Do-it-yourself rocket fuel. How do I make rocket motors. This is dangerous! You do it at your own peril and risk.

Rocket modelers call a classic fuel, consisting by weight of 35% sorbitol and 65% potassium nitrate, without any additives. This fuel has been studied quite well, has characteristics not worse than that of black powder, but it is much easier to manufacture it than the correct powder.
For the classics, only potash 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,
selling mineral fertilizers. Previously, photo shops also sold potash (potassium carbonate), which is also suitable for obtaining potassium nitrate from ammonium nitrate. When hot saturated solutions of sodium nitrate and potassium chloride are mixed, potassium nitrate will immediately precipitate. Homemade saltpeter will have to be cleaned by recrystallization, for this you need to dissolve it in a small amount of hot boiled water, filter through cotton wool and put the solution in the refrigerator. Then drain the solution, dry the saltpeter on a battery, and then in the oven at about 150 ° C for one to two hours. The main thing here is compliance with the temperature regime. At a higher 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 by this temperature it can be distinguished from sorbitol monohydrate, which is sometimes sold as sorbitol. The monohydrate melts at 84 ° C and not suitable for fuel.
Despite the frivolous name, caramel rocket fuel is primarily rocket fuel, and must be treated with respect. The first and foremost safety rule is that under no circumstances cook caramel over an open fire! Only a hotplate with a closed heater and temperature controller. If there is no suitable electric stove, you can use a regular iron, only you need to make a stand that holds it upside down, with the sole up. The three-point knob position is great for making caramel.
Do not measure the components by eye or by volume - only on the balance. In appearance, a pile of 35 g of sorbitol and 65 g of potassium nitrate are almost the same in volume. And this plays into our hands, 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 do not overdo it: the crystals should be like fine salt - if you grind saltpeter into dust, it will be difficult to work with fuel, as it will become too viscous. 20 seconds is what you need.
Now you can mix the nitrate and sorbitol powders and lay out in a layer no more than a centimeter thick in the pan. It is advisable to stir the mixture continuously. It is convenient to use a wooden popsicle stick for stirring. Gradually, the sorbitol will begin to melt, after a while, as it is stirred, the powder will turn into a homogeneous substance, similar to liquid semolina. Part of the nitrate dissolves in molten sorbitol, so the finished fuel remains quite liquid even at 95 ° C. You should not overheat the fuel, because at 140 ° C the solubility of nitrate increases abruptly and, in the same way, the viscosity of this composition increases.
As soon as the last lumps of nitrate are stirred, the fuel is ready - now it must 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 parameters are not required, nozzleless becomes preferable. It only consists of a body and a charge. Although some of the fuel energy is wasted without a nozzle, by saving the body and nozzle weight, you can add more fuel and compensate for losses.
For the case, you 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 - and the fuel freezes faster, and it is difficult to pack it in a small tube. Its length should be 7-15 times the diameter. It is possible at 20, but filling the fuel is already very inconvenient.
You will also need a rod to form a channel in the fuel - in caramel-fueled 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 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 than the inner diameter of the pipe.
Having inserted the lug into the lower end of the pipe and the rod into it, fill the remaining space with "semolina" from saltpeter and sorbitol. 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 time is recorded from the video. Of course, the length of the stick must be measured before lighting it. Normally made sorbitol caramel should burn at a speed of 2.6 to 2.8 mm / s, that is, a stick 5 cm long will burn out in 17-19 s.
After about six hours - while the fuel is still soft - remove the boss and rod. It remains to make a plug of epoxy resin where the boss was: glue a circle of adhesive tape on the exposed fuel surface to cover the channel, and make a side around the cardboard tube from the adhesive tape, and then pour epoxy resin with a hardener there. The resin level should be 0.5 cm above the end of the tube for the resin to soak into the end. Sometimes they still do
three to 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. To ignite it, Chinese "electric matches" sold in online stores are perfect, you just need to lengthen the wires and insert the fuse into the engine until it stops, up to the epoxy plug - if the engine lights up in the middle, it will not give out full thrust.
But, having flown on a "classic", the rocket enthusiast often feels the need to improve it somehow. This is where the invention of different compounds and technologies begins. The magic word "perchlorate" excites the hearts of DIY designers. But it will not work directly to replace potassium nitrate with potassium perchlorate - the fuel will have different characteristics. Without the third component - the catalyst - the composition exhibits pulsating combustion until it explodes. And it is dangerous to melt fuel with a catalyst, so you have to use heated vacuum pressing and other exotic things.

