R/C Information Page

Here we will try to introduce new and potential new radio control modelers to some of the necessary information and guidelines for operation of their models. The keys to a successful outing and to enjoying the hobby is understanding the basics. Below are some of the primary things all R/C boat modelers should know. Much was learned by trial and error at some cost to models, equipment, and sanity. It is not a all inclusive list but is a foundation to building a better understanding of what being a part of this hobby entails.

Several things go into making and operating a radio controlled model boat, car, or airplane. Here we will focus on electric and sail powered boats.

The first and most important item is a model. Decide what you are most interested in be it tugs, military vessels, sailboats, racing boats, or whatever. You may choose to do some of each or stay with one type. Once you have made a decision on what you want to build find a kit which is suited to your skill level. Don't be too ambitious at the start. A complex kit will frustrate you and may cause you to despair of ever starting in this hobby. Skill is built over time with experience.

During the building process you will have to plan where everything will fit inside. Things like motor size and placement, battery requirements, speed control, additional functional details will effect the layout of the interior of your model. In beginner kits this will be worked out for you in the plans. It is a good idea to take the opportunity to carefully examine the what, where, and why of the layout. Try to understand why the manufacturer did something a certain way. Getting a feel for common practices will help you develop your building skills more quickly. Later on when you are doing a scratch built model you can apply the knowledge to your project. Never pass up a free education.

The pieces you will need beside a model are a radio system, motor (for motor boat), speed control (for motor boat) or sail winch (for sailboat), and a propulsion battery (for motor boat). You will also need a battery charger of the proper type to charge your propulsion batteries. The cost of each item as in most cases is dependent upon quality and features. Your hobby dealer, area club members, or other modelers will be able to offer guidance in choosing the right pieces for your project. Don't be afraid to ask. There are no dumb questions. Only dumb mistakes. If you can't find someone near you to ask just e-mail us and we'll try to help out.

Below we will give some basics on each of the more technical parts that make up a R/C scale boat.

In the olden days operational model boating consisted of building a nice model and releasing it on the water to fend for itself. Some models were fitted with a wind vane system to steer the rudder, or a clock work unit to steer a predetermined course. During WW II radio control was developed to guide munitions to targets. This was the forerunner to modern cruise missiles. Naturally the people who gained this knowledge during the war applied it to other areas after the war was over. The equipment of the time was very crude by present standards but a revolution was just around the corner. In the 1960's the introduction of the transistor made radio gear smaller, less expensive, and more reliable. This made access to R/C technology available to more people and the hobby began to grow.

With success comes government regulation. The Federal Communications Commission set aside a block of frequencies for use in radio controlling devices. Originally all R/C models shared a single band in the 72 mhz range. By the end of the 1980’s this was insufficient for the expanding use of the limited bandwidth. Aircraft and Surface Vehicles were split apart with the air frequencies remaining in the 72 mhz range and the surface vehicles moving to 75mhz. The R/C flyers have a strong international organization in The Academy of Model Aeronautics. The Academy of Model Aeronautics works with the FCC on R/C related issues and has become a central spokesman for the R/C hobby. They have been the watchdogs looking out for the interests of all R/C modelers in the US. As the airwaves fill up and available frequencies are maxed out our small piece of the radio pie is coveted by other users. The AMA fights to hold our share and protect our interests. Just making its debut is the DSM system. Digital Spectrum Modulation does away with crystals and standard channels. This is the wave of the future.

When purchasing radio equipment make sure you get the correct frequency range for your application, 72 mhz for aircraft, or 75 mhz for surface vehicles. There is also the 27mhz and 43 mhz bands which are used by the ready to run toys widely available in stores. You can purchase 27mhz radio systems but you do risk interference from the toy radios. We are not aware of any manufacturer selling a radio system on 43 mhz. Amateur radio license holders can opt for the 50 mhz and 53 mhz bands.

Below is a list of US surface R/C frequencies with their corresponding channel number. We have omitted the aircraft frequencies as we are concerned only with the surface ones here. If you need the aircraft frequencies they are readily available online. For information on the federal regulations governing Radio Control see the links below.

