The list of innovations that make the Comp Crawler an RC revolution is long, and it starts with a solid foundation. The Twin Vertical Plate (TVP) chassis with adjustable upper shock mounts offers unbeatable stability and rigidity in a durable, lightweight design. The result is confident handling over any terrain and outstanding suspension articulation. And Team Losi Racing has gone one step further, by offering this innovative crawling chassis pre-built and tuned right out of the box. All you have to do is add the electronics of your choice and paint the included Lexan Grappler Pro body.

Team Losi Racing’s Comp Crawler is the first rock crawling platform in the industry to offer a revolutionary front and rear “dig” transmission. The use of an optional third channel setup allows the front or rear drive axle to be disengaged, locking the wheels in place and acting as a steering brake for precise lateral movement on and over obstacles. The transmission case has been fitted with adjustable servo mounts that will allow for the use of most “mini” servos and includes an aluminum servo arm. The third channel on a 3-channel radio (such as the Spektrum DX3R) allows the full use of the DIG transmission, and also requires a micro servo installation for actuation. If you do not have a 3-channel radio system or extra servo, there is no need to worry – the Comp Crawler will function with full-time 4WD with our without a dig servo hooked up.

The solid axle setup on the Comp Crawler offers a significant reduction in flex for improved performance. Inside, the axles utilize a worm gear drive for outstanding precision in throttle control and maneuverability. Another benefit of the worm gear drivetrain design is the elimination of the “torque twist” commonly found in shaft driven rock crawlers. As a result, the Comp Crawler stays in contact with the ground for uninterrupted grip.

The Comp Crawler features a 4-link suspension layout that offers 70 degrees of suspension articulation. This specially designed 4-link suspension setup is used in combination with the Twin Vertical Plate chassis to reduce axle swing and eliminate side-to-side movement for increased steering and maneuvering precision. 7mm diameter aluminum suspension links are hard anodized and triangulated to the center of the chassis for better balance front to rear when the suspension starts to twist. 4-inch aluminum threaded shocks with titanium nitride (TiNi) shafts allow the suspension to articulate without any binds.

Just like full-size crawlers, the 1/10 Comp Crawler utilizes functional beadlock wheels with aluminum outer rings. The functioning beadlock allows for the tires to maintain more contact and traction, while the aluminum outer rings provide evenly distributed pressure for unbeatable tire mounting. Losi’s National Champion Rock Claws 2.2 Tires come mounted on the beadlock wheels, complete with foam inserts. The added ground clearance from the Rock Claws tires makes conquering any and all courses easier.

Features:

• COMPACT FRONT & REAR LOCKING (DIG) CENTER TRANSMISSION ALLOWS THE CRAWLER TO OVERTAKE OBSTACLES WITH EASE
• FRONT AND REAR SOLID AXLE WITH WORM GEAR DRIVE
• FRONT AND REAR LOCKED DIFFERENTIAL PROVIDES FULL TIME 4WD
• 4-LINK SUSPENSION MINIMIZES REAR AXLE SWING,ALLOWING FOR MORE PRECISE HANDLING
• 3-PIECE 2.2″ BEAD LOCK WHEELS WITH ALUMINUM OUTER RINGS
• 2.2 LOSI ROCK CLAWS TIRES WITH FOAM INSERTS
• 4″ ALUMINUM THREADED SHOCKS WITH TITANIUM NITRIDE (TiNi) SHAFTS ALLOW THE SUSPENSION TO ARTICULATE WITHOUT ANY BINDS
• DURABLE CV FRONT AXLE SHAFTS ALLOW FOR INCREASED STEERING RANGE
• TWIN VERTICAL PLATE CHASSIS WITH ADJUSTABLE SHOCK MOUNTS
• ZERO ACKERMAN STEERING PROVIDES CLASS LEADING PERFORMANCE WITH 45 DEGREES OF STEERING THROW
• ALUMINUM UPPER AND LOWER SUSPENSION LINKS FOR ADDED STRENGTH
• RACE ROLLER CHASSIS IS PREASSEMBLED; SIMPLY ADD ELECTRONICS, PAINT AND GO

“The Most Advanced R/C Car.- says Popular Science” The new 1/10th scale Losi TEN T is one of the coolest new cars to come out since the traxxas T-max. This new RTR truggy is packed with new innovation and performance. Losi’s revolutionary Remote Onboard Starting System (R.O.S.S.) and Spektrum’s DX3S radio system with integrated Telemetry means you can not only start your RC car with a touch of a button on your remote, you can also see the speed temperature RX voltage and more. All this and a spectrum radio to boot.