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Composition No. 1: 60% (9KNO 3) + 30% (9SORBITA) + 10% (9S) 9 - higher ductility

Composition No. 2: 63% (KNO 3) + 27% (SORBITA) + 10% (S) - maximum specific thrust

This propellant is a new and significantly improved sorbitol fuel. Its higher burning rate and high specific impulse make it suitable for use in both medium and large rocket engines. It was developed by me recently, i.e. improved, tk. I didn’t come up with sorbitol as a binder. However, compositions similar to it have been published on some Internet web pages. But they never became popular with rocket scientists. And I think you know why.

The new sorbitol fuel contains 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 (theoretical)

In fact, the reaction proceeds according to a more complex mechanism, according to the redox properties of the elements, it can be argued that at the very beginning, the reaction will proceed precisely according to a simple mechanism, and only then the reaction products will interact with each other, giving already other compounds. The correct ratio of components ensures high efficiency of this fuel. This fuel has a relatively high energy performance. The fact is that sulfur is involved here as a reducing agent and displaces the remaining oxygen atom from the molecule K 2 O, as a result of which the energy yield of the reaction increases. Besides K 2 S does not take CO 2 how does it do K 2 O... 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 specific fuel thrust. Thus, the efficiency of the engine increases on average by 15 - 20% (by rough estimates), and maybe more. So we can say that this rocket fuel is a worthy replacement for gunpowder and ordinary caramel.

The disadvantages of this fuel in comparison with conventional sorbitol are: complexity in manufacture, low plasticity, impossibility of pouring the composition into the engine casing, fast solidification rate, with insufficient heating of sorbitol, the fuel quickly solidifies. Experience has shown that it is good to prepare and use this fuel in the cold season, since the humidity in the air is much lower than in the summer. Perhaps the most important problem with this fuel is the fast solidification rate and the impossibility of pouring fuel directly into the engine housing. This fuel also has a very unpleasant thing - with insufficient compaction of the mass inside the fuel charge, voids are formed, which greatly affects the uniformity of combustion of the entire charge. Simply put, the structure becomes porous, which contributes to the occurrence of abnormal burning- unstable intermittent combustion caused by a decrease in the supply of heat to unreacted fuel, lasting from a few 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 complicated, but on large engines such a thing practically does not affect, because relative to the entire volume of fuel, the air voids are insignificant. Although this fuel quickly solidifies, this problem can be easily eliminated by placing a container with fuel in a heated sand bath. This is a very convenient way, well, look, do not overdo it with the temperature, otherwise the sulfur in the fuel will melt and the mixture will become heterogeneous.

MANUFACTURING

At first, during its manufacture, there were serious problems. It was difficult to find a balance between the melting point of sorbitol and the melting point of sulfur, and when the melts of both components were mixed, the fuel turned out to be extremely uneven. An option was considered using glycerin so that the mass retained its plasticity for a long time. But the use of glycerin led to a decrease in the strength of the fuel checker and increased hydroscopicity.

Sorbitol does not solidify immediately upon strong heating and subsequent cooling and retains its plasticity for a sufficiently long time, which is enough for refueling 2 - 3 small engines. Sorbitol must be heated to a sufficiently high temperature (about t bale). When I heat it to this temperature, it smokes a little, becomes transparent (slightly yellowish), and small bubbles form at the bottom, which indicates the beginning of a boil.

Before you start melting sorbitol, you should prepare all the ingredients in advance.

1. First, weigh the required amount of sorbitol and set it aside away from the place of work.

2. Next, you will need to grind the potassium nitrate. Before grinding, it should be thoroughly dried, it is possible on a battery, 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 less adhered to the walls of the grinder than wet. I made the grinding in an electric coffee grinder for about seconds 40 ... If it sticks to the walls, then it can be scraped off with cotton swabs or with your hands, just not with your bare hands, but using disposable gloves.

3. After grinding, weigh the required portion of nitrate and place it in a clean jar, I used a plastic one, because it stuck to the glass.

