RADIO CONTROL MODEL

While RC planes are a truly entertaining pastime, an even more entertaining pastime is to be had with RC boats. Electric boats fly across the water’s surface as an RC boat operator remains safe and dry on shore! Whether engaging in the pastime alone, or engaging in the hobby together, there are a million ways to love and appreciate the hobby of operating RC boats of all kinds. What’s more, RC boats prove to be an outstanding hobby, simply because one’s budget does not necessarily define the hobby’s accessibility; there are RC boats for sale that are quite affordable thereby making the pastime something that is accessible to just about everyone.
Choosing electric boats can be quite overwhelming for the individual new to RC boating endeavors. With a choice of engines, colors, designs, sizes, and styles, the act of selecting a single boat might seem cumbersome. Some come preassembled and ready to use while other electric boats require assembly and later ornamentation. How a consumer wants to handle the endeavor is really up to the individual, but both options can prove quite entertaining. It is possible to use some electric boats fresh out of the box or the consumer can get total enjoyment out of the build your electric boat feel. When assembling an RC boat, the assembler becomes more attached to the item because they really put a part of themselves into the work. The majority of boats out there come with simplified instructions and everything one needs to get the process started.
In terms of self assembling, it is recommended that new electric boat users carefully review all instructions before beginning the process. Not every kit comes with everything needed so the RC boat builder will want to make sure they have all necessary materials. In addition, when putting a RC boat together one will find that there are certain steps that must be taken in a specific order. This ensures that once the boat is completed it will run smoothly for the operator. If instructions are not followed precisely, the boat operator may find that the boat does not hold up well during use, that it breaks with ease, or that, in worse case scenarios the boat fails to operate at all.
When it comes to electric boats and options, there are indeed many. You might find that you want an electric boat which is easily operated by remote control, but you may also find that electric boats powered by gasoline are an equally nice option. There are differences in the latter selections which particularly pertain to speeds; if speed is not an issue and you simply want to let the RC boat cruise along the water’s surface then an electric boat with radio control options will clearly suffice. Higher speeds do call for gasoline powered engines however, and if speed is a concern, the RC boat one purchases should certainly be of the gas-powered variety.
It is a good idea to seek out an RC boating mentor if this is your first time purchasing electric boats. Someone that loves RC boats will be more than happy to provide you with advice concerning what RC boats are the best, what kind of accessories you might like, and an RC boating mentor may also help you learn how to manage your boat correctly. It never hurts to ask someone in the business any questions one may have and most people who are into RC boats are fond of talking about their passion! Someone who is skilled in the hobby can also provide advice about putting boats together, and special tips for making your boat operate at its best!

RC boat - Interesting hobby

2009-08-12T02:24:00.000-07:00

If you want an interesting hobby, it might be time for you to take a look at radio controlled boats. What kind of boat do you want, and how much cash can you invest in them? What kind of boat are you interested in, and do you want to put the boat together yourself or do you want to purchase one ready to run?
Let’s start by seeing what kind of space you have available. Do you have a large body of water near you that is weed free and calm? When you have located a good place to run your boats, this is a sign that it is definitely time to get started.
Consider the three types of RC boats that are available to you. The three categories are divided into how they are fueled. Electric RC boats are perhaps the easiest and least expensive to start off with, and they use batteries that you charge in a wall outlet. They are not as powerful as the other types, and when the batteries get drained, you need to think about replacing the batteries or plugging them back in to recharge. Take some time to see if they are the boats that you should get started with.
The second type, which is often popular with intermediate rc boat hobbyists is the nitro-powered rc boat. These boats are fueled with a nitro-methane mix and provide the boat with a lot of power. However, this type of fuel is also the most expensive. Unlike electric-powered rc boats, you can quickly and easily refuel and be back in the race again.
Finally, we have the gasoline powered boats, which are the most powerful RC boats on the market as well as being the fastest. They run off of a mixture of oil and gasoline and these boats are considered the top of the line. It is important to remember, however, that they are also the most expensive and the loudest. Finding a place where you can use them can be difficult, but you’ll find that the high initial investment is worth it because it has lower refueling costs than the nitro-methane powered boats. What boats are you interested in picking up?
Whether you choose a high end gasoline RC boat, a nitro RC boat or an electric RC boat, make sure that you take some time to see how the boat handles. A single hull that has a deep V shape will give you the best handling without impacting your speed.
If you are limited by your budget or the size of the water available to run your boat, you might be best off to start out with an electric rc boat. While not as powerful as gasoline and nitro rc boats, there are some upscale electric rc boats on the market today that can reach speeds as high as 40mph.
An electric rc boat might also be the best solution if you have to run your boat in or near a residential neighborhood where nitro and gasoline rc boats would be way too loud and might even get you banned. Electric rc boats are very quiet and will not disturb the peace.
When you are looking for a new hobby that is fun to start and easy to try out, consider RC boating. There are a lot of different boats out there and you can build them, run them or even race them. So find a way to enter the hobby if it really appeals to you.
In conclusion I recommend that you purchase a radio controlled boat that is suitable for your environment, your desires, and your budget.