The engine is a jaw dropping 3.4cc 34000 rpm with a beautiful ionized aluminum heat sink.
Some of the main features of this truggy are..

2-Shoe Clutch
The TEN-T’s 2-shoe clutch is based on Losi’s race-oriented clutch design for incredible durability and acceleration. Whether you’re racing on a track or tearing up the backyard, the clutch design will give you the power you need.

4mm Tie Rods with Captured Ends.
We’ve designed the TEN-T’s tie-rods with captured ends to stand up to extreme impacts and virtually any terrain you’ll encounter. Captured rod ends prevent accidental disconnection and keep the suspension solid and reliable.

Black Anodized Aluminum Chassis
Precision formed and machined from 3mm thick premium aluminum alloy, the TEN-T’s chassis provides a rock-solid foundation for unbeatable strength and stability. The chassis plate features a black anodized coating for increased durability and resistance to the elements.

Losi Digital High-Torque Steering Servo
The Ten-T’s high-torque digital servo gives you incredibly strong, fast and precise steering response and control.

I would not be surprised to see this as the next big movement in RTR Nitro cars. The bar has been raise again!

]]> http://www.rcgawker.com/2010/04/losi-ten-t-closest-thing-to-a-real-car-yet/feed/ 0 http://www.rcgawker.com/2009/10/crash-your-rc-car-like-a-superstar/ http://www.rcgawker.com/2009/10/crash-your-rc-car-like-a-superstar/#comments Fri, 02 Oct 2009 22:30:35 +0000 rcgawker http://www.rcgawker.com/?p=1400 I laughed out loud when i saw this. Look at the expression on the drivers face. He is crest fallen. I have never seen a car break in half.

Ok one more got to love the slow motion crashes.

OVAL COURSE 2
Have two or three pairs of pylons forming gates and run your car through them as accurately as possible. You will find it much harder than the oval course No.1. For the first period of time, arrange the pylons at a wide space, narrow them gradually, then at last put them at a space of one meter. Practice in both rotations, clockwise and counterclockwise.

ROAD COURSE
When finishing course No.1 and No.2 you have mastered the basic driving techniques. Now you should proceed to complex courses. Build a road course with the pylons, from basic figure “T” and “L” courses to more complicated circuits, assortment of figure “L” and hairpin curves, high speed curve and slaloms.

CAR STEERS OPPOSITELY?
If you are a novice driver and not sufficiently accustomed to R/C car driving, you may feel as if the car steered oppositely to the transmitter movement when the car runs toward you. To solve this problem, try to imagine you were driving in the R/C car. As you repeat the basic exercise, you will get used to this way of thinking and control the model smoothly.

WHERE TO LOOK WHEN DRIVING
When you drive a car, it is important what you keep your eye on. Suppose the squares described are the field of vision, Put your Point of sight on the forward part of the area of vision with a car placed at the rear. The car moves at a rate of 8.3meters per sec when the hourly speed is 30km/h. With your point of site on the car itself you cannot keep clear of obstacles ahead, because it is to late to notice them; nor can you take corners easily.

Vivid Fluorescent orange pylons are useful for marking a track. Soft resin material does not damage your R/C car during impacts. To find out more about purchasing click the image on right.

Corner Pylon
Improving your R/C skills on the Track
Operating a radio controlled car in the open is one thing, but running it on a closed track is entirely different. Even though you are not competing, and only practicing, driving on a track will add much to your driving skills. You can also observe techniques used by experienced drivers running highly tuned cars at the track.