The FCC is responsible for administering radio frequencies in the US under the Code of Federal Regulations. Below is the CFR sections of interest to R/C modelers.

Federal regulations governing the use of radio frequencies by private citizens with Amateur Radio Licenses.

Listed below are the frequencies and channel numbers for the 75 mhz and 27 mhz bands. The 49 mhz band is listed because several RTR toy boats use this frequency.

75 mhz
Channels 61-90:

Channel      Frequency                                  Channel     Frequency
61 ---------- 75.41                                         76 ---------- 75.71
62 ---------- 75.43                                         77 ---------- 75.73
63 ---------- 75.45                                         78 ---------- 75.75
64 ---------- 75.47                                         79 ---------- 75.77
65 ---------- 75.49                                         80 ---------- 75.79
66 ---------- 75.51                                         81 ---------- 75.81
67 ---------- 75.53                                         82 ---------- 75.83
68 ---------- 75.55                                         83 ---------- 75.85
69 ---------- 75.57                                         84 ---------- 75.87
70 ---------- 75.59                                         85 ---------- 75.89
71 ---------- 75.61                                         86 ---------- 75.91
72 ---------- 75.63                                         87 ---------- 75.93
73 ---------- 75.65                                         88 ---------- 75.95
74 ---------- 75.67                                         89 ---------- 75.97
75 ---------- 75.69                                         90 ---------- 75.99

27 mhz
This band is mostly used for toys along with 49 mhz. Some R/C Radio manufacturers offer radios on 27mhz.

The frequencies on the 27mhz band have another distinguishing characteristic. They also are designated by color.

Channel      Frequency              Color
1                26.995                   Brown
2                27.045                   Red
3                27.095                   Orange
4                27.145                   Yellow
5                27.195                   Green
6                27.255                   Blue

If you would like to download a copy of this frequency list in MS Word .doc format this click here.

If you would like to download a copy of a complete R/C frequency list (air and surface) in MS Word .doc format this click here.

There are many choices available today in Radio Control technology. Having a basic idea of your needs and wants will make buying the right system much easier. You can easily get bogged down by all the techno talk associated with current R/C systems. Lets break it down to the simplest terms just to get started. A standard radio control system will come with a transmitter, receiver, servos, receiver battery pack or holder, power cable with on/off switch, a channel flag, and a manual. Some systems will come with Ni Cad battery packs and a charger for the transmitter and receiver. The transmitter NiCad pack will usually come installed in the transmitter. The number of servos may vary with the system, and some systems may substitute a servo with a speed controller. There are several manufacturers of good systems and they all work the same basic way. You will find brand loyalty here just as much as anywhere so take advice on R/C systems as you would for anything else. A long established name brand system will give you good service and you should do some shopping to find the system right for you.

Buying your first radio you could choose a basic system just to get started. Something to consider is your ability to purchase additional equipment as your needs increase. It may be wise to go with a slightly more capable unit at the beginning thus allowing you to delay major new purchases for some time. You should consider paying a few extra dollars for a radio with servo reversing. It is one of the little features you may think is not necessary until you wish your radio had it. As you progress further into the hobby you can buy a more capable system that will meet the current needs and anticipated future needs. The most popular multi-channel radios are four channel units. They offer flexibility at a reasonable price. Scale builders love transmitters with multiple channels. This makes possible additional operating items like anchors, horns, lights, sounds, etc. On twin screw boats each motor can have its own throttle.

Some features to look for on a transmitter are servo reversing, trim, and dual rate. Servo reversing is nothing more than a small switch which allows you to "reverse" the operation of the servo on that channel. This is handy if you happen to wire the motor backwards and can't redo it right away, or your rudder is working opposite of the stick. Trim is a fine adjustment on the stick so you can "zero" a speed control or your rudder without having to make small linkage adjustments on the model. Dual rate is a adjustment of the sensitivity of the stick function. A good example is the Aquacraft Pro Fisherman Outboard. The steering rate can be dialed down so a child or novice will not spin the boat out in sharp turns. A more skilled operator would turn up the rate to allow full responsive control.

