How to make caramel fuel: step by step instructions. DIY rocket fuel Rdtt fuel ratio for saltpeter models
Few of my peers were not interested in building model rockets. Maybe it was due to mankind’s worldwide fascination with manned flights, or maybe it was the apparent simplicity of building the model. A cardboard tube with three stabilizers and a head fairing made of foam or balsa, you will agree, is much simpler than even a basic model of an airplane or car. True, the enthusiasm of most young Korolevs, as a rule, disappeared at the stage of searching for a rocket engine. Those who remained had no choice but to master the basics of pyrotechnics.
Alexander Grek
There was an unspoken struggle between the Chief Designer of our rockets, Sergei Korolev, and the Chief Designer of our rocket engines, Valentin Glushko, for the title of the Most Important: who is really more important, the designer of rockets or their engines? Glushko is credited catchphrase, allegedly thrown by him in the midst of such a dispute: “Yes, I’ll tie a fence to my engine - it will go into orbit!” However, these words are by no means empty boasting. The rejection of the Glushkov engines led to the collapse of the royal H-1 lunar rocket and deprived the USSR of any chance of winning the lunar race. Glushko, having become the general designer, created the super-powerful Energia launch vehicle, which no one has yet been able to surpass.
Cartridge engines
The same pattern worked in amateur rocket science - a rocket that had a more powerful engine flew higher. Despite the fact that the first rocket modeling engines appeared in the USSR even before the war, in 1938, Evgeniy Buksh, the author of the book “Fundamentals of Rocket Modeling” published in 1972, took a cardboard cartridge case of a hunting cartridge as the basis for such an engine. The power was determined by the caliber of the original sleeve, and engines were produced by two pyrotechnic workshops of DOSAAF until 1974, when the decision was made to organize rocket modeling sports in the country. To participate in international competitions, engines were required that were suitable in their parameters to the requirements of the international federation.
Their development was entrusted to the Perm Research Institute polymer materials. Soon an experimental batch was produced, on the basis of which Soviet rocket modeling began to develop. Since 1982, serial production of engines began intermittently at the state-owned Impulse plant in the Ukrainian Shostka - 200-250 thousand units were produced per year. Despite the severe shortage of such engines, this was the heyday of Soviet amateur model rocketry, which ended in 1990 simultaneously with the closure of production in Shostka.
Engine tuning
The quality of serial engines, as you might guess, was not suitable for serious competitions. Therefore, a small-scale pilot production appeared next to the plant in 1984, providing the national team with its products. Particularly notable were the engines privately manufactured by master Yuri Gapon.
What exactly is the difficulty of production? At its core, a model rocket engine is the simplest device: a cardboard tube with DRP-3P black powder pressed inside (smoky gun powder 3rd composition for pressed products) with a ceramic plug with a nozzle-hole on one side and a wad with an expelling charge on the other . The first problem that serial production could not cope with was the accuracy of the dosage, on which the final total impulse of the engine depended. The second is the quality of the cases, which often cracked when pressed under pressure of three tons. Well, the third one is the quality of the pressing itself. However, quality problems arose not only in our country. The serial rocket engines of another great space power, the United States, do not shine with them either. And the best model engines are made by microscopic factories in the Czech Republic and Slovakia, from where they are smuggled for especially important events.
Nevertheless, under socialism there were engines, albeit unimportant and in short supply. Now they don't exist at all. Some children's rocket modeling studios fly on old, Soviet reserves, turning a blind eye to the fact that the expiration date has long passed. Athletes use the services of a couple of lone craftsmen, and if they are lucky, then smuggled Czech engines. The only way left for amateurs is to first become Glushko before becoming Korolev. That is, make the engines yourself. Which, in fact, is what my friends and I did as children. Thank God, everyone’s fingers and eyes remained in place.