No particular skill is required for driving a car just straight, and the drag speed is limited by the car’s own inherent performance capability. However, at curves, your finesse of taking corners affects the result even among cars of the same performance. Especially in speed races, the cornering technique is one of the decisive factors. After becoming accustomed to the car, try to practice smooth, speedy and stable cornering.

“Slow-In and fast-Out” is a golden rule In speed controlling at curves, and “Out-ln-Out” instructs how to steer a car. Briefly, you should control speed in “Slow-In and Fast-Out” manner and steer a car in “Out-ln-Out” way.

WHAT’S “SLOW-IN AND FAST-OUT”
Decelerating when entering into a curve and picking up the speed after a vertex of the curve is the technique. In the case of entering bends without reducing speed, the car is forced to slow down before finishing comers to lose speed and stability. In the worst cases, the car might spin or run off the course. It also gets the car moving too late to pick up speed. As a result “Slow-In and Fast-Out” is the fastest way to take corner’s.

WHAT’S “OUT-IN-OUT”
It is, as illustrated, a way of turning curves from the outside line of a course Into the inside line to which the car will come closest at the vortexes (clipping points) and finishing the cornering approach back to the outside line, thus making the longest possible turning radius. By utilizing the full width of the course, the car will make an easier turn than the actual curve. So the car may be allowed to run through It faster.

SET THE CUPPING POINT AFTER THE VERTEX
As a matter of fact, however, it seems more advantageous to set the clipping point a little after the vertex, because it allows easier latter half cornering and enables the car more powerful acceleration into the straight course, in spite of sharper first half cornering.

ACCELERATION DURING THE LATTER HALF OF A CURVE IS IMPORTANT
Both “Slow-In and Fast-out” and “Out-in-Out” techniques are established from attaching more importance to velocity in the latter half of cornering than the first half. This has something to do with the acceleration of a car; that is a car increasing speed faster than other cars at the latter half can take the lead in the successive straight track, provided the cars should have the same pickup and maximum speed capability. This principle is true anywhere except in a very wide road where you are not required to reduce the speed at all.

THE LAST CURVE IS THE MOST IMPORTANT IN A CHAIN
The last curve is the most important In continuous curves. In successive bends of a road, steer your car so that it will make the easiest turn at the last curve. Then you will be able to speed it up as soon as getting into the straight course.

CONSIDER COMPLEX CURVES AS ONE
Consider complex curves as one integrated compound. In the case of complex curves with different radii, you can manage to get through by considering them as one complex curve and making a cornering passage.

TAKE THE INSIDE LINE ON GENTLE CURVES
Although the “slow-In, fast-out” and the “out-in-out” rules are basic for cornering. If the curve Is gentle enough, there is little, or no need to reduce speed. Naturally, it is advantageous to use the inside line throughout the curve, when possible

OBSERVE THE ENTIRE TRACK LAYOUT
Although several tips are offered when describing Individual curves, a track Is a succession of straights and curves, it is therefore Important to observe the entire layout and select a smooth running line for completing a lap. Repeat practice laps, trying various routes to find the ideal line. Shortening your lap times during trials is one of radio control’s greatest enjoyments.

WHEN PERFORMANCE GETS BETTER, THE DRIVING LINE SHOULD BE ALTERED
When your car’s top speed becomes faster by using a higher performance motor, etc. more deceleration will be required when entering corners. Not only the speed, but the handling characteristics, tire grip etc. will influence the driving line a car should take.

Not just steering alone, but combining with throttle control, various cornering techniques can be obtained. Practice and master this for much faster and smoother cornering.

FOUR WHEEL DRIFT
This technique is achieved by over steering white deceleration during the early stage of cornering. As the rear wheels start to slide outward and the nose heads towards the inside of the corner, neutralize the steering and add power. The car will take the comer with all wheels sliding. This technique is suitable for rear wheel drive and 4WD race care.

