RC Helicopter Channels 101: What They Are and How They Work


RC Helicopter Channels 101

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For those who are interested in RC helicopters, they may wonder what channels are and how they work. Radio-controlled helicopters (RC helicopters) are model aircraft similar to RC airplanes. However, RC helicopters are different in their construction, aerodynamics, and flight controls. Therefore, when searching for RC helicopters, it’s important to determine how many channels you require. Each channel controls a corresponding surface or component on the RC helicopter.

So, what are RC helicopter channels, and how do they work? RC helicopter channels are essentially the means by which a pilot can fly and control the helicopter. Each RC helicopter features a remote control with a certain number of channels that transmit corresponding actions to the RC helicopter to operate and influence its flight. The fewer the channels available, the less control the pilot has over the RC vehicle, yet the more channels available, the greater the difficulty in flying the helicopter. 

RC flight controls allow their pilots to control the throttle, pitch and roll, and tail rotor. These controls together enable RC helicopters to maneuver in the same way as their full-sized counterparts, with hovering and flying backward, as well as make maneuvers that full-sized helicopters could not do. The more complex the RC helicopter, the more channels are required for operation. Therefore, RC helicopter pilots need to understand what channels are and how they work.

What Are RC Helicopter Channels?

Remote control helicopters have increased in popularity and advanced equipment technology. There are RC helicopters available for wide ranges of budgets and abilities, making it an ever-growing hobby for those interested in RC flight. Some of the benefits of choosing RC helicopters as a hobby are:

· No need for a mowed or paved runway (unlike RC airplanes)

· Vertical take-off and landing for nearly any open area

·  Convenience of minimal preparation for flight 

· Time saver due to less gear and equipment

· Available models for indoor flight

RC helicopters allow hobbyists to learn about rotary flight and is the only RC hobby that equally combines the aspects of aeronautics, mechanics, and electronics.

RC helicopter channels are what allow pilots that participate in this hobby to operate the helicopter. Each channel on the remote-control transmitter corresponds to and controls an action on the RC helicopter. The number of channels on the RC transmitter determines how many independent functions can be controlled on the RC helicopter. 

Here are some examples of the helicopter functions that channels can control and what the terms mean:

· Throttle—how fast the main rotor blades spin

· Yaw—turning to face left or right

· Elevator—tilting the main rotors to move the helicopter forward or backward

· Aileron—tilting the main rotors to move the helicopter left or right

· Collective—tilting of the main rotor blades in collective pitch helicopters

· Adjustments—gyro stability and others

Main rotor RC helicopter control channels come in two forms: cyclic and collective. Cyclic controls directional movement through the air, whether left, right, back, or forth. Collective controls altitude, which would involve going up and down.

How Do RC Helicopter Channels Work?

All RC helicopters have one channel designed to control the throttle. Control of the other functions of the helicopter depends on the number of channels featured and the type of RC helicopter being flown. Beginner RC helicopter models feature fewer channels, which makes them easier to operate but far more difficult in truly controlling subtle movements. More advanced, complex models feature more channels which increase the level of pilot control but also the level of difficulty in operating them.

RC helicopters receive “instructions” through radio signals from the transmitter controller. Each specialized movement requires its own individual transmission channel. Therefore, the more advanced the RC helicopter, the more channels it will feature. Here is a brief summary showing the relationship between the number of RC helicopter channels and the functions they control:

· 2 Channel: throttle and yaw

· 3 Channel: throttle, yaw, and elevator

· 4 Channel: throttle, yaw, elevator, and aileron

· 6 Channel (Full 3D Flight Control): throttle, yaw, elevator, aileron, collective pitch, special features such as lights, cameras, etc.

· 7 Channel (Full 3D Flight Control): throttle, yaw, elevator, aileron, collective pitch, special features, scale effects, IC mixing control (a software system run by the transmitter to mix the control inputs and reduce mechanical complexity)

In general, RC helicopters use micro-processor controlled printed circuit boards (PCB). These PCBs save space and weight. Depending on the type of helicopter, the PCB base unit is the device featuring channels to control the receiver, gyro, and motor electronic speed. Larger RC helicopters may be able to carry extra components. However, the most common models tend to be 3 or 4-channel control units.

To control the movement of remote-controlled helicopters, the pitch angle of the main rotor blades must be changed in relation to the air that flows over them. This change varies the amount of lift for the helicopter generated by the blades. When the blades are moving through the air, the pitch angle is referred to as the angle of attack.

The channel for yaw is a function that turns the RC helicopter to face left or right and is controlled by the tail rotor paired with or against the natural torque force generated by the spinning main rotors. The tail rotor generates sideways thrust. Yaw control in RC helicopters is made easier through the use of a gyro, which is an electronic device that connects the receiver and the tail rotor control.

