A scaled model is generally a physical representation of an object, which maintains an accurate relationship between all important aspects of the model, although the absolute value of the original property is unnecessary. It is possible to demonstrate some behavior or properties of the original object without checking the original object. The most recognizable scale model represents the physical appearance of an object in a miniature form, but there are many other types.
Scale models are used in many areas including engineering, architecture, filmmaking, military command, sales, and hobby modeling. Although each field can use scale models for different purposes, all scaled models are based on the same principle and must meet the same general requirements to function. Detail requirements vary depending on the needs of the modeler.
To be a true scale model, all relevant aspects must be accurately modeled, such as material properties, so that model interaction with the outside world can be reliably related to the interaction of the original object with the real world.
Video Scale model
Requirements
In general the scale model should be designed and built especially considering the similitude theory. However, other requirements on practical issues should also be considered.
Similitude Requirements
Similitude is the theory and art of predicting the prototype (original object) performance of the scale model observation. The main requirement of similarity is that all dimensionless dimensions must be the same for both scaled and prototype models under conditions that the modeler wants to make observations. Unlimited quantity is generally referred to as the Pi term, or the term ? . In many fields, the term ? has been well defined. For example, in fluid dynamics, a notable dimensionless number called the Reynolds number often appears in the test of a scale model with a fluid moving relative to a stationary surface. Thus, for reliable scale model tests, the Reynolds number, as well as all other significant dimensionless numbers, should be the same for both scale models and prototypes under the conditions that the modeler wishes to observe.
An example of a Reynolds number and its use in similitude theory satisfaction can be observed in testing fluid flow scale models in a horizontal pipe. The Reynolds number for the scale model pipe should be the same as the Reynolds number of the prototype pipe for measurement of scale model flows to fit the prototype in a meaningful way. This can be written mathematically, with the subscript m referring to the scale model and subscript p referring to the prototype, as follows:
dimana
- adalah kecepatan rata-rata dari objek relatif terhadap cairan (unit SI: m/s)
- adalah dimensi linier karakteristik, (panjang perjalanan fluida; diameter hidrolik ketika berhadapan dengan sistem sungai) (m)
- adalah viskositas dinamis dari cairan (Pa ·s atau N ·s/m² atau kg/(m · s))
- adalah densitas cairan (kg/m³).
Observing the above equation is clear to see that while the Reynolds number must be the same for scale models and prototypes, this can be solved in various ways, for example, in this problem by changing the dynamic viscosity scale of the model to work on a long scale. This means that different quantity scales, such as the elasticity of the material in scale versus prototype models, are arranged by equalizing the dimensionless amount and other quantity scales in dimensionless quantities to ensure an equally dimensionless quantity of interest for scale and prototype models.
Scaling
Denuncia pemahaman atas persyaratan kemiripan, menjadi jelas skala yang sering dilaporkan dalam model skala hanya mengacu pada skala geometrik, (L mengacu per panjang), give bukan skala parameter yang berpotensi penting untuk dipertimbangkan dalam desain dan fabrikasi model skala. Secara umum scala cuantitas apapun i, mungkin kepadatan material atau viskositas, didefinisikan sebagai:
dimana
- adalah nilai cuotitas prototipe
- adalah nilai cuantitas dari model skala
This relationship should be applied to all amounts of interest in the prototype, observing similitude requirements - so scale models can be constructed using dimensions and materials that make meaningful scale model test results with respect to prototypes. One method for determining the amount of unattended attention to a given problem is to use dimensional analysis.
Practical requirements
Practical concerns include the cost of building models, test facilities available to condition and observe the model, the availability of certain materials, and even who will build them. Practical requirements often vary greatly depending on the purpose of the scale model and they should all be considered to have a successful scale model experience.
For example, aerospace companies may need to test new wing forms. In accordance with the similitude requirements, testing should be performed in a wind tunnel that can lower air temperatures up to -128 ° C (-198 ° F), such as Transonic Cryogenic Tunic 0.3 meters (12 inches) at NASA Langley Research Center. However, if such facilities are unusable, perhaps due to cost constraints, the similarity requirements should be loosened or the tests redesigned to accommodate the restrictions.