The sulfur that I use in fuel contains coal in the following ratio: 100% (S) + 5% (C) (by mass).
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, grind intermittently to prevent the sulfur from melting from excessive friction. After grinding, it remains highly electrified and will form lumps. As I have noticed, it takes a long enough time for the sulfur to become crumbly after grinding, so it should be ground beforehand. ()

5. Only after you have measured everything can you melt sorbitol. For these purposes, I used my favorite miniature stove, but when I did not have one I got by with a stove. Sorbitol is placed in a metal container, or better in a stainless steel container (I personally use a stainless steel mug that I purchased in a 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 cover it, shake the bottle of saltpeter well to make it more crumbly.

7. The mixture is mixed until completely homogeneous. With this ratio of nitrate to sorbitol, the mixture begins to harden quickly, so you will have to reheat the contents of the glass until the mixture is ready 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 obtained mixture of nitrate 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 that, pull out the plastic mass (preferably using 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 to make it more uniform (use plastic gloves!).

I want to note that the fuel begins to solidify quickly, so I put it in a mug again and put it in a heated oven, but only turned off. it has retained heat in itself and perfectly helps to maintain the temperature of the fuel melt and it does not remain plastic for a sufficiently long time. You can also put some heat-consuming materials in the oven: clean dry sand, metal nuts, nails, lead is perfect. As necessary, pieces of fuel are pinched off from the bulk and carefully pressed into the engine body.

The fuel should be pressed in small portions, because if the fuel is not pressed in under sufficient pressure, then a lot of air bubbles will remain inside the fuel block. Experience has shown that for pressing it is better to use a graphite stick impregnated with paraffin and with a polished tip. For these purposes, fluoroplastic is also suitable, but the fuel still sticks to it and it is advisable to have a rag on hand with which you will remove plaque. It is advisable to carry out all work in a dry room. As I have already noted, this fuel is more suitable for the manufacture of large fuel charges (from 70g) for large motors.

From the author: I do not know if this fuel will become popular among rocket scientists and chemists, but in the course of long-term 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 sorbitol content makes it a little more profitable to use, unless of course your sulfur is cheaper than sorbitol. The first time, you will not be able to cook it the way you need it, but in the course of a long work with it, you will really see the difference. It may seem to you that this method of making this fuel is unsafe, but in all my practice there was not a single State of emergency, because I strictly adhere to the purity of the reagents and do not allow the ingress of substances that ignite below 200 0 C... With strict adherence to the cleanliness of the workplace, 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 mankind raved about space exploration, the passion for rocketry was rampant. Both schoolchildren and adult men enthusiastically designed 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 do you make a rocket take off? The most affordable and practical is to use caramel fuel, a mixture of nitrate and carbohydrate.

What is required

The set of components is not that great.

1. Sugar or sorbitol - raw material 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 even 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 - you cannot cook fuel on a gas stove!

5. Newspaper or other paper with good absorbency (if your goal is to make not just caramel fuel, but caramel paper). It is also used in rocket engines, impregnated with finished "caramel" and dried (without heating).

6. Protective equipment: glasses and gloves.

7. Ventilation.

Three manufacturing methods

There are many ways to make caramel fuel. The easiest thing is to just mix the ingredients. Still "caramel" is cooked - simply or with evaporation. In normal mixing, the fuel is poured into a glass jar and shaken several times, then tightly closed to prevent water absorption. When used directly in rocket engines, this type of fuel must be well sealed, 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, similar in consistency to liquid semolina. It is not necessary to grind the components beforehand. It is very important to constantly stir it so that no air bubbles form. Evaporation cooking involves adding water and then evaporating it. Disadvantages of this method: moisture remains in the fuel, and this reduces the rate of its combustion.

Recipe number 1

Caramelized fuel is the best option. The ingredients are taken in the following proportions: sugar or sorbitol - 35%; saltpeter - 65%. Saltpeter is dried in a flat wide frying pan about 100-150 degrees for about two hours. Then grind for about 20 seconds - you can use a mortar or coffee grinder.

Lay 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 do not need to grind or dry anything. To increase efficiency, 1% iron oxide (Fe 2 O 3) can be added to the mixture.

Recipe number 2

Sodium nitrate caramel fuel. The peculiarity of this mixture is that it is more hygroscopic. You will need 70% nitrate, 30% sugar and two volumes of water (200%).

Recipe number 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 compound and anything can go wrong when heated. As a result, the venture is likely to end in fire!

