A general-purpose bomb is an air-dropped bomb intended as a compromise between blast damage and fragmentation in explosive effect. They are designed to be effective against enemy troops and buildings. General-purpose bombs use a thick-walled metal casing with explosive filler composing about 30% to 40% of the bomb's total weight; the British term for a bomb of this type is "medium case" or "medium capacity". The GP bomb is a common weapon of fighter bomber and attack aircraft because it is useful for a variety of tactical applications and cheap. General-purpose bombs are identified by their weight. In many cases this is a nominal weight, the actual weight of each individual weapon may vary depending on its retardation, fusing and guidance systems. For example, the actual weight of a U. S. M117 bomb, nominally 750 lb, is around 820 lb. Most modern air-dropped GP bombs are designed to minimize drag for external carriage on aircraft lacking bomb bays. In low-altitude attacks, there is a danger of the attacking aircraft being caught in the blast of its own weapons.
To address this problem, GP bombs are fitted with retarders, parachutes or pop-out fins that slow the bomb's descent to allow the aircraft time to escape the detonation. GP bombs can be fitted with a variety of fins for different uses. One notable example is the "daisy cutter" fuze used in Vietnam War era American weapons, an extended probe designed to ensure that the bomb would detonate on contact rather than burying itself in earth or mud, which would reduce its effectiveness. GP bombs are used as the warheads for more sophisticated precision-guided munitions. Using various types of seeker and electrically controlled fins turns a basic'iron' bomb into a laser-guided bomb, an electro-optical guided bomb, or, more GPS-guided weapon; the combination is cheaper than a true guided missile, but is more accurate than an unguided bomb. During the Korean War and Vietnam War the U. S. used older designs like the M117 and M118, which had an explosive content about 65% higher than most contemporary weapons.
Although some of these weapons remain in the U. S. arsenal, they are little used and the M117 is carried only by the B-52 Stratofortress. The primary U. S. GP bombs are the Mark 80 series; this class of weapons uses a shape known as Aero 1A, designed by Ed Heinemann of Douglas Aircraft as the result of studies in 1946. It has a length-to-diameter ratio of about 8:1, results in minimal drag for the carrier aircraft; the Mark 80 series was not used in combat until the Vietnam War, but has since replaced most earlier GP weapons. It includes four basic weapon types: Mark 81 – nominal weight 250 pounds Mark 82 – nominal weight 500 pounds Mark 83 – nominal weight 1,000 pounds Mark 84 – nominal weight 2,000 pounds Vietnam service showed the Mk 81 "Firecracker" to be insufficiently effective, it was withdrawn from U. S. service. However precision-guided variants of the Mk 81 bomb have begun a return to service, based on U. S. experience in Iraq after 2003, the desire to reduce collateral damage compared to Mk 82 and larger bombs.
Since the Vietnam War, United States Navy and United States Marine Corps GP bombs are distinguished by a thick ablative fire-retardant coating, designed to delay any potential accidental explosion in the event of a shipboard fire. Land-based air forces do not use such coatings because they add some 30 lb to the weight of the complete weapon. Fire is less a danger in a land-based facility, where the personnel can be evacuated with relative ease, the building be the only loss. At sea, the crew and munitions share a facility, thus are in much more danger of fire reaching munitions. Losing a munitions storage building on land is far cheaper than sacrificing an entire naval vessel if one could evacuate the crew. All Mk80 bombs can accept a variety of fuzes. Various nose and tail kits can be fitted to adapt the weapon for a variety of roles. In the Mk 80 series bomb bodies is used in the following weapons: BDU-50 A practice version of the Mk 82 bomb body BDU-56 A practice version of the Mk 84 bomb body Dumb Mk 80 bombs could be converted to smart bombs with attached kits: GBU-12D Paveway II laser-guided GBU-16B Paveway II laser-guided GBU-24B Paveway III laser-guided GBU-38 JDAM INS/GPS guided GBU-32 JDAM INS/GPS guided GBU-31 JDAM INS/GPS guided GBU-X - a new guided general-purpose bomb under development.