Radio Control Boat - Fast, Faster and fastest

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Float your electric RC boat in a pond, or for your gas boats try a wide-open lake and watch the rooster tails fly! A radio control boat makes great summertime fun for the whole family because they're easy to control and don't take any special skills to learn. Imagine your children playing with their very own affordable mini boats, like the one on the right, in the bathtub or backyard pool and it's so safe they can't hurt themselves. You'll hear their shouts of joy as they skipper their little maritime fleet!
And for the big kids around the house, they'll get full-throttle excitement out of a gas RC boat on their favorite lake or pond with plenty of room to race each other. This type of sophisticated remote control boat is powered by a small gasoline motor or the more potent nitro engines for reaching incredible speeds!
rc boat RC sailboats skim across the water and respond to your every command while being powered only by Mother Nature's gentle wind. They also have the advantage of being completely silent. Generally regarded as a more refined RC boat, they can feature a large amount of detail due to the sails and rigging which provides a real challenge for the hobbyist who wants to build one from a kit.
There are three main types of racing hulls: three-point hydros, tunnel hulls, and V-hulls. The different types of hulls require different water conditions. Tunnel hulls and hydros run best on smooth water whereas a deep vee hull is better for choppy water.
The motors for an RC boat come in two main types: inboard and outboard and of course you can choose between either a super quiet electric or the noisier, but more powerful gas powered motors.
I'm sure you'll discover that the electric boats are more convenient to play with since they don't disturb the neighbors and usually need a smaller lake or pond. But if you do have access to a suitably large lake then by all means go for the bigger thrills of a gas RC boat!

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If you find the noise made by model aircraft engines excessive you can power yours with an almost silent electric motor or, as something a little different, you can fly a glider. This can be towed up to height by a powered model or can itself be powered by a small electric motor which is turned off when you get high enough. Or you can launch your glider off the top of a hill and fly it round for an hour or more in the lift generated by the wind blowing up the hillside, then land back on top of the hill.

Don't fancy building a model? You don't have to! For little or no additional cost you can buy one ready, or almost ready, to fly. But if you do like building things there are tens or hundreds of hours to be spent in your workshop putting your creation together before eventually getting the satisfaction of seeing it take to the sky.

Whatever branch of aircraft modeling you choose, you will experience exhilaration, disappointment, maybe even occasional despair, but, most certainly, great satisfaction. You can take up the hobby on your own (although it's difficult) or you can enjoy the company of (and benefit from the experience of) like minded people with the same interest by joining one of the thousands of clubs which are scattered around the world.

Home

RC Radio Modes

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When talking about rc transmitter modes we are referring to how the transmitter is set up to control the airplane of helicopter ie which sticks operate which controls on the model. There are four different modes available, but only modes 1 and 2 are commonly used by the majority of radio control pilots. Which mode you will fly with depends on a couple of factors:

if you buy an RTF airplane or helicopter the transmitter will already be set up

if you learn to fly at a club you will take on the mode of your instructor's transmitter.

