Decided to write after a few days suffered from starting the engine. I hope the article will be useful. As it turned out, the problems were just in the heat. For those who do not know what it is for, I will tell you in a nutshell. The glow of the candle is designed to start the glow type of the engine, it allows you to warm up the candle before starting the engine. You can read in detail on the expanses of the world ...
And now to the point, I bought this glow more than a year ago, I decided to check it, put in the battery, lit the candle and silence. More precisely, the candle does not heat up. I started to figure it out, it seems that there is contact everywhere, there is no short circuit, the battery directly lights the candle, but does not work with heat. In the comments to the product, it is recommended to change the polarity when installing the battery, and I did it, the glow worked and I calmed down on this, I had it for a year and then they gave me fuel, I had free time, I decided to start and drive the car. But it wasn't there, it won't start. At first I thought that the jamb in the settings of the carburetor. I twisted the needles - there are no shifts. After several overflows of the engine, I began to look for reasons deeper. I started with a candle, checked it separately by connecting it directly - it works. I plug it in, it works. Well, I think it's weird. I'm still trying. Will not start, I unscrew the candle, but it is wet. It became clear that the heat was naughty. I came home, took it apart, checked the contacts with a tester, and as it turned out, the contacts disappeared both on the "+" and on the "-". All this happened while shaking, and sometimes just like that. As one film said: "Only Allah knows where the spark goes from this ...". It would be possible to throw the heat on the cabinet, leave an appropriate comment about the product, go and buy a new one, but this is not our method.
So we need:
1 - foil. I used regular food.
2 - an awl or something similar, for example, a thin screwdriver.
3 - File or sandpaper.
4 - pliers.
And now the revision itself.
We disassemble. 
into the "+" contact we push a little foil twisted into a tube, we do not push it far, so that it does not fall out and sticks out a little from the hole.
Next, we take the "-". We pick out the "snail" and bend it so that there is an even spiral without overlaps. 
We assemble, insert the battery and everything works like a clock.
From myself I will say the following, the glow of my money is worth it, simple and convenient. I would say nothing more. Perhaps for many it will work without modifications, but I would recommend at least sanding the contacts. I hope the material will be useful. Thank you for your attention.
Damn, I'm completely confused. Read the text below...
All modelers sooner or later face a choice - to put a cold or hot candle. Let's look at the pros and cons The glow plug provides heat to ignite the fuel, much like a spark plug, except it stays hot all the time. If the heat of the glow increases, the ignition timing is accelerated, followed by an increase in engine speed. Nitromethane mixes with alcohol, providing oxygen for more power, but it also lowers the flash point of the fuel. Thus, increasing the nitromethane content speeds up the ignition timing. The trick with spark plugs is to use as much nitro as you need to get the job done and use a PLUG to control ignition timing.
A hot engine (high compression) and hot fuel (high nitro) usually require a cold plug. A cold engine and cold fuel usually require a hot plug.
The main symptoms when the candle?
TOO COLD
1. The engine gives weak flashes when trying to start it, but does not start. Can also mean a dead filament battery.
2. The engine does not lean to a flat high-pitched sound, but always sounds rich. The exhaust sound is very uneven.
3. The engine may stop when the heater is removed, even though it is running normally with the heater connected.
4. During operation, the engine becomes progressively richer until it finally stalls. This is due to additional cooling in the initial boundary situation.
5. A moderate situation occurs with a slight decrease in engine speed when the heater is removed. This should serve as a warning that the spark plug has deteriorated and should be replaced.
TOO HOT
1. The engine backfires when trying to start it and kicks back. May lead to reverse run. Can also be caused by using a 2V battery with some spark plugs.
2. The engine cannot be smoothly brought out of the high sound mode by enriching the mixture. This usually happens when high nitro content is used in low compression engines.
3. If you turned out the needle in step 2, the engine may suddenly become rich during operation. Check your fuel lines for blockages, but keep this trick in mind.
4. The engine is more likely to overheat and sag. Always run on the rich side of the peak setting. Sagging is characterized by a thin, smooth exhaust sound. He just squeaks.
5. If the sound of the engine exhaust has sharp clicks superimposed on a smooth sound, this is pre-ignition of the fuel or detonation. This condition causes loss of power, increased engine wear, and can cause the engine to overheat.
Note:
All conditions TOO HOT can lead to destruction of the engine and this can happen within a single start! Therefore, watch for such symptoms in particular.
Conditions TOO COLD, as a rule, do not hurt anything except your ego.
Glow plug power supply for model aircraft engine
The block allows you to power the glow plug from a source of 6-12 Volts
A few years ago I made a simple pulse-width (PWM) converter (GDriver) to power a glow plug from a 12 volt battery. In recent days, interest in this design has "woke up" again - so I had to write an article on this topic.
A diagram of such a converter is shown in the figure at the top left.