Of all the arts
Of all the arts, cinema is the most important for us, Ilyich liked to say. For amateur rocket scientists of the middle of the last century, too. Because film and photographic films of that time were made from celluloid. Tightly rolled into a small roll and stuffed into a paper tube with stabilizers, it allowed a simple rocket to take off to the height of a five-story building. Such engines had two main drawbacks: the first was low power and, as a consequence, low flight altitude; the second is the non-renewability of celluloid film reserves. For example, my father’s photo archive was only enough for a couple of dozen launches. Now, by the way, it’s a pity.
Maximum height with a fixed total engine impulse, it was achieved with a short-term fourfold jump in power at the start and a further transition to a smooth average thrust. The thrust jump was achieved by forming a hole in the fuel charge.
The second version of the engines was assembled, so to speak, from waste products Soviet army. The fact is that when firing at artillery ranges (and one of them was located not far from us), the propellant charge does not burn out completely when fired. And if you searched carefully in the grass in front of the positions, you could find quite a lot of tubular gunpowder. The simplest rocket was made by simply wrapping such a tube in ordinary chocolate foil and setting it on fire at one end. Such a rocket flew, although it was not high and unpredictable, but it was fun. A powerful engine was obtained during assembly long tubes into a bag and pushing them into a cardboard case. A primitive nozzle was also made from baked clay. This engine worked very effectively, lifted the rocket quite high, but often exploded. Besides, it doesn’t look much like an artillery range.
The third option was an attempt to almost industrial production rocket model engine using homemade black powder. It was made from potassium nitrate, sulfur and activated carbon(he constantly jammed his parents' coffee grinder, on which I ground him into dust). I admit honestly, my powder engines worked intermittently, raising the rockets only a couple of tens of meters. I found out the reason only a couple of days ago - the engines had to be pressed in not with a hammer in the apartment, but with a school press in the laboratory. But who, one wonders, would have let me press in rocket engines in the seventh grade?!
Two of the rarest engines that PM managed to get: MRD 2, 5−3-6 and MRD 20−10−4. From the Soviet reserves of the rocket model section in Children's home creativity on Vorobyovy Gory.
Working with poisons
The pinnacle of my engine-building activity was a rather toxic engine that ran on a mixture of zinc dust and sulfur. I traded both ingredients with a classmate, the son of the director of the city pharmacy, for a pair of rubber Indians, the most convertible currency of my childhood. I got the recipe from a terribly rare translated Polish rocket model book. And he filled the engines in my father’s gas mask, which was kept in our closet - in the book, special emphasis was placed on the toxicity of zinc dust. The first trial run was carried out without parents in the kitchen. A column of flame from the engine clamped in a vice roared towards the ceiling, smoking a spot a meter in diameter on it and filling the apartment with such stinking smoke that a box of smoked cigars cannot be compared. It was these engines that provided me with record launches—probably fifty meters. Imagine my disappointment when, twenty years later, I learned that the children’s rockets of our scientific editor Dmitry Mamontov flew many times higher!
1, 2, 4) If you have a factory rocket engine, even a schoolboy can handle building a simple rocket primary classes. 3) A product of amateur creativity - an engine made from a cartridge case.
On fertilizers
Dmitry's engine was simpler and more technologically advanced. The main component of its rocket fuel is sodium nitrate, which was sold in hardware stores as fertilizer in 3 and 5 kg bags. Saltpeter served as an oxidizing agent. And the fuel used was ordinary newspaper, which was soaked in a supersaturated (hot) saltpeter solution and then dried. True, during the drying process, saltpeter began to crystallize on the surface of the paper, which led to a slowdown in combustion (and even extinguishing). But here know-how came into play - Dmitry ironed the newspaper with a hot iron, literally melting the saltpeter into the paper. This cost him a damaged iron, but such paper burned very quickly and stably, emitting a large number of hot gases. Cardboard tubes stuffed with saltpeter paper rolled into a tight roll with improvised nozzles made from bottle caps flew up a hundred or two meters.
Caramel
Paranoid prohibition Russian authorities the sale to the public of various chemical reagents from which explosives can be made (and they can be made from almost anything, even from sawdust), is compensated by the availability via the Internet of recipes for almost all types of rocket fuel, including, for example, the composition of the fuel for the Shuttle boosters (69 .9% ammonium perchlorate, 12.04% polyurethane, 16% aluminum powder, 0.07% iron oxide and 1.96% hardener).