Mk 82 Snake Eye was a standard Mk 82 with folded. Mk 82 Retarded was a standard Mk 82 with a ballute. Mk 83 Retarded was a standard Mk 83 with a ballute. Mk 84 Retarded was a standard Mk 84 with a ballute; the principal modern British bombs are 540 lb and 1,000 lb, with a wide variety of fin and retarder options. Usag
General Dynamics F-111 Aardvark
The General Dynamics F-111 Aardvark was an American supersonic, medium-range interdictor and tactical attack aircraft that filled the roles of strategic nuclear bomber, aerial reconnaissance, electronic-warfare aircraft in its various versions. Developed in the 1960s by General Dynamics, it first entered service in 1967 with the United States Air Force; the Royal Australian Air Force ordered the type and began operating F-111Cs in 1973. The F-111 pioneered several technologies for production aircraft, including variable-sweep wings, afterburning turbofan engines, automated terrain-following radar for low-level, high-speed flight, its design influenced variable-sweep wing aircraft, some of its advanced features have since become commonplace. The F-111 suffered a variety of problems during initial development. Several of its intended roles, such as an aircraft carrier-based naval interceptor with the F-111B, failed to materialize. USAF F-111 variants were retired in the 1990s, with the F-111Fs in 1996 and EF-111s in 1998.
The F-111 was replaced in USAF service by the F-15E Strike Eagle for medium-range precision strike missions, while the supersonic bomber role has been assumed by the B-1B Lancer. The RAAF was the last operator of the F-111, with its aircraft serving until December 2010; the May 1960 U-2 incident, in which an American CIA U-2 spy plane was shot down over the USSR, stunned the United States government. Besides damaging US-Soviet relations, the incident showed that the Soviet Union had developed a surface-to-air missile that could reach aircraft above 60,000 feet; the United States Air Force Strategic Air Command and the RAF Bomber Command's plans to send subsonic, high-altitude B-47 and V bomber formations into the USSR were now much less viable. By 1960, SAC had begun moving to low-level penetration which reduced radar detection distances. At the time, SAMs were ineffective against low-flying aircraft, interceptor aircraft had less of a speed advantage at low altitudes; the Air Force's Tactical Air Command was concerned with the fighter-bomber and deep strike/interdiction roles.
TAC was in the process of receiving its latest design, the Republic F-105 Thunderchief, designed to deliver nuclear weapons fast and far, but required long runways. A simpler variable geometry wing configuration with the pivot points farther out from the aircraft's centerline was reported by NASA in 1958, which made swing-wings viable; this led Air Force leaders to encourage its use. In June 1960, the USAF issued specification SOR 183 for a long-range interdiction/strike aircraft able to penetrate Soviet air defenses at low altitudes and high speeds; the specification called for the aircraft to operate from short, unprepared airstrips. In the 1950s, the United States Navy sought a long-range, high-endurance interceptor aircraft to protect its carrier battle groups against long-range anti-ship missiles launched from Soviet jet bombers and submarines; the Navy needed a fleet air defense fighter with a more powerful radar, longer range missiles than the F-4 Phantom II to intercept both enemy bombers and missiles.
Seeking a FAD fighter, the Navy started with the subsonic, straight-winged aircraft, the Douglas F6D Missileer in the late 1950s. The Missileer was designed to carry six long-range missiles and loiter for five hours, but would be defenseless after firing its missiles; the program was formally canceled in 1961. The Navy had tried variable geometry wings with the XF10F Jaguar, but abandoned it in the early 1950s, it was NASA's simplification. By 1960, increases in aircraft weights required improved high-lift devices, such as variable geometry wings. Variable geometry offered high speeds, maneuverability with heavier payloads, long range, the ability to take off and land in shorter distances; the U. S. Air Force and Navy were both seeking new aircraft when Robert McNamara was appointed Secretary of Defense in January 1961; the aircraft sought by the two armed services shared the need to carry heavy armament and fuel loads, feature high supersonic speed, twin engines and two seats, use variable geometry wings.