In addition, extremely toxic fumes are emitted from ammonium nitrate when making "caramel". Therefore, all recipes using ammonium nitrate contain additional components to convert it to sodium or potassium. The easiest option is with sodium. We take 40% nitrate, 45% baking soda and 200% water. We note the level of the liquid and evaporate until the smell of ammonia disappears. Then we add water to the original level (it has partially evaporated), add 15% sugar and wait for it to dissolve.

Catalysts

To increase the effectiveness of the "caramel", various catalysts are added to it. The most popular is iron oxide. Less well known are caramel fuels with aluminum. Attention! A mixture of aluminum and nitrates can 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 made on its own. Therefore, in a 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 nitrate. Bornaya is the best option. Oxalic and acetic acid are not suitable - aluminum reacts with them. If during the cooking process the mixture heats up very much, foams and emits a pungent 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 will not hurt to learn chemistry: using ready-made advice is simple, but knowledge and understanding of what you are doing and what reactions occur in the mixture are much more valuable.

Aluminum is added to the potassium caramel. Allowable variations are from 2.5 to 20%. A different amount gives a different change in the rate of combustion of the fuel. It is recommended to use spherical aluminum ASD-4.

How to stay whole and healthy

The most dangerous thing is to prepare caramel fuel 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 of open flames nearby - 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!

It is best to use a wooden stick when stirring to avoid side reactions. 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, it is also necessary to ensure that there are no bubbles. It is necessary to work with a hood or in the fresh air, especially for a recipe with ammonium nitrate.

Do not grind sugar and saltpeter together in a coffee grinder! Grind separately, mix, shaking, in a glass container.

Beginners should not mess with ammonium nitrate: first try the simplest and safest (based on potassium nitrate) caramel fuel. The manufacture of any home-made fuel must take place under the strictest control of the quality of ingredients, temperature, moisture content and in compliance with all safety measures!

Where to get ingredients

Saltpeter is sold as a fertilizer in agricultural stores and summer residents' departments. Sorbitol is a sugar substitute for diabetics. Sold, respectively, in the pharmacy. Fe 2 O 3 - iron oxide - used to be sold under the name You can try to make it yourself, having studied the relevant literature. Mineral hematite - this also aluminum is sold by manufacturers of chemical reagents.

Few of my peers were not fond of building model rockets. Maybe it was the worldwide fascination of mankind with manned flights, or maybe the apparent simplicity of building a model. A cardboard tube with three stabilizers and a head fairing made of foam or balsa, you see, is much simpler than even an elementary model of an airplane or car. True, the enthusiasm of the majority of young Korolevs, as a rule, evaporated at the stage of searching for a rocket engine. The rest had no choice but to master the basics of pyrotechnics.

Alexander the Greek

Between the Chief Designer of our missiles, Sergei Korolev, and the Chief Designer of our rocket engines, Valentin Glushko, there was an unspoken struggle for the title of Most Important: who is really more important, the designer of missiles or engines for them? Glushko is credited with a catch phrase, allegedly thrown by him in the midst of such a dispute: "Yes, I will tie a fence to my engine - it will go into orbit!" However, these words are by no means empty bragging. The abandonment of the "Glushkov" engines led to the collapse of the royal lunar rocket H-1 and deprived the USSR of any chance of winning the lunar race. Glushko, having become the general designer, created the super-powerful launch vehicle Energia, which no one has yet been able to surpass.

Cartridge motors

The same pattern worked in amateur rocketry - a rocket flew higher, which had a more powerful engine. Despite the fact that the first rocket model engines appeared in the USSR even before the war, in 1938, Yevgeny Buksh, the author of the book "Fundamentals of Rocket Modeling" published in 1972, took the cardboard sleeve of a hunting cartridge as the basis for such an engine. The power was determined by the caliber of the original sleeve, and the engines were produced by two DOSAAF pyrotechnic workshops until 1974, when it was decided to organize a rocket modeling sport in the country. To participate in international competitions, engines were required that were suitable in terms of their parameters to the requirements of the international federation.

Their development was entrusted to the Perm Research Institute of Polymeric Materials. Soon an experimental batch was released, on the basis of which the Soviet rocket-modeling sport began to develop. Since 1982, serial production of engines has been intermittently launched at the state state-owned plant "Impulse" in the Ukrainian Shostka - 200-250 thousand copies were produced per year. Despite the severe shortage of such engines, this was the heyday of the 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 competition. Therefore, next to the plant in 1984, a small-scale pilot production appeared, which provided the national team with its products. The engines, which were privately made by master Yuri Gapon, stood out in particular.