Cardboard or foam rocket bodies and gunpowder-based fuel do not seem to be very serious achievements. But who knows - maybe these are the first steps of a future designer of interplanetary spacecraft?
The undisputed hit of amateur rocket engine building now are the so-called caramel engines. The fuel recipe is indecently simple: 65% potassium nitrate KNO3 and 35% sugar. The saltpeter is dried in a frying pan, after which it is crushed in a regular coffee grinder, slowly added to the melted sugar and hardens. The result of creativity is fuel bombs, from which any engines can be assembled. Spent cartridge cases from hunting cartridges are perfect for engine housings and shapes - hello to the thirties! There are unlimited quantities of cartridges at any shooting stand. Although recognized experts recommend using not sugar, but sorbitol caramel in the same proportions: sugar develops greater pressure and, as a result, inflates and burns the cartridges.
Back to the Future
The situation can be said to have returned to the 1930s. Unlike other types of model sports, where the lack of domestic engines and other components can be compensated for by imports, this does not happen in rocket modeling sports. In our country, model rocket engines are equated to explosives, with all the attendant conditions for storage, transportation and transportation across the border. A Russian person capable of organizing the import of such products has not yet been born on earth.
There is only one way out - production at home, fortunately the technology here is not space technology at all. But factories that have licenses to produce such products do not take on them - they would be interested in this business only with millions of copies. So novice rocket modelers from the largest space power are forced to fly on caramel rockets. Whereas in the United States, reusable model rocket engines running on hybrid fuel have now begun to appear: nitrous oxide plus solid fuel. What country do you think will fly to Mars in thirty years?
Rocket modelers call a classic a fuel consisting by weight of 35% sorbitol and 65% potassium nitrate, without any additives. This fuel has been studied quite well and has characteristics no worse than black powder, but it is much easier to produce than proper gunpowder.
For classics, only potassium nitrate is suitable. If you do not find it on sale, you will have to make it yourself from sodium or ammonia and potassium sulfate or chloride. All this is easy to buy in stores,
trading mineral fertilizers. Previously, photo stores also sold potash (potassium carbonate), which is also suitable for producing potassium nitrate from ammonium nitrate. When mixing hot saturated solutions of sodium nitrate and potassium chloride, potassium nitrate will immediately precipitate. Homemade saltpeter will have to be purified by recrystallization; to do this, it must be dissolved in a small amount of hot boiled water, filtered through cotton wool and put the solution in the refrigerator. Then drain the solution, dry the saltpeter on the radiator, and then in the oven at about 150°C for one to two hours. The main thing here is compliance temperature regime. With more high temperature the saltpeter will melt and become unsuitable for further processing. Sorbitol (a sugar substitute] is sold in pharmacies and grocery supermarkets. The melting point of pure sorbitol is 125 ° C, and at this temperature it can be distinguished from sorbitol monohydrate, which is sometimes also sold under the guise of sorbitol. Monohydrate melts at 84 ° C and not suitable for fuel.
Despite its frivolous name, candy rocket fuel is rocket fuel first and foremost and should be handled with respect. The first and most important safety rule is to never cook caramel over an open fire! Only an electric stove with a closed heater and temperature regulator. If you don’t have a suitable electric stove, you can use a regular iron, but you just need to make a stand to hold it in an upside-down position, with the sole up. The three-point position of the knob is perfect for making caramel.
You should not measure components by eye or by volume - only on scales. In appearance, heaps of 35 g of sorbitol and 65 g of potassium nitrate are almost identical in volume. And this is to our advantage, since it is easier to mix fuel. If the saltpeter is large, it will have to be crushed in a mortar or ground in a coffee grinder. But don’t overdo it: the crystals should be like fine salt - if you grind the saltpeter into dust, it will be difficult to work with the fuel, as it will become too viscous. 20 seconds is what you need.