On 14 February 1961, McNamara formally directed the services to study the development of a single aircraft that would satisfy both requirements. Early studies indicated that the best option was to base the design on the Air Force requirement, use a modified version for the Navy. In June 1961, Secretary McNamara ordered the go ahead of Tactical Fighter Experimental, despite Air Force and Navy efforts to keep their programs separate; the Air Force and the Navy could agree only on two-seat, twin-engine design features. The Air Force wanted a tandem-seat aircraft for low-level penetration ground-attack, while the Navy wanted a shorter, high altitude interceptor with side-by-side seating to allow the pilot and radar operator to share the radar display; the Air Force wanted the aircraft designed for 7.33 g with Mach 2.5 speed at altitude and Mach 1.2 speed at low level with an approximate length of 70 ft. The Navy had less strenuous requirements of 6 g with Mach 2 speed at altitude and high subsonic speed at low level with a length of 56 ft.
The Navy wanted the aircraft with a nose large enough for a 48 in diameter radar dish. McNamara developed a basic set of requirements for TFX based on the Air Force's requirements and, on 1 September 1961, ordered the Air Force to develop it. A request for proposals for the TFX was provided to industry in October 1961. In December, proposals were received from Boeing, General Dynamics, Lockheed, McDonnell, North American and Republic; the evaluation group found all the proposals lackin
The ballute is a parachute-like braking device optimized for use at high altitudes and supersonic velocities. Invented by Goodyear in 1958, the original ballute was a cone-shaped balloon with a toroidal burble fence fitted around its widest point. A burble fence is an inflated structure intended to ensure flow separation; this stabilizes the ballute. The ballute is inflated either by a gas generator or by air forced into the structure by ram air inlets. Ballutes have been proposed in stacked toroidal and tension cone form factors, in addition to the more standard isotensoid ballute; the ballute has been used. It was used as part of the escape equipment for the Gemini spacecraft, it has been proposed for use during aerobraking. In the 1984 film 2010: The Year We Make Contact, a ballute is used on the space vehicle Leonov to establish a gentle orbit around Jupiter. Extended designs using inflatable tension cone ballute technology have been proposed for deorbiting NanoSats and recovering low-mass satellites from low Earth orbit.
Armadillo Aerospace used a ballute in the testing of its STIG-A rocket in early 2012. As of February 2015 Danish nonprofit aerospace organization Copenhagen Suborbitals were testing a ballute for its Nexø rockets. In April 2018 SpaceX's Elon Musk tweeted "SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon." Http://www.esa.int/esapub/bulletin/bullet103/marraffa103.pdf http://www.parachutehistory.com/other/ballute.html
A contact fuze, impact fuze, percussion fuze or direct-action fuze is the fuze, placed in the nose of a bomb or shell so that it will detonate on contact with a hard surface. Many impacts are unpredictable: they may involve a soft surface, or an off-axis grazing impact; the pure contact fuze is unreliable in such cases and so a more sensitive graze fuze or inertia fuze is used instead. The two types are combined in the same mechanism; the British Army's first useful impact fuze for high-explosive shells was the Fuze No. 106 of World War I. This used a simple protruding plunger or striker at the nose, pushed back to drive a firing pin into the detonator, its ability to burst at ground level was used to clear the barbed wire entanglements of no man's land, rather than burying itself first and leaving a deep, but useless, crater. The striker was protected by a safety cap, removed before loading, but there was no other safety mechanism; the simplest form of artillery contact fuze is a soft metal nose to the shell, filled with a fulminating explosive such as lead azide.