Incidentally, rc transmitter modes only apply to radio gear with 4 or more channels, where each stick has both vertical and horizontal movement.
The four different rc transmitter modes for rc airplanes are illustrated below:

Mode 1 left stick operates elevator & rudder, right stick operates throttle & ailerons.
Mode 2 left stick operates throttle & rudder, right stick operates elevator & ailerons.

Mode 3 left stick operates elevator & ailerons, right stick operates throttle & rudder.

Mode 4 left stick operates throttle & ailerons, right stick operates elevator & rudder.

Troubleshooting RC Radio System

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RC Model communicate through radio signals between the receiver in the RC Model and a transmitter. When an RC won't respond to signals from the transmitter there is often an easy solution. Before declaring the RC defective, try these steps. If it still won't work, you may have to resort to returning the RC or attempting more extensive repairs.

Check On/Off Switches.

It might seem obvious, but the RC and transmitter must be switched on before they'll work. It can be easy to forget. Check the switches on both the RC itself and on the transmitter.

Check Your Frequency.

Make sure you have the right transmitter at the right frequency for the Model. If you purchased the Model and transmitter separately and you're using your original receiver you might not have the same frequency crystal in the Models's receiver as you have in the transmitter. Get a matched set. It's possible that there was a mix-up at the manufacturer and the wrong transmitter was put in the box or the RC was damaged during shipping. You may need to take it back for an exchange.

Check Your Batteries.

Put good, fresh batteries in the RC Model and in the transmitter. Doublecheck that you installed the batteries correctly -- installed backwards and the RC Model won't work. Even nitro RC Models need a battery pack to run the internal electronics. Make sure it is fully charged. If this is an RC Model you've used previously but it's been sitting unused for a while, check the battery compartment for corrosion. It's always a good idea to remove batteries from an RC Model or its transmitter when its going to sit on a shelf or in storage for more than a few days.

Check Your Antenna.

The signals between the receiver in the RC Model and the transmitter travel between the antennas. If you have a telescoping antenna on your transmitter, make sure it is fully extended. Make sure the receiver antenna on your RC Model is properly installed, not twisted or broken, not touching metal parts inside the RC Model, and not dragging on the ground.

Try Your Transmitter With Another RC.

If you have another RC Model of the same frequency as your transmitter, try using the transmitter with that RC Model to see if the problem is in your RC Model itself or in the transmitter. If it works, the problem may be in the original RC Models receiver.

Try Your RC With Another Transmitter.

If you have another transmitter of the same frequency as your RC Model, try using it with your RC Model to see if the problem is in your RC Model or in the original transmitter. If it works, the problem is probably in your original transmitter.

Check Your Servos.

The problem might not be in the radio system at all. It could be that one or more of your servos have stopped working. One sign that the problem is in your servos is if the RC Model responds only to some commands from the transmitter but not others -- for example the wheels will turn but it won't move forward. Try unplugging your servos from the receiver and plugging them into a receiver that you know is working (be sure to match the frequency of the receiver and transmitter). If the RC Model still doesn't respond then your servos, not the receiver or transmitter, may need repair or replacement.

2009-07-31T01:53:00.000-07:00

Flying Radio Control Model AirCraft-The Best Hobby?

********

1.About Engine for Radio Controler Model

2.Electric Power
3.RC Servos
4.Radio Control System
5.RC Aircraft
6.RC Helicopter
7.Free RC Aircraft Plan

(I'm not a copyrighted of all article. I have copied it from some website on internet)

2009-07-31T01:46:00.000-07:00

Flying Radio Control Model AirCraft-The Best Hobby?

********

1.About Engine for Radio Controler Model
2.Electric Power

3.RC Servos
4.Radio Control System
5.RC Aircraft
6.RC Helicopter
7.Free RC Aircraft Plan

(I'm not a copyrighted of all article. I have copied it from some website on internet)

Programmable Radios

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A basic RC transmitter, be it a three- or four-channel-function unit, will not be what we call a "computer" or microprocessor-type radio. It will not have a Liquid Crystal Display (LCD) screen that allows you to set the special commands or controls. Most basic transmitters have servo reversing, and a few might even offer dual rate control on two-channel functions. Servo direction is usually changed with the flip of a tiny switch. Dual rate control cutback is adjusted by rotating a small potentiometer control (dial). These basic radios have a few switches and potentiometers (dials) but no internal computer circuitry and certainly no memory circuits.