In technical terms, the gyro is known as an accelerometer. It senses the rotational movement of the helicopter that doesn’t originate as a result of a signal to the receiver. In this way, the accelerometer can make both rapid and fine adjustments to the tail rotor speed or blade pitch to match the torque force in the moment. 

This hinders and corrects for any undesired yaw almost instantaneously in order to stabilize the helicopter. The pilot can also adjust the gyro’s sensitivity on the gyro or remotely from the transmitter channel.

How Many Channels Do You Need for an RC Helicopter?

The number of channels you need for an RC helicopter depends on your level of experience and aptitude for flying and how much control you want of the RC helicopter’s functions. Essentially, fewer channels allow ease of flying for beginning pilots of RC helicopters. The more channels present, the more is allowed for complete control, maneuverability, and realism of the RC vehicle, yet more complex and advanced skills are required to operate a higher number of channels.

Since each channel controls a different type of movement for RC helicopters (up and down, left and right, spin, etc.), the handling style of a helicopter can vary widely depending not only on how many channels it features but which channels as well. Therefore, it’s important to consider how many channels you may need or want for your RC helicopter and which functions you wish to control as a pilot of the helicopter.

For example, one of the problems or difficulties with the beginner’s 2 and 3-channel RC helicopters, in addition to fixed pitch, is what’s known as latency. This indicates the lag between the pilot operating the channels and moving the controls of the transmitter and the corresponding change in the helicopter’s movement or operation. 

This delay between operating the controller and the resulting controlled movement of the helicopter can hinder the feeling of accurate piloting and precise, operational skill sets for the vehicle when it comes to direction, lift, yaw, etc. 

An RC helicopter with few channels and fixed pitch is therefore limited in terms of aerobatic capabilities. A helicopter with more channels and collective pitch control allows for various forms of aerobatic flying and much more complexity and precision in movement.

Overall, RC helicopters are outfitted with two to seven or more channels. Beginners would start with either two or three channels and work their way up to more as their piloting skills and experience developed across time in pursuing this hobby.

Pitch

One of the key factors that influences the number of RC helicopter channels is pitch. When it comes to an actual helicopter, the primary method of making it change direction while flying is through pitch control of the main rotor blades, either independently or collectively. 

For radio-controlled helicopters, some have been developed without independent pitch control. These helicopters are known as fixed pitch and are very popular with beginner pilots. Collective pitch helicopter models are more complex, making them more difficult to master but more agile and smooth for flying due to their controls and channels being closer to actual helicopter piloting.

The main difference between fixed and collective pitch RC helicopters is in the collective pitch control, which is influenced by the lift that is generated through the main blades acting together. With a fixed pitch helicopter, the main blades are fixed to the main rotor holder and can’t be pivoted along their perpendicular axis. Therefore, with fixed pitch, altitude is controlled by the speed of the blades and motor; the faster the blades spin, the more lift experienced by the helicopter.

Beginner Level Channels

Understanding and learning about RC helicopter controls and channels is fundamental to the hobby, yet beginner pilots sometimes find difficulty in grasping how everything interacts. Therefore, it’s important to get a firm grasp of controlling RC helicopters with limited channels in the beginning in order to get solid footing for piloting them and then moving to more advanced models.

Though they offer little pilot control, RC helicopters with just 2 or 3 channels are often ideal for those starting out in this hobby field. Such helicopters are relatively inexpensive. Therefore, if younger or less experienced pilots end up crashing 2 or 3-channel helicopters, the cost to repair or replace them is minimal compared to more advanced and complex models.

2 Channel Helicopters

Helicopters with 2 channels are considered basic, stable, inexpensive, and very easy to fly. They are generally suited for first-time and/or younger pilots. These helicopters are fixed pitch and generally feature two counter-rotating blades to improve stability. Most 2-channel helicopters are limited, controlling just the functions of throttle and turning (yaw).

Yaw allows the helicopter to make level turns, either left or right, and can be controlled through tail rotor speed. Sometimes the yaw is controlled by the relative speed of the counter-rotating main blades in dual-blade coaxial RC helicopters.

Two-channel helicopters are usually designed to always fly forward. They allow no pitch control but simply main and tail motor speed control, which may even be reduced to an on/off function. With the yaw control, the pilot can fly the RC helicopter forward in straight lines as well as curving paths.

3 Channel Helicopters

RC helicopters with 3 channels are also considered good for beginner pilots as a basic model and are one of the most common models found in the hobby-grade market. These helicopters are designed for entry-level or even casual use. They allow control over up and down movement, left and right spin, and throttle for forward and backward speed. These features are considered the basic group that a pilot needs to control an RC helicopter with confidence and without unnecessary complications to flight.

