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Elevation (ballistics)
In ballistics, the elevation is the angle between the horizontal plane and the axial direction of the barrel of a gun, mortar or heavy artillery. Originally, elevation was a ''linear'' measure of how high the gunners had to physically lift the muzzle of a gun up from the gun carriage to compensate for projectile drop and hit targets at a certain distance. Until WWI Though early 20th-century firearms were relatively easy to fire, artillery was not. Before and during World War I, the only way to effectively fire artillery was plotting points on a plane. Most artillery units seldom employed their guns in small numbers. Instead of using pin-point artillery firing they used old means of " fire for effect" using artillery en masse. This tactic was employed successfully by past armies. By World War I, reasonably accurate artillery fire was possible even at long range requiring significant elevation. However, artillery tactics used in previous wars were carried on, and still had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ballistics
Ballistics is the field of mechanics concerned with the launching, flight behaviour and impact effects of projectiles, especially ranged weapon munitions such as bullets, unguided bombs, rockets or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance. A ballistic body is a free-moving body with momentum which can be subject to forces such as the forces exerted by pressurized gases from a gun barrel or a propelling nozzle, normal force by rifling, and gravity and air drag during flight. A ballistic missile is a missile that is guided only during the relatively brief initial phase of powered flight and the trajectory is subsequently governed by the laws of classical mechanics; in contrast to (for example) a cruise missile which is aerodynamically guided in powered flight like a fixed-wing aircraft. History and prehistory The earliest known ballistic projectiles were stones and spears, and the throwing stick. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artillery Battery
In military organizations, an artillery battery is a unit or multiple systems of artillery, mortar systems, rocket artillery, multiple rocket launchers, surface-to-surface missiles, ballistic missiles, cruise missiles, etc., so grouped to facilitate better battlefield communication and command and control, as well as to provide dispersion for its constituent gunnery crews and their systems. The term is also used in a naval context to describe groups of guns on warships. Land usage Historically the term "battery" referred to a cluster of cannon in action as a group, either in a temporary field position during a battle or at the siege of a fortress or a city. Such batteries could be a mixture of cannon, howitzer, or mortar types. A siege could involve many batteries at different sites around the besieged place. The term also came to be used for a group of cannon in a fixed fortification, for coastal or frontier defence. During the 18th century "battery" began to be used a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitching Moment
In aerodynamics, the pitching moment on an airfoil is the moment (or torque) produced by the aerodynamic force on the airfoil if that aerodynamic force is considered to be applied, not at the center of pressure, but at the aerodynamic center of the airfoil. The pitching moment on the wing of an airplane is part of the total moment that must be balanced using the lift on the horizontal stabilizer. More generally, a pitching moment is any moment acting on the pitch axis of a moving body. The lift on an airfoil is a distributed force that can be said to act at a point called the center of pressure. However, as angle of attack changes on a cambered airfoil, there is movement of the center of pressure forward and aft. This makes analysis difficult when attempting to use the concept of the center of pressure. One of the remarkable properties of a cambered airfoil is that, even though the center of pressure moves forward and aft, if the lift is imagined to act at a point ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altitude (astronomy)
The horizontal coordinate system is a celestial coordinate system that uses the observer's local horizon as the fundamental plane to define two angles: altitude and azimuth. Therefore, the horizontal coordinate system is sometimes called as the az/el system, the alt/az system, or the alt-azimuth system, among others. In an altazimuth mount of a telescope, the instrument's two axes follow altitude and azimuth. Definition This celestial coordinate system divides the sky into two hemispheres: The upper hemisphere, where objects are above the horizon and are visible, and the lower hemisphere, where objects are below the horizon and cannot be seen, since the Earth obstructs views of them. The great circle separating the hemispheres is called the celestial horizon, which is defined as the great circle on the celestial sphere whose plane is normal to the local gravity vector. In practice, the horizon can be defined as the plane tangent to a quiet, liquid surface, such as a pool of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MANPADS
