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Rotary Engine
The rotary engine is an early type of internal combustion engine, usually designed with an odd number of cylinders per row in a radial configuration. The engine's crankshaft remained stationary in operation, while the entire crankcase and its attached cylinders rotated around it as a unit. Its main application was in aviation, although it also saw use in a few early motorcycles and automobiles. This type of engine was widely used as an alternative to conventional inline engines ( straight or V) during World War I and the years immediately preceding that conflict. It has been described as "a very efficient solution to the problems of power output, weight, and reliability". By the early 1920s, the inherent limitations of this type of engine had rendered it obsolete. Description Distinction between "rotary" and "radial" engines A rotary engine is essentially a standard Otto cycle engine, with cylinders arranged radially around a central crankshaft just like a conventional ra ...
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Monosoupape Engine
The ''Monosoupape'' ( French for single-valve), was a rotary engine design first introduced in 1913 by Gnome Engine Company (renamed Gnome et Rhône in 1915). It used a clever arrangement of internal transfer ports and a single pushrod-operated exhaust valve to replace the many moving parts found on more conventional rotary engines, and made the ''Monosoupape'' engines some of the most reliable of the era. British aircraft designer Thomas Sopwith described the ''Monosoupape'' as "one of the greatest single advances in aviation". Produced under license in both seven and nine-cylinder versions in large numbers in most industrialized countries including Germany (by Oberursel), Russia, Italy, Britain and the US. Two differing nine-cylinder versions were produced, the 9B-2 and 9N, with differing displacements giving the larger displacement 9N version a nearly-cylindrical shaped crankcase, with the 9N also adopting a dual ignition system for increased flight safety. 2,188 units we ...
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Kill Switch
A kill switch, also known as an emergency stop (E-stop), emergency off (EMO) and as an emergency power off (EPO), is a safety mechanism used to shut off machinery in an emergency, when it cannot be shut down in the usual manner. Unlike a normal shut-down switch or shut-down procedure, which shuts down all systems in order and turns off the machine without damage, a kill switch is designed and configured to abort the operation as quickly as possible (even if it damages the equipment) and to be operated simply and quickly (so that even a panicked operator with impaired executive functions or a bystander can activate it). Kill switches are usually designed to be noticeable, even to an untrained operator or a bystander. Some kill switches feature a removable, protective barrier against accidental activation (e.g. a plastic cover that must be lifted or glass that must be broken), known as a mollyguard. Kill switches are features of mechanisms whose normal operation or foreseeable ...
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Throttle
A throttle is the mechanism by which fluid flow is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' has come to refer, informally, to any mechanism by which the power or speed of an engine is regulated, such as a car's accelerator pedal. What is often termed a ''throttle'' (in an aviation context) is also called a thrust lever, particularly for jet engine powered aircraft. For a steam locomotive, the valve which controls the steam is known as the regulator. Internal combustion engines In an internal combustion engine, the throttle is a means of controlling an engine's power by regulating the amount of fuel or air entering the engine. In a motor vehicle the control used by the driver to regulate power is sometimes called the throttle, accelerator, or gas pedal. For a gasoline engine, the throttle most commonly regulates the amount ...
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Gyroscopic Precession
Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In other words, if the axis of rotation of a body is itself rotating about a second axis, that body is said to be precessing about the second axis. A motion in which the second Euler angle changes is called ''nutation''. In physics, there are two types of precession: torque-free and torque-induced. In astronomy, ''precession'' refers to any of several slow changes in an astronomical body's rotational or orbital parameters. An important example is the steady change in the orientation of the axis of rotation of the Earth, known as the precession of the equinoxes. Torque-free Torque-free precession implies that no external moment (torque) is applied to the body. In torque-free precession, the angular momentum is a constant, but the angular velocit ...
