• What can be cooked from squid: quick and tasty

    I am building a model that simulates a real mini jet engine, even if my version is electric. In fact, everything is simple and everyone can build jet engine do it yourself at home.

    How I designed and built a homemade jet engine is not The best way do it. I can imagine a million ways and schemes how to create best model more realistic, more reliable and easier to manufacture. But now I have assembled one.

    The main parts of the model jet engine:

    • DC motor strong enough and at least 12 volts
    • DC power source of at least 12 volts (depending on which DC motor you have).
    • A rheostat, the same one sold for adjusting the brightness of the bulbs.
    • The flywheel gearbox is found in many car toys. It is best if the gear housing is made of metal because plastic can melt at such high speeds.
    • A sheet of metal that can be cut to make fan blades.
    • Ammeter or voltmeter.
    • Potentiometer approx. 50K.
    • An electromagnet coil from a solenoid or any other source.
    • 4 diodes.
    • 2 or 4 permanent magnets.
    • Cardboard to assemble a jet-engine-like body.
    • Filler for car bodies, to create an exterior.
    • Hard wire to support everything. I usually use wires from cheap hangers. They are strong enough and flexible enough to give them the desired shape.
    • Glue. I prefer hot glue for most parts, but just about any glue will work now.
    • White, silver and black paint.

    Step 1: Connect the DC motor to the flywheel of the transmission


    The basics of my jet engine model are very simple. Connect the DC motor to the transmission. The idea is that the motor drives the part of the gearbox that was attached to the wheels of the toy car. Place the plastic lever so it hits the small flywheel gear and it makes a noise. Some gearboxes are already equipped with this device and some are not.

    Step 2: Connect the magnets and the sensor coil

    Place 2 or 4 permanent magnets on the main shaft so that the coil can be close to them as they rotate. Place them so that the polarity pattern is - + - +. The idea is that the magnets will travel close to the coil and generate a small amount of current that we will use to move the sensor. But for this to work, you need to put 4 diodes in a bridge configuration to convert the AC current we generate to DC.

    Google "diode bridge" for more information on this. Also, to calibrate the sensor to the desired sensitivity, you need to place a potentiometer between the coil and the sensor.

    Step 3: Rheostat for speed control

    We need to control the speed of the engine. To do this, place a rheostat between the outlet and the power source. If you don't know how to do this, google how to connect a rheostat to light bulbs. But instead of a light bulb, we will put a power supply unit.

    Don't try this if you are not 100% sure. We are dealing with a lot of current, and using the wrong power source can destroy it and damage it. How easier block food is better. The alternative is to find a DC rheostat so that we can monitor the voltage after power up. I could not find one in any store, so I use a rheostat for light bulbs. But if you can find one that works with a DC motor, then get one. The idea is to just control how much current goes to the motor, so that will be our choke.

    Step 4: fan

    You can make the fan however you want. I cut each blade from thin sheet metal and glued them together. You can make them out of cardboard and then paint them. Or, if you have access to a 3D printer, you can print a 3d fan. There are some great 3D fan models on www.thingiverse.com.

    Step 5: case

    You can make the box out of cardboard and then add an outer filler to shape it. You will have to sand a lot, so it's hard and messy work. When you've got it all flattened, paint over the body with glossy white paint.

    The inside of the engine must be painted black. The front of the engine usually has a silver edge that you can paint if you want.

    Step 6: starter mechanism

    The starter and fuel handles are mechanically linked. The starter motor has a switch that connects the engine to a power source. This switch can also be activated by the fuel control lever when in the run position.

    The starter spring must be loaded in such a way that it wants to return to its normal position and will only block the start position if the fuel control lever is in the off position.

    The idea is to keep the starter in the home position until you move the fuel lever to the operating position, and now the fuel control lever will keep the switch on. Also, the fuel arm is part of the rheostat base. The rheostat must be installed in such a way that it is possible to rotate not only the part of the handle that should rotate, but the entire base of the rheostat. This base is what the fuel control propels to increase speed when it is in the operating position. This is difficult to explain and therefore you should watch the third part of the video to better understand the concept.

    Definition and technical description.

    * - automatic translation of a part of the book.

    It is a curiolls fact that you will not find the term "turbine" in most physics books.