Rechargeable batteries are also an option on some systems. Most Multi-channel systems come this way. It will save you money on Alkaline Batteries but you have to remember to keep the transmitter and receiver packs charged. The systems with Ni Cads will come with a charger that plugs into the transmitter, and will have a plug for the receiver pack.

A basic AM radio system will start at about $50.00. As you add more channels, features, and functions the price naturally goes up.

R/C transmitters come in two basic styles, stick, and pistol grip. Stick radios will have two or more "sticks" to operate the individual functions. Pistol Grip radios typically have a wheel for steering, and a trigger for speed, and forward and reverse direction . Stick radios have the ability of handling multiple channels (up to 14), while pistol grip radios usually come with a maximum of three channels. A word on "channels" here. The term channels is used two ways in R/C. In reference to frequencies it is the number assigned to a specific frequency. When referring to radio functions it means the channel from the transmitter, through the receiver, to a servo. A two channel R/C system will have the capability of operating two servos independently and simultaneously. A servo can be replaced by a electronic speed control.

Transmitters also come in AM, FM, PCM, and DSM versions. AM and FM are what they sound like, AM radio and FM radio. PCM is a digital signal which is more stable than AM or FM. The new kid on the block is Digital Spectrum Modulation. This system does away with conventional frequencies altogether. In our club most members use AM with little problem. Our generally slow models don't get into too much trouble if we are hit with a "glitch". "Glitch" is when your model does the unexpected due to interference. With a increase of speed or altitude where accidents are worse a system less prone to interference like FM, PCM, or DSM may be advisable.

Pictured below are a two channel stick radio, a two channel pistol grip radio, and a five channel radio. The five channel radio has two throttle sticks, one rudder stick, and two small levers on the top to control secondary functions.

Each frequency in the band has a channel number assigned to it, just like broadcast television. It is easier to say and remember channel 66 than it is 75.510 Megahertz. Keep in mind that the term "channel" has two meanings in the R/C language.

When talking about radio functions you are talking about the connection via radio signal from the "stick" to the receiver, and then to the servo. For example lets say we have a tugboat with a two channel radio. Channel 1 is the steering channel and channel 2 is the throttle channel. The sticks are oriented to make them feel natural in the typical use. The left stick moves up and down, and is normally used as the throttle. The right stick moves left and right and is used for steering. Both sticks are neutral in the center and are self centering. The throttle stick would be set so when you push up the boat goes forward and down it goes backwards.

The receiver gets the signal from the transmitter and relays it to the servo or speed control. The receiver will have ports to plug in the servos. There should be enough ports to correspond with the number of channels on the transmitter. The receiver ports will be marked with identification of which stick controls it. The markings may vary so consult the manual. A battery port is also provided. The batteries power the receiver and the servos.

Servos provide the muscle to turn stick movement into action on the model. Most systems come with a standard servo which is good for most applications. Other servos can be purchased separately to fit specific requirements. Micro servos are widely used in aircraft and small boat models. Large high torque servos are used as sail winches or heavy use applications.

The question "What frequency channels does the hobby shop have available?" is important. Ask the hobby shop what channels they have. The 75 mhz band only had the even channel numbers when it first came out. The odd channel numbers were added later. If you can choose a odd channel you stand a slightly less chance of running into someone on your channel. Also ask the hobby dealer for a channel that he has sold less of. For a time a few years back everyone seemed to be getting channel 84. If you are joining a club or are in one ask what the most common channels are, and avoid them.

The last item is "What components come with the system?" The components and accessories which come in a system will affect its usefulness and price. A standard two channel radio system with two servos start around $50.00. A Futaba system which replaces one servo with a electronic speed control will add about $40.00 to the price. A four channel system will be more than double the price of a two channel system. The quantity and type of servos in the system can also effect price. Discuss your needs with your dealer to get the system right for you.