Now you can mix the saltpeter and sorbitol powders and lay them out in a layer no more than a centimeter thick in a frying pan. It is advisable to stir the mixture continuously. It is convenient to use a wooden popsicle stick for mixing. Gradually, the sorbitol will begin to melt; after a while, as you stir, the powder will turn into a homogeneous substance similar to liquid semolina porridge. Part of the nitrate dissolves in molten sorbitol, so the finished fuel remains quite liquid even at 95°C. The fuel should not be overheated, because at 140°C the solubility of nitrate increases abruptly and the viscosity of this composition also increases abruptly.
As soon as the last lumps of saltpeter are mixed, the fuel is ready - now it needs to be poured into the mold. Perfect simplicity! It would be nice to make the engine as simple as possible, and such an option exists - if record-breaking parameters are not required, a nozzleless design becomes preferable. It consists only of a housing and a charge. Although without a nozzle some of the fuel's energy is wasted, by saving the weight of the housing and nozzle, more fuel can be poured in and compensate for the losses.
For the body you will need a cardboard tube with a wall thickness of 1-2 mm. Its diameter can be from a centimeter to three, but for the first experiments it is better to take not the smallest one, since it is inconvenient to work with small engines - the fuel hardens faster, and it is difficult to pack it into a small tube. Its length should be 7-15 times greater than its diameter. It’s possible at 20, but adding fuel is already very inconvenient.
You will also need a rod to form a channel in the fuel - in caramel engines, the fuel burns along the surface of the channel, and not from the end of the charge; there is not enough area at the end. And to center the rod, you will need a wooden or plastic boss that is suitable in diameter for both the cardboard tube and the central rod. The diameter of the channel should be approximately three times smaller internal diameter pipes.
Having inserted the boss into the lower end of the pipe and the rod into it, we pour “semolina porridge” of saltpeter and sorbitol into the remaining space. The fuel cools and solidifies, but not completely. From its remains, you need to roll a sample stick - usually the size of a man's little finger. It is used to measure the burning rate of the resulting fuel - for this it is filmed and the time is recorded from the video. Of course, the length of the stick must be measured before lighting. Normally made sorbitol caramel should burn at a speed of 2.6 to 2.8 mm/s, that is, a 5 cm long stick will burn in 17-19 s.
After about six hours - while the fuel is still soft - you need to remove the boss and rod. All that remains is to make a plug of epoxy resin where the boss was: stick a circle of tape on the exposed surface of the fuel to cover the channel, and use the tape to make a side around the cardboard tube, then pour it there epoxy resin with hardener. The resin level should be 0.5 cm above the edge of the tube so that the resin is absorbed into the end. Sometimes they still do
three or four holes with a diameter of 3 mm, in the fuel-free part of the tube, so that the epoxy plug holds better.
After the glue has hardened, the engine is ready to start. Chinese “electric matches”, sold in online stores, are excellent for igniting it; you just need to lengthen the wires and insert the fuse into the engine all the way to the epoxy plug - if the engine lights up in the middle, it will not produce full thrust.
But, having flown a “classic”, a rocket enthusiast often feels the need to somehow improve it. This is where the invention of different compositions and technologies begins. The magic word “perchlorate” excites the hearts of homemade designers. But it will not be possible to directly replace potassium nitrate with potassium perchlorate - the fuel will have different characteristics. Without a third component - a catalyst - the composition exhibits pulsating combustion until it explodes. But melting fuel with a catalyst is dangerous, so you have to use vacuum pressing with heating and other exotic stuff.
| | | | r-s | t-y | f-c | sh-i
Composition No. 1: 60% (9KNO 3) + 30% (9SORBITOS) + 10%(9S)9 - higher ductility
Composition No. 2: 63% (KNO 3) + 27% (SORBITLE) + 10% (S) - maximum specific thrust
This propellant is a new and much improved version of sorbitol propellant. Its more high speed combustion and high specific impulse allow its use in both medium and large rocket engines. It was developed by me recently, i.e. modified, because It was not my idea to use sorbitol as a binder. However, compositions similar to it were published on some Internet web pages. But they never became popular among rocket scientists. And I think you know why.