TACKING-1N
This technique is unique to front wheel drive care. Enter a curve straight, then cut power and steer around the curve at the same time The car will change direction quickly. Straighten out and accelerate going through the corner.

COUNTER OR OPPOSITE LOCK STEERING
The term means to steer the wheels against the turn of a comer. If a car enters the corner too fast, the rear wheels could start to skid, resulting in a spin. To stop this, steer into the direction of the skid. This technique is used to prevent the car from spinning and is not for enhancing cornering speed.

WEIGHT LOAD SHIFT ACCORDING TO POWER APPLIED
When running at a steady speed, the load is divided between the car’s front and rear wheels in a fixed ratio. During deceleration, more of a load is put on the front wheel because of inertia, resulting in sharper steering response. Opposite of this is acceleration,

where more of a load is put on the rear wheels, producing a slower steering response. Both the four-wheel drift and tack-in use this weight load shift to obtain desired cornering results.

A race is run with many cars at the same time. If you want to become familiar with racing, the best way is to hold practice sessions with your friends as a group. It is important to feel the difference between driving a car by yourself and competition racing. You’ll notice that
the track seems somewhat narrower with all those care and it becomes difficult to steer the car on the line you desire. Experience is what counts to get your car ahead of other.

START
The result of a race sometimes depends upon the start. However, a quick start is not always advantageous. Accidents are most liable to occur between the start and the first corner because participating cars are running close to one another. Decide how you should start according to the characteristics of your car, course layout, etc.

TAKE AND HOLD THE INSIDE LINE DURING CORNERING
When competing with your rivals during cornering, take and keep the inside line for maintaining the lead. It is difficult for you to beat your opponent in the corner by trying to pass him on the inside line because both cars are running about the same speed. If your car can manage a higher maximum speed than the others, only then is passing on the outside line possible. Trying to take the inside line too early can lead to over-running the corner resulting in a loss of time and running space for your car. While you’re at the edge of the track, your rival can easily pass you on the inside. In order to avoid this, stick to the inside, forcing him to delay his acceleration. Tacking and holding the inside line in the corner is a golden rule for taking the lead at corners. Confrontation between cars during cornering are the most exciting moments during a race, but be sure to avoid the selfish type of running that can cause a collision and damage that will spoil the overall race for everyone.

HOW TO PASS OTHERS
There are various places in which you can try to pass another car. A straight Is the safest place to do so. It is dangerous to start passing a car when you are following close behind it. When you judge it is possible to pass, steer your car a little as soon as possible and attempt to pass. You may pass on either side, wherever there is more room. If the space on each side is about the same, it is advisable to go inside to make the next corner to negotiate. Passing on a corner is dangerous as compared with passing on a straight. If the driver of the car you are going to pass to not skillful In control, your car Is liable to be Involved in its spinning. To make passing easier, it is advisable to go inside the rival’s car and pass it after turning the corner. It is very difficult to pass it on the outside of the corner even if your car is much faster.

IF THE CAR LOSES STABILITY
If your car has hit another car and lost its stability, reduce the speed by turning down the speed control switch. If you try to restore stability by steering, the car might be further disturbed. Start acceleration again only after the car has slowed down and is stable.

Source: TamiyaUSA ]]> http://www.rcgawker.com/2009/09/tips-to-improve-your-driving-skills-on-the-track/feed/ 0 http://www.rcgawker.com/2009/08/electric-nitro-or-gas-which-rc-car-to-get/ http://www.rcgawker.com/2009/08/electric-nitro-or-gas-which-rc-car-to-get/#comments Mon, 31 Aug 2009 21:16:22 +0000 rcgawker http://www.rcgawker.com/?p=1197 Those of us who are looking to get started in the RC world have to make a tough decision very early on: Electric vs. Gas powered RC cars. Since start up costs can be expensive, most people can’t afford to invest in both.

What many newcomers don’t realize is that gas powered RC cars should actually be sub-divided into two categories: Nitro, and Gas. Here are some of the key differences I gathered from wikipedia. Hopefully this helps you make an informed decision!