Webster's dictionary defines "Glitch" as a malfunction, or mishap, or an error. Radio Control systems are susceptible to interference from outside sources. This can cause your model to act in strange ways. Outside interference can be caused by police and aircraft radios, proximity to marine or aircraft radar, another transmitter operating on your frequency, and other things. AM systems are the most susceptible and DSM the least. FM falls in between. A common source of glitching when running with a group is 3IM (3rd Order Intermodulation). It is when two transmitters combine to send a harmonic on a third frequency. In 1987 WSBA member Roland Schaefer created a chart to detect 3IM conditions at the pond. Note: this chart was made before odd channels were added.

We all know what effect a glitch can have on our boats when we gather at the pond. While many glitches can be caused by transmitters in other services such as Police, Marine, Taxicabs, Mobile telephones, etc., etc., one type of glitch can be caused by interaction between our own R/C systems. The output frequency and second harmonic output of a couple of transmitters used by fellow members will sometimes combine in the detector circuit of YOUR receiver and cause a signal the same as your channel even though their transmitters are on other frequencies than yours. I do not have space enough here to explain the details but, suffice to say, you get a glitch - especially if you turn on your receiver and your transmitter is off.

If you are standing some distance away from the other club members and your boat is closer to them than to you, your boat may act up due to what is known as 3IM (3rd order Intermodulation). The chart that I worked out after much head scratching shows the relationship between channels. It takes two to tango but it takes three to glitch. Your R/C system and two other R/C systems.

If you get a glitch, try using the chart. Locate your channel in the left hand column. To the right will be the pairs of channels that may cause you to have a glitch.

For example; - Mike was on channel 84 and was standing away from other members when his lobster boat came close to the other said members and presto, a glitch. Using the chart, we found one person had channel 80 and

one had channel 76. As I said before, many other factors cancause a glitch and this is but one of them.

* Webster's dictionary defines "Glitch" as a malfunction, or mishap, or an error.

If you are using a channel listed on the left any of the pairings on the right have the potential to cause 3IM on your frequency.

Motor technology has come a long way in the last few decades. The basic "Can" motor has changed little in the last 50 years. The advances have come in low weight and high torque motors, and brushless motors. Matching a motor to the model is critical in that a poor pairing will result in non scale performance, poor battery life, heat buildup in the model, motor, and battery, and premature equipment failure. Using a high speed can motor in a tugboat is always a bad idea. Using a slow turning Pittman motor in a speed boat is just embarrassing. The stress a motor is put to is only partly comes from the model size and weight. The choice of propeller can make a motor run at peak efficiency or burn up.

Your model will need a method of controlling the speed and direction of the motor you just installed. There are two types of speed control in common use. The first and older technology is a resistor speed control. This type uses a switch wired to one or more ceramic resistors which control how much power gets to the motor from the battery. A second type of resistor speed control uses a coil off resistor wire with a wiper which moves along the coil, giving better control of speed. These units become very hot and will burn a careless finger (personal knowledge). With the wide availability of affordable electronic speed controls this type is rarely seen any more.

The second type is the electronic speed control (ESC). ESCs come in a wide variety of shapes, sizes, and capabilities. The lowest rated units will typically handle a 4.8 volt Nickel Metal Hydride battery pack. I have seen some ESCs rated at 24 volts and 300 amps. On most units they have a rating of the number of cells they can handle. Look at all specifications when selecting a ESC. Your ESC will have to match the boats power supply and power demand so keep those numbers in mind while you shop.

There are choices available in supplying your model with power. In scale boats the most common are gel cell and Nickel Cadmium (NiCad) rechargeable batteries. Nickel Metal Hydride is a improvement over Nickel Cadmium. The new kids on the block are , Lithium Polymer, and Lithium Ion. Since Lithium Polymer, and Lithium Ion are recent technology they cost more but offer longer run times at lower weight. Battery capacity is rated in Amp Hours. If your boat draws 1 ampere of power theoretically it should run 1 hour on a full charge. In real life your results may vary. NiCad battery packs being smaller are rated in milliamps, which is 1000 milliamps = 1 amp.