An example is the British World War II Fuze, Percussion, D. A. No. 233 The primary explosive transmits its detonation to an explosive booster within the fuze in turn to the main charge of the shell. As an artillery shell lands with a considerable impact, the "soft" nose may be made robust enough to be adequately safe for careful handling, without requiring any protection cap or safety mechanism; as a matter of normal practice though and shells are transported separately and the fuze is only installed shortly prior to use. These simple contact fuzes are used for anti-tank shells, rather than high-explosive. A more sophisticated fuze is the double-acting fuze, sensitive to both contact and grazing. An example of such a double-acting fuze is the British WW II Fuze, D. A. and percussion, No. 119 This fuze uses a nose striker, as for the original No. 106, but is rather more complex with an added inertia mechanism for grazing impacts and three automatic safety devices. Simple contact impacts drive as before.
Graze impacts trigger the inertia mechanism, where instead the pellet in a heavy carrying plug travels forwards onto the striker. The striker is protected in storage by a nose safety cap; this is removed before loading, but it may be left in place if the target is behind cover. This reduces the sensitivity of the striker to light impacts through vegetation, but the fuze will still function through the inertia mechanism, or through a hard impact. Three safety devices are provided, one released by inertia during firing, which unlocks a second, released by centrifugal force of the spinning shell; these are mechanical locks. A third device is a centrifugal shutter that blocks propagation from the detonator pellet to the booster explosive. Most artillery contact fuzes act although some may have a delay; this allows a high-explosive or semi-armour-piercing shell to penetrate a wall before exploding, thus achieving the most damage inside the building. Where a shell is used against strong armour and requires all of its explosive power to penetrate, a delay is not appropriate.
Most such delayed fuzes are thus switchable to immediate mode. Timed fuzes are used for airbursts, they take their delay time from firing, not from impact. These fuzes may offer a contact fuzed ability; as this type of fuze is complex and more sensitive, they have a deliberate safing mechanism such as an arming wire that must be removed before use. Fuzes for air-dropped bombs have used an internally mounted inertia fuze, triggered by the sudden deceleration on impact. Owing to the risk of an aircraft crash, or the need to land with an undropped bomb still on board, these are protected by sophisticated safety systems so that the fuze can only be triggered after it has been dropped intentionally. StaboThe German Stachelbombe or stabo of WWII was a standard bomb, from 50 kg to 500 kg, modified for use from low altitude. To avoid the risk of ricochet from the ground, a nose spike was fitted to penetrate first and anchor the bomb against bouncing — without this, there was a risk of the dropping aircraft not only missing the target, but being damaged by its own weapon.
As the German electric fuzes had an arming delay after dropping, the bombs were dropped at such low altitude as to leave insufficient time for this to arm, they were sometimes fitted with additional contact fuzes on the tips of these nose spikes. Similar devices were employed by Russian forces, in a similar ground attack role using the Il-2 Sturmovik. Fat ManNotable examples of air-dropped bombs that did use contact fuzes include the Fat Man atomic bomb dropped on Nagasaki; the bomb was intended for air burst detonation and was fitted with both radar height-finding and barometric fuzes. As the device was so secret, the risk of informative fragments or plutonium being recovered after a failed drop was considered to be unacceptable, it was fitted with supplementary contact fuzes that were only intended to destroy the weapon beyond recognition. Four AN-219 piezo-electric impact fuzes were fitted to the nose of the bomb casing. BLU-82The BLU-82 was a large conventional explosive bomb, used to make helicopter landing clearings in forests.
The intended fusing was an low air burst of only a few feet, so as to maximize the clearance effect and minimize cratering. The fuze was a mechanical impact fuze on a 38-inch nose spike. Other fuzesThe contact fuze is set off when a series of connected crush switches that are placed on the exterior
Ballistics is the field of mechanics that deals with the launching, flight and effects of projectiles bullets, unguided bombs, rockets, or the like. A ballistic body is a body with momentum, free to move, subject to forces, such as the pressure of gases in a gun or a propulsive nozzle, by rifling in a barrel, by gravity, or by air drag. A ballistic missile is a missile only guided during the brief initial powered phase of flight, whose trajectory is subsequently governed by the laws of classical mechanics, in contrast to a cruise missile, aerodynamically guided in powered flight; the earliest known ballistic projectiles were stones and spears, the throwing stick. The oldest evidence of stone-tipped projectiles, which may or may not have been propelled by a bow, dating to c. 64,000 years ago, were found in Sibudu Cave, present day-South Africa. The oldest evidence of the use of bows to shoot arrows dates to about 10,000 years ago, they had shallow grooves on the base. The oldest bow so far recovered is about 8,000 years old.