Electric batteries, however, take some time to charge; peak chargers can accomplish this in about fifteen to forty-five minutes. Stock top speeds for Electric models are around 30 mph, but depend greatly on the model and motor.

Nitro:
Nitro powered RC cars can reach moderate speeds unmodified. Maximum power is generally achieved at medium to high speeds, and a slightly slower throttle response than electrically powered vehicles is to be expected. Electric motors effectively produce instantaneous torque, where nitro engines, like full-sized gasoline engines, take time for the engine to spool up and for the clutch to engage. Nitro (and gas) powered cars may be refueled and returned to action in a few seconds, as opposed to electrics needing to remove the body shell and battery fasteners to replace a discharged battery.

Because of higher stock performance and their ability to be driven for longer periods of time, mechanical wear in nitro vehicles is generally greater than in electric vehicles. In addition, the increased speed and weight of fuel-powered vehicles generally lead to higher speed collisions, causing greater damage to the collided vehicles, and a greater degree of safety concern needs to be taken into account. However, nitro vehicles are more durable due to stronger components to sustain the greater stresses of more power.

Gas:
Gas powered RC cars, also known as “fuelies” or “gassers”, run on premixed gasoline and oil. They cost much more (usually $800-$3000 rtr) than nitro and electric cars. They are also much bigger and therefore require much more space to run. They don’t usually have high top end speeds (compared to nitro and some electrics) but have lots of power and don’t take a lot of fuel to run, and run times average 45 minutes. Over time the cost of a gas powered car can be less than some nitro powered vehicles, because of the high cost of nitro fuel and buying new nitro motors to replace worn out ones. In addition, gas powered motors rarely if ever require tuning and have a very long lifespan.

So, you can see there are definitely some major differences to consider.

During the 80’s and 90’s electric RC cars were king. Rarely did you see a nitro RC car buzzing around bashing, and you almost never saw them race. Sure they were out there, but the popularity of the electric RC car far out weighed that of the nitro RC car. During the late 90’s nitro cars started showing up more and more. New model designs and the advent of the EZ-Start engine gave nitro a foot hold in the RC market place. Now a days it seems as if there are more nitro than electrics running around the track, but that could all change. With the recent adoption of the lithium based battery and brushless motor, more and more people are seeing the benefits of electric power. They are faster, lighter weight, and getting cheaper all the time. Not only that, they come in a variety of sizes, ranging from 1/16 to 1/8 scale.

Not everyone knows the difference between brushed and brushless motors so here’s a short explanation.

Brushed
The brushed electric motor is generally the only kind of motor found in toy-grade and beginner hobby-grade RCs. Kits and other hobby-grade RCs still commonly use brushed motors although brushless is becoming more readily available. Small contact brushes inside the motor cause the motor to spin. Brushed motors come in fixed and nonfixed versions. Electric motors with fixed brushes are nonadjustable and can’t be modified or tuned. Nonfixed brushed motors have replaceable brushes and the motor can be modified and tuned to a certain degree as well as being cleaned of dust and debris that accumulates during frequent use.

Brushless
Brushless is becoming increasingly more popular, but are still slightly high-priced compared to brushed motors. They are only just now becoming legal in some professional RC racing circuits. The appeal of brushless motors is the sheer power they can give to your electric RC. Brushless motors, as the name implies, do not have contact brushes, don’t require frequent cleaning, and because there are no brushes there is less friction and less heat — the number one killer in motor performance.

Brushless motors can also handle a lot higher voltage than brushed motors. With a high voltage supply brushless motors can help a beginner RC race at blistering speeds. RCs equipped with brushless motors currently hold the fastest speed records for RC — yes, faster than nitro.

The brushless motor is not the only thing that is causing a stir in the RC world. In fact, brushless motors have been around for quite a while. The real reason is the combination of the burshless motor with the lithium-based battery, or Lipo. Lipo batteries pack a powerful punch. Combine that punch with the brushless motor, and RC cars can hit speeds never before dreamed of out of the box.