Maps Scale model
Class
For scale models to represent prototypes in the right way, all dimensions without dimensions, or ? , should be the same for the scale model during the observation and prototype periods under the desired conditions of the modeler. to learn. However, in many situations, design a scale model that equates all the terms ? to the prototype is not possible due to lack of materials, cost limitations, or limitations of testing facilities. In this case, concessions should be made for practical reasons for requirements of similarity.
Depending on the observed phenomenon, it is possible that some dimensionless numbers are unattractive and thus negligible by the modeler and the scale model results can still be assumed to be in accordance with the prototype. This example of fluid dynamics is the fluid flow in a horizontal pipe. Possible ? terms that need to be considered in this situation are Reynolds number, Weber number, Froude number, and Mach number. For this configuration flow, however, no surface tension is involved, so the Weber number is not appropriate. Also, fluid compression does not apply, so the Mach number can be ignored. Finally, gravity is not responsible for flow, so the Froude number can also be ignored. This makes the modeler only with Reynolds numbers to worry about in terms of equalizing values ​​for scale models and prototypes.
In general, scale models can be classified into three classes depending on the level of satisfaction of the similitude they show. To get started, the correct model is one with the complete similarity - that is, all the terms ? is the same for scale models and prototypes. The correct model is difficult to manifest in reality because of the many possibilities that modelers have to think about. Consequently, the modeler identifies an important quantity without dimensions and builds a scale model that satisfies this. An important dimensionless quantity is called the first-order dimension requirement. Models that meet first-order similarity are called adequate models . Finally, for scale models that fail to meet one or more of the first-order requirements, the name distorted model is given.
Example
Scale models are used by many fields for various purposes. Some specific uses of scale models by specific fields are described below in the example.
Structural scale model
Although structural engineering has been a field of study for thousands of years and many major problems have been solved using analytical and numerical techniques, many problems are still too complicated to be understood analytically or numerical techniques today have no real-world confirmation. When this happens, for example the complicated reinforced concrete beam-colum interaction problem, the scale model can be constructed by observing the similarity requirements to study the problem. Many structural laboratories exist to test structural-scale models such as Newmark's Civil Engineering Laboratory at the University of Illinois, UC.
For structural engineering scale models, it is important for certain amounts to be increased according to the theory of similarity. This amount can be grouped into three categories: loading , geometry , and material properties . A good reference for considering the scale for the structural scale model under static loading conditions in the elastic regime is presented in Table 2.2 of the book Structural Modeling and Experimental Techniques .
Structural engineering scale models can use different approaches to meet the requirements of similarity of scale modeling and testing models. A practical introduction to the scale of model design and testing is discussed in the paper "Pseudodynamic Testing of the Scale Model".
Aircraft model
The model aircraft is divided into two main groups: static and flying models.
Plane static model
Static model aircraft are generally built using plastics, but wood, metal, card and paper can also be used. Model sold is painted and assembled, painted but not assembled (snap-fit), or not painted and not assembled. The most popular types of aircraft for the model are commercial aircraft and military aircraft. Aircraft can be modeled in many "scales". Scale notation is a model size compared to the actual size, full-size aircraft called "prototype". Scale 1: 8 will be used as an example; read as: "1 inch (or any measurement) on the model is the same (: means the same) up to 8 inches on the real plane (prototype)". Sometimes scale notation is not used; it simply states: "my model is an eighth scale (1/8)", which means "my model is eighth the size of a real plane" or "my model is eight planes as big as a real plane". The popular scales are, in order of size, 1: 144, 1:72 (at most), 1:48, 1:32, 1:24, 1:16, 1: 8 and 1: 4. Some European models are available on a more metric scale like 1:50. The highest quality models are made of cast or injected molded cast resin. Models made of vacuum-shaped plastic are generally for more skilled builders. The cheaper models are made of thick paper or stock cards. Ready-made die-cast metal models are also very popular. As well as traditional scale, die-cast models are available on a 1: 200, 1: 250, 1: 350, 1: 400, and 1: 600 scale.
This scale is usually reserved for civilian aircraft. Static-scale plane models fall widely into three categories: kit assembly, initial excavation, and collection of ready-made models. Early makers tend to be the top echelons of skills and expertise. They tend to be the sharpest in terms of accuracy and detail and they spend more time on far less models than the assembler kit.
The kit assembly is divided into two categories: OOB (Out of box) and modified. Out of Box refers to the act of assembling the kit only from what is contained in the box provided, while Modifier uses after-market products such as alternative decals, detailed metal parts of photo engraved, and detailed resin or conversion parts prints to enhance or change the model in several ways. The collectors are concerned about the theme issues, and are not particularly interested in such personal constructions.
