane generally refers to the size of engine, in cubic inch displacement, required to fly it successfully. The most popular sizes are 20 (requiring a .20-.36 engine), 40 (.40-.53 engine) and 60 (.60-.75 engine). Many other sizes are available, too, ranging from small, .049-powered craft up to massive, giant-scale models.

Most trainers fall into the 40-size category. That's because 40s are fairly stable, with enough heft to fly well in breezy conditions, but still small enough to be affordable for new hobbyists. Many 60-size trainers are also available, and offer the advantage of even greater stability—plus easier visibility once aloft—both due to their larger dimension.

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Choosing Your Type of Plane

Flight controls allow pilots to control the collective and throttle (usually linked together), the cyclic controls (pitch and roll), and the tail rotor (yaw). Controlling these in unison enables the helicopter to perform most of the same maneuvers as full-sized helicopters, such as hovering and backwards flight, and many that full-sized helicopters cannot.

The various helicopter controls are affected by means of small servomotors, commonly known as servos. A piezoelectric gyroscope is typically used on the tail rotor (yaw) control to counter wind- and torque-reaction-induced tail movement. This "gyro" does not itself apply a mechanical force, but electronically adjusts the control signal to the tail rotor servo.

 The engines typically used to be methanol-powered two-stroke motors, but electric brushless motors combined with a high-performance lithium polymer battery are now more common and provide improved efficiency, performance and lifespan compared to brushed motors, while decreasing prices bring them within reach of hobbyists. Gasoline and jet turbine engines are also used.

Types of R/C helicopters

Common power sources are nitro (nitro methane-methanol internal combustion), electric batteries, gas turbines, petrol and gasoline.

Mechanical layouts include CCPM (cyclic/collective pitch mixing) in all power sources, fixed- pitch electric rotors and coaxial electric rotors.

Practical electric helicopters are a recent development but have rapidly developed and become more common, overtaking nitro helicopters in common use. Gas-turbine helicopters are also increasing in popularity, although the high cost puts them out of reach of most people.

Nitro (glow fuel)

Nitro or glow fuel helicopters come in different sizes: 15, 30, 50, 60 and 90 size. These numbers originated from the size of engine used in the different models (0.30 cu in, 0.50 cu in and so on). The bigger and more powerful the engine, the larger the main rotor blade that it can turn and hence the bigger the aircraft overall.  Typical flight times for nitro helicopters is 7-14 minutes depending on the engine size and tuning.

Electric

Recent advancements in battery technology are making electric flying more feasible in terms of flying time. Lithium polymer (LiPo) batteries are able to provide the high current required for high performance aerobatics while still remaining very light. Typical flight times are 4-12 minutes depending on the flying style and battery capacity.

In the past electric helicopters were used mainly indoors due to the small size and lack of fumes. Larger electric helicopters suitable for outdoor flight and advanced aerobatics have become a reality over the last few years and have become very popular. Their quietness has made them very popular for flying sites close to residential areas and in places such as Germany where there are strict noise restrictions. Nitro helicopters have also been converted to electric power by commercial and homemade kits.

A recent innovation is that of coaxial electric helicopters. The system's inherent stability has, in recent years, made it a good candidate for the design of small models for beginner and/or indoor use. Models of this type, as in the case of a full-scale helicopter, eliminate rotational torque and extremely quick control response, both of which are very pronounced in a CCPM model.

While a coaxial model is very stable and can be flown indoors even in tight quarters, such a helicopter has limited forward speed, especially outdoors. Most models are fixed-pitch, i.e. the collective pitch of the blades cannot be controlled, plus the cyclic control is only applied to the lower rotor. Compensating for even the slightest breeze causes the model to climb rather than to fly forward even with full application of cyclic. More advanced coaxial constructions with two swash plates and/or pitch control - common for the big coaxial helicopters like Kamovs- have been realized as models in individual projects but have not seen the mass market as of 2009.

Radio gear

Small fixed-pitch helicopters need a 4-channel radio (throttle, elevator, aileron, rudder), although micro helicopters that utilize a 2-channel infrared control system also exist; while collective-pitch models need a minimum of 5 channels with 6 being most common (throttle, collective pitch, elevator, aileron, rudder and gyro gain). Because of the normal interaction of the various control mechanisms, advanced radios include adjustable mixing functions, such as throttle/collective and throttle/rudder.