Gel cell batteries are similar to a car or motorcycle battery except that the electrolyte (liquid acid) is made into a gel and the battery case is sealed. This allows the battery to be placed in any position and is safe inside a rocking boat model. They have to be slow charged and not allowed to discharge completely.

Nickel Cadmium (Ni-Cad) batteries are made up of cells a little smaller than a size C alkaline, and they are called sub C cells. The normal packs are 6 cell 7.2 volts, or 7 cell 8.4 volts. Packs can be purchased in different capacities (milliamp rating) and matched cell packs. Matched cell packs are constructed of cells individually tested for capacity, so all cells charge and discharge evenly. Cadmium is environmentally unfriendly so old batteries should be disposed of properly.

Nickel Metal Hydride (NiMH), NiMH is very popular in electric aircraft and they are readily available. You need a charger that can handle NiMH so check before you buy.

Lithium Ion Polymer (LiPo) and Lithium Ion (Li-Ion) batteries are the latest technology Li-Ion and LiPo are still a bit exotic and there have been some safety questions with this type. They are commonly used in low demand devices like cell phones and laptops with no trouble. Models have a significantly higher power demand and this is where the trouble seems to surface. Careful charging and monitoring of Lithium batteries is critical. If depleted they may not recharge. If overcharge they may burst into flame or explode. The problems with Lithium batteries include volatility, thermal runaway, high cost, and limited shelf and cycle life.

The type of battery you use will determine the type of charger you will need. Gel Cell batteries need a low amperage slow charge (typically 24 hours). NiCads will take a fast charge at higher amp input (15 to 30 minutes at about 3 amps). NiMH packs will quick charge but your charger has to be NiMH capable. Chargers come with different features. Some are AC or DC powered or can use either. They can have peak detection, amperage control, meters, audible signals, discharging, and a host of other bells and whistles. WSBA and Madison RC Boat Club member Doug Robichaud gives this advice on his choice for a good all round charger.

Quite a few WSBA members have been asking me about battery chargers lately, especially those that will handle NiMH cells.

I think the best value on the market today is by GWS. $44.95 available at www.offshoreelectrics.com. Greenfield might even carry it. Radio Shack has some relatively inexpensive power supplies that you can use for AC power.

GWS Battery Charger GWS-MC2002

Input Voltage Range: DC 9.0 ~ 15.0 V
Charging Current: 0.25 ~ 6.00A Continuous
Battery Types: 50 mAh ~ 3300 mAh Ni-Cd or Ni-MH
Charge 4 to 12 cells at once.
Cut-off: Microprocessor Controlled Automatic Delta-Peak Cut-off
Protection: Output Reverse Polarity and Short Protection
Maximum Charge Time: 90 Minutes with Safety Cut-off
Readout: Large Scale Current Meter
Cooling: Sturdy Aluminum Case with Heavy Duty Heat Sink
Requires 12v power supply or car battery

The information above is provided to give an idea of what goes into a R/C model boat. Every possible scenario cannot be anticipated so each modeler must make his/her own decisions on the best equipment to suit their needs. When in doubt seek information and advice from your hobby dealer, local modelers, online forums, books and magazines, or e-mail us. Our hobby thrives because it is a enjoyable and rewarding pastime. We will be glad to help you find the same enjoyment we do.

Enjoying the hobby also brings with it a responsibility to respect others rights too. Nothing ruins a day of fun like a confrontation which could have been avoided.

The first thing you as a new R/C‘er should be aware of is all modelers share the frequency band we use. R/C aviators are most susceptible to interference by others on their channel. More than one deep hole has been dug by a out of control airplane in this manner. Consequently aircraft modelers have strict rules about transmitter use and usually impound transmitters to prevent this problem. Other fast moving models such as cars and gas or fast electric boats can also suffer serious damage from loss of control. Scale boaters are a little less formal about transmitter control but it is still taken seriously.

If you are running a surface model you should not be on 72mhz. Remember a airplane is up high where it can pick up stray radio signals at a greater range than a surface model. Distance only insures you won't hear the scream or see the wreckage.