Aircraft modelers often fall into more than one category, because luxury takes them. Most aircraft modelers pay attention to themselves with real-life plane depictions, but there are smaller modeler cadres who gain extra pleasure by 'bending' history a little by making models of aircraft that never really fly or exist, or by painting them in schemes the actual color does not exist. This is usually referred to as' What-if 'or' Alternative 'modeling, and the most common themes are' Luftwaffe 1946 'or' Luftwaffe '46'. This theme stems from the idea of ​​modeling a secret German project that never saw the light of day because of the closure of World War II. This concept has been extended to include British, Russian, and US experimental projects that never make it into production.
Flying model plane
The flying model aircraft consists of two types: those built for aerodynamic research and for recreation or aeromodeling.
Aerodynamic models can be constructed for use in wind tunnels or in free flight. Small scale driven aircraft are even built to test some aspects of the proposed full size design, but these are not considered models although they may be accurate to scale.
Recreational models are often made to resemble some real types. However the aerodynamic requirements of the small model differ from the full-size model, so the flying model is rarely fully accurate to scale. Most flying model aircraft can be placed in one of three groups: free flight, control lines and radio controlled. Fly models can be built from scratch or from kits. Some kits take hours to unite and some kits are almost ready to fly or ready to fly.
Relief plans
With elements similar to miniature wargaming, building models and architectural models, aid plans are a means of geographic representation in aid as a scale model for military use, to visualize development projects in fortresses or campaigns involving fortifications.
Model building
Most fans who build the building model do so as part of the diorama to improve their other models, such as model trains or model war machines. As a stand-alone hobby, the building model may be most popular amongst the toy construction enthusiasts like Erector, Lego and K'Nex. Famous landmarks such as the Empire State Building, Big Ben, and the White House are common subjects. Standard scales do not appear in this hobby yet. Train models use the railway scale for their buildings: HO scale (1: 87), OO scale (1: 76), N scale (1: 160), and O scale (1:43). The Lego maker uses the miniland scale (1:20) and the minifig scale (1:48) and the micro scale (1: 192) Generally, the larger the building, the smaller the scale. Model buildings are usually made of plastic, foam, balsa wood or paper. Card models are published in book form, and some models are made like 3-D puzzles. Professionally, the building model is used by architects and salesmen.
Architecture model
Architectural companies usually hire model makers or contract modeling companies to create project models to sell their designs to builders and investors. These models are traditionally handmade, but technological advances have turned the industry into a very high tech process than it could involve a Class IV laser cutter, a five-axis CNC machine as well as rapid prototyping or 3D printing. The typical scale is 1:12, 1:24, 1:48, 1:50, 1: 100, 1: 200, 1: 500, etc.
House portrait model
Usually found on a 1:50 scale and also called a model house, model house or displayhouse, this type of model is usually found in magnificent houses or specially designed homes. Sometimes such models are assigned to mark special dates such as birthdays or architectural completions, or this model may be used by sellers who sell homes in new environments.
Bus and truck models
Usually found on a 1:50 scale, most commercial vehicle manufacturers and commission-scale heavy-duty models are made of die-cast metal as promotional items to be given to potential customers. These are also popular children's toys and collectibles. The main producers of these goods are Conrad and NZG in Germany. Corgi also made several models of 1:50, as well as the makers of Dutch Techno.
Trucks are also found as diecast models on a 1:43 scale and injection molding kits (and children's toys) on a scale of 1:24. Recently some manufacturers have appeared on a 1:64 scale like Code 3.
Car model
Although the British scale for measuring 0 was first used for model cars made of rectilinear and circular sections, it is the origin of the European scale for cast car cast or injection models. The 1:45 scale MOROP specification for Europe 0 does not change the series of cars on a 1:43 scale, as it has the widest distribution in the world.
In America, a series of cars developed from the first cast metal models and then styrene ("promos") offered at new car dealerships to liven up interest. The company's monogram, and then Tamiya, first produced them on a scale derived from the Architect's scale: a 1:24 scale, while AMT, Jo-Han, and Revell firms chose the 1:25 scale. The monogram then switched to this scale after the company was bought by Revell. Some cars are also made on a 1:32 scale, and rolling toys are often made on a 1:64 scale scale. Chinese die-cast manufacturers have introduced the 1/72 scale into their range. Smaller scales are usually die-cast cars and not in the classroom as model cars. Except on rare occasions, Johnny Lightning and Ertl die-cast cars are sold as kits for buyers to assemble.