    The turbine jet jet produces axial pressure, accelerating the air mass. When air masses are accelerated in a stream, they create thrust. Forces are measured in Newtons, not kilograms and grams! The force of 1 Newton (denoted by the letter N) acts when a mass of 1 kg is accelerated or decelerated by 1 m / s. The change in speed over a period of time is defined as acceleration and is measured in m / s.

    In the encyclopedia in the "turbine" section it is written: "A POWERFUL ENGINE, in which the energy of a moving medium
    (water, steam, gas) is converted into useful energy. Another name is turbojet engine.
    The forerunners were windmills and waterwheels, Specialist technical books on the subject explain the various tourist escapes in some detail under the main heading of a jet engine jet.

    In Dubbel Engineering you will find the definition: "a gas turbine is a machine that uses heat to transfer mechanical energy (shaft power) or thrust (eg aircraft engines)", respectively, the term gas turbines is a general term for all types of Turbo Jet engines.
    Jet turbines as well as turboprop motors. They are all considered “gas turbines; from aircraft modeling systems such as JPX. FD. micro-turbines.
    Turbomin and Pegasus, as well as KJ-66, .1-66 and TK-50 turbo engines feawred in this book, and including
    ING is any such type of engine that either currently exists or has not yet been invented. They are all "gas turbines" for generating thrust!

    Indeed, an alternative and more apt name for such devices is model aircraft engines with a turbocharged air jet. I prefer a term that is often used by specialists: “jet turbines, some people call them jet engines.
    As you can see, we already have more than enough definition at our disposal. There is no need to come up with any new definitions. Unfortunately. technical experts do not always speak a language that is logically correct and clear. Of course, to help the understanding of readers who do not have special knowledge, it is necessary to always indicate what exactly is meant by the word wrbines. it turbojet engine drawings.

    Not a great example, the engine draws in air at a speed of 0.25 kg / second and accelerates it at the same time to a speed of 400 m / s static axial pressure - 100 N *

    Download the drawings of the model aircraft turbojet engine.

    Sample page with drawings.

    The simplest jet engine is a valveless pulsating unit. After his invention, it became obvious that he could move a rocket even in. Due to the fact that the development of the considered type of propulsion system was suspended everywhere. But many amateurs continue to be interested in, study and even assemble the unit on their own. Let's try to make a jet engine with our own hands.

    Motor patented by Lockved

    The device can be built in any size, if the necessary proportions are strictly observed. hand made, will not have moving parts. It is capable of operating on any type of fuel, if a device is provided for its evaporation before entering the combustion chamber. However, the start is made on gas, since this type of fuel is much more convenient than others. It is easy to build a structure, and it will not take much money. But we must prepare for the fact that the jet engine will work with great noise.

    An evaporating atomizer for liquid fuel is also installed with our own hands. It is placed on the end of a metal tube through which propane enters the combustion chamber. However, if you plan to use only gas, then this device is not necessary to install. You can simply run propane through a 4 mm diameter tube. It is attached to the combustion chamber with a ten millimeter fitting. Sometimes they also provide different pipes for propane, kerosene and diesel fuel.

    At the start, gas enters the combustion chamber, and when the first spark occurs, the engine starts. It is not difficult to acquire cylinders today. Convenient is, for example, having eleven kilograms of fuel. If a high flow rate is expected, the reducer will not provide the required flow. Therefore, in such cases, simply install a needle valve. In this case, the cylinder must not be completely emptied. Then there will be no fire in the tube.

    To install a spark plug, a special hole must be provided in the combustion chamber. It can be made using a lathe. The body is made of of stainless steel.

    Reinst: the necessary details

    It is optional to use metal pipes and other complex details for a common man in the street. If a do-it-yourself jet engine is supposed to be made of a very small size, the following components at hand will be required for its manufacture:

    • a glass jar of four hundred milliliters;
    • can of tin from under condensed milk, from which only the side part is required;
    • alcohol or acetone;
    • compass;
    • scissors;
    • dremel or ordinary awl;
    • pliers;
    • pencil;
    • paper.

    How to make a jet engine

    A twelve millimeter hole is made in the lid of a glass jar.