The composition of the new sorbitol fuel includes sulfur, which is involved in the combustion reaction:
6C 6 H 14 O 6 + 26KNO 3 +13S = 13K 2 S + 36CO 2 + 13N 2 + 42H 2 O (theoretically)
In fact, the reaction proceeds according to a more complex mechanism; based on the redox properties of the elements, it can be argued that at the very beginning, the reaction will proceed exactly according to simple mechanism, and only then the reaction products will interact with each other, giving other compounds. The correct ratio of components ensures the high efficiency of this fuel. This fuel has relatively high energy characteristics. The fact is that sulfur participates here as a reducing agent and displaces the remaining oxygen atom from the molecule K2O, as a result of which the energy yield of the reaction increases. Besides K2S doesn't pick up CO 2 how it does K2O. The released energy is enough to shift the equilibrium towards the formation of such low molecular weight products as CO And H 2. This contributes to a significant increase in the specific thrust of the fuel. Thus Engine efficiency on average increases by 15 - 20% (based on rough estimates), and maybe more. So we can say that this rocket fuel is a worthy replacement for gunpowder and regular caramel.
The disadvantages of this fuel compared to conventional sorbitol are: difficulty in manufacturing, low plasticity, impossibility of pouring the composition into the engine housing, fast solidification rate; if sorbitol is not heated sufficiently, the fuel quickly solidifies. Experience has shown that this fuel is good to prepare and use in the cold season, since the humidity in the air is much lower than in summer time. Perhaps the most important problem with this fuel is the rapid solidification rate and the inability to pour fuel directly into the engine housing. This fuel also has a very unpleasant thing - if the mass is not compacted enough, voids form inside the fuel charge, which greatly affects the uniformity of combustion of the entire charge. Simply put, the structure becomes porous, which contributes to the occurrence abnormal combustion- unstable intermittent combustion caused by a decrease in the heat supply to unreacted fuel, lasting from several fractions to 2 seconds. This problem is especially typical only for small engines with a fuel charge 30 - 35 grams- pressing "Powerful caramel" In such engines, the work is very painstaking and complex, but on large engines this thing has practically no effect, because relative to the entire volume of fuel, the air voids are insignificant. Although this fuel hardens quickly, this problem can be easily eliminated by placing the container with fuel in a heated sand bath. This is a very convenient method, but be careful not to overdo it with the temperature, otherwise the sulfur in the fuel will melt and the mixture will become inhomogeneous.
MANUFACTURING
At first, during its manufacture, serious problems arose. It was difficult to find a balance between the melting point of sorbitol and the melting point of sulfur, and when mixing melts of both components, the fuel turned out to be extremely uneven. An option was considered using glycerin so that the mass retains its plasticity long time. But the use of glycerin led to a decrease in the strength of the fuel block and increased hydroscopicity.
With strong heating and subsequent cooling, sorbitol does not harden immediately and retains plasticity for quite a long time, which is enough for refilling 2 - 3 small engines. Sorbitol must be heated to a fairly high temperature (about t kip). When I heat it up to this temperature, it smokes a little, becomes transparent (slightly yellowish), and small bubbles form at the bottom, which indicates the beginning of boiling.
Before you start melting sorbitol, you should prepare all the components in advance.
1. First, weigh out the required portion of sorbitol and put it away from the place of work.
2. Next, you will need to grind the potassium nitrate. Before grinding, it should be dried thoroughly, you can use a radiator, but I dried it in the oven at t ≈ 200 0 C, it is impossible to exceed this temperature, because its melting and then decomposition begins. Dried potassium nitrate is easier to grind and sticks less to the walls of the electric coffee grinder than wet one. I did the grinding in an electric coffee grinder for about seconds. 40 . If it sticks to the walls, you can scrape it off with cotton swabs or your hands, but not bare hands, but using disposable gloves.
3. After grinding, weigh out the required portion of saltpeter and place it in a clean jar, I used a plastic one, because... It stuck to my glass.