Radio prices vary from $100-$2,000 USD.

Well-known manufacturers of helicopter-specific radio controllers include: JR, Spektrum, Futaba, Hitec, Sanwa(known as "Airtronics" in North America), Multiplex(a division of Hitec)

Modulation

Radios emit the FM signal in two types of modulation.

PPM is cheaper than PCM and is generally used in low-end helicopters. The lack of a failsafe in PPM makes it more suited to small, less dangerous models. Higher-end radios offer PCM and PPM modulation for better compatibility with all radio receivers.

Pulse Code Modulation. A scheme in which the commanded position for each servo is transmitted as a digitally encoded number. Manufacturers use their own proprietary system to encode this number with various levels of precision (i.e. variable number of bits per servo position). JR use Z-PCM (9 bits, 512 different values: 0 ... 511) then S-PCM (10 bits, 1024 values: 0 ... 1023). Futaba use PCM-1024 and G3 PCM (11 bits, 2048 values: 0 ... 2047). With PCM not all positions are broadcasted at one time (each frame) to save time. The odd numbered positions are sent as absolute in one frame, with the even sent only as differences

from their previous values. The next frame the opposite is done. PCM includes a check sum at the end of the frame to check the signal's validity. Hence, if there is interference and the signal arrives distorted at the Receiver, utilizing the checksum it is able to know if it is the original. In case it is not, a feature called Fail-Safe is implemented to set servo positions to a predefined position, or to hold them at the last valid position.

PPM

Pulse-position modulation. A scheme in which the commanded position for each servo is transmitted as the duty-cycle of the transmitted pulses 1 per servo position.

Spread spectrum

 Systems such as FHSS (Frequency-hopping spread spectrum) used by Futaba employ frequency hopping on the 2.4 GHz band instead of the various frequencies in the lower MHz ranges. The advantage is that radios are no longer using a fixed frequency during flight but a multitude of frequencies.

Systems such as Spektrum and JR use the DSM2 DSSS (Direct-sequence spread spectrum) method, where they transmit on a pair of fixed channels chosen when the radio and receiver are turned on. Any subsequent systems would avoid using these channels and continue searching for another unused pair of channels.

With either method many radios can be transmitting at once without interfering with each other. The Futaba systems change frequency approximately every two milliseconds, so even if two transmitters are using the same channel they are not doing so for long. The pilot will not notice any abnormal behavior of the model in the 1/5OOth of a second that they are interfering. This gives one the advantage of turning on a transmitter without regard to channels currently in use by other pilot's radios.

One downside to 2.4 GHz is that precautions must be taken during installation since certain materials such as carbon fiber can mask the signal. In some cases, "satellite" receivers with secondary antennas need to be used to maintain better line-of-sight with the transmitter

Competition

Aerobatic helicopter flying has historically followed the Federation Aeronautique International rules, which for helicopters are labeled F3C. These include a predetermined routine of hovering and aerobatics.

An advanced form of RC helicopter flying is called 3D. During 3D flying, helicopters perform advanced aerobatics, sometimes in a freestyle form, or in a predetermined set of moves drawn up by the organizers of the competition. There are a number of 3D competitions around the world, two of the best known being the 3D Masters in the UK and the extreme Flight Championship (XFC) in the USA.

Commercial applications

Although RC helicopters are generally used by hobbyists for recreational purposes, they are sometimes used in applications such as low altitude aerial photography, filming, policing, and remote observation or inspection. Some companies make RC helicopters specifically for these uses.

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Electric Helicopters and Airplanes

Electric Safety Procedures; The electric airplane prop is dangerous and can easily mangle a finger or cut it off.  Don't connect the motor battery until you are ready to fly on the runway or hand-launch. Don't turn on the radio system until you are ready for your flight. Turn off the radio system as soon as possible after the flight. Make sure the throttle is set to off before turning on your transmitter. Many digital speed controls have a function that won't allow the motor to turn until the throttle stick has been in or moved to the low position. Do not make it a habit of testing this function. Motor-on radio checks must be done with the aid of a helper.