There are few things in this world that we need, but there are many things available to make our lives much easier! Programmable radios not only make setting up your airplane a breeze, they also provide an entire range of features that maximize the performance of your airplane while making it easier to fly! Without computer radios, the type of flying that many pilots now enjoy would simply not be possible.

An advanced RC transmitter has an internal computer chip that contains a great deal of stored program information in its memory circuits. It can also store your control inputs, allowing you to operate several models from a single transmitter.You can tell that it is a computer-driven system because it has an LCD screen on the front of the transmitter case. The LCD screen displays a variety of parameters; some are basic and preplanned for you, and others you can call up from a menu system that is programmed into the transmitter.How you access these menus, make changes, and store the new inputs in the memory is what an advanced RC transmitter is all about. Once learned, you will have many more control features available for your use. You can start with an advanced RC transmitter, but use only basic controls until you gain a certain amount of experience.

The prices of programmable radios have come down significantly in the past few years. This combined with the fact that computer radios bring the control of RC aircraft to an entire new level has made programmable radios the choice of most pilots.

Radio Functions

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You will also see the terms 4-channel, 6-channel, etc. What is a channel and how many do you need? Think of a channel as a specific function or task performed by the radio system.Generally speaking, each servo plugged into the receiver requires one channel. Don't get "function" channels confused with "frequencies."A number is designated to the frequency that the transmitter is using. This is also called a channel. Confusing huh?.4-channel Transmitter

My recommendation for beginners is to get at least a four channel radio control system. These may be more expensive than 2 or 3-channel, but they have more potential for your growth in the hobby. Even if your trainer airplane only needs three functions (throttle, rudder, elevator), you will someday want the more advanced flying performance of a 4-channel airplane. If you are thinking that you are just trying the hobby, a 4-channel radio generally has a higher resale value.6-channel Transmitter

If you are already convinced that you will be staying with the hobby, and perhaps someday build scale planes or fly helicopters, get the best radio you can afford. A good 7- or 9-channel radio can stay with your for many years. These have not only more channels, but many other useful features. These include mixing of channels, as well as the ability to store model configurations (memory). You will not believe me when I tell you that you will use these features someday, but it’s likely to happen. Again, these more complex systems have good resale value.

9-channel Transmitter

Frequency Control

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The FCC (Federal Communications Commission) has designated certain portions of the frequency band for radio control use. For example, 72MHz designates the frequency band most often used for RC aircraft (50MHz is another, but requires an amateur “ham” radio license). 75 MHz is used for rc cars and boats. Note that the permitted frequencies vary from country to country.

That 72MHz is really not a single number, but designates a “band” of frequencies that can be used. For example, one of the sub-frequencies is 72.030 MHz, also known as Channel 12. It’s vitally important that you know what channel your radio uses! Why? Because switching on your Tx while someone else is flying on your channel will create radio interference for that person’s aircraft, very likely resulting in a crash. This unfortunate event is called a “shoot-down”, and is a generally unpleasant event (not to mention unsafe). The model could have cost thousand of dollars or man-hours. So, the first order of business when you go flying should always be to check that no else is on your channel. Look at the back of your radio for a frequency sticker, or check the box that it came in.

Also note that radio control systems for planes should not be used interchangeably with those for cars and boats. The reason is that surface models and airborne models inhabit different regions of space. Someone running a model boat in a pond near your flying field is likely to be unaware of your airplane (and you will be unaware of his or her boat.) Using separate frequency bands helps reduce unnecessary incidents.

Signal Modulation

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The four ways that the transmitter converts the pilots movements into radio signals are:

Amplitude Modulation(AM)

With AM, the radio signal is switched on/off rapidly on a single frequency to modulate the modulate the signal. AM is more prone to interference than frequency modulation.

