|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
MODELING
Solar engines for models. Tips for a modeller
Directory / Radio control equipment When working on a model - be it a ship or an aircraft model - the young designer has to solve many questions, and one of them is what engine to install. The simplest is mechanical, powered by the energy of a stretched rubber band or twisted steel spring. Miniature electric motors powered by chemical sources (batteries or accumulators) and miniature internal combustion engines are more complex designs. Along with advantages, each of these drives has disadvantages. In fact, engines that use the energy of stretched rubber or a twisted spring must be restarted every time the model is stopped. Electric motors also work for a short time. The batteries or accumulators run out and the model stops. Internal combustion engines require even more attention. And it's all about fuel. There is fuel - the model is moving, no - it stops. But there is another, perhaps already forgotten, method of driving models. It does not require any mechanical energy storage, no chemical sources, no gasoline. On a hot day, direct sunlight heats up the surface of the soil, roofs of houses, and asphalt of roads. Invisible heat rays heat the air and water, and all this is nearby, around us. Energy that can drive various mechanisms. Today we offer to get acquainted with three unusual engines. Without consuming fuel, each of them can produce useful work. But don’t think that they are perpetual motion machines. The secret of their performance is simple. The shaft is rotated by the energy of the sun's rays. Unlike most known solar installations, in which solar energy is converted into mechanical energy only with the help of intermediate devices, in these engines the light-rotation conversion cycle is carried out in one installation. Let's consider the simplest solar engine, the design of which was proposed by the inventor D. Pasechnyuk. Look at the picture. A cylindrical vessel, painted black on the outside, is mounted on a rigid stand. Holes of different diameters are cut in the end parts. Inside, on the side of the larger hole, a rotor with two multi-bladed wheels is inserted. The blades in them are inclined in the same direction and at the same angle. The rotor shaft rotates on bearings.
This is how Pasechnyuk’s engine works. The sun's rays falling on the black surface of the vessel heat the air inside it. The pressure in the vessel increases, and it acts equally from the inside on both wheels. But the wheels have different diameters. Therefore, the torque of the large wheel will be greater than the torque of the small wheel. The blades of a large wheel, reminiscent of fan blades, will begin to continuously pump out some of the heated air from the vessel. But nature does not tolerate a vacuum, so at the same time, cold air from the atmosphere will be sucked into the vessel through the small wheel. Inside, it will heat up and come out again, but from the opposite end. So, like a fan, this fuel-free engine works. You can make such an engine quite quickly. A tin can with a capacity of 4-5 liters, for example, tomato paste, is suitable as a vessel. Carefully cut a hole with a diameter of 60-80 mm in one bottom. Remove the contents of the jar. Rinse the interior walls thoroughly. In the other bottom, cut a hole with a diameter of 30-40 mm. Paint the jar black. Take a flat copper tube. Solder tin blades to it. Insert the rotor with blades inside the vessel. Put the bearings on it and fix them on the supports. The engine is ready. The engine designed by T. Burov has an efficiency. slightly higher than that of D. Pasechnyuk's engine. As a working substance, it uses not air, but water. Look at the picture. Its operating principle is based on changes in the elasticity of water vapor under the influence of heating and cooling. Consider a closed system consisting of two cans connected to each other by a tube. For example, the top one. Here, one can is in the shade under the protection of the screen, and the other is illuminated by the sun's rays. The rays heat the black surface of the wall. The temperature of the water in the jar rises. The water begins to evaporate and the pressure in the jar increases. According to the law of communicating vessels, the pressure in both the heated and still cold jars will tend to balance. Under the influence of excess pressure, part of the liquid from the heated can will be forced through the tube into the cold one. Redistribution of water in the vessels will lead to an unbalanced state in which the left side of the rotor will be heavier than the right. The rotor will begin to rotate.