The car model is also used in car design.
Model of construction vehicles
A model construction vehicle (or engineering vehicle) is a scale model or a die-cast toy that represents a construction vehicle such as bulldozer, excavator, crane, concrete pump, backhoe, etc.
The model of a construction vehicle is almost always made on a 1:50 scale, mainly because the crane on this scale is usually three to four feet when the extended and larger scales are not suitable for display on a desk or table. These models are popular as children's toys in Germany. In the US they are generally sold as promotional models for new construction equipment, commissioned by real-world prototype equipment manufacturers. The main producers in Germany are Conrad and NZG, with some competition from Chinese companies that have entered the market.
Model train
The train model comes in a variety of scales, from 1: 8 on the big end and 1: 450 (T scale) on small. Each scale has its own strengths and weaknesses, and fills a different niche in the hobby. The largest model is 3 meters (9.8 feet) long, the smallest few centimeters. The most popular sizes are the HO scale (1: 87) and the second is the N scale (1: 160).
Model trains initially use the term gauge , which refers to the distance between the rails, as do the full-length train tracks. Although the model trains are also built for different gauges, the "standard size" in a 1: 1 scale rail scale is 4 '8.5 ".Thus therefore, model trains reduce the standard to scale.A model of the HO will have a 1/87 line of 4 '8.5 ", or about 0.65" from rail to rail. It is now more common to refer to the scale of the model, and the term scale has replaced the "gauge" in most uses. regardless of the confusion between states as with the definition of scale 0 and scale N.
The confusion often arises when it refers to "scale" and "measure", especially since words are sometimes used interchangeably. The word "scale" refers to the proportional size of the model; the word "gauge" applies to the measurement between the inner parts of the rail face. To highlight these differences, consider the various gauges used in the HO scale; The 16.5 mm size is used to represent the "standard gauges" 4Ã, ftÃ, 8 1 / 2 in ( 1,435 mm ) (HO scale), size 12 mm is used to represent 1,000 mm ( Measurement 3Ã, ftÃ, 3 8 in ) (HOm) and 3Ã, ftÃ, 6Ã, in ( 1,067Ã, mm ) gauges (HOn3-1/2) and size 9 mm are used to represent the prototype gauge 2Ã, ft ( 610Ã, mm ). It is completely incorrect to refer to the general scale as "HO gauge", "N gauge" or "Z gauge"
The most popular scale to go with a given meter is often lowered in the following roundabout process. German craftsmen will take strips of standard metric metric sizes to make things for blueprints whose dimensions are in inches: then "4 mm to feet" yields a 1: 76.2 size of "OO scale". The British scale is anomalously used on a standard HO/OO scale (16.5 mm gauge of 3.5 mm/ft), but because the earliest electric motors are not commercially available in smaller sizes.
There are three different standards for the "O" scale, each of which uses 32 mm tracks for standard gauges. The American version continues the dollhouse scale 1:48. Sometimes called a "quarter-gauge", like "a quarter of an inch to a foot". The English version continues the sub-contract pattern to Germany; so, at 7 mm to the foot, it works to a 1: 43.5 scale. Then, MOROP, the European authority of the model railroad company, stated that the "O" meter (still 32 mm) should use a 1:45 scale. That is, in Europe the dimensions under-chassis should be slightly toward 4 feet 6 inches, to allow cleaning of the smaller wheel/tire/splasher than the realistic curve part.
The "Live steam" trains, which people ride, are built on multiple scales, such as 1-1/2 ", 1", and 3/4 inches to the foot. Common gauges are 7-1/2 "(West US) and 7-1/4" (East US & worldwide), 5 ", 4-3/4". Smaller live vapor gauges do exist, but as the scale gets smaller, attractiveness decreases. One of the smallest gauges in which a live steam engine can attract passengers is a 2-1/2-inch gauge almost dead now.
Model robot
Japanese companies have marketed toys and models of what are often called mecha, robotic humanoid fighters. Robots, which appear in animated shows (anime), are often depicted with sizes between 15-20m, so the 1: 100 and 1: 144 scales are common to this subject, although other scales like 1: 72 are commonly used for robots and subjects related to different sizes.
