Different types of power source options are available for application in RC cars and RC trucks. These different power sources can be suitable for different type of applications, uses, type of users, type and level of competitions, and terrains. Of course, like any other set of options, these power source options have their own advantages and limitations, so each of them is not completely replaceable by any other source. We will discuss these power source options in detail so that we have a clear idea about what each power source is capable of and where you can face problems using it. The limitations can be related to power, safety, life, cost etc.
Electric Models:
The first one in the category and perhaps the most popular one, due to its cost effectiveness and simplicity, has been the electrical powered model. Electrically powered models are run by electrical motors. These electrical models utilize either mechanical or the electronic type speed control units that adjust the level of power provided to electric motor. The control depends upon the input provided by the remote control. The input from the remote control determines the amount of power to be supplied or the desired speed for the motor. The electrical circuits convert those inputs to provide appropriate voltage and current to the electrical motors that provide the desired output. Electronic units for speed control use solid state components to regulate duty cycle, adjusting the power that is supplied to the electrical motor. In addition, most electronic speed controllers use the electric motor as a magnetic brake, offering better control of the model than is possible with a mechanical speed control.
Apart from the electrically controlled systems, mechanically operating speed controllers are also implemented that use a combination of resistors or switches that work by rotation of a head element with a metal electrode built around a metal plate that contains electrical contacts. Mostly, mechanical control has been a traditional technology and is hardly in use these days due to lots of limitations. Mechanical type speed control units are generally slow in reacting, waste lot of energy as heat through the resistors, collect lot of dust, perform irregularly, and are devoid of special braking ability. These models however are cheaper than high performing electronic type speed control versions and are generally used only in the older type of hobby type models.
Mechanical controllers are almost obsolete now and electronic controllers are extensively in use. A lot of technical research and advancement has been done both on the front of electrical motors and the electronic control circuits to make them fast, increase their capability, low-power consuming and rugged to face harsh conditions. With regard to motors as well, most electrical motor driven RC vehicles used to incorporate brushed motors which are not being replaced by brushless motors. They have huge advantages of being able to supply substantially greater power and require lesser maintenance due to lesser wear and tear. Due to the higher capabilities, brush-less motor can also be used in extreme RC car sports and monster trucks or buggies.
Fuel-Powered and Nitro-Powered models
The next type of power source is the fuel-powered engine. The most commonly used fuel in RC cars and trucks is nitromethane fuel. This is why the fuel-powered vehicles are also commonly known as nitro-powered vehicles though other fuels may also be used occasionally. These engines work on the principle of internal combustion and are generally known to provide more power and speed than the electrical motors. However, one limitation of fuel or nitro engines is that they require more maintenance and are costlier.
The models powered by Nitromethane fuel incorporate servos for providing the throttle and controlling for braking; if the servo rotates in one of the directions it causes carburetor on the throttle to open, which provides more amount of mixture of air-fuel mixture inside an internal combustion type engine. If the servo rotates in the opposite direction, it causes application of torque to a braking element which results in building up of frictional force with the brake material. The brakes are installed on driveshafts, which are able to stop two out of four wheels of a 2wd (2-wheel drive) vehicle whereas all the four wheels are stopped in a 4wd (4-wheel drive) vehicle.
The models that utilize fuel-powered engines are able to reach moderate speeds if they do not undergo any modification. These models are able to generate maximum power when they are operating at either medium or high ranges of speed. Also you can expect somewhat slower response on the throttle than is provided by vehicles that are powered electrically. The RC cars and trucks that use Electric motors are successful in generating lot of torque very quickly; however models with the nitro type engines (such as large-size gasoline based engines) generally take some time in sufficient spooling up of engine and before the clutch can be engaged. One advantage with the Nitro or fuel powered RC car and truck models is that they can be refueled quickly and therefore they can return to the play field or the race track immediately, whereas it is not possible with the electrically fed models that need a longer process of removing the body cover, open the battery cover, take out the old batteries and replace them with the new charged ones. Nitro cars also have a very effective air cooling system that enables them to run continuously for longer periods of time with no requirement of taking breaks or wait for the system to cool. Nitro cars are generally larger in size than the electric RC cars and trucks. This is because high-performing yet affordable electronic components are mostly available with the 1/10 scaled and the smaller versions. However, equivalent scale models are also available in nitro as well as electric powered types.
The sizes of fuel engine sizes have range from 0.12 cubic inches to 0.35 cubic inches. The authorities and sanctioning associations generally provide rules for RC racing that also contain size specifications. However, engines in other sizes are also produced but they are generally for unofficial uses like household or toy-use purpose and are not used for professional racing as they are considered ‘outlaw’ due to their non-compliance with size specifications. Engine sizes always depend on the category to which the car belongs to; for example the 1:10 scale on-road type and off-road type vehicles generally utilize engines ranging between .12 and .18 cubic inches in size; whereas the 1:8 scale RC vehicles use engines from .21 to .32 cubic inches.
Nitro/fuel powered RC car models are closer to full-sized actual fuel vehicles in operation than the electric powered versions, as they make use of two-stroke engines as against the electric motor. Other main advantages of the nitro engines are their sound and interesting design of drive trains that attract the nitro enthusiasts. The disadvantage is that their chassis gets coated with the unburned oil that is produced by the exhaust. This results in requirement of more cleaning as compared to electric-powered models. Generally, the cleaning of the nitro models is performed by using compression type air nozzles and special cleaning solvents, for example denatured alcohol. The next big task in a fuel-powered RC vehicle is tuning that needs to be learned and implemented in order to maintain maximum levels of performance and economical fuel consumption. It also helps in minimizing the wear-and-tear and overheating of the engines. This special may be required in RTR model kits as well.
Wear and tear is a major concern in nitro or fuel models due to greater performance and general tendency of users to run nitro or fuel vehicle for longer durations of time, which is not the case with electrically powered vehicles. Moreover, the increase in the weight and speed specifications of nitro or fuel energized vehicles tends to increase the chance of collisions at higher speed, causing more frequent and more severe damages to the colliding vehicles, therefore, greater consideration is required to be given to the safety aspects of nitro or fuel driven vehicles.
Gas-powered Models
The third and the last type of power source is a gas powered engine. Gasoline or gas powered vehicles are also known by names such as “fuelies” and “gassers” and run on a fuel that is a mixture of oil and gasoline. They are much more costly than nitro powered and electric powered cars. The cost differences are approximately $1000–$3000 RTR. They are much bigger in size as well and hence require larger spaces for running and racin. They are generally not very high on speeds but do pack a lot of power as compared to their fuel and electric powered companions. The gas powered versions are also fuel efficient and require lesser amount of fuel. Therefore, the running costs of gas powered RC vehicles can be much lower than the nitro powered models due to the higher costs of nitromethane fuel and higher wearing-out rate of nitro-running engines. On the other hand, gas powered engines always have a longer time span and hardly require any tuning or modifications. These gas powered large models have mostly been popular across Europe for almost a decade.