Airplanes:

There are different electric airplanes, Indoor, Electric Slow and Park Flyer and what we will call full size airplanes.  In this group there are planes the size of small to large gas airplanes as well as jets which travel up to 200mph.  

Indoor models are typically the smallest, lightest and slowest of the three, usually weighing less than 8 ounces. Many indoor venues impose a maximum weight limit, often 150 grams. Indoor models have very low wing loadings and use the smallest available cells, 50 or 110mAh being fairly usual, as well as specialized, often coreless motors.

Electric Slow Flyers are sometimes regarded as an in-between type, the next level up from indoor models. The term "Slow Flyer" is often used to describe both indoor models and park flyers. They’re basically small, light and slow enough to be flown in a backyard or Neighborhood Park, rather than a standard club flying field.

Park Flyers are generally too large or heavily loaded to fly indoors. They tend to use Speed 280-size motors and up, often geared, and batteries up to about 600mAh. They can weigh anything up to 18 ounces, though they’re often quite large and still have light wing loading. They’re also intended for use in relatively small outdoor areas such as schoolyards or local parks.

Full size electric airplanes can be as large as gas airplanes and weight the same.  The EDF jets can reach speeds of 200mph.  They require large batteries in the range of 3000mAh and larger with voltages up to 22.2v and beyond.

The comparison between electric motor and gas engine is as follows: 1 brake horsepower = 750 watts. The problem is that electric motors have many more variables than gas engines. In order to determine the performance of an electric motor, you must first answer questions such as how much duration you want, how much power you need, etc. Gearing also heavily influences the comparison.

Brushless electric RC motors

 At the forefront of the advance in electric rc modeling is the brushless motor.

Traditionally, electric powered models have used standard DC 'brushed' motors. In these, as part of the motor's operation, carbon brushes press against a spinning commutator and this causes friction. This unwanted but inevitable friction puts extra strain on the motor and makes the motor less efficient. Also, the brushes wear down with use and so need periodical replacement. These are the two big disadvantages with brushed motors.

Gearing allows a motor to turn a larger prop at lower rpm. This allows the system to produce more thrust while drawing the same number of amps. The trade-off is that top speed is reduced, which makes gearing suitable mostly for slow-flying aircraft. Sport electric planes are usually run with a direct drive system.

While such motors do work well, a brushless motor uses electronic circuitry and powerful magnets to do the job of the brushes/commutator system and no revolving parts ever touch each other. As a result there is no friction and therefore much greater efficiency, meaning a huge increase in power - brushless motors can be up to 300% more powerful than their brushed counterpart, and they also do away with the issue of periodical brush replacement.

There are two types of brushless motor used in radio control modeling; the inrunner motor and outrunner motor. The inrunner motor is closer to a brushed motor in that the body remains stationary while the permanent magnets and shaft spin within the fixed stator. Inrunner motors, although much more powerful than brushed motors, are still limited in their torque and usually need gearing when used in an airplane or helicopter.

Outrunner brushless motors are different because the permanent magnets are attached to the inside of the motor casing, or 'can', and it's the can that rotates around the fixed stator. When you see an outrunner in operation you will see the outer can spinning. Outrunners generate more torque than inrunners and are very suitable for larger models, and a gearbox is often not necessary as the torque from the motor alone is sufficient.

Inrunner brushless motors, generally speaking, are more suited to swinging a smaller propeller at higher RPM whereas outrunners are more suited to swinging a larger prop at lower RPM.

As with most things electronic, brushless motors carry a rating system, in this case known as a kV rating. The kV value is the RPM (revs per minute) of the motor per volt fed to it. For example, a 2500kV motor powered by a 7.4V Li-Po battery pack will give 2500 x 7.4 = 18,500 RPM with no load.

Motor constants are Kv, Io and Rm.