Three-channel helicopters are fixed pitch, and in addition to channels for controlling throttle and yaw, they feature a channel for elevator control for the function of forward and backward movement. This forward and backward movement is generally controlled by a small rotor in the tail that is parallel to the main rotors. Due to this control of forward and backward movement, 3-channel helicopters are often able to hover in place.

Though these helicopters are recommended for beginners and are considered close to “toy-grade,” there are differentiations among these models that feature high-tech and even customized working parts. Some models have a smooth, aerodynamic shape as well as built-in LED headlights and taillights for flying at night. However, 3-channel RC helicopters cannot move as elegantly as 4-channel models and will, therefore, remain at the beginner level.

Intermediate and Advanced Level Channels

No matter the level, RC helicopters take patience and practice to master when it comes to piloting and utilizing channels. However, for RC helicopters to model proper and realistic control beyond a beginning pilot level, most agree that there must be at least 4 channels present in order to control the following:

· Left/right cyclic

· Fore/aft cyclic

· Left/right yaw

· Collective pitch and/or throttle

The primary difference between beginner and intermediate and advanced level channels when it comes to the operating systems of RC helicopters is the added function of sideways movement to the left and right as well as spin. This is what makes up the fourth channel. The most high-tech and best quality 3-channel helicopters cannot achieve the precision and movement of their 4-channel counterparts. 

For example, when it comes to landing, a 4-channel helicopter can hover, shift to the left or right to get in position, and then gently land. A 3-channel helicopter, on the other hand, must make several moves to back up, spin, move forward, and straighten before landing. Many of the more serious RC helicopter hobbyists skip mastering 3-channel models and instead choose to move up to 4-channel versions.

4 Channel Helicopters

Helicopters with 4 channels are an excellent choice for intermediate pilots who have had experience or some training with either a beginner helicopter or simulator. When it comes to 4-channel helicopters, they can be either fixed pitch or collective pitch. Such helicopters feature channels to control throttle, yaw, elevator, and aileron functions—meaning left and right movement.

Channel control of these functions gives the pilot full maneuverability of strafing (strategic sideways movement) as well as the abilities of a 3-channel helicopter, including hovering. A basic 4-channel fixed pitch RC helicopter will feature two channels controlling the cyclic pitch to fly left and right, backward and forwards. The other two channels would control the main motor speed and tail rotor motor speed (left/right yaw).

5 Channel Helicopters

It would seem that the next logical model of RC helicopters would be a 5-channel version. However, very few of these models are produced. Therefore, nearly everyone advances to 6-channel control models in order to increase the number, complexity, and types of movements their helicopter can make.

6 Channel Helicopters

A 6-channel RC helicopter is capable of executing the same moves as its 4-channel counterpart with the added features of left and right control at the tail as well as pitching the helicopter up and down on its horizontal axis. This allows the advantage of smoother flight due to the especially precise control potential for banking and turning with the added tail control.

RC helicopters with 6 channels are great for intermediate to advanced pilots with solid training and experience in piloting lower channel helicopters or simulators and are ready to expand their skills. Most 6-channel helicopters are collective pitch, with channel control of the following common functions:

· Throttle

· Turning/yaw

·  Elevator (forward/backward movement)

· Aileron (left/right movement)

· Collective pitch (tilt of main rotor blades)

· Turning gyro or other adjustments

There are fixed pitch 6-channel RC helicopters, which are essentially 4-channel helicopters with two channels of possible adjustments. A collective pitch 6-channel helicopter, however, is capable of full dimensional flight. This includes inverted flying and advanced aerobatics such as diving, climbing, rolls, and loops—all of which are very challenging to learn.

Mastering 6-channel models can prevent many potential crashes that other versions would normally experience due to situations such as sudden breezes. Therefore, 6-channel controls can be a protective measure for a hobbyist’s investment. However, the greater number of channels also indicates more delicate working parts and more complicated control, which means that more things can potentially go wrong with these models as well.

7-Plus Channel Helicopters

When it comes to the popularity of products within the hobby, 6-channel models are about as complicated as radio control helicopters get. However, some expert models feature as many as 9 channels. RC helicopters with 7 or more channels feature the same movement functions as 6-channel helicopters. Additional channels allow for even more adjustments in flying.

With so many additional channels and such complex control systems, the expense and complicated manual operation of 7-plus channel helicopters often require in-built computers. In general, this makes them cost-prohibitive for most RC helicopter hobbyists who prefer the reward of mastering the advanced 6-channel models as opposed to tackling the unnecessary complications of versions with 7 channels or more. 