    For the layout of the diffuser, a template is drawn on paper using a compass. The near radius is taken at 6, and the far radius is taken at 10.5 centimeters. From the sector that turned out, measure 6 cm. Trimming is carried out at the near radius.

    The template is applied to a tin can, circled and the required piece is cut out. From both edges, bend over the millimeter at the resulting part. Next, make a cone and connect parts of the bent edges. This is how a diffuser is obtained.

    Then four holes are drilled on its narrow half. The same is repeated on the lid around the hole made earlier. Using a wire, hang the diffuser under the hole in the cover. The distance to the top edge should be approximately 5 to 5 mm.

    It remains only to pour alcohol or acetone into the jar half a centimeter from the bottom, close the jar and light the alcohol with a match.

    You can also make miniature pulsating jet engines for model aircraft. Some amateurs even today use literature written during the Soviet era, in the sixties of the last century, when installing the motor structure. Despite such a significant period of time since its publication, it continues to be relevant and is able to help young designers acquire new knowledge and practice.

    The valveless pulsating engine is the world's simplest jet engine. Its development was unfortunately put on hold with the start of widespread use of turbojet engines, but it continues to be of interest to hobbyists as it can be built in a home workshop. I built my engine after studying Lockwood's patent that the device can be of any size, subject to certain proportions. The engine has no moving parts, and it can run on any fuel if it is vaporized before entering the combustion chamber (I used a mixture of gasoline and diesel in equal parts), but starting is on gas (this is much easier). The design is simple and relatively inexpensive to repeat. I do not know with what frequency explosions occur in the combustion chamber of my engine, but I guess that this happens about 30-50 times per second, the operation of the device is accompanied by a very strong noise. I hope to measure this frequency someday.

    The engine runs on propane, which enters the combustion chamber through a long metal tube, at the end of which is an atomizer that helps vaporize the liquid fuel. When using propane, a spray is not necessary, in my case the gas flows directly through a 4 mm ID tube. The tube is connected to the combustion chamber with a 10mm fitting. I have made three of these pipes - one for propane, the other two for diesel and kerosene.

    During the starting process, propane is fed into the combustion chamber, and then just one spark on the spark plug is enough to start the engine.

    According to the patent, such a motor of any size can be built. My drawing shows my version of the device, which is slightly different from the design of the exhaust pipe proposed in the patent, which simplifies manufacturing, however, since I did not measure the thrust, this may have affected the efficiency. Flow straighteners usually double the thrust and I'm going to try them.

    Abbreviations in the drawing:

    • NL - nozzle length
    • NM - nozzle diameter
    • CL - Combustion chamber length
    • CM - combustion chamber diameter
    • TL - Tail pipe length
    • TM - Tail pipe diameter

    Gas cylinders can be bought anywhere, I chose the 11 kg, with an industrial connector. I did not use any reducers, I just installed a needle valve, since the gas flow is quite large and a regular reducer will not give the required flow. The chance that the propane in the tube and cylinder will catch fire is very small if the cylinder is not completely emptied. In the pictures below you can see how it looks.

    The spark plug is screwed into a specially made on lathe part welded into the combustion chamber. Any candle can be used, I put the NGK BP6E S without additional resistance, and I used the bobbin from an old car. Also I did electronic circuit to obtain a spark, which needs to be obtained only once, at the time of engine start.

    The pipe body is welded from 316L stainless steel. I didn't know how to calculate the thickness, and just took a thicker sheet with a margin. The engine was started many times and no problems were found.

    Piloting airplanes has become a hobby that has united adults and children from all over the world. But with the development of this entertainment, propellers for mini planes are also developing. The most numerous engine for this type of aircraft is electric. But more recently, jet engines (RD) have appeared in the arena of engines for RC model aircraft.

    They are constantly supplemented by all sorts of innovations and notions of designers. The task before them is rather difficult, but possible. After the creation of one of the first scaled-down engine models, which became significant for aeromodelling, a lot changed in the 1990s. The first turbojet engine was 30 cm long, about 10 cm in diameter and weighing 1.8 kg, but over decades, the designers managed to create a more compact model. If you thoroughly take up the consideration of their structure, then you can reduce the difficulties and consider the option of creating your own masterpiece.