The most productive producer of the mecha models is Bandai, whose line of gundam kits greatly influenced the genre in the 1980s. Even today, Gundam devices are the most numerous in the mecha modeling genre, usually with dozens of new releases each year. The features of modern Gundam kits, such as color printing and snap-fit ​​construction, have become standard expectations for other mecha kit models.
Due to the fantasy nature of most anime robots, and the simplicity of cel-animation designs required, mecha models lend themselves to simple work styles, improvisations, and scratches. One of Gundam's contributions to this genre is the use of wartime backstory as part of the fantasy, and so it is almost equally fashionable to build robots in a beat-up, beaten style, as is often expected for AFV kits to build it in a more stylish and pure fashion.
Rocket models and spacecraft
The rocket kit model started as a model airplane development, but the 1: 72 scale [V.close to 4 mm.::1foot] was never caught. Scales 1:48 and 1:96 are used. There are several scale rockets 1: 128, 1: 144, and 1: 200, but Russian firms are installing their large rockets at 1:28. Heller SA offers several models on a 1: 125 scale.
The science fiction space ships are very popular in the modeling community. Models based on ships from franchises such as Star Trek, Star Wars and Battlestar Galactica are regularly sold and made on a scale ranging from 1:24 to warriors and smaller vessels to 1: 1000, 1: 1400, and 1: 2500 for most major franchise vessels, and up to 1: 10,000 for larger Star Wars vessels (especially objects such as Death Star and Super Star Crushers, smaller scales are used). Finemolds in Japan recently released a series of high quality injection made Star Wars kits at 1: 72, and this range comes with a resin kit from Fantastic Plastic.
Model of living creatures
Models of human and animal scales are found in various places, and may be single objects or kits that must be assembled, usually depending on the model's purpose. For example, models of both domestic and wild animals are often produced to be displayed in model cities or railroads to provide a measure of detail or realism, and relative scales to trains, buildings, and other accessories of a particular line of models. If rail or building lines do not show models of living things, those who make models often purchase these items separately from other lines so they can show people or animals. In other cases, the scale model scale displays living creatures exclusively, often focusing on educational interests.
Models of living things that require assembly are not as common as a one-part unit, but of course are unheard of. One of the most productive types of kits that require assembly featuring living things is the model of human and animal skeletons. Like their one-part counterparts, such devices are often cited as educational activities. Skeleton kits often have unique features such as glow-in-the-dark pieces or attachable internal organs. Again, dinosaurs are a popular subject for such models. There are also garage kits, which often become characters of anime characters in some parts that require assembly.
In the first half of the 20th century, the navy used a model of handmade warships for identification and instruction at various scales. That 1: 500 is called "teacher scale." In addition to models made on a 1: 1200 and 1: 2400 scale, others are made for 1: 2000 and 1: 5000. Some, made in the UK, are labeled "1 inch to 110 feet", which would be 1: 1320 scale , but not always accurate.
Michele Morciano says small-scale ship models were produced around 1905 linked to wargaming and other publications of Fred T. Jane. The company standardized at 1: 1200 was Bassett-Lowke in 1908. The British Navy subsequently contracted with Bassett-Lowke and other companies and individual craftsmen to produce a large number of recognition models, for this scale, in 1914-18.
Just before the Second World War, the American naval historian (and science fiction writer) Fletcher Pratt published a book on marine wargaming as civilians could use a water-cut ship model to be moved on the floor of a basketball court and the like. local. The scale used is not standardized (reported 1: 666), and may be influenced by the available toy boats, but as the hobby develops, and other rule tools are being used, it is increasingly added by the 1: 600, 1: 1200, and 1: 2400. In the UK, 1: 3000 became popular and these models also began to be used in the US. It has the advantage of approaching nautical miles as 120 inches, 60 inches, and 30 inches, respectively. Because the knot is based on this mile and 60 minutes, this is quite useful.
After the war, the company appeared to produce models of the same white metal used to make toy soldiers. One UK company offers a very broad line of shipbuilding and shipbuilding equipment on a 1: 1200 scale. In the US, at least one producer, from the 1: 1200 warfare recognition model, makes it available for the post-war civil market, which also drives the change to this scale. In addition, continental European manufacturers and European flagship book publishers have adopted a 1: 1250 image scale because of its similar convenience in sizes to both models and comparative images in the book.