Kv = Speed / Voltage: With the motor shaft in a drill press running at a known speed, measure the voltage at the motor terminals. So if the speed is 6000 rpm and the voltage is 3V, then Kv = 6000/3 = 2000 rpm/V

Io:  Simply run the motor with no load (no propeller) and measure the current taken. You can use almost any voltage, because the current does not vary with voltage. However, the motor will still be turning at the rpm defined by V x Kv.
Both Kv and Io should be measured with the motor neutral-timed. For most can-type motors, this is where they are fixed. If you do have a motor with adjustable timing, you can try (carefully) adjusting it as you measure Io. It will be neutral-timed when Io is at its lowest value.

Rm:

Speed control

The speed of electric motors is controlled by speed controls. Traditional mechanically operated controls have been replaced with much more effective Electronic Speed Controls (or Electronic Speed Controllers), or ESCs, which plug directly into the model's receiver throttle slot instead of being linked to a servo, as a mechanical one needs to be.

Whereas mechanical speed controls varied the amount of volts entering the motor, ESCs allow the maximum volts through but at varying rates depending on the throttle stick position. The micro-processor in an ESC opens and closes tens of times a second to let the current pass.

ESCs for brushless motors are different to ones for brushed motors, technology-wise, and this is an important factor to consider when upgrading your model; never use a brushless motor with an ESC designed for a brushed motor.

Brushless electric motors combined with Li-Po battery packs and ESCs are the ultimate combination for power when it comes to electric RC.

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Engines

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.

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RC Radios

The Academy of Model Aeronautics in its efforts to make R/C modeling safer by reminding everyone that there are specific reserved channels for aircraft and surface (car/boat) use. Why separate channels? In today’s crowded urban areas, it is not uncommon to find R/C cars (75 MHZ) being run within radio range of a model aircraft (72 MHZ) flying site. Without channel separation, the possibility of interference would always exist. Most of the crashes that have occurred were caused by people unknowingly operating on an improper channel and they were also unaware that any R/C flying was taking place in the area. Remember that our Broadcast Channels were granted to us by the FCC and we are able to obtain and keep our R/C exclusive channels thanks in part to the excellent safety record of R/C modelers. In other words, this channel system is not just an AMA guideline for members; it’s the law of the land that applies to all R/C users. So please, be aware of the aircraft only/surface only channel system. The model you save just might be your own.

Mode 1 / Mode 2

Refers to the stick configuration of an aircraft transmitter's control sticks. Mode 1 has the aileron/throttle on the right stick and the rudder/elevator on the left. Mode 1 is popular in Europe and Asia. Mode 2 is the USA standard and has the elevator/aileron on the right stick and the rudder/throttle on the left. Almost all radios used in the USA, Canada, Central and South America are Mode 2.

72 MHz Frequency (Channel Number)

Like all radio equipment, an R/C system broadcasts its signal at a specific wave rate and this is known as its "frequency". Just as commercial radio stations that you listen to each operate on their own frequency, so do R/C transmitters. There are several different frequencies to choose from and these are now referred to in the R/C industry by "Channel Number". This channel number is easily confused with the number of control channels used in the model but the two are quite different - the channel number that your transmitter broadcasts on (e.g., channel 26 or channel 50) refers to its frequency, not the number of model features it can control. If there was only one R/C frequency or channel number available, only one person in any given area could operate their model - just as if there were only one TV channel, you would only be able to choose one show to watch! By having a number of different channels available, many models can fly at the same time. Many old fliers are switching over to 2.4 GHz, so old 72 MHz transmitters are selling cheap. What use to sell for $200 - $400 is now selling for around $50. These transmitters work great and are a cheap way for a beginner to start in the hobby.

Radio Modulation

AM: (72 MHZ) Stands for Amplitude Modulation which transmits by a variation in the amplitude of signals; it is subject to interference more than FM.

FM: (72 MHZ) Stands for Frequency Modulation which transmits signals by variations in frequency, reduces the risk of "glitches" due to signal interference.

PCM: (72 MHZ) Stands for Pulse Code Modulation uses binary code to digitize the signal, providing the most accurate signal possible.