Coaxial RC Helicopter Controls

The recent development of electric coaxial helicopters, also known as dual rotor or contra rotating helicopters, has provided another introduction to radio control helicopter flying and brought many newcomers to the hobby. These coaxial helicopters are considered very easy to fly with their inherent stability, making them good and interesting choices for both new pilots as well as experienced RC helicopter pilots that are used to operating multiple complex channels.

There have been several technological advancements in RC helicopters, and the hobby itself, and “ready to fly” coaxial RC helicopter models are examples of such advancements. Coaxial RC helicopters feature two sets of main rotors, placed one above the other, and feature no tail rotor. These main rotors spin in opposite directions to each other, which cancels out the individual rotor torque force. Therefore, when both rotors are spinning at the same speed, the helicopter is relatively stable and won’t spin in any particular direction.

These coaxial helicopters are easier for pilots to master than conventional single rotor and tail rotor helicopters due to their capability of steady hover. In addition, the range of coaxial models is proving to be popular as hobby grade helicopters that provide a full range of spare parts and upgrade options for many such aircraft. This makes these RC vehicles a great choice when it comes to those pilots looking for an easy and interesting introduction to RC helicopter flying.

Difference Between Conventional and Coaxial Remote-Control Helicopters

Conventional RC helicopters have single main rotors consisting of two or more separate blades. When the helicopter motor powers on and turns the main blades, this generates the force of torque as a result of the blades’ spinning motion. The natural reaction to this torque is for the helicopter’s fuselage (main body section) to spin in the opposite direction of the main blades.

A tail rotor is used to generate sideways thrust as a means of counteracting this torque. The tail rotor is a vertically mounted rotor which pushes air against the direction of the fuselage rotation in order to prevent the helicopter from spinning out of control from the torque. RC helicopter tail rotors are either variable pitch with servo control or fixed pitch with motor control. 

The amount of thrust generated by the tail rotor can be changed by altering the pitch angle of the tail rotor blades or changing the speed of the tail rotor motor. The change in thrust controls the yaw of the helicopter and in which direction the nose is pointing.

Coaxial RC helicopters, on the other hand, do not feature tail rotors or a single main rotor. Instead, they feature two sets of main rotors mounted directly above each other, with blades that spin in opposite directions. Since the blades spin against each other, they cancel out any torque generated by the other. As a result, there is little tendency for the fuselage of the helicopter to spin around one way or the other.

It’s important to note that this is only the case as long as both sets of blades are spinning at precisely the same speed. As soon as one set of blades changes speed relative to the other set, then torque is generated instantly. This generated torque is how yaw is controlled in coaxial RC helicopters. One set of blades spins faster or slower than the other set to purposely generate torque, which naturally causes the nose of the helicopter to point in a different direction.

In this case, directional control is achieved through a channel that changes the speed of one of the rotors in relation to the other. This generates a small amount of torque, which then results in the helicopter changing direction in order to yaw one way or another. These helicopters are fixed pitch, which means that altitude is controlled by adjusting the motor speed to generate the desired lift.

RC Helicopter Channels and Safety

Regardless of the number of channels featured by a radio-controlled helicopter, the most important thing to remember when piloting such a vehicle is safety. Even the least expensive and most basic of 2-channel helicopters with soft plastic blades can still cause damage and injury.

Therefore, understanding how channels and primary RC helicopter controls will influence piloting the RC helicopter itself is fundamental to flying the vehicle properly and safely. This will not only serve to enhance the safety of your investment in RC helicopters and minimize crashes, but it will also allow you to take part in this hobby with less chance of personal injury as well.

How Big of a RC Helicopter Should I Get? 

While there is no specific guild to how big of one you should get, there are a few recommendations. You should never get one that is out of your price range. While it may be awesome to own the biggest and best RC Helicopter in your circle of friends, it is not worth going into debt over. They will be impressed, but they would be just as impressed if you purchased one in your price range and you learned how to master that one and maneuver it and do tricks with it. What is better than being able to out pilot all of your friends every single time you get together, and while they may not be able to fly due to high winds, you can show off your skills at this time and make them jealous. If you have the money though, and you love having the biggest and best stuff, here is a short video of the top 10 biggest and baddest RC Helicopters. 

Conclusion

Today is the day to go out and start on your RC Helicopter journey. They are not extremely complicated, and with advancing technology, are great for beginners, and will make you the most popular with your friends! You can go anywhere from small to big, but make sure you work your way up in skill and do not overbuy the amount of skill that you have learned since starting to fly. 

Matt Robbs

I love to spend time with my wife and 3 kids. There is no better way to get them off the couch and outside than for us to grab the RC cars or boat and enjoy the sunshine!

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