Cars and Trucks have been the fastest growing category of radio control in the past decade and rightly so. They are fast, exciting, and something everyone of all ages can take part in at their own level. R/C land vehicles fit into four main interest categories: Off Road Buggies, On Road Cars, Monster Trucks, and Stadium Race Trucks. In addition, you can find any of these types of vehicles powered either electrically or by nitro/gas.
Off Road Buggies
The Off Road Buggy has been a very popular R/C vehicle and is the vehicle that started the R/C car craze. They are of open-wheel design with lots of ground clearance, full-travel suspension and knobby tires for lots of grip. They can travel almost anywhere; the rougher the terrain the better. Off Road Buggies can be found in both two (2WD) and four wheel drive (4WD). The most common size is 1/10 scale although you can also find them in 1/8 through 1/4 scale. Off road buggies are both electric and nitro powered. Larger versions would normally be powered by gas.
On Road Cars
On Road car racing has really become popular and in many areas has exceeded Off Road in popularity. On Road racing has branched into two streams of activity, one very smooth surface for running, usually a paved outdoor or carpet indoor track. A gym floor or concrete surface is not suitable as they are too slippery and the car will “spin out” too easily.
The second is the newer parking lot racing, known as sedan or touring car racing, where cars are fashioned after a broader range from sports cars, to Indy cars, to stock cars, etc. They are designed to work well on pavement and are more capable in the dirt than the original On Road.
The On Road cars can reach very high speeds and both oval track racing and road racing are popular. Electric on road cars are generally 1/12 and 1/10 scale while the nitro-powered versions are 1/10 and 1/8 in scale. More recently, the “micro” size vehicles have come into their own, being only 1/18 scale in size.
Monster Trucks are the big boys of off road and although not as fast as the buggies, they can climb, pull, crush, and generally make themselves known on any terrain. Monster Trucks are characterized being the original On Road cars which are extremely low to the ground and are fashioned after the full size NASCAR and Indy style cars. They must have a by four huge, deep tread tires, usually in 4WD configuration, and some even with four wheel steering. Quite often two electric motors will power these brutes for lots of torque. Nitro versions are also popular. The common size for these vehicles is 1/10 scale although models are inching towards the larger size of 1/8 scale.
Stadium Racers are a combination Off Road Buggy and Monster Truck and they have become just about the most popular facet of R/C vehicle. They sport truck bodies and knobby truck tires on 1/10 scale off road cars, and boy, do they move! They are available in both electric and nitro-powered versions. The electrics have performance similar to their buggy counterparts and they share many of the same parts. The nitro machines have come along way in the past number of years and have surpassed electric in popularity. They are very dependable, quite rugged, and very fast.
What You Will Need for Electrics
Vehicles are available pre-built and packaged with a radio system or in kit form that requires assembly. The model will usually include all parts necessary to assemble the car. Some kits, especially on road cars, may require the motor, body, and electronic speed control as an extra purchase. Ready-to-run packages come with just about everything. The body is usually a clear Lexan plastic that requires being cut out and painted with a special polycarbonate paint. It is painted on the inside leaving the smooth and shiny plastic surface on the outside. The remainder of the chassis goes together with simple tools such as screw drivers, nut drivers, pliers, etc. and rarely needs special shaping or finishing. Purchasing your model in kit form is advantageous as you learn how the car works during assembly. This experience can be valuable when it comes to maintaining and tuning your car.
Most radio systems for R/C cars and trucks are simple, 2-channel units that are much less expensive than those used for aircraft. They will usually not come with rechargeable batteries so it will be necessary to purchase 8 alkaline cells to power the transmitter. Most systems today are equipped with a Battery Eliminator Circuit (BEC) in the receiver so that the radio in the vehicle can be powered by the motor’s battery pack. Rechargeable NiCds may also be used for the transmitter and are available separately.
The biggest decision in selecting a radio system is whether to go with a 2- stick or pistol grip transmitter. Pistol grip is more popular with the racing crowd as it gives the driver better control over the car and has a more natural feel. For more information on radio systems, refer to our Introduction to Radio Systems section.
The Battery Pack
A rechargeable battery pack is required to run virtually all electric cars and trucks. These are typically made up of 6 or 7 NiCd cells wired together in a pack which is removable for charging. Most racers will have several battery packs, running with one while another is charging. Charge times are usually about 20 minutes.
Matched battery packs are also available and these give you the most power right till the end of the pack’s discharge. All NiCd cells are not created equal and some will have more capacity than others. A 6-cell pack, made up of six different NiCd cells, will only give good power while all six are delivering their best. If one cell drops off first, the pack will have lost its oomph and that could be critical in a race (not so serious for sport running).