2.4GHz Transmitters

One of the most exciting new breakthroughs in hobby radio technology is the use of 2.4GHz. The Spektrum system does not actively use timeline sharing -- it appears to be solely Frequency division (grabbing sole ownership of two frequencies and denying any other Spektrum transmitter the right to use those frequencies). In this respect it's little different to a smart synthesized 72MHz system that checks what channels are free before firing up then chooses the quietest one and uses it. Of course the Spektrum also only uses a small percentage of the available time on its chosen channels so other systems could (in theory) slip into the gaps without having too much effect but no two Spektrum 2.4GHz systems will share frequencies with each other in the way that Futaba or XPS do. The Futaba FAAST uses both time division and frequency division by performing pseudo-random frequency hopping -- meaning that it not only transmits in short bursts like the rest but also keeps constantly changing its frequency so as to dodge interference and reduce the effect of other signals.

Radio Receivers (Rx)

The radio unit in an airplane or vehicle which receives the transmitter signal and relays the control to the servos.

Trainer System

This effective method of training allows two transmitters to be connected by means of a trainer cord. The instructor can pass control over to the student's transmitter so that he can fly. If the student gets into trouble, the instructor can regain control instantly saving your airplane.

Note: Be sure to check your radio instructions for proper connection and for compatibility with other radio systems.

R/C Radio Systems Features and Control Channels

The first thing you need to decide is how much you want your model to do. For each control function, you need one channel of control. The usual uses for control channels are:

One Control Channel.....Rudder

Three Control Channels....Rudder or aileron, elevator, throttle.

Four Control Channels....Rudder, aileron, elevator, throttle.

Five Control Channels....Rudder, aileron, elevator, throttle, flaps or retracts.

Six Control Channels....Rudder, aileron, elevator, throttle, flaps or retracts.

When you have more than 6 control channels, you can add such features as bomb drops, dive brakes, parachute drops, sliding canopies or other operating parts to your model. The most common number of control channels used on a powered aircraft model is 4. Four-channel control gives you full acrobatic capability and will enable you to fly most airplane models.

Servos

A servo contains an electric motor and is the "muscle" that moves the rudder, elevator, or other control surfaces. For each channel of control, you need a servo. Most 4 or more control channel radios come with 2-4 servos. There is a wide variety of servo types depending upon their intended use. If your 4-channel radio only comes with 3 servos and you wish to fly a "full-house" airplane (one that has 4 controllable features) you'll want to purchase one additional servo.

Servo Reversing

This feature allows you to reverse servo rotation. If a channel operates opposite of its intended direction, a simple flick of a switch corrects the problem.

Adjustable Travel Volume (End Point Adjustments)

ATV allows you to preset the maximum travel of a servo to either side from its neutral position. Such settings help tailor control action to suit your flying or driving style.

Exponential Rate (Adjustable Rate Control)

This feature smoothes responses between stick and the controlling servo movement.

Mixing (Coupling)

Two control channels can be coupled together so that they move together when only one control channel is activated. Many 1/4 scale models require a combination of aileron and rudder to turn. Mixing does this electronically at the transmitter. V-tailed models, where the two halves of the V-tail must move not only together but independently, are another use of control mixing.

Electronic Speed Control:

Electronic speed controls replace the mechanical speed control and servo providing enhanced power efficiency and precision. In addition, they are lighter which improves the performance of some electric models.

Servo Arms:

Connect the servo to either a pushrod or cable. Adjustable servo arms are available for some radios which can be made shorter or longer.

Servo Connectors/Adapters:

Most manufacturers offer servo plugs that are compatible with their radio systems. This allows you to adapt other brands of servos to your radio system or repair damaged plugs.

Servo Extension Cable:

(Aileron Extension): These cables simply increase the distance between a servo and the receiver. Note: Very long servo leads may cause radio interference. Chokes or radio noise traps may be required.

 Y-Harness: Two servos can be plugged into one channel with a Y-harness. The two servos will then operate simultaneously. It is most often used in areas where the strength of one servo is not adequate. An example of this would be the ailerons and elevator on larger airplanes.

Dual Rates

A dual rate switch on the transmitter can reduce the amount of servo travel. This makes the controls less sensitive. The aileron and elevator control channels are the most common channels with this feature, although some radios will also have a rudder dual rate switch. Select low rate, and an over responsive model can be made easier to control. Since beginners tend to over-control the model, low rate can also tame their models.

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Batteries