A nitro engine generally refers to an engine powered with a fuel that contains some portion (usually between 10% and 40%) of nitromethane mixed with methanol. Nitromethane is a highly combustible substance that is generally only used in very specifically designed engines found in Top Fuel drag racing and miniature internal combustion engines in radio control, control line and free flight model aircraft.
The term "nitro" has come into use in the last few decades[when?] to describe these engines and has its origins in marketing hype in the model car market. For the fifty or so years prior to this term since the engines were first developed, they were simply referred to as "glow engines", but the term "nitro" has more impact in ad copy. These engines are actually fueled by methanol, but the fuel is often doped with nitromethane as a performance additive. The ignition system consists of a glow plug - hence the older term "glow" engine - which has a coil of platinum-containing wire alloy, usually platinum-Iridium. The glow plug is heated with electric current for starting, after which power is disconnected and the combination of residual heat and catalytic action of the platinum alloy with methanol ignites the fuel mixture.
Combustion rc cars need a clutch since the engine is always spinning and not having it, the engine will stop since being at idle it will not have enough force to move the car also our car will always be in motion in case of that the motor if it manages to move the car, rc cars use centrifugal clutches, this means that they start to work when the motor increases the RPM, the clutch is formed by the body, the pads and the campaign that comes together with the pinion. When the RPM rises, the pads open to touch the hug campaign, which is where the pinion that enters the mobility of the car is fixed. These pads are pressed by springs so that they do not open at low RPM
This has 3 functions:
1- Mute the sound of the motor which can be quite loud.
2- Inside they restrict the smoke output to maintain a certain pressure inside the engine, this sounds absurd but it is so and it has to do with calibration issues in engine carburetion.
3- In this high pressure zone there is a small outlet, this outlet is connected to the fuel tank and this is done so that this pressure pushes the fuel towards the engine since they do not have a fuel pump.
When starting, the glow plug is electrically preheated by electric current. The glow plug is not to be confused with a spark plug - there is no spark in the glow plug. Catalysis from methanol vapor on the heated platinum element keeps it red-hot even after voltage has been removed, which ignites the fuel and keeps the engine running. Whereas spark plugs are constantly used to ignite the fuel/air mix every time the piston comes up, as seen in the petrol engine where the spark plug is used, the fuel cannot be ignited with compression alone. It is the plug's temperature, still red-hot from previous ignition and from catalysis with the new compressed mixture, that ignites the fuel.
This is in charge of containing the fuel of our car, it must be completely watertight since having leaks will escape the pressure that the exhaust supplies to be able to pump the fuel to our engine.
RC glow fuel, also often called nitro fuel, is a special blend of three main ingredients, plus a few minor additives, used in radio control model engines. There are several different blends of glow fuel available, suited to different types of engine and performance requirements.
The three main ingredients are methanol, oil (Castor or synthetic) and nitromethane, the latter being the one that puts the word nitro into so many rc terms (nitro plane, nitro car, nitro engine...) even though rc glow fuels don't always contain it!
Oil after run
The After Run is designed for explosion micro-motors used in motor racing. Its main function is to protect the internal components of the engine and prevent the formation of rust, although it also cleans the engine of fuel residues that have not been burned. It is a type of oil that all motorists have, because it increases the useful life of the engine and helps to keep it in good condition.
It is also important to apply it if you are going to last a while without using your car since the oil that brings the fuel can lock the engine to the point of having to disassemble the entire engine to find a way to unlock it.
Nitro rc cars don't need electricity to keep them on, but they do need it for the receiver that controls the servos.
The battery for receivers are normally from 6v to 9.6v so the batteries cannot exceed that voltage according to the specifications of the manufacturer of your receiver.