Always make sure a channel is free BEFORE you turn on your transmitter.

If a frequency board is present, use it.

Have your channel flag attached to you transmitter antenna.

Share the channels. Check occasionally to see if someone is waiting for the channel you are using. They have an equal right to it.

Mark your equipment. Have your name on radios, gear, lawn chairs, and field boxes. If you leave something behind you stand a better chance of getting it back. Most modelers look out for each other.

Share knowledge. If you know of a hazard warn your fellow modelers. A submerged rock is hard on hulls and propellers.

Take care of the site. Don’t leave litter around the area and please help keep the area clean. Many sites are in public parks in residential areas. Maintaining a good relationship is vital to continued use of a site.

Next to impounding transmitters a frequency board is the best solution to frequency control. Organized facilities will have a frequency board available. If the site you use has one please use it. The most common frequency board method used is for the modeler to have a spring loaded clothes pin with his/her name on it. This pin is clipped to the board at the appropriate channel number. Clubs and organized events will have some sort of frequency control.

Casual or non-organized running will typically not have any frequency control in place. It falls to the modelers to police themselves on these occasions. If you are at a park and you see another modeler, walk over and ask what channel they are on. You will get the necessary information and you may make a new friend. A good practice is to use the frequency flag which came with your radio. It attaches to the antenna and is easy for other modelers to read. In organized events the flags may be required. If you do not have the flag see your hobby dealer. It is important for every modeler to use common sense at the running site so all will have a enjoyable day.

If you have been in this hobby for any length of time you will have a “transmitter story”. The most common ones are “I drove 50 miles to a event and my transmitter was on my work bench.” “I got to the park and the batteries were dead. I guess I should have charged them.” “ I got to the park and I had the right boat and the wrong transmitter, or the right transmitter and the wrong boat.” Everyone has done it or will do it eventually. A little planning goes a long way to making your outing a success. Design yourself a routine to follow for preparing to go out. Charge all your batteries. Do routine maintenance on your model (lubrication, checking fasteners, checking electronics and motors, checking for damage). Make sure your field box has all the tools and supplies you may need at the run site. Check the weather report. Bring a comfortable chair. Bug spray and sunscreen are also nice things to have along. Trial and error will help you decide what items you will want along with you for a day of fun with your models.

Once you have your model ready to go and your heading to the pond the most important thing is to pay attention. The transition from the work bench to the water can be smooth or a catastrophe depending largely on you. Before you power up and get the boat wet take a walk around and look at the water. Are there sticks or trash floating? Can you see any submerged obstructions? Are there weeds or shallow areas? If you can find potential trouble before it finds you it is much better. Another hazard to look for is fishing line. Monofilament line will clog a driveshaft quicker than anything I have seen, and it takes a troop of Boy Scouts to untangle it. Beware of hooks on the line too.

When you are ready for launch turn on the transmitter first. If there is another radio near your model it may overpower your receiver and drive your boat nuts. Remember transmitter on first, off last.

While the boat is still on the stand check for throttle and rudder control. The most common mistake at this point is launching the boat with the receiver turned off. The second is not having the drive battery connected.

When you pick up the model keep your fingers away from the prop. This is not a good way to get a manicure.

Pick a stable place along the shore to launch. You could wind up in the drink on top of your model if the shore line were to break away under your feet.

After your run reverse the order. Check the prop and rudder for weeds. Open the model up and air out the interior, especially if your motor or speed control heat up. Place your drive batteries out to cool if they become warm. Heat is a byproduct of high power demand. If you have a heavy model the motor has to work hard. If you have a fast model the rapid drain of the batteries will cause heat. In severe heat situations a cooling system may be needed.

In no time most of this becomes second nature. Simple planning, attention, and common sense will allow you to enjoy the hobby for many years to come.

In June of 2007 a model boater in Ohio went into the water (swam) to retrieve his stalled boat. He didn't make it back to shore alive. No model is worth a life. NEVER swim after a disabled boat model.