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Bentley BR2
The Bentley B.R.2 was a nine-cylinder British rotary aircraft engine developed during the First World War by the motor car engine designer W. O. Bentley from his earlier Bentley BR.1. Coming as it did near the end of the war, the BR.2 was built in smaller numbers than the earlier BR.1 – its main use being by the Royal Air Force in the early 1920s. Design and development The initial variant of the BR.2 developed , with nine cylinders measuring for a total displacement of 1,522 cubic inches (24.9 L). It weighed , only more than the Bentley B.R.1 (A.R.1). This was the last type of rotary engine to be adopted by the RAF – later air-cooled aircraft engines such as the Cosmos Jupiter and Armstrong Siddeley Jaguar being almost entirely of the fixed radial type. With the BR.2, the rotary engine had reached a point beyond which this type of engine could not be further developed, due to its inherent limitations. Applications The type selected as the standard single-seat fighter o ...
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Gnome Monosoupape
The ''Monosoupape'' (French for single-valve), was a rotary engine design first introduced in 1913 by Gnome Engine Company (renamed Gnome et Rhône in 1915). It used a clever arrangement of internal transfer ports and a single pushrod-operated exhaust valve to replace the many moving parts found on more conventional rotary engines, and made the ''Monosoupape'' engines some of the most reliable of the era. British aircraft designer Thomas Sopwith described the ''Monosoupape'' as "one of the greatest single advances in aviation". Produced under license in both seven and nine-cylinder versions in large numbers in most industrialized countries including Germany (by Oberursel), Russia, Italy, Britain and the US. Two differing nine-cylinder versions were produced, the 9B-2 and 9N, with differing displacements giving the larger displacement 9N version a nearly-cylindrical shaped crankcase, with the 9N also adopting a dual ignition system for increased flight safety. 2,188 units w ...
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Two-stroke Engines
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of the crankshaft. A four-stroke engine requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust (or scavenging) functions occurring at the same time. Two-stroke engines often have a high power-to-weight ratio, power being available in a narrow range of rotational speeds called the power band. Two-stroke engines have fewer moving parts than four-stroke engines. History The first commercial two-stroke engine involving cylinder compression is attributed to Scottish engineer Dugald Clerk, who patented his design in 1881. However, unlike most later two- ...
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Total-loss Oiling System
A total-loss oiling system is an engine lubrication system whereby oil is introduced into the engine, and then either burned or ejected overboard. Now rare in four-stroke engines, total loss oiling is still used in many two-stroke engines. Steam engines Steam engines used many separate oil boxes, dotted around the engine. Each one was filled before starting and often refilled during running. Where access was difficult, usually because the oil box was on a moving component, the oil box had to be large enough to contain enough oil for a long working shift. To control the flow rate of oil from the reservoir to the bearing, the oil would flow through an oil wick by capillary action, rather than downwards under gravity. On steamships that ran their engines for days at a time, some crew members would be "oilers" whose primary duty was to continuously monitor and maintain oil boxes. On steam locomotives, access would be impossible during running, so in some cases centralised mec ...
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Power-to-weight Ratio
Power-to-weight ratio (PWR, also called specific power, or power-to-mass ratio) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power source. It is also used as a measurement of performance of a vehicle as a whole, with the engine's power output being divided by the weight (or mass) of the vehicle, to give a metric that is independent of the vehicle's size. Power-to-weight is often quoted by manufacturers at the peak value, but the actual value may vary in use and variations will affect performance. The inverse of power-to-weight, weight-to-power ratio (power loading) is a calculation commonly applied to aircraft, cars, and vehicles in general, to enable the comparison of one vehicle's performance to another. Power-to-weight ratio is equal to thrust per unit mass multiplied by the velocity of any vehicle. Power-to-weight ...
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Aerodynamics
Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics. The term ''aerodynamics'' is often used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the modern sense in the eighteenth century, although observations of fundamental concepts such as aerodynamic drag were recorded much earlier. Most of the early efforts in aerodynamics were directed toward achieving heavier-than-air flight, which was first demonstrated by Otto Lilienthal in 1891. Since then, the use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, and computer simulations has formed a rational basis fo ...
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