And what, in fact, is the complexity of production? At its core, the rocket engine is the simplest device: a cardboard tube with DRP-3P brand black powder pressed inside (black gunpowder 3rd composition for pressed products) with a ceramic plug with a hole nozzle 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 dosage accuracy, on which the final total impulse of the engine also depended. The second is the quality of the hulls, which often cracked when pressed under a pressure of three tons. Well, and the third - in fact, the quality of the press fitting. However, quality problems arose not only in our country. Serial model 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 enterprises in the Czech Republic and Slovakia, from where they are smuggled for especially important events.

Nevertheless, under socialism there were engines, albeit unimportant and with a deficit, but there were. Now they are not there at all. Separate children's rocket modeling studios fly on old, still Soviet stocks, turning a blind eye to the fact that the expiration date is long gone. Athletes use the services of a pair of solo craftsmen, and if they are lucky, even contraband Czech engines. For amateurs, there is only one way left - before becoming Korolyov, first to become Glushko. That is, to make the engines ourselves. What, in fact, did I and my friends in childhood. 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 loved to say. For amateur rocket modelers of the middle of the last century - too. For the film and photographic film of that time was made of celluloid. Tightly rolled up into a small roll and tucked into a paper tube with stabilizers, it allowed a simple rocket to take off to the height of a five-story building. These engines had two main drawbacks: the first was low power and, as a result, 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.

The maximum altitude with a fixed total impulse of the engine was achieved with a short-term four-fold power jump at the start and further transition to an even 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 the waste of the Soviet army. The fact is that when firing at artillery ranges (and one of them was just not far from us), the propellant charge does not completely burn out when fired. And if you looked carefully in the grass in front of the positions, you could find quite a lot of tubular powder. The most uncomplicated rocket was obtained by simply wrapping such a tube in ordinary chocolate foil and setting it on fire at one end. Such a rocket flew, however, not high and unpredictable, but fun. A powerful engine was obtained by collecting long tubes into a bag and pushing them into a cardboard box. A primitive nozzle was also made of baked clay. Such an engine worked very effectively, raised the rocket quite high, but often exploded. Besides, you don't really look like an artillery range.

The third option was an attempt to almost industrialize a rocket engine using homemade black powder. They made it from potassium nitrate, sulfur and activated carbon (it constantly jammed the parent coffee grinder, on which I ground it into dust). To be honest, my powder engines worked intermittently, lifting rockets just a couple of tens of meters. I found out the reason only a couple of days ago - it was necessary to press in the engines not with a hammer in the apartment, but with a school press in the laboratory. But who, one wonders, would have let me press 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 stocks of the rocket-modeling section in the Orphanage of Creativity on Vorobyovy Gory.

Working with poisons

The pinnacle of my engine-building activity was a rather poisonous engine that ran on a mixture of zinc dust and sulfur. I traded both ingredients with a classmate, the son of the director of a city pharmacy, for a pair of rubber Indians, the most convertible currency of my childhood. I got the recipe in a very rare translated Polish rocket model book. And he stuffed 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 test run was carried out in the absence of parents in the kitchen. A pillar of flame from a gripped engine roared up to the ceiling, smoking a meter in diameter on it and filling the apartment with such stinking smoke as a box of smoked cigars cannot be compared. It was these engines that provided me with record launches - perhaps 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) In the presence of a factory rocket engine, a primary school student can also cope with the construction of a simple rocket. 3) A product of amateur creativity - an engine 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 as fuel, an ordinary newspaper acted, which was soaked in a supersaturated (hot) solution of nitrate, and then dried. True, saltpeter in the process of drying 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 was ironing the newspaper with a hot iron, literally melting saltpeter into the paper. It cost him a ruined iron, but such paper burned very quickly and steadily, giving off a large amount of hot gases. Cardboard tubes stuffed with nitrate paper rolled into a tight roll with improvised nozzles from bottle corks soared a hundred or two meters.