Frequency Modulation(FM)

With FM, this single switches between two frequencies to modulate the signal. FM is less prone to interference than AM . Standard FM is also referred to as PPM (Pulse Position Modulation).

Pulse Code Modulation(PCM)

PCM is a digital form of FM. The transmitter basically sends the data to the receiver in binary code, which is "0's" and "1's". The standard FM(PPM) transmitter sends the signal to the
receiver in a series of pulses.

Spread Spectrum

This is the latest and greatest technology available for RC airplanes. The transmitter checks which frequencies are available and only transmits on frequencies that are not being used by someone else. The transmitter continuously changes the frequency several times a second.

How RC Radio System work

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The transmitter sends out a radio signal on a certain frequency, this is called a carrier.Think of it as a road to somewhere, but there is nothing on it.

The next thing is the transmitter sends a second signal.This signal is like actuating a switch. On or Off.If you turn the switch on for half the time (call that a plus) and turn it off for half the time (call that a minus) you have a net amount of zero.

Think of it this way. If you had an electric motor and applied electricity to it so it would turn one direction, and then switched the polarity so it tried to go in the other direction so quickly that it didn't move you would have the basis for a servo. The plus one direction equals the minus other direction.

If you then favored the plus side a little more than the minus side the motor or servo will turn one direction a little. Favoring the other direction the motor will favor the other direction.

The receiver in the airplane receives this carrier and pulsed signal and converts it to an electrical pulse to a servo. the servo is mechanically hooked up to a flight control. As you vary the pulse plus or minus, the flight control will change position.

If the plane or heli is powered by an electric motor, there is an electronic speed control (ESC) to convert the pulse signal to a electric source for the electric motor. This will cause the motor to spin and control the speed.

2009-07-30T23:28:00.000-07:00

...

Flying Radio Control Model AirCraft-The Best Hobby?

********

1.About Engine for Radio Controler Model
2.Electric Power
3.RC Servos

4.Radio Control System
5.RC Aircraft
6.RC Helicopter
7.Free RC Aircraft plan

RC Radio System consist of

2009-07-30T21:11:00.000-07:00

The typical a RC Radio control system consists of

The Transmitter

The transmitter is what you hold and use to control the RC model with one or two joysticks, switches, and knobs. The number of channels determines the layout of the transmitter. A three channel model has only one stick and a four (or more) channel has two sticks. Note that each control function is dedicated to a channel. Computerized radios will also have a LCD menu screen with additional switches for choosing and entering data.

The Receiver

The radio unit in an airplane or vehicle which receives the transmitter signal and relays this information to each servo. This is somewhat similar to the radio you may have in your family automobile, except the radio receiver in the airplane perceives commands from the transmitter, while the radio in your car perceives music from the radio station.

The Servos

The servos are small electro-mechanical devices that respond to a control signal, which instructs them to move their output shaft to a certain position. A servo is normally plugged into a radio receiver with a three pin connector.

The Battery and Switch

The receiver battery pack is used to supply power to the receiver and the servos. The switch harness is used to turn the power from the battery pack to the receiver on and off. Most switch harnesses also have a charging plug (the orange one) that is used to charge the battery.

The Heart of R/C Modeling

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The radio control (R/C) system is the heart of our hobby. This magic box can turn a lifeless pile of balsa into a graceful soarer, a flashy acrobat or a snarling 150-mph pylon racer, a car or a boat and any RC model

RC radios are very important. Other than your RC model, the radio is the most important piece of equipment you will own.Because the RC model is controlled as radio signals pass from the transmitter to the receiver.

After all, without a radio – there is no radio control. The radio basically puts you (or at least your commands) inside your RC model.A good radio will serve you for years and computerized ones with model memory can be used for many models of aircraft from helis to fixed wing... In short, one radio for everything.

In fact; most RC pilots will say the radio is most important.

2009-07-30T03:44:00.000-07:00

....