Understanding LiPos
Lipo batteries are very different from previous generation batteries and understanding how they work, and especially how to charge them, is the key to getting the best performance.

Unlike Ni-Cd and Ni-MH cells that self-discharge when wired in parallel, LiPo cells can be hooked up, charged and discharged in parallel with no detrimental effect. Wiring two LiPo cells in parallel doubles the capacity (more run time), plus an important advantage of wiring in parallel is that each cell only sees half the total current.

C Rating
LiPo cells are also commonly given a C or current rating. This is the equivalent the the capacity of the battery pack in amps. This is also the maximum average recommended discharge current for the cell. For example, the Thunder Power 1900mAh packs have a 6C rating. To determine the maximum recommended discharge rate multiply the capacity times the C rating. 1900mAh x 6C = 11,400. So the maximum recommended discharge rate would be 11,400mA or 11.4 amps. Why do we care about this? Because the higher the C-rating the more punch the battery pack can give, which equals more speed.

So what does this all mean? Will the popularity of the bushless motor and Lipo battery be the death of the nitro based car. Probably not, like everything in life there are fans on both sides of the spectrum. Nitro folks love nitro for there reasons and electric people like electrics for there reasons, which is a good thing. Be that as it may there is no denying that as the coming years brushless motors will become more and more popular as prices get lower.

References
About.com
rchobbies.org ]]> http://www.rcgawker.com/2009/07/will-the-rise-of-the-brushless-rc-electric-car-kill-the-nitro-car/feed/ 1 http://www.rcgawker.com/2009/07/basic-setup-for-your-rc-car-understanding-toe-camber-caster-and-ride-height/ http://www.rcgawker.com/2009/07/basic-setup-for-your-rc-car-understanding-toe-camber-caster-and-ride-height/#comments Wed, 29 Jul 2009 13:41:25 +0000 rcgawker http://www.rcgawker.com/?p=728 If you enjoy this article please click on one of my sponsors, help me support this site.
Camber Angle
Camber angle is the angle between the vertical axis of the wheel and the vertical axis of the vehicle when viewed from the front or rear. There are three possible camber types, positive, neutral, and negative camber.

If you were to drive your RC car round a fast right-hand corner, the body rolls to the left. This reaction also happens to the wheel, if there is no camber on the wheels the top of the left wheels will lean out and you will end up running on the outside tire. To counteract this you would need to put negative camber on the wheels. This allows the wheel to tip over in corners but still maintains full surface contact on the track giving maximum grip on corners.

Camber is adjusted by lengthening or shortening the top wishbone. A good starting point is 2 degrees negative on the rear and 1/2 to 1 degree negative on the front.

Toe-in & Toe-out
These angles are the direction the wheels are pointing when looking at the car from above The below pictures show the toe angles on the front wheels only but the same rules apply to the rear wheels.
On a rear wheel drive car the front wheels will have neutral toe, or toe-out. The rear wheels will have neutral toe or toe-in.

With the correct toe angle on the front you will have a stable car that has good front end grip. The correct toe angle on the rear will give good rear end traction through corners.

The front end toe angle is adjusted on the steering links on your RC car. Shorten the links will allow more toe-out, lengthen the links will allow for less toe-out. There are different methods to adjust the rear toe angle depending on which model of RC car you drive, almost all cars adjust the rear lower wishbone to give desired angle.

To measure the toe angle is not easy, one method is to use the camber gauge. If you want 1 degree toe-in set your wheels up with one degree of negative camber. Take a measurement from the top center of the inside rim on the left wheel to the top centre inside rim of the right wheel. Do the same for bottom center inside rim on both wheels. Transfer these measurements so that the distance top center is the same as front center on the inside of the rim, this sounds complicated but when you try it it’s not that bad. Another way of putting it is measure at 12 o’ clock and 6 o’ clock and transfer to 3 o’clock and 9 o’ clock. A good start settings are 2 degrees toe in at the rear and 1 degree toe-out at the front.