A nickel-metal hydride (Ni-MH) battery is a type of rechargeable battery that uses a nickel oxyhydroxide (NiOOH) anode, as in the nickel cadmium battery, but whose cathode is made of a metal hydride alloy. This makes it possible to eliminate cadmium, which is very expensive and, in addition, represents a danger to the environment. Likewise, it has a greater charging capacity (between two and three times more than that of a NiCd battery of the same size and weight) and a lower memory effect. Each Ni-MH cell can provide a voltage of 1.2 volts and a capacity of between 0.8 and 2.9 amp-hours. Their energy density reaches up to 100 Wh / kg, and the charge cycles of these batteries range from 500 to 2000 charges. This type of batteries are less affected by the so-called memory effect, in which the voltage or capacity is limited with each recharge (due to a long time, a high temperature, or a high current), making it impossible to use all their energy. On the contrary, they present a higher rate of self-discharge than NiCd (30% monthly compared to 20%), which relegates the latter to uses characterized by long periods between consumption (such as remote controls, emergency, etc.), while they are displaced by NiMH for continuous consumption.
LiPo batteries operate on the same principle as lithium ion batteries, the exchange of electrons between the negative electrode material and the positive electrode material using a conductive medium. To prevent the electrodes from touching directly, a material with microscopic pores is placed between them that allows only ions (and not particles from the electrodes) to migrate from one electrode to another.
LiPo batteries are characterized by being light and able to store a large amount of energy. Normally LiPo batteries are made up of a multitude of cells. Normally each cell has a nominal voltage of 3.7V and a maximum voltage of 4.2V depending on the materials with which the battery has been made.
LiPo batteries suffer from the same safety problems as lithium-ion batteries, so great care must be taken with their use. If the battery becomes overheated, overcharged or damaged it may catch fire.
Cuidado de las baterías LiPo.
LiPo batteries are quite delicate. Although a well-used and well-maintained battery can carry out more than 300 charge and discharge cycles, a poorly maintained battery may not even reach 50 cycles.
Furthermore, improper use, especially overcharges, can cause LiPo batteries to burn.
Therefore, to handle batteries safely and to extend their useful life, it is important to follow certain precautions:
Never leave batteries unattended while charging, they may burn. Charge them in a place where there are no flammable materials.
It is necessary to charge them with a specific charger. If possible with a balancing charger that charges each cell independently. Using the wrong charger will damage the battery and can cause it to catch fire.
Never charge batteries above the voltage indicated by the manufacturer. There is danger of burning.
The best way to store batteries for a long time is to leave them with around 40% charge.
There are special fireproof covers that are used to store batteries safely.
For safety reasons, batteries that are neither too cold (less than 5ºC) nor too hot should be charged.
The ideal operating temperature of a LiPo battery is between 30 and 40ºC. Below this, the battery will not perform 100%. Above 60ºC, the battery begins to be damaged.
We should never use a battery that we see is damaged or bulky..
To prolong the life of the battery, it is not necessary to discharge it completely. We must try to keep a minimum of 30% charge.
The batteries must be stored in a dry place, at a temperature between 5 and 25ºC, and if possible inside a safety bag for LiPo batteries.
When the useful life of our battery ends (it does not conserve 80% of maximum charge), we can recycle it in an authorized center, as long as we have previously discharged it.
A lithium-ferrophosphate or LiFe battery is similar to polymer lithium batteries but with some advantages and disadvantages that I discuss below,
-They don't catch fire! -They can be fully downloaded and recharged at 2-3 C.
- They are 100% usable since they are always charged at maximum capacity and can be fully discharged at zero volts and are recovered immediately when recharging.
-Can be charged up to 10A, which charges much faster and without risks.
-It is not necessary to balance it like LiPo.
- Easier maintenance.
-The voltage varies depending on the temperature.
-They are heavier than LiPo.
-While the LiPo have a nominal voltage of 3.7v and a maximum of 4.2v per cell, the LiFe has them of 3.3 and 3.6v respectively.
The receiver is the element that is located inside the radio controlled vehicle. It is a tiny device that has the appearance of a small rectangular box where the connections of the servos, batteries and other accessories are inserted. Just as the radio has a broadcast antenna, the receiver has a receive antenna, albeit much smaller.