Flying Radio Control Model AirCraft-The Best Hobby?

********

1.About Engine for Radio Controler Model
2.Electric Power
3.RC Servos
4.Radio Control System

5.RC Aircraft
6.RC Helicopter
7.Free RC Aircraft plan

Modification For Continuous Rotation

2009-07-30T01:48:00.000-07:00

One popular modification to RC servos sets them up for "continuous rotation". Instead of moving through a range of about 90 degrees, a modified servo spins around and around. This modification is often used by those building their own miniature robots: the servo is turned into a combination motor, gearbox, speed control, and reversing switch.

I won't go into details of how this is done, but I will outline the general principle.

A normal servo uses feedback to determine where the current angle is, as opposed to where the pulse train says it should be.

The feedback comes from a potentiometer attached to the output shaft. The potentiometer is used in a voltage divider that produces a voltage proportional to the current angle.

The incoming pulse train is measured, producing a voltage proportional to the desired angle.

The one voltage is subtracted from the other.

This difference drives me motor. Big differences drive the motor rapidly. Small differences drive it slowly.

The modification removes the feedback and substitutes a fixed voltage divider set for 50%. [It also removes any mechanical "stops" used to prevent 360-degree rotation.]

Now, the speed and direction of the motor is relative to a fixed voltage, not the current position. Pulses of medium width produce 50% voltage, no difference, no movement. Slightly longer pulses move the motor slowly. Longer pulses more the motor faster. Pulses shorter than the medium width cause the motor to spin in the opposite direction.

You can see how handy this is to robot builders. Just bolt a couple of modified servos to the bottom of the robot, and put tires on the output shafts. Then just generate a stream of pulses to control speed and direction.

Choosing the Servo

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Servos have a number of defining properties that make them suitable for different applications:

Torque – This is a measure of the servos strength, or how much “push” it has. More precisely, torque is the product of force and the radius at which it acts. This is shown graphically in the figure on the right. Bigger planes need high torque servos to move their large control surfaces. In general, servo size goes up with rated torque.

Dimensions – Servos come in many different sizes, which you can choose from depending on your application.

Weight – The weight of a servo depends on several variables. Most often recorded in grams, the weight of a servo is always reported on the package.

Bearings – There are two ways to support the output shaft of a servo – bearings and brushes. Brushes are cheaper, but bearings last longer and operate more smoothly. Very small and very cheap servos tend to be brushed, while high end and very large servos generally have bearings. It’s possible to upgrade a brushed servo to bearings, with several upgrade kits being available on the internet.

Gears – Most hobby grade servos use nylon gears, while higher end servos use metal gears. Metal gears add more weight, but their advantage is that they can’t “strip”, causing an RC helicopter or airplane to crash. Metal gears wear over time, which can cause “slop” in their rotation, but the gears can be replaced somewhat economically. In general, nylon servos are adequate for sport flying. If you’re particularly worried about losing a model in a crash, or are flying intense aerobatics, a metal geared servo is probably the right choice.

Speed – Speed measures how fast the servo can move from one position to another. Different RC airplanes and helicopters will need servos with different speeds. For example: a trainer doesn’t need to change control surface positions rapidly, but a 3D helicopter or plane does. High speed servos are many times more expensive than standard ones.

Digital / Analog – Servos can be of two types: digital, or standard. Both digital and standard servos can be used with a normal receiver, the real difference is performance. All servos use a series of short pulses as signals that determine what angular position they should maintain. This series of signals is usually very fast, somewhere around 50 pulses per second maximum. On a standard servo, this rate is so fast that small movements of the control sticks may not have an affect. This means that there’s a small deadband on the control sticks, in which no servo movement takes place. Although it’s not a problem on trainers and most sport class models, the deadband becomes a significant issue with 3D aircraft. Even a small delay with a 3D aircraft could cause a crash.

All RC kits and ARFs will specify the type and brand of servo required. Generally, you should adhere to these recommendations.

Servo Plugs and Wires

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All RC servos will have three wires. One wire is positive lead (+) from the battery. One wire the ground (-) from the battery. The third wire is the control input from the receiver.