Archery seems to have arrived in the Americas with the Arctic small tool tradition, about 4,500 years ago. The first devices identified as guns appeared in China around 1000 AD, by the 12th century the technology was spreading through the rest of Asia, into Europe by the 13th century. After millennia of empirical development, the discipline of ballistics was studied and developed by Italian mathematician Niccolò Tartaglia in 1531, although he continued to use segments of straight-line motion, conventions established by Avicenna and Albert of Saxony, but with the innovation that he connected the straight lines by a circular arc. Galileo established the principle of compound motion in 1638, using the principle to derive the parabolic form of the ballistic trajectory. Ballistics was put on a solid scientific and mathematical basis by Isaac Newton, with the publication of Philosophiæ Naturalis Principia Mathematica in 1687; this gave mathematical laws of motion and gravity which for the first time made it possible to predict trajectories.
The word ballistics comes from the Greek βάλλειν ballein, meaning "to throw". A projectile is any object projected into space by the exertion of a force. Although any object in motion through space is a projectile, the term most refers to a ranged weapon. Mathematical equations of motion are used to analyze projectile trajectory. Examples of projectiles include balls, bullets, artillery shells, etc. Throwing is the launching of a projectile by hand. Although some other animals can throw, humans are unusually good throwers due to their high dexterity and good timing capabilities, it is believed that this is an evolved trait. Evidence of human throwing dates back 2 million years; the 90 mph throwing speed found in many athletes far exceeds the speed at which chimpanzees can throw things, about 20 mph. This ability reflects the ability of the human shoulder muscles and tendons to store elasticity until it is needed to propel an object. A sling is a projectile weapon used to throw a blunt projectile such as a stone, clay or lead "sling-bullet".
A sling has a small pouch in the middle of two lengths of cord. The sling stone is placed in the pouch; the middle finger or thumb is placed through a loop on the end of one cord, a tab at the end of the other cord is placed between the thumb and forefinger. The sling is swung in an arc, the tab released at a precise moment; this frees the projectile to fly to the target. A bow is a flexible piece of material. A string joins the two ends and when the string is drawn back, the ends of the stick are flexed; when the string is released, the potential energy of the flexed stick is transformed into the velocity of the arrow. Archery is the sport of shooting arrows from bows. A catapult is a device used to launch a projectile a great distance without the aid of explosive devices — various types of ancient and medieval siege engines; the catapult has been used since ancient times, because it was proven to be one of the most effective mechanisms during warfare. The word "catapult" comes from the Latin "catapulta", which in turn comes from the Greek καταπέλτης, itself from, "downwards" and πάλλω, "to toss, to hurl".
Catapults were invented by the ancient Greeks. A gun is a tubular weapon or other device designed to discharge projectiles or other material; the projectile may be solid, gas, or energy and may be free, as with bullets and artillery shells, or captive as with Taser probes and whaling harpoons. The means of projection varies according to design but is effected by the action of gas pressure, either produced through the rapid combustion of a propellant or compressed and stored by mechanical means, operating on the projectile inside an open-ended tube in the fashion of a piston; the confined gas accelerates the movable projectile down the length of the tube imparting sufficient velocity to sustain the projectile's travel once the action of the gas ceases at the end of the tube or muzzle. Alternatively, acceleration via electromagnetic field generation may be employed in which case the tube may be dispensed with and a guide rail substituted. A rocket is a missile, aircraft or other vehicle that obtains thrust from a rocket engine.
Rocket engine exhaust is formed from propella