The function of the receiver is to be able to receive the orders from the radio transmitter and communicate it to the servos, which are devices made up of a motor and a very important small force reducing or multiplying mechanism in charge of moving the steering and the acceleration and braking mechanisms by mobile arms with rods, transforming the energy they receive from the receiver into motion, regulated by a potentiometer.
These come in various channels, the channels are each function that the receiver can execute, for example, a channel for accelerator and brake, a channel for steering, and extra channels that can be used to connect telemetry, lights, additional servos for extra functions.
Receivers can work with different voltages depending on the model, we can find receivers of 6V 7.4V and 9.6V, the interesting thing about higher voltages is that they can work with higher voltage servos so we will have greater options of force and speed.
Wheels are the element that connects the axle of the car with the tire, they are made of various types of plastics and metals of different qualities, they generally support the weight and stresses of our car without problems, so when choosing them we basically We will base on the appearance and compatibility since instead of having 4 bolts like a full-size car they go on a hexagon of different measures to which a single nut is placed, there are brands that have wheels whose fastening system is by means of 6 or 8 bolts looking to improve the appearance similar to that of real cars.
This is one of the most important and least valued aspects of our car, since it is the only one that has contact with the ground and will be in charge of transmitting all the power and grip we need, these are hollow and have a type of foam that is responsible for giving hardness to the tire. When buying them, it is advisable to do it from well-known brands since the cheapest ones do not have a very good grip and tend to break quite quickly. It is important to consider that for some time tires have been manufactured with an internal band that prevents them from stretching when turning at high speed, this is quite useful if you like running since it makes the vehicle much more stable.
This part is the one that will fit on the wheel, they come in various sizes and materials, they also sell adapters in case we want to place a wheel with a different hexagon than the one that our car brings.
Our car will be replaced with bearings in all the places where friction is generated, this will avoid the wear and overheating of parts in addition to favoring the sliding of the pieces, in each wheel our car will have 2 bearings. one internal and one external. These are recommended to be of quality since they suffer a lot with the handling of the car and may have premature wear generating an excessive play in the wheels. This occurs most of all in Truggys and Monster Trucks.
This piece supports the bearings that in turn support the axle and the wheel. These are generally plastic, they can be replaced by metal depending on the brand. Depending on the type of which they are (axes or ball joints) they will have more or less wear, although in general this part works well over the years.
A differential is the mechanical element that allows the right and left wheels of a vehicle to rotate at different speeds, depending on whether it is taking a curve to one side or the other.
When a vehicle turns around, for example to the right, the right wheel travels a shorter path than the left wheel. To understand this, remember that on a running track, the runner who turns the open corner travels more distance than the opponent of the closed lap.
In the past, vehicle wheels were fixedly mounted on the axle. This fact meant that one of the two wheels was not turning properly, destabilizing the vehicle. By means of the differential, each wheel can be turned correctly in a curve, without losing the fixation of both on the axle, so that the traction of the motor acts with the same force on each of the two wheels.
The location of these is in the center of each axis, if the car is rear-wheel drive it will only have one. if it is 4x4 it will take 2, one in front and one in the back.
A fixed differential means that it does not fulfill the differential function since it is fixed, it has both axles locked, so the 2 wheels will always turn at the same speed, this is only used in 4x4 vehicles since when one wheel remains in the Air all traction is lost, with a fixed or blocked differential this is not possible and thus one wheel is in the air the other will continue to rotate so the vehicle can continue on its way.
This differential goes in the central axis or cardan of our car, it is also located within the transmissions and this is in charge of sharing the power between the front and rear wheels in order to give stability to the car and avoid loss of traction. This is only brought by some 4x4 cars, it is also very common in competition cars.
This differential has the advantage of being able to be blocked only when necessary, so you can circulate normally in any terrain without losing traction and when you need to block the differentials to pass an obstacle you can do it from the control without problems.
Silicone differential oil
Radio controlled car differentials have silicone oil inside. What do we achieve by adding this oil inside?