It is important to note that you can't just swap the pos.(+) and neg.(-) to reverse the servo. Doing so may damage your servo and receiver. You can buy connectors that act as a servo reverser by reversing the control signal. A Y connector is commonly used with two ailerons servos that share the same receiver output. The Y connector reverses the signal to one servo so that the two aileron servos act opposite of one other.

Futaba's "J" connector is a plug with a little plastic tab, or key, that prevents you from plugging it in backwards.

Futaba's J plugs, Airtronic's Z plugs, Hitec's S plugs, Hobbico's U plugs, and JR's connectors are all compatible as long as you make sure the wires are in the correct order within the plug. If you want to plug a male Futaba plug into another brand you will have to shave the safety tab off.

If your servo is a different brand than your receiver, it is critical that you have the appropriate wires lined up before plugging the connectors together. The wires can easily be popped out of the connector for rearrangement. The images below show you the wiring schematic for the plugs of the four major servo manufacturers.

Coreless and Brushless Servo Motors

2009-07-30T01:24:00.000-07:00

Most low cost and standard servos (analog or digital) use what is called a 3 pole electric motor. This is just a standard 3-pole wire wound DC motor – the most common type of DC motor in existence. One step up from the 3 pole is the 5 pole servo motor. As you can imagine, two more wire windings will give a 5 pole motor quicker acceleration and more torque on start up.

You know by now the faster the servo ramps up to speed and the more torque it produces; the better it is for most applications. Well, improving the electric motor itself will produce more speed and torque too; coupled with digital technology, the resultant speed and torque are indeed impressive.

Coreless Servo Motors:

A standard 3-pole wire wound servo motor uses a steel core with wires wound around the core, this core is then surrounded by permanent magnets.

As you can imagine, the core and all that wire weighs a fair bit. When voltage is applied to turn the motor, it has to first overcome this weight to get things turning – it is slow to accelerate. Once up to speed, it also continues to turn for a while when the voltage is removed – it is slow to decelerate.

In a Coreless design, the heavy steel core is eliminated by using a wire mesh that spins around the outside of the magnets. This design is much lighter resulting in quicker acceleration and deceleration. The result is smoother operation, more available torque, and faster response time.

Brushless Servo Motors

The latest advancement is to use a small brushless DC motor in the servo. This is the exact same principle and has the same advantages as larger brushless DC motors that are used in electric RC helis, planes, and cars. There are no brushes that add drag or can wear out.

Brushless motors are more efficient, provide more power, speed, and acceleration - once again raising the bar on the level of speed, torque, response time, and smooth operation.

Digital Servos

2009-07-30T01:21:00.000-07:00

Digital servos to the rescue! Like I said before, a digital servo has all the same parts as an analog servo, even the three wire plug that plugs into the receiver is the same. The difference is in how the pulsed signals are sent to the servo motor.

A small microprocessor inside the servo analyzes the receiver signals and processes these into very high frequency voltage pulses to the servo motor. Instead of 50 pulses per second, the motor will now receive upwards of 300 pulses per second. The pulses will be shorter in length of course, but with so many voltage pulses occurring, the motor will speed up much quicker and provide constant torque.

Incidentally, if you have ever wondered why digital servos "sing" when very light force loads are placed on them, what you are hearing is the short high frequency voltage pulses acting on the motor.

The result is a servo that has a much smaller deadband, faster response, quicker and smoother acceleration, and better holding power. You can test this very easily by plugging in a digital servo and an analog servo to your receiver. Try to turn the servo wheel off centre on the analog RC servo.

Notice how you will be able to move it slightly before the servo starts to respond and resist the force - it feels a bit spongy.

Now do the same thing with the digital RC servo. It feels like the servo wheel and shaft are glued to the case – it responds that fast and holds that well.

Now nothing is perfect and this increase in speed, torque, and holding power does come with a small disadvantage. Power Consumption!