The sulfur used in fuel contains coal in the following ratio: 100% (S) + 5% (C) (by weight).
When using coal, the mass forms fewer lumps, becomes more crumbly and practically does not stick to the walls of the electric coffee grinder during grinding. However, you need to grind intermittently so that the sulfur does not melt due to excessive friction. After grinding, it remains highly electrified and will form lumps. As I noticed, it takes quite a long time for the sulfur to become crumbly after grinding, so it should be ground in advance. ()
5. Only after you have measured everything can you melt the sorbitol. For these purposes, I used my favorite miniature oven, but when I didn’t have one, I made do with a stove. Sorbitol is placed in a metal container, or preferably in a container made of of stainless steel(personally, I use a stainless steel mug that I purchased at the store "Everything for fishing and hunting") and heats up to a temperature close to its boiling point.
6. Then finely ground and dried potassium nitrate (potassium nitrate) is added to it. Before you add it, shake the bottle of saltpeter thoroughly to make it more crumbly.
7. The mixture is stirred until completely homogeneous. At this ratio of saltpeter and sorbitol, the mixture begins to harden quickly, so you will have to reheat the contents of the glass until the mixture is suitable for stirring.
8. After the mixture has cooled to a temperature below the melting point of sulfur, sulfur itself is added to it. The temperature can be checked by throwing a small amount of sulfur into the above mixture of saltpeter and sorbitol; if the temperature is too high, the sulfur will melt and form small, shiny droplets on the surface. All components must be mixed very quickly so that the mixture does not have time to harden.
10. After this, remove the plastic mass (it is advisable to use disposable plastic gloves) with a knife or other metal object. The mixture should also be scraped off the sides of the mug and kneaded again with your hands for greater homogeneity (use plastic gloves!).
I would like to note that the fuel begins to quickly solidify, so I put the mug of it again and put it in a heated oven, but only now turned off, because. it retains heat and perfectly helps maintain the temperature of the fuel melt and it does not remain plastic enough for a long time. You can also put some heat-intensive materials in the oven: clean dry sand, metal nuts, nails, lead is perfect. As necessary, pieces of fuel are plucked off from the main mass and carefully pressed into the engine housing.
Fuel should be pressed in in small portions, because if the fuel is not pressed in under sufficient pressure, then many air bubbles will remain inside the fuel block. As experience has shown, for pressing it is better to use a graphite stick soaked in paraffin and with a polished tip. PTFE is also suitable for these purposes, but fuel still sticks to it and it is advisable to have a cloth on hand with which you will remove the deposits. It is advisable to carry out all work in a dry room. As I already noted, this fuel is more suitable for the manufacture of large fuel charges (from 70g) for large engines.
From the author: I don't know whether this fuel will become popular among rocket scientists and chemists, but in the course of long work with it I came to the conclusion that this is the only powerful fuel that can be obtained without much difficulty, compared to perchlorate. And the lower content of sorbitol makes it a little more profitable to use, unless, of course, your sulfur costs less than sorbitol. You won’t be able to cook it the right way the first time, but as you work with it for a long time, you will really see the difference. You might think that this method making this fuel is unsafe, but in all my practice there has not been a single Emergency, because I strictly maintain the purity of reagents and do not allow substances that are flammable below 200 0 C. If the workplace is strictly kept clean, this method is relatively safe.
Attention! If you have any comments, questions or suggestions on this topic, please let me know.
Several decades ago, when humanity was delirious about space exploration, the passion for rocket science was widespread. Both schoolchildren and adult men enthusiastically built in garages and kitchens from scrap materials. Now the excitement has subsided a little, but what could be more exciting than launching a self-made aircraft into the air? How to make a rocket take off? The most affordable and practical thing is to use caramel fuel, a mixture of saltpeter and carbohydrate.
What you need
The set of components is not so large.
1. Sugar or sorbitol - raw materials for caramelization.
2. Saltpeter (you can use different ones, more on this below).
3. Metal container- most often they take ordinary cans, although it is preferable to take dishes with thick walls - for more uniform heating. Even better - enameled or stainless steel, so that there is no reaction of the solution with the material of the dishes.