Caramel

The paranoid ban of the Russian authorities on the sale of various chemical reagents to the population, from which explosives can be made (and it can be made from almost anything, even from sawdust), is compensated by the availability of recipes for almost all types of rocket fuel via the Internet, including, for example, the composition of fuel for accelerators " Shuttle "(69.9% ammonium perchlorate, 12.04% polyurethane, 16% aluminum powder, 0.07% iron oxide and 1.96% hardener).

Cardboard or foam rocket bodies, propellants, and propellants do not seem to be very significant advances. But who knows - maybe these are the first steps of the future designer of interplanetary ships?

The unconditional hit of the amateur rocket engine is now the so-called caramel engines. The fuel recipe is obscenely simple: 65% potassium nitrate KNO3 and 35% sugar. Saltpeter is dried in a frying pan, after which it is crushed in a conventional coffee grinder, slowly added to the melted sugar and solidified. The result of creativity is fuel sticks, from which you can recruit any engines. As engine casings and shapes, spent hunting cartridges are perfect - hello thirties! There are unlimited cartridges on any shooting stand. Although recognized masters recommend using not sugar, but sorbitol caramel in the same proportions: sugar caramel develops more pressure and, as a result, inflates and burns the sleeves.

Back to the Future

The situation, one might say, returned in 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 work in rocket modeling. Our rocket engines are equated to explosives, with all the ensuing conditions for storage, transportation and transportation across the border. A Russian person has not yet been born on earth who is capable of organizing the import of such products.

There is only one way out - production at home, since the technology here is not at all cosmic. But factories that have licenses for the production of such products do not undertake them - they would be interested in this business only with millions of circulations. 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 have now begun to appear that run on a hybrid fuel: nitrous oxide plus solid fuel. What country do you think will fly to Mars in thirty years?

Sometimes you want something strange. Here, recently I was drawn to rocket modeling. Since I build rockets at the Nubian level, for me a rocket consists of two parts - an engine and a body. Yes, I know that everything is much more complicated, but even with this approach, rockets fly. Naturally, you are wondering how the engine is made.

I want to warn you that if you are going to repeat what is written in this article, you will do it at your own peril and risk. I do not guarantee the accuracy or safety of the proposed technique.

I use 3/4 '' thick PVC pipe for the motor housing. Pipes of this diameter are relatively cheap and widely available. The pipes are best cut with special scissors. I suffered a lot, trying to cut such pipes with a jigsaw - it always turned out very crooked.

I mark the pipe like this:

All dimensions are in inches. who does not know, the size in inches must be multiplied by 2.54 and you get the size in centimeters. I found these dimensions in a wonderful book

There are a bunch of other designs too. The upper piece of the engine (which is empty) I do not do. There should be an expelling charge for the parachute, I'm still far from that.

The cut piece of pipe is inserted into a special device. I will show all the adaptations at once, so that there are no questions:

A long stick plays the role of a “pestle” Clay and fuel are compacted with it. The second piece is the conductor. It serves to drill the nozzle exactly in the center of the engine. Here are their blueprints:

The drill is used long - 13cm long. It is just enough to drill a channel through all the fuel.

Now you need to knead the fuel. I use the standard "caramel" - sugar and saltpeter in a ratio of 65 saltpeter / 35sugar. I don't want to melt caramel - it's a risky job, and it's not worth the hemorrhoids. I'm not trying to get the best out of the fuel. This is amateur rocket science. I just mix the powdered sugar and saltpeter:

We hammer in the powder according to the marking. You need to hit pretty hard.

Fuel plugging and plugging are no different. It seems that it is dangerous to knock on fuel, but caramel is difficult to ignite even from a match. Naturally, basic precautions should be taken - do not lean over the engine, work in a protective mask, etc.

I leave the last 5mm plugs for the hot melt glue. Several times I tried to make a rocket without a plug from hot melt glue, the top plug was pulled out by pressure. Hot glue has excellent adhesion to plastic and does not have time to melt when the engine burns.

We drill the nozzle through the jig:

Fuel is very poorly drilled - sugar melts and sticks to the drill, so you often have to pull it out and clean off the stuck fuel. Checking the nozzle:

Fill the last 5mm of the tube and its end with hot melt glue

That's it, the engine is ready. This is what the engine looks like in static tests. Unfortunately, the video is not indicative - in this engine, the channel was drilled in half, and the camera did not record the sound correctly. In real life, the "roar" of the engine is very loud and serious, and not as toy-like as on the record.