This seeks to create a semi-lock of the differential, so if you put a sufficiently dense oil, you could eventually be able to pass complex obstacles since although a wheel is in the air, the oil being so dense will not allow it to turn freely and will transmit part of the force to the wheel that has contact with the ground, in the case of competition or street cars this oil is much more fluid and its density will make it change the behavior of the car when entering or leaving corners.
Large gear that has contact with the engine sprocket, this transmits the force to the transmission or to the central axle. They come in various sizes to change the ratio and thus make your car faster and with less force or slower with greater force. These are made of metal or plastic. the size is indicated in steps and number of teeth.
Glow or nitro rc cars have no way to stop since the motor cannot reverse the turn like electric cars, so these have a metallic central disc brake, it has two pads the same as a real car but only one has movement, and that movement is powered by a servo, it is ideal that this servo is fast and has strength since it is the same that drives the car's carburetor.
The shock absorbers a device built with a shaft, a tube and a piston, these are filled with oil. The perforated piston restricts the passage of oil through the holes to a greater or lesser extent, providing hardness and greater capacity for absorbing impacts.
Its main functions are:
-Safety contribution when cornering
-Permanent absorption of irregularities.
This is in charge of giving the height to the car, it is important that once the car is placed on the ground it compresses at least 20% to guarantee that it will fulfill its function, if it does not compress it means that it has excess compression and does not It will absorb irregularities unless they are very large.
This will be in conjunction with the oil to brake the rebound that our car may have, they can come with more or less holes or with the same number of holes but with different diameters, both in order to more or less restrict the passage of oil.
Silicon Shock Oil
This is the same as the oil used by the differentials, but much less dense. its function in conjunction with the piston is to absorb the irregularities of the terrain, they come in many brands and presentations,
A servo motor generally known as a servo is a device that has the ability to position itself in any position within its Position range, and to remain stable in that position. It consists of a direct current motor, a gearbox, and a control circuit, and its operating range is typically less than one full turn.
The servomotors have three connection terminals: two for the electrical supply of the circuit and one for the input of the control signal. The supply voltage is generally around 6 volts, because although the motor supports higher working voltages, the control circuit does not. Currently there are servos that tolerate 8.4 volts.
These come in different voltages and qualities, with plastic or metal gears. Below is a short list of the types of servos that exist.
They are used to give movement to the wheels and accelerator of the car, while the fast is the best servo will be the response times of these.
They are simple servos, made of plastic with plastic gears, these are quite economical and their voltage ranges from 4.8 to 6. They are around 4 kilos of force at a speed of 0.18 seconds.
They are servos resistant to water, they bring seals that prevent the entry of dirt and dirt into the interior. some manufacturers make them blue to differentiate them from the rest.
the first servos were analog, these have a potentiometer inside, with that the receiver could interpret the position of the servo and send the corresponding voltage, digital servos have a more accurate positioning sensor, so they have better response times and accuracy in their movements.
High torque servo.
These can go from 15kg to 65Kg of force at 8.4 Volts in exchange for not so high speeds of 0.11 seconds or so.
High speed servo
These can go from 0.7 seconds to 0.042 seconds at 8.4 Volts with force handles ranging from 10 to 25 kilos.
High voltage servo.
all servos that work with 7.4 volts or more.
The drive shaft have the function of transmitting the power of the transmission or central differential to the front and rear differentials and from these differentials to each of the wheels, these are plastic or metal,
The chassis is the main part of the car, it supports the different components. It consists of a frame that integrates with each other and holds both the mechanical components, such as the engine and transmission group, the wheel suspension and bodywork. These can be flat or in the form of bars, and can be plastic or metallic, the metallic ones are resistant to impacts.
The body is the body of the radio controlled car, they are made in lexan and it comes in various thicknesses, it may look fragile but it is made in this way to be able to withstand impacts without breaking. these can be bought in different models and then painted.
The arms support the wheels that in turn support the car, these are connected to the car suspension, they are made of plastic, these can be replaced by metal.