4. Electric stove - prepare fuel on gas stove it is forbidden!
5. Newspaper or other paper with good absorbent properties (if your goal is to make not just caramel fuel, but caramel paper). It is also used in rocket engines, soaked in the finished “caramel” and dried (without heating).
6. Protective equipment: glasses and gloves.
7. Ventilation.
Three manufacturing methods
You can make caramel fuel in different ways. The easiest thing is to simply mix the ingredients. “Caramel” is also boiled - simply or with evaporation. During normal mixing, fuel is poured into glass jar and shake several times, then close tightly to prevent water absorption. When directly used in rocket engines, this type of fuel must be well compacted, otherwise an explosion is possible.
Caramel fuel is boiled, or rather melted, at a temperature of 120-145 degrees until the sugar is completely converted and a mass is formed, the consistency of which is similar to liquid semolina porridge. There is no need to pre-grind the components. It is very important to stir it constantly to prevent air bubbles from forming. Evaporation cooking involves adding water and then evaporating it. Disadvantages of this method: moisture remains in the fuel, and this reduces its burning rate.
Recipe No. 1
Caramel fuel from is the best option. The ingredients are taken in following proportions: sugar or sorbitol - 35%; saltpeter - 65%. The saltpeter is dried in a flat wide frying pan at 100-150 degrees for about two hours. Then grind for about 20 seconds - you can use a mortar or coffee grinder.
Place in equal portions, 50 grams each. In order not to bother with grinding sugar, it is better to buy ready-made powdered sugar. For “boiled” caramel fuel, you don’t need to grind or dry anything. To enhance effectiveness, 1% iron oxide (Fe 2 O 3) can be added to the mixture.
Recipe No. 2
Caramel fuel from sodium nitrate. The peculiarities of this mixture are that it is more hygroscopic. You will need 70% saltpeter, 30% sugar and two volumes of water (200%).
Recipe No. 3
It is not recommended to use it. fuel for (ammonium nitrate). Why is it better to pay attention to other recipes? Because it is an unstable connection, and when heated, anything can go wrong. As a result, the undertaking will most likely end in fire!
In addition, when making “caramel” from ammonium nitrate extremely toxic fumes are released. Therefore, all recipes using ammonium nitrate contain additional components to convert it into sodium or potassium. The easiest option is sodium. We take 40% saltpeter, 45% baking soda and 200% water. Note the liquid level and evaporate until the smell of ammonia disappears. Then add water to the original level (it has partially evaporated), add 15% sugar and wait for it to dissolve.
Catalysts
To increase the efficiency of the “caramel”, various catalysts are added to it. The most popular is iron oxide. Less known is caramel fuel with aluminum. Attention! A mixture of aluminum and nitrates may ignite in the presence of water. Particularly dangerous is the presence of any alkaline impurities that may be present in saltpeter that is not pure enough or is made independently. Therefore, in fuel based on nitrates with aluminum as a catalyst, it is necessary to add 0.5-1% of some weak acid, and it is not a fact that this amount will be enough - it all depends on the quality of the nitrate. Bornaya - best option. Oxalic acid and vinegar are not suitable - aluminum reacts with them. If during the cooking process the mixture becomes very hot, foams and emits a strong smell of ammonia, you must immediately remove it from the stove and immerse it in water.
In general, it is better for experienced rocket scientists who have mastered the simplest types of fuel to experiment with catalysts. Yes, and it doesn’t hurt to learn chemistry: use ready-made advice simple, but much more valuable is knowledge and understanding of what you are doing and what reactions occur in the mixture.
Aluminum is added to potassium "caramel". Allowable variations are from 2.5 to 20%. Different amounts give different changes in the rate of fuel combustion. It is recommended to use spherical aluminum ASD-4.
How to stay whole and healthy
The most dangerous way to prepare caramel fuel is by melting sugar and saltpeter, but this option is also the most effective. The container in which the caramel is cooked must be perfectly clean - foreign substances can cause a fire.