    Taxiway device

    Turbojet engines (TJE) work by expanding the heated gas. These are the most efficient engines for aviation, even mini carbon-fueled engines. Since the inception of the idea of ​​creating an aircraft without a propeller, the idea of ​​a turbine began to develop throughout the society of engineers and designers. The turbojet engine consists of the following components:

    • Diffuser;
    • Turbine wheel;
    • The combustion chamber;
    • Compressor;
    • Stator;
    • Nozzle cone;
    • Guiding apparatus;
    • Bearings;
    • Air intake nozzle;
    • Fuel pipe and more.

    Principle of operation

    The structure of a turbocharged engine is based on a shaft that rotates with the help of the compressor thrust and pumps air with a fast rotation, compressing it and directing it from the stator. Once in a freer space, the air immediately begins to expand, trying to gain the usual pressure, but in the internal combustion chamber it is heated by fuel, which makes it expand even more.

    The only way the pressurized air can escape is through the impeller. With tremendous speed, it strives for freedom, heading in the opposite direction from the compressor, to the impeller, which is spun by a powerful stream, and begins to rotate rapidly, giving traction force to the entire engine. A part of the received energy begins to rotate the turbine, driving the compressor with greater force, and the residual pressure is released through the engine nozzle with a powerful impulse directed to the tail section.

    The more air is heated and compressed, the greater the pressure generated and the temperature inside the chambers. The generated exhaust gases spin the impeller, rotate the shaft and enable the compressor to constantly receive fresh air streams.

    Types of turbojet control

    There are three types of motor control:


    Types of engines for aircraft models

    Jet engines on model aircraft are of several basic types and two classes: air-jet and missile... Some of them are outdated, others are too expensive, but gambling fans of controlled aircraft are trying to try new engine In action. With an average flight speed of 100 km / h, model aircraft only become more interesting for the viewer and the pilot. The most popular engine types differ for driven and bench models, due to different efficiency, weight and thrust. There are few types in aircraft modeling:

    • Missile;
    • Direct-flow air-jet (PRVD);
    • Pulsating air-jet (PURVD);
    • Turbojet (turbojet engine);

    Missile it is used only on bench models, and that is quite rare. Its principle of operation differs from the air-jet. The main parameter here is the specific impulse. Popular due to the lack of the need to interact with oxygen and the ability to work in zero gravity.

    Straight-through burns air from the environment which is sucked from the inlet diffuser into the combustion chamber. The air intake in this case directs oxygen to the engine, which, thanks to internal structure forces to build up pressure at the fresh air stream. During operation, the air approaches the air intake at a flight speed, but in the inlet nozzle it sharply decreases several times. Due to the closed space, pressure is generated, which, when mixed with fuel, splashes the exhaust from the back side at a tremendous speed.

    Throbbing works identically to direct-flow, but in its case, the combustion of fuel is intermittent, but periodic. With the help of valves, fuel is supplied only at the necessary moments when pressure begins to drop in the combustion chamber. For the most part, a pulsating jet engine performs from 180 to 270 fuel injection cycles per second. In order to stabilize the state of pressure (3.5 kg / cm2), forced air supply is used by means of pumps.

    Turbojet engine, the device which you considered above has the most modest fuel consumption, due to which it is valued. Their only drawback is their low weight-to-traction ratio. Turbine engines allow the model to reach speeds of up to 350 km / h, while the idle speed of the engine is kept at 35,000 rpm.

    Specifications

    An important parameter that makes aircraft models fly is thrust. It provides good power to lift large loads into the air. The thrust of the old and new engines is different, but the models created according to the drawings of the 1960s, running on modern fuel, and modernized with modern devices, have a significant increase in efficiency and power.