Man-portable air-defense systems (MANPADS or MPADS) are portable surface-to-air missiles. They are guided weapons and are a threat to low-flying aircraft, especially helicopters. Overview MANPADS were developed in the 1950s to provide military ground forces with protection from jet aircraft. They have received a great deal of attention, partly because armed groups have used them against commercial airliners. These missiles, affordable and widely available through a variety of sources, have been used successfully over the past three decades both in military conflicts, as well as by terrorist organizations. Twenty-five countries, including the United Kingdom, the United States, Poland, Sweden, Russia, and Turkey, produce man-portable air defense systems.CRS RL31741 page 1 Possession, export, and trafficking of such weapons is officially tightly controlled, due to the threat they pose to civil aviation, although such efforts have not always been successful. The missiles are about ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guided Missile
In military terminology, a missile is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles are thus also called guided missiles or guided rockets (when a previously unguided rocket is made guided). Missiles have five system components: targeting, guidance system, flight system, engine and warhead. Missiles come in types adapted for different purposes: surface-to-surface and air-to-surface missiles ( ballistic, cruise, anti-ship, anti-submarine, anti-tank, etc.), surface-to-air missiles (and anti-ballistic), air-to-air missiles, and anti-satellite weapons. Airborne explosive devices without propulsion are referred to as shells if fired by an artillery piece and bombs if dropped by an aircraft. Unguided jet- or rocket-propelled weapons are usually described as rocket artillery. Historically, the word ''missile'' referred to any projectile that is thrown, shot or propelled towards a target; this usage is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Rangefinder
A laser rangefinder, also known as a laser telemeter, is a rangefinder that uses a laser beam to determine the distance to an object. The most common form of laser rangefinder operates on the time of flight principle by sending a laser pulse in a narrow beam towards the object and measuring the time taken by the pulse to be reflected off the target and returned to the sender. Due to the high speed of light, this technique is not appropriate for high precision sub-millimeter measurements, where triangulation and other techniques are often used. Pulse The pulse may be coded to reduce the chance that the rangefinder can be jammed. It is possible to use Doppler effect techniques to judge whether the object is moving towards or away from the rangefinder, and if so, how fast. Precision The precision of the instrument is determined by the rise or fall time of the laser pulse and the speed of the receiver. One that uses very sharp laser pulses and has a very fast detector can ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire-control System
A fire-control system (FCS) is a number of components working together, usually a gun data computer, a director, and radar, which is designed to assist a ranged weapon system to target, track, and hit a target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more accurately. Naval based fire control Origins The original fire-control systems were developed for ships. The early history of naval fire control was dominated by the engagement of targets within visual range (also referred to as direct fire). In fact, most naval engagements before 1800 were conducted at ranges of . Even during the American Civil War, the famous engagement between and was often conducted at less than range. Rapid technical improvements in the late 19th century greatly increased the range at which gunfire was possible. Rifled guns of much larger size firing explosive shells of lighter relative weight (compared to all-metal balls) so greatly increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Sight
Iron sights are a system of physical alignment markers (usually made of metallic material) used as a sighting device to assist the accurate aiming of ranged weapons (such as a firearm, airgun, crossbow or even compound bow), or less commonly as a primitive finder sight for optical telescopes. The earliest sighting device, it relies completely on the viewer's naked eye (mostly under ambient lighting), and is distinctly different to optical sights such as telescopic sights, reflector (reflex) sights, holographic sights and laser sights, which make use of optical manipulation and/or active illumination, as well as the newer optoelectronics, which use digital imaging and even incorporate augmented reality. Iron sights are typically composed of two components mounted perpendicularly above the weapon's bore axis: a rear sight nearer (or ''proximally'') to the shooter's eye, and a front sight farther forward (or ''distally'') near the muzzle. During aiming, the shooter alig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, massa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tank Gun
A tank gun is the main armament of a tank. Modern tank guns are high-velocity, large-caliber artilleries capable of firing kinetic energy penetrators, high-explosive anti-tank, and cannon-launched guided projectiles. Anti-aircraft guns can also be mounted to tanks. As the tank's primary armament, they are almost always employed in a direct fire mode to defeat a variety of ground targets at all ranges, including dug-in infantry, lightly armored vehicles, and especially other heavily armored tanks. They must provide accuracy, range, penetration, and rapid fire in a package that is as compact and lightweight as possible, to allow mounting in the cramped confines of an armored gun turret. Tank guns generally use self-contained ammunition, allowing rapid loading (or use of an autoloader). They often display a bulge in the barrel, which is a bore evacuator, or a device on the muzzle, which is a muzzle brake. History World War I The first tanks were used to break through tre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