There should be no sources nearby open flame- We don't need explosions in the kitchen. It is very important to monitor the temperature of the mixture - it should not rise above 180 degrees under any circumstances!
When stirring, it is better to use a wooden stick to avoid adverse reactions. You should mix very carefully, but evenly: air bubbles in the finished fuel when used lead to an explosion of the rocket. When pouring this fuel into molds, you also need to make sure that there are no bubbles. It is necessary to work with a hood or on fresh air, this is especially true for the recipe with ammonium nitrate.
Do not grind sugar and saltpeter together in a coffee grinder! You need to grind separately, mix, shaking, in a glass container.
Beginners should not mess with ammonium nitrate: first try the simplest and safest (potassium nitrate-based) caramel fuel. The production of any homemade fuel must be carried out under careful control of the quality of ingredients, temperature, moisture content and in compliance with all safety measures!
Where to get ingredients
Nitrate is sold in agricultural supply stores and departments for summer residents as a fertilizer. Sorbitol is a sugar substitute for diabetics. Sold, accordingly, in a pharmacy. Fe 2 O 3 - iron oxide - was previously sold under the name You can try to make it yourself by studying the relevant literature. The mineral hematite - this is also Aluminum sold by chemical reagent manufacturing companies.
To begin with, I think it would be reasonable to make a small homemade engine, to get used to it, so to speak. Since I was making rockets for the MRD, maybe the mandrel was left for the body, so make it for that caliber. Take a 12-gauge hunting cartridge case - this is the engine body, without a capsule - this is the nozzle. Prepare the fuel like this .Find potassium nitrate, where I don’t know, ammonium and sodium nitrate will not work. The spirit writes that in the Urals they simply sell it freely in stores. I took it from a workshop where glass was boiled. Well, and regular sugar. Grind SEPARATELY in an electric coffee grinder and mix in the ratio 60% saltpeter and 40% sugar. Make homemade scales from caps, threads and sticks. Weights-copper Soviet coins (1, 2, 5 kopecks) corresponding to grams. About 10 grams go to the engine. Mix the components by pouring from side to side side on a piece of paper. So. Now we need to heat this thing up to about 150 degrees. In principle, we heated SUCH QUANTITIES simply on an electric stove, but we need equipment. When overheated (no need to have illusions), the flash of a hot mixture smeared over the vessel is very active .THE THINGS LIKE NOT BENDING OVER THE MIXTURE AND WORKING WITH ALMOST EXTENDED ARMS SHOULD BE AN INSTINCT. Then, if something happens, you’ll just burn your hand—it’s painful, but instructive (honor the cosmos—a happy childhood) Yes, you can heat it in a small tin can by attaching a handle to it, better than a frying pan from a children's kitchen set. Today I tried to melt sugar on an inverted iron and it melted. In principle, I’m almost sure that the temperature given by the iron is less than the flash point of the mixture. Check your iron - put a match on it, wait 15 minutes, it won’t flare up OK. You need to insert a stick onto the cone into the engine nozzle - use a wooden children's brush, cutting it so that after it fits tightly in the nozzle, it extends about 2 cm inward, and rub it with paraffin. So, when you heat the mixture, it will first start to the edges become transparent, in general, the resulting glassy mass must be pushed into the sleeve with a wooden stick, this cannot be explained in detail, you have to try it yourself. And compact it, the muck cools quickly. As a result, the sleeve will have a charge with a channel of about half. I recommend doing all this with the mixture in the same proportions, but instead of saltpeter, take table salt (Varban’s idea - just five!), then tear the cartridge case and see what the charge looks like. Are there many potholes and inhomogeneities? Pack the rest of the cartridge case tightly with paper. Everything is ready, ignition by entering nichrome wire nozzle on the wires, just like in the MRD. Good luck!
Only after mastering the production of such engines successfully can we talk about somewhat larger charges, otherwise it is difficult to talk about something that a person has not tried, considering that the mixture can be poured into the engine (through a funnel). Your injuries will be on my conscience.