In other words, a pack is as good as its weakest cell! A matched pack is assembled from cells that have been tested for capacity, all cells being more or less equal, delivering the same power and lasting about the same duration. Refer to the Technical Articles on this site for more information on batteries.
There are various types of chargers available for R/C car packs and these are powered from either 110 VAC or 12 VDC or both.
Overnight chargers are inexpensive and give a good charge, equalizing the cells in the pack (every pack should be slow charged at an overnight rate every four to six charges). However, they are slow, taking 10 to 15 hours for a complete charge. This makes them impractical for use at the track unless you have a lot of packs charged and ready to go. Most beginners to the sport will get a timed charger that will operate from both wall current and a 12V car battery. That way you can charge from your home or at the track from a car if no AC is available.
After the battery is connected, a discharge circuit is turned on discharge the pack completely. This ensures that all cells are in the same charge state and that you will not overcharge the pack. After discharging, a timer is turned on and the pack charges for as long as the timer is set. Most chargers will take between 15 and 25 minutes to charge a 1400maH pack. These chargers usually also have a trickle charge mode where the pack may be charged at the overnight rate.
Another popular charger, used by most competitors and advanced racers, is the “peak detection charger”. These units have electronic circuitry which can detect when a battery has had a full charge. You can plug the battery in, activate the charge, and leave it until the unit kicks back to the trickle charge rate. These also take approximately 15 to 25 minutes to charge.
Electric Motors for R/C cars and trucks are almost all of the “Mabuchi 540” design with a many different kinds of winds and number of winds of the armature. The different winds give a different compromise between speed and torque. They are broken down into two main classes, stock and modified.
Stock motors must be run as is and cannot be opened for modifications. Modified motors can have their timing changed (position of the magnets with respect to the armature) or whatever modifications the driver wishes to make. Modified motors generally have more power than stock motors but will drain the battery pack faster. Be careful when installing a modified motor in a vehicle meant for a stock one. The gears and the speed control may not be able to handle the extra demands of the greater torque and higher current.
There are two basic kinds of speed controls used in R/C vehicles, the mechanical kind and the electronic kind. Many of the kits (but not all) will come with a mechanical unit. These are generally 3-speed forward, 3-speed reverse and are less expensive than the electronic ones.
Electronic speed controls are far superior to the mechanical ones as they give precision control of the current going to your motor, fully proportional from stop to full speed; they almost always have brakes and may or may not have reverse. Some electronic speed controls are available with radio systems as a substitute for one of the servos.
What You Will Need to go Nitro
Just as with the electric cars and trucks, you can get your model already pre-assembled or in kit form. These models are built very similarly to the electric ones except the transmission and gear train are sturdier to withstand the added stress of the more powerful glow or gas engines. The engine may or may not come with the model.
Your needs for a radio system will be the same as for an electric model except you will need batteries to power the radio in your vehicle. There is no battery pack for the motor to run a BEC. You will also have to make the decision of either a stick control or pistol grip set-up. Refer to our Introduction to Radio Systems section (page 19) for more information.
Most combustion powered vehicles are currently using 2-cycle glow engines unless the vehicle is 1/6 scale or greater in size where gasoline motors are common. Glow car engines are similar in operation to model aircraft engines. Refer to our Introduction to Model Engines section (page 7) for a more detailed description of glow engine operation.
Nitro-powered cars and trucks are very similar to model aircraft in their support equipment needs. First you will need fuel (usually sold by the gallon jug) and a way of getting it from the container into the fuel tank. This could be as simple as a bulb fuel pump, a handpump, or as elaborate as a battery powered electric fuel pump. The second basic necessity is power for your glow plug. As described in our Introduction to Model Engines, a glow engine needs to have current run through its glow plug before it can start running. This must be supplied by a 1.2 to 1.5 volt battery or by an adjustable circuit called a glow driver, frequently found on power panels. A third item that is sometimes required is an electric starter. Some glow powered vehicles come with recoil pull starters and some do not. If the engine you choose does not, you will need a starter, a 12V battery to power it, and a battery charger to charge the battery.
Once into the hobby, most modelers will go with field support consisting of the following: A field box to hold everything; a power panel; a 12 volt battery to power the power panel; a charger to charge the 12 volt battery; a glow plug clip to apply power to the glow plug from the power panel; an electric fuel pump which can be operated from the power panel; fuel line, filters, and cap fittings for the fuel container to connect to the pump and the fuel tank; a 12 volt electric starter which can be powered from the power panel; a 4-way glow plug wrench; miscellaneous tools; and spare glow plugs. The level of field support you choose initially will usually depend on how much you want to spend.
True gas-powered vehicles are always equipped with a recoil pull starter and require very little in the way of field equipment. Gasoline and a method for getting it into the tank is about all that is necessary.