The prestige scale for ships, comparable to 1:32 for fighter aircraft, is 1: 72, yielding large models, but there are very few kits that are marketed on this scale. Now there are several clubs around the world for those who choose to scratch models of radio-controlled boats and submarines at 1: 72, which is often done due to compatibility with navy aircraft equipment. For smaller vessels, board-in-frame or other wood construction tools are offered in traditional ship scales from 1:96, 1: 108, or 1: 192 (half of 1:96). In an injection-molded plastic kit, Airfix created a full-hull model on a scale used by the Royal Navy to compare the ship's relative size: 1: 600. Revell made several kits up to half the US Army's standard scale: 1: 570. Some American companies and foreigners have made models in proportion of the Engineer scale: "one-sixty inches-inch-to-feet", or 1: 720.
Manned vessel models
Many research workers, hydraulics specialists, and engineers have been using scale models for more than a century, especially in tank pullers. The manned model is a small-scale model that can carry and be handled by at least one person on an expanse of open water. They must behave like a real ship, giving the same sensation to the ship's passengers. Physical conditions such as wind, currents, waves, water depths, canals and berths must be reproduced realistically.
Manned models are used for research (eg ship behavior), techniques (eg port layout) and for training in ship handling (eg maritime pilots, masters and officers). They are usually on a 1:25 scale.
Tank model and wargaming
Just before the twentieth century, the English historian (and the great science fiction author and forgotten novelist) H. G. Wells published a book, Little Wars, on how to play in combat in miniatures. Her books use the 54 mm numbers, especially those produced by Britains. The fighting system uses a spring-type rifle that fires matches.
The use of this physical mechanism is echoed in the game of Fred Jane, whose rules require throwing an arrow into the silhouette of a ship; a collection of data about the world's fleet was then published and became famous. Dice has replaced this toy mess for consumers.
For more than a century, toy soldiers are made of white metal, lead-based alloys, often in scale-based architect ratios in English-speaking countries, and are called tin soldiers. After the Second World War, such toys were sold in the market for children but now made of plastics safer than styrene. American children call this "men's army". Many sets are made on a new scale of 1:40. Some styrene models of soil kit kits are offered on this scale and on a 1:48 and 1:32 scale. However, this is drifted by the number of kits on a 1:35 scale.
Those who continue to develop wargaming miniatures prefer a smaller scale model, the soldiers are still made of soft plastic. Airfix especially wants people to buy 1.76 army and tank scales to go with the "00" train equipment. Roco offers 1.87 styrene-style military vehicles to go with model houses "HO". However, although there is no 1:72 scale train model, more toy soldiers are now offered on this scale as it is the same as the popular aircraft scale. The number of combat vehicles on this scale is also increasing, although the number of available additional vehicles is much less than the 1.87 scale.
More recent developments, especially in terrestrial combat, are miniature 15 mm white metals, often referred to as 1: 100. The use of 15 mm metals has grown rapidly since the early 1990s as it allows more affordable options above 28 mm if the battle large must be repaired, or a large number of vehicles represented. The rapid increase in detail and quality of castings on a 15 mm scale has also helped trigger their uptake by the wargaming community.
Soldiers are still using a smaller scale. The US Army sets a 1: 285 scale model for its sand field game. There are metallic ground vehicles and helicopters on this scale, which are close to the "quarter inch to six foot" scale. The NATO continent's strength has developed a similar scale of 1: 300, although the metric standards really dislike dividers in addition to factors 10, 5, and 2, so maps are not commonly offered in Europe on a scale with i> "3" in denominator.
Consumer wargaming has since evolved into a fantasy sphere, using a scale large enough to be painted in imaginative detail - the so-called "heroic" 28 mm, (approximately 1:64, or S scale). The company that produces this produces a lot of white metal.
As an alternative to commercial models, some modelers also tend to use snippets to achieve a homemade warfare model. While not always involving wargaming, some modelers incorporate realistic procedures, allowing certain realisms such as firing a weapon or a deflection of a shell on a small scale model.
Model engine
Kit for building machine models available, especially for children. The most popular are internal combustion engine models, steam, jet, and stirling. Usually they move using electric motors or hand crank, and many of them have transparent cases to show the internal processes in action.
Thumbnail in contemporary art
Source of the article : Wikipedia
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