Caster Angle
The purpose of caster angle is basically to allow the front wheels to self-center. Imagine the wheels on a good shopping trolley (if you can find one), if you look at the wheels the spindle of the wheel is not directly below the mount but trailed back at an angle, this is the caster angle. When you push the trolley the wheels all point in the direction of motion so are self-center.

All rear wheel drive cars have positive caster on the front wheels. Although the main reason for the caster angle is to self-center the wheels the angle can affect the car handling, too much caster and you can get wheel shimmy. This is when the front wheels flick side to side rapidly .Too little caster can make the car over steer. The caster angle is adjusted by sliding the front wishbones on the hinge pins. To increase caster slide the top wishbone back or the bottom one forward or a bit of both, and do the opposite to reduce the caster. Measuring caster angle is more a case of trial and error to get the correct setting.

The best starting point would be both wishbones in the center of the hinge pins as there is positive caster built into the steering hubs.

Ride Height
Try to run the car as low to the ground as you can without the chassis scraping the ground. Ride height can be adjusted on the collars of the shocks, screw them down increases the ride height. Set the rear end a couple of millimeters higher than the front.

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2.4 GHz spread spectrum radios have taken the RC world by storm. In a few years time this could be the only technology that will be offered on everything but the cheapest toy grade RC radios. So why is spread spectrum modulation so good? To answer this question, let’s first look at the other “narrow band” modulation methods: AM, FM, PCM.

For your RC radio system to work the receiver must be tuned into the exact same frequency as the RC radio, this allows several models to be flying at once provided they are all on different frequencies within the allowed band range. However, space is limited on this band, and there lies the problem.

With only a limited amount of channels available, it’s important that only one person be transmitting on a specific channel at a time. This is why you see frequency boards and pins at RC clubs. When it is your turn to drive or fly, you take the frequency pin off the board and this lets others know that frequency is in use.

Simple enough, but with more people getting in to the RC hobby, there is always the possibility that another RC radio on the same frequency will accidentally be turn on creating interference.

Spread spectrum radios are not bound by narrow band frequencies they spread their signals out over a large radio spectrum. They also use the frequency range 2.4 GHz. That is a frequency of 2.4 billion cycles per second. This is well beyond the range of most RF making 2.4 GHz much more immune to interference. Let’s now look at how narrow band RC radios transmit their signals.

AM RC Radios
AM stands for amplitude modulation. This is the first and most basic method used for controlling RC models. The problem is it is really easy for the AM signal to be affected by almost any electrical noise generating device.

Any type of electrical or metal on metal noise from lighting to car ignition systems will result in interference (if you ever listen to an AM station when it’s raining out you get the idea). It is all these sources of interference that will cause loss of control on your RC model.

FM RC Radios
FM stands for frequency modulation. It is also referred to as PPM – Pulse Position Modulation and was introduced to the RC world in the early 80’s.

FM receivers are less prone to electrical or metal noise from outside, but there are times when moving parts can send out electrical noise that can be interpreted by the receiver as a legitimate signal and cause a “glitch”. So every now and then your model might twitch. If the glitch was bad enough or lasted more than a few seconds your model could end up in a heap of broken parts.

PCM RC Radios
PCM stands for Pulse Code Modulation and works by embedding a digital signal within the basic FM radio wave. A digital processor chip inside the RC radio encodes a digital transmission and sends it out on a standard narrow band FM carrier wave. The receiver also has a processor chip that decodes this digital data back into a usable analog signal for the servos.

This method all but eliminates any glitching caused by electrical noise because unless the receiver “hears” a digital command that it understands, it won’t respond. It is this ability to ignore outside interference that makes PCM so perfect for all kinds of RC control.

PCM RC radio receiver can ride out interference because it doesn’t understand it and simply ignores it. This makes it possible to add a secondary feature to that ability called “Fail Safe”. Fail Safe is a safety function that allows you to tell the receiver what to do if it no longer sees or understands the radio signals it receives.

