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Bombsight
A bombsight is a device used by military aircraft to drop bombs accurately. Bombsights, a feature of combat aircraft since World War I, were first found on purpose-designed bomber aircraft and then moved to fighter-bombers and modern tactical aircraft as those aircraft took up the brunt of the bombing role. A bombsight has to estimate the path the bomb will take after release from the aircraft. The two primary forces during its fall are gravity and air drag, which make the path of the bomb through the air roughly parabolic. There are additional factors such as changes in air density and wind that may be considered, but they are concerns only for bombs that spend a significant portion of a minute falling through the air. Those effects can be minimized by reducing the fall time by low-level bombing or by increasing the speed of the bombs. Those effects are combined in the dive bomber. However, low-level bombing also increases the danger to the bomber from ground-based defences, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norden Bombsight
The Norden Mk. XV, known as the Norden M series in U.S. Army service, is a bombsight that was used by the United States Army Air Forces (USAAF) and the United States Navy during World War II, and the United States Air Force in the Korean and the Vietnam Wars. It was an early tachometric design that directly measured the aircraft's ground speed and direction, which older bombsights could only estimate with lengthy manual procedures. The Norden further improved on older designs by using an analog computer that continuously recalculated the bomb's impact point based on changing flight conditions, and an autopilot that reacted quickly and accurately to changes in the wind or other effects. Together, these features promised unprecedented accuracy for daytime bombing from high altitudes. During prewar testing the Norden demonstrated a circular error probable (CEP) of , an astonishing performance for that period. This precision would enable direct attacks on ships, factories, and ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bombsight
A bombsight is a device used by military aircraft to drop bombs accurately. Bombsights, a feature of combat aircraft since World War I, were first found on purpose-designed bomber aircraft and then moved to fighter-bombers and modern tactical aircraft as those aircraft took up the brunt of the bombing role. A bombsight has to estimate the path the bomb will take after release from the aircraft. The two primary forces during its fall are gravity and air drag, which make the path of the bomb through the air roughly parabolic. There are additional factors such as changes in air density and wind that may be considered, but they are concerns only for bombs that spend a significant portion of a minute falling through the air. Those effects can be minimized by reducing the fall time by low-level bombing or by increasing the speed of the bombs. Those effects are combined in the dive bomber. However, low-level bombing also increases the danger to the bomber from ground-based defences, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boeing B-17
The Boeing B-17 Flying Fortress is a four-engined heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC). Relatively fast and high-flying for a bomber of its era, the B-17 was used primarily in the European Theater of Operations and dropped more bombs than any other aircraft during World War II. It is the third-most produced bomber of all time, behind the four-engined Consolidated B-24 Liberator and the multirole, twin-engined Junkers Ju 88. It was also employed as a transport, antisubmarine aircraft, drone controller, and search-and-rescue aircraft. In a USAAC competition, Boeing's prototype Model 299/XB-17 outperformed two other entries but crashed, losing the initial 200-bomber contract to the Douglas B-18 Bolo. Still, the Air Corps ordered 13 more B-17s for further evaluation, then introduced it into service in 1938. The B-17 evolved through numerous design advances but from its inception, the USAAC (later, the USAAF) promoted the aircraft a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dive Bomber
A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target simplifies the bomb's trajectory and allows the pilot to keep visual contact throughout the bomb run. This allows attacks on point targets and ships, which were difficult to attack with conventional level bombers, even ''en masse''. After World War II, the rise of precision-guided munitions and improved anti-aircraft defences—both fixed gunnery positions and fighter interception—led to a fundamental change in dive bombing. New weapons, such as rockets, allowed for better accuracy from smaller dive angles and from greater distances. They could be fitted to almost any aircraft, including fighters, improving their effectiveness without the inherent vulnerabilities of dive bombers, which needed air superiority to operate effectively. Method A dive bomber dives at a steep angle, normally between 45 and 60 degrees or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Computer
A mechanical computer is a computer built from mechanical components such as levers and gears rather than electronic components. The most common examples are adding machines and mechanical counters, which use the turning of gears to increment output displays. More complex examples could carry out multiplication and division—Friden used a moving head which paused at each column—and even differential analysis. One model, the Ascota 170 accounting machine sold in the 1960s calculated square roots. Mechanical computers can be either analog, using smooth mechanisms such as curved plates or slide rules for computations; or digital, which use gears. Mechanical computers reached their zenith during World War II, when they formed the basis of complex bombsights including the Norden, as well as the similar devices for ship computations such as the US Torpedo Data Computer or British Admiralty Fire Control Table. Noteworthy are mechanical flight instruments for early spacecraft, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head-up Display
A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view information with the head positioned "up" and looking forward, instead of angled down looking at lower instruments. A HUD also has the advantage that the pilot's eyes do not need to refocus to view the outside after looking at the optically nearer instruments. Although they were initially developed for military aviation, HUDs are now used in commercial aircraft, automobiles, and other (mostly professional) applications. Head-up displays were a precursor technology to augmented reality (AR), incorporating a subset of the features needed for the full AR experience, but lacking the necessary registration and tracking between the virtual content and the user's real-world environment. Overview A typical HUD contains three primary components: a ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bomber Aircraft
A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped from an aircraft occurred in the Italo-Turkish War, with the first major deployments coming in the First World War and Second World War by all major airforces causing devastating damage to cities, towns, and rural areas. The first purpose built bombers were the Italian Caproni Ca 30 and British Bristol T.B.8, both of 1913. Some bombers were decorated with nose art or victory markings. There are two major classifications of bomber: strategic and tactical. Strategic bombing is done by heavy bombers primarily designed for long-range bombing missions against strategic targets to diminish the enemy's ability to wage war by limiting access to resources through crippling infrastructure or reducing industrial output. Tactical bombing is aimed at counteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Velocity
Terminal velocity is the maximum velocity (speed) attainable by an object as it falls through a fluid ( air is the most common example). It occurs when the sum of the drag force (''Fd'') and the buoyancy is equal to the downward force of gravity (''FG'') acting on the object. Since the net force on the object is zero, the object has zero acceleration. In fluid dynamics an object is moving at its terminal velocity if its speed is constant due to the restraining force exerted by the fluid through which it is moving. As the speed of an object increases, so does the drag force acting on it, which also depends on the substance it is passing through (for example air or water). At some speed, the drag or force of resistance will equal the gravitational pull on the object (buoyancy is considered below). At this point the object stops accelerating and continues falling at a constant speed called the terminal velocity (also called settling velocity). An object moving downward faster t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Of Attack
In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air. In aerodynamics, angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Since a wing can have twist, a chord line of the whole wing may not be definable, so an alternate reference line is simply defined. Often, the chord line of the root of the wing is chosen as the reference line. Another choice is to use a horizontal line on the fuselage as the reference line (and also as the longitudinal axis). Some aut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Momentum
In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass and is its velocity (also a vector quantity), then the object's momentum is : \mathbf = m \mathbf. In the International System of Units (SI), the unit of measurement of momentum is the kilogram metre per second (kg⋅m/s), which is equivalent to the newton-second. Newton's second law of motion states that the rate of change of a body's momentum is equal to the net force acting on it. Momentum depends on the frame of reference, but in any inertial frame it is a ''conserved'' quantity, meaning that if a closed system is not affected by external forces, its total linear momentum does not change. Momentum is also conserved in special relativity (with a modified formula) and, in a modified form, in electrodynamics, quantum mechanics, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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