The PWM voltage converter for glowing a glow plug is assembled on an LM2576ADJ microcircuit according to a typical switching circuit, and can be operated from an external source of constant voltage of 6-12 volts. The adjustment of the output voltage, and hence the current of the candle, is carried out by the potentiometer P1, which, together with the resistors R1 and R2, forms an output voltage divider. With the indicated ratings of these parts, the circuit provides current regulation in the load (KS-2 candle) from about 1.5 to 3.5 A. A larger current is the limit for this microcircuit, and is limited by the internal protection circuit, so the circuit is not afraid of short circuits at the output. Ballast resistor R3 is an ammeter shunt and does not affect the operation of the circuit. As an ammeter, I used some old imported voltmeter with a total deviation scale of 200 mV - this is exactly the voltage that drops on shunt R3 at a load current of 4 A. You can use any suitable pointer voltmeter by calibrating it with a series-connected resistor (the value will have to be selected) . In principle, you can refuse to measure the current of a candle at all (but this is not very convenient, because the device also shows whether the candle is “alive”), then R3 will not be needed, which I have composed of five 0.25 Ohm resistors connected in parallel and a power of 0.5 watts. Diode D1 protects the circuit from the wrong polarity of the input voltage, here you can use any silicon diode, rated for a current of at least 5-10 A. As a diode D2, you can use another Schottky diode, rated for a maximum current of at least 10 A. Capacitors C1 and C3 - electrolytic, any type, C2 and C4 - ceramic. Inductor L1 with an inductance of approximately 50 mH is wound on an M700 ferrite rod with a diameter of 10 mm, a length of 25 mm, and contains 20 turns of PEL-0.76 wire. Winding is done on a metal mandrel with a diameter of ~ 8.5 mm (approximately 22-23 turns are wound), after which the finished "spring" is transferred to a ferrite core, conclusions are formed at the inductor, and it is covered with a heat shrink tube. The circuit needs almost no tuning, the only thing that may be needed is a change in the ratings of P1, R1 and R2 (shown with asterisks in the diagram) to expand (or limit) the output current range. It is desirable that the microcircuit be installed on a radiator with an area of at least 50-100 sq.cm. As a radiator, you can use the aluminum front panel of the converter, on which the printed circuit board of the device is mounted, terminals for connecting a candle, a control potentiometer and a control ammeter are installed.
I.V. Karpunin
| Created Feb 14, 2011 | |||||||||
Many beginners in modeling have little idea of what a glow plug is, how it works, and how it differs from a spark plug for an internal combustion engine, and dwell only on scarce information: an internal combustion engine needs a candle, it is used to start and run the engine, and .... All.
In fact, the glow plug is the engine ignition system for the model. It is installed on engines running on a mixture of nitromethane, as an alternative to spark ignition.
The glow plug has no moving parts. Its working element is a fixed spiral.
With the help of a glow plug, the internal combustion engine is started. To do this, you need to connect an incandescent heater to the glow plugs (this device heats the coil to the ignition temperature of the fuel). After ignition of the fuel mixture, the engine starts, and the operating temperature of the combustion of the fuel maintains the glow plug coil in a hot state (without a glow plug).
There are two types of glow plugs: standard plugs and turbo plugs. Standard spark plugs have a straight body with a thread through which the spark plug is screwed into the cylinder head.
Turbo plugs have a conical part that screws into the combustion chamber. The conical part of the candle is connected to the head in a special conical cavity (the head is specially designed for this type of candle). Through the use of special candles and a head designed for them, they achieve an increase in compression, a decrease in losses, and, as a result, greater performance.
The standard plug is sealed in the head with a copper gasket, while the turbo plug is sealed with its conical shape.
Turbo spark plugs are used on 3.5 cc engines. at competitions. In other disciplines, their use (in competitions) is limited. When choosing standard or turbo plugs for your model, it is better to give preference to traditional plugs, as they are easier to buy and they are much cheaper.
Glow plugs must be of the type recommended for your engine by the manufacturer. When choosing a candle, pay attention to the code that indicates the working temperature of the candle (coil). However, it is this notorious code that can prevent you from choosing the right candle. Unfortunately, manufacturers do not have a unified system for marking candles, and each of them produces from 2-4 to 10 or more types of glow plugs. This is where you get lost. If you are not a professional racer who knows in detail all the features of candles available for purchase, it will be difficult for you to navigate.
Remember: the choice of cold or hot plug in most cases comes down to the volume of your internal combustion engine. Smaller models need hot plugs, while larger engines need cooler plugs. If you are using high nitro fuel you need a cold plug, if low nitro then a hot plug.
Those who are going to race, for which performance is important, must take into account the compression ratio. High compression motors like cooler plugs, while low compression motors do the opposite. Of course, in order to find out the compression ratio, you need to measure the compression of your internal combustion engine, but sooner or later an experienced modeler will still have to get a compression gauge. We also recall that the regulation of engine compression can be carried out by means of a gasket under the engine head. The thicker the gasket, the less compression. And installing a thin gasket increases compression. But such adjustment is already the domain of experienced modellers who know how to regulate internal combustion engines.
Using the wrong spark plugs will do nothing good for your engine. If the plug is too hot, it will manifest itself in detonation, too early ignition and an increased operating temperature of the internal combustion engine. These symptoms indicate an incorrectly selected candle; operation in this type of motor is unacceptable! Very often, when using too hot candles, the internal combustion engine fails.
The use of a too cold spark plug has a less destructive effect on the motor: idling will be poorly adjusted, the motor will burn more fuel and develop a lower maximum speed.
Glow plugs are best stored in their original packaging, which shows the code and (most often) operating temperature. This way you will be less likely to mix up the candles. Visually, you can try to determine whether your candle is cold or hot in a spiral. A thinner spiral with more turns indicates that the candle is hot. And the thick wire of the spiral and fewer turns indicate that the candle is cold.
Beginner modellers often ask which spark plugs are best, cold or hot, in terms of durability. With proper adjustment, both cold and hot plugs last quite a long time. But still, the thicker wire and fewer turns of a cold candle allows them to last longer.
Experienced modellers who use nitromethane internal combustion engines on their models try to have a whole set of candles and, due to their experimental selection, get a significant increase in power. This is due to the fact that with the correct selection of a spark plug, the modeler “catches” the ignition moment most accurately due to a change in the temperature range that directly affects the ignition moment. Of course, the correct selection of a candle requires experience, skills, but having mastered this nuance, you can get some "trump cards" in competitions.