No, this doesn’t mean the receiver is capable of flying and then landing your helicopter if there is radio signal corruption, but it will move the servos to a predetermined value. For safety reasons that usually means throttle off and all other control functions at neutral. This is a good feature to have to insure if you do loose radio communication with your RC helicopter or plane, as to cause excessive damage to your model or hurt people. This is not to say it will absolutely crash if the radio signal is lost, the receiver will continue listening for the signal and if reacquired, control will be regained. But again much like FM and AM PCM is still not immune to interference. If another PCM receiver transmitting on the same frequency you will still have problems.

Spread Spectrum RC Radios.
This brings us to the 2.4GHz spread spectrum radio. No other advancement in RC radio technology has changed the hobby in such a profound and positive way. Interference issues are all gone! No more frequency conflicts! No more Worries! 2.4GHz spread spectrum technology has been widely available since the 90’s with cordless phones, cell phones, and later wireless computer technologies such as Wi-Fi and now Blue-tooth.

The main idea behind spread spectrum is to spread the radio transmission out over a wide range of the radio spectrum. This makes a spread spectrum signal much less likely to run into interference or glitching issues that are common with all narrow band radio transmissions.Even with many spread spectrum radios all transmitting at the same time they are very unlikely to interfere with each. In most cases any signal conflict would happen for such a brief moment – you would never notice it.

So how does it work?
RC spread spectrum radios use the same type of digital signal that is used in PCM giving all the same advantages that PCM has. The difference is how that digital signal is transmitted and received.

There are essentially two different types of spread spectrum modulation methods that have been developed, FHSS and DSSS.

Frequency Hopping Spread Spectrum (FHSS)
Frequency hopping, as the name suggests, transmits on a narrow band frequency, but changes the frequency of the transmission hundreds of times a second. For FHSS to work, the receiver has to know the frequency changing pattern so it can hop to the different frequencies in the same order and time frame as the transmitter does.

Direct Sequence Spread Spectrum (DSSS)
Invented later and is harder to achieve. Unlike frequency hopping, direct sequence uses a special code sequence and spreads data over a wide band width on a select frequency. DSSS is said to provide somewhat faster data transmission and shorter delays because the transmitters and receivers don’t have to spend time switching to different frequencies. However, with the high speed micro processors of today, this is really not the issue it once was.

So which is better?
It depends who you ask and what spread spectrum radio manufactures web site you visit. You can read arguments for and against each method of spread spectrum radio control. Futaba’s spread spectrum radios use frequency hopping (FHSS) technology. Futaba’s trademark name for their system is F.A.S.S.T, Futaba Advanced Spread Spectrum Technology. The FASST system hops to a different frequency every 2 milliseconds. Futaba claims the frequency hop method is better at overcoming signal conflicts or interruptions than DSSS .

Spektrum/JR’s spread spectrum radios use direct sequence (DSSS) technology. Their system is called DSM and now DSM2 which stands for Digital Spectrum Modulation. It works by dividing the 2.4 GHz band into 80 individual channels (frequencies) and codes the direct sequence modulation with an embedded GUID (Globally Unique Identifier) code for each radio.

Spektrum claims direct sequence modulation is more costly and harder to develop than the frequency hopping method and because the gain rate is higher, the range is improved. Spektrum/JR unlike other DS systems on the market selects and transmits on two different frequencies to avoid the possibility of blocked or corrupted signals. Spektrum/JR also has a range of dual receivers to provide better path diversity
2.4GHz limitations

What about the cons
You should know by now almost nothing in this world is perfect and spread spectrum radios are no exception. Unlike the longer wave lengths used in 27-75 MHz RC radios that pass through almost anything, 2.4GHz has short wave lengths are easy absorbed or reflected by many objects. Absorption and reflection of the 2.4GHz signal by parts of the model aircraft could lead to fail safe lock out of control if the signal is not strong enough for the receiver to hear or identify from shielding or reflecting. Different manufactures solve this issue in different ways.

So my advice would be to go visit your local hobby store, find out what others in your area are using and determine if you spread spectrum is right for you.