    Depending on the type of taxiway, the characteristics, as well as the principle of operation, may differ, but all of them need to create optimal conditions... The motors are started using a starter - other motors, mainly electric ones, which are attached to the motor shaft in front of the inlet diffuser, or the start occurs by untwisting the shaft using compressed air supplied to the impeller.

    engine GR-180

    On the example of data from the technical passport of a serial turbojet engine GR-180 you can see the actual characteristics of the working model:
    Traction: 180N @ 120,000rpm, 10N @ 25,000rpm
    RPM range: 25,000 - 120,000 rpm
    Exhaust gas temperature: up to 750 C °
    Jet stream flow rate: 1658 km / h
    Fuel consumption: 585ml / min (under load), 120ml / min (idle)
    Weight: 1.2kg
    Diameter: 107mm
    length: 240mm

    Usage

    The main area of ​​application was and remains aviation focus... Quantity and size different types The turbojet engine for aircraft is stunning, but each of them is special and applied when necessary. Even in model aircraft of radio-controlled aircraft from time to time, new turbojet systems appear, which are presented for general review to spectators of exhibitions and competitions. Attention to its use allows you to significantly develop the capabilities of engines, complementing the principle of operation with fresh ideas.
    In the last decade, parachutists and extreme wingsuit athletes have been integrating mini Turbojet engine as a source of thrust for flight with wing suit wingsuit fabric, in which case the motors are attached to the legs, or hard wing, worn as a backpack on the back, to which the motors are attached.
    Another promising area of ​​use is combat drones for military, at the moment they are actively used in the US Army.

    The most promising direction for using mini turbojet engines is drones for transportation goods between cities and around the world.

    Installation and connection

    Installing a jet engine and connecting it to the system is a complex process. It is necessary to connect the fuel pump, bypass and control valves, tank and temperature sensors into a single circuit. Due to the impact high temperatures flame retardant connections and fuel pipes are commonly used. All is fixed with homemade fittings, a soldering iron and seals. Since the tube can be as large as the head of a needle, the connection must be tight and insulated. Incorrect connection can lead to destruction or explosion of the motor. The principle of connecting the chain on bench and flying models is different and must be carried out in accordance with the working drawings.

    Advantages and disadvantages of the taxiway

    The advantages of all types of jet engines are many. Each of the types of turbines is used for specific purposes, which are not afraid of its features. In aircraft modeling, the use of a jet engine opens the door to overcoming high speeds and the ability to maneuver independently of many external stimuli. Unlike electric and internal combustion engines, jet models are more powerful and allow the aircraft to spend more time in the air.
    conclusions
    Jet engines for aircraft models can have different thrust, mass, structure and appearance... For aircraft modeling, they will always remain indispensable due to their high performance and the ability to use a turbine using different fuels and operating principles. By choosing certain goals, the designer can adjust the rated power, the principle of thrust formation, etc., applying different types turbines for different models. The operation of the engine on combustion of fuel and injection of oxygen pressure makes it as efficient and economical as possible from 0.145 kg / l to 0.67 kg / l, which aircraft designers have always achieved.

    What to do? Buy or do it yourself

    This question is not easy. Since turbojets, whether they are full-scale or scaled-down models, they are technically complex devices. Making from is not an easy task. On the other hand, mini turbojet engines are produced exclusively in the USA or European countries, therefore, their price is on average $ 3,000, plus or minus 100 bucks. So buying a finished turbojet engine will cost you $ 3,500, including shipping and all associated pipes and systems. See the price for yourself, just google "P180-RX turbojet engine"

    Therefore, in modern realities, it is better to approach this matter as follows - what is called to do it yourself. But this is not entirely correct interpretation, rather give the work to contractors. The engine consists of a mechanical and an electronic part. We buy components for the electronic part of the propulsion unit in China, we order the mechanical part from local turners, but this requires drawings or 3D models and, in principle, the mechanical part is in your pocket.

    Electronic part

    The controller for maintaining engine modes can be assembled on an Arduino. To do this, you need a chip flashed with Arduino, sensors - a speed sensor and a temperature sensor and actuators, an electronically controlled fuel flap. You can flash the chip yourself if you know programming languages, or go to the forum for arduino players for a service.

    Mechanical part

    With mechanics, all the parts in theory can be made more and more interesting by turners and milling operators, the problem is that for this you need to look for them specially. It is not a problem to find a turner who will make the shaft and shaft sleeve, but here is the rest. The most difficult part to manufacture is the centrifugal compressor wheel. It is made either by casting. or on the 5-coordinate milling machine... The easiest way to get an impeller centrifugal pump it is to buy it, as a spare part for a turbocharger of an internal combustion engine of a car. And already under it to orient all other details.

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