Such an engine can also be made from scrap materials. Take tin cans, for example condensed milk. Make a hole on the side. Drain the contents and rinse the jar. Make another hole on the opposite side. Then take copper tubes 350 mm long. Drill holes in them at each end for a length of 60 mm. Bend the tubes in the middle and insert the ends into the jars. Carefully solder the places of entry and exit of the tubes from the cans with a thick layer of solder. Paint the jars black. Pour 400 cm3 of water into the jars through one of the open ends of the tube. Use wire cutters to squeeze the ends of the tubes, and solder the flattened joints. The rotor is assembled from three to four pairs of cans connected in this way. Solder the bending points to the copper shaft. Place a protective cardboard screen on top. The engine is ready to work. Set the axis of rotation of the rotor so that the sun's rays illuminate the surface of all cans located on the right side. The rotor will begin to rotate counterclockwise. To adjust the shadow, the screen can be made rotating and placed at an angle, as shown in the figure. This will improve engine performance. By moving the screen to one side or the other, you can change the direction of rotation of the rotor. The power of T. Burov's engine can be significantly increased if a two- and even three-row design of large-capacity tin cans is used. The jars must be positioned so that each of them (of course, on the uncovered side) is evenly heated by the sun's rays. Unlike the two solar engines already discussed, the last, third, is more efficient. His project was proposed by American scientists. The operating principle of this engine resembles the operation of an internal combustion engine. It has both a cylinder and a piston, but only the upper cavity above the working piston has a larger volume. He also has another piston, called the displacer. True, it is more like a filter than a piston. The top of the displacer is covered with wire mesh painted black. In the body it has a vertical conical drip, clogged with thin copper wire. Both the piston and the displacer are attached by rods to the crankshaft on which the flywheel is mounted. The working fluid in this engine is air, which is almost transparent to thermal sunlight. To understand how an engine works, let's first consider the position when the displacer is at the bottom and the piston is at top dead center. Thermal rays, freely passing through the transparent dome, fall on the grid. It absorbs heat energy and heats up. Together with it, the air is heated, filling the space between the dome and the mesh. As the air heats up, it presses against the walls of the cylinder with greater force. Atmospheric pressure acts on the working piston from below, and excess pressure acts on it from above at this moment. As a result, the working piston will move down, and the displacer - up. The heated air passes freely through the metal filter of the displacer and gives off part of its heat to the copper wire. In the increased volume of the working chamber, the temperature, and therefore the air pressure, will decrease. Now the working piston is exposed to atmospheric pressure from below, which is slightly higher than the pressure inside the working chamber. The piston begins to move up and the displacer down. Cooled air from the working chamber passes through a heated copper wire, is heated and fills the space under the dome. The engine returns to its original state and the cycle repeats.
The efficiency of such an engine is small. It can be increased by using a system of optical lenses or mirrors to concentrate the energy of the light flux. Efficiency will increase. and if you use double glazing of the dome to reduce heat loss to the surrounding space or use water cooling to increase the temperature difference in the working chamber. In order to obtain one horsepower using an engine of a similar design, it is necessary to focus on a transparent dome the luminous flux “collected” from the surface of a mirror measuring approximately one square meter. So, three solar engines. With their help you can get power from hundredths to one horsepower! Where can I use it? Of course, both the first and second engines, as they are simpler to manufacture, can be used on ship and car models. On a clear sunny day, without consuming a single gram of fuel, they will be able to rotate not only the drive wheels of toy cars, trucks and tractors, but also the propellers and blades of model boats, boats and ships. It is important to correctly manufacture the engine with any predetermined dimensions. Author: V.Zavorotov
A New Way to Control and Manipulate Optical Signals
05.05.2024 Primium Seneca keyboard
05.05.2024 The world's tallest astronomical observatory opened
04.05.2024
▪ Quantum teleportation over urban fiber ▪ Depression and anxiety change brain volume ▪ Atmospheric nitrogen battery
▪ site section Clocks, timers, relays, load switches. Article selection ▪ article Social Pedagogy. Crib ▪ article Cotton. Legends, cultivation, methods of application ▪ article Typographic inks. Simple recipes and tips
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
We recommend interesting articles Section 
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page