Yup, digital servos are power hungry. All those hundreds of power pulses per second use up more battery power than an analog servo would. This really is not that much of a problem these days since battery packs have at least double or triple the capacity of what the same size/weight pack had just a few years ago.

So yes, digital RC servos are much better than analog. You can still fly a RC helicopter with analog servos, but once you switch over to digital, you will likely never go back. Don’t forget about that heading hold gyro – he needs to be paired with a fast digital servo to work correctly – no exceptions!

One last point I should clarify with this whole analog/digital RC servo discussion. Remember those speed and torque specifications I talked about earlier... You will find analog servos that have better speed and torque ratings than some digital servos; so why not get one of them over a more expensive slower digital?

Remember, the analog servo is slow to respond and provides little torque during small, fast command inputs. Those good looking specifications are given at full stick movement when the servo has ramped up to full speed and torque. The slower spec digital servo in this case will still provide much more speed and torque where it is needed most.

Analog Servos

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An analog RC servo controls the speed of the motor by applying on and off voltage signals or pulses to the motor. This voltage is constant (the voltage of the receiver battery pack to be exact - 4.8 or 6.0 volts).

This on off frequency is standardized to 50 cycles a second. The longer each on pulse is, the faster the motor turns and the more torque it produces.

This is the same way the speeds of most motors are controlled. For instance, if you have a ceiling or exhaust fan in your house that is controlled with a variable rotary dial speed switch; the fan motor is not given lower and higher voltages to adjust the speed.

The speed switch simply cycles the 120 volts to the fan motor on and off many times a second. The longer each on pulse is, the faster the fan runs. This is also the same way electronic speed controllers for electric RC helicopters , planes, cars, and boats work.

Now back to our analog RC servo. At rest, there is no voltage going to the motor. If a small transmitter command is given or some external pressure is applied to the servo horn forcing it off neutral, a short duration voltage pulse will be sent to the motor.

The larger the stick movement or potentiometer movement, the longer this "on" pulse will be in order to move the servo quickly to the desired position.

Remember me saying that these voltage pulses are sent 50 times a second. This means that in one second, there are 50 windows that last 20 milliseconds each (50x20 = 1000 ms = 1 second). The longer each on voltage pulse is in each of these fifty 20 millisecond windows, the faster the servo motor turns and the more torque it produces.

I just included this info for those of you who really want to know what makes a servo tick. You don’t have to understand all that however, as long as you understand that during small amounts of stick movement or when external forces are applied forcing the servo off its neutral or holding position; only a short duration voltage pulse will be sent to the servo motor every 20 milliseconds. With large stick movements, a long voltage pulse will be sent every 20 milliseconds to the servo motor.

As you can imagine, a short power pulse every 20 milliseconds doesn’t get the motor turning that quickly or allow it enough time to produce much torque. This is the problem with all analog servos; they don’t react fast or produce much torque when given small movement commands or when external forces are trying to push them off their holding position. This area of slow sluggish response and torque is called deadband.

Much of RC control, especially with RC helicopters is done with small quick stick movements moving the servo back and forth in very small increments. There are also many changing loads on the rotor system (both main and tail) that are always trying to force the servo off its hold position as well. Don’t forget about the gyro either. The new heading hold gyros or electronic flybar systems are sending hundreds of small correction changes to the RC servos every second.

If I did a good job at explaining all this, you should realize by now that much of RC helicopter control and movement actually happens within the deadband area of an analog servo.

This is not really that big of deal for slow human response times, but as I mentioned, a problem for lightning fast gyros and electronic flybars or advanced 3D pilots with cat like reflexes.

RADIO CONTROL MODEL

Table Of Contents

home luu

RC boat - Get started

RC boat - Interesting hobby

Radio Control Boat - Fast, Faster and fastest

RC Radio Modes

Troubleshooting RC Radio System

Programmable Radios

Radio Functions

Frequency Control

Signal Modulation

How RC Radio System work

RC Radio System consist of

The Heart of R/C Modeling

Modification For Continuous Rotation

Choosing the Servo

Servo Plugs and Wires

Coreless and Brushless Servo Motors

Digital Servos

Analog Servos