Misplaced Pages

#175824

68-736: The Akizuki -class ships were originally designed as anti-aircraft escorts for carrier battle groups, but were modified with torpedo tubes and depth charges to meet the need for more general-purpose destroyers. The ships measured 134.2 meters (440 ft 3 in) overall , with beams of 11.6 meters (38 ft 1 in) and drafts of 4.15 meters (13 ft 7 in). They displaced 2,701 long tons (2,744  t ) at standard load and 3,420 long tons (3,470 t) at deep load . Their crews numbered 300 officers and enlisted men . Each ship had two Kampon geared steam turbines , each driving one propeller shaft using steam provided by three Kampon water-tube boilers . The turbines were rated at

136-600: A 75 mm 12-pounder, and even a 105 mm gun. Erhardt also had a 12-pounder, while Vickers Maxim offered a 3-pounder and Schneider a 47 mm. The French balloon gun appeared in 1910, it was an 11-pounder but mounted on a vehicle, with a total uncrewed weight of two tons. However, since balloons were slow moving, sights were simple. But the challenges of faster moving aeroplanes were recognised. By 1913 only France and Germany had developed field guns suitable for engaging balloons and aircraft and addressed issues of military organisation. Britain's Royal Navy would soon introduce

204-628: A full military structure. For example, the UK's Anti-Aircraft Command, commanded by a full British Army general was part of ADGB. At its peak in 1941–42 it comprised three AA corps with 12 AA divisions between them. The use of balloons by the U.S. Army during the American Civil War compelled the Confederates to develop methods of combating them. These included the use of artillery, small arms, and saboteurs. They were unsuccessful, and internal politics led

272-451: A large traverse that could be easily transported on a wagon. Krupp 75 mm guns were supplied with an optical sighting system that improved their capabilities. The German Army also adapted a revolving cannon that came to be known to Allied fliers as the " flaming onion " from the shells in flight. This gun had five barrels that quickly launched a series of 37 mm artillery shells. As aircraft started to be used against ground targets on

340-543: A maritime force against attacks by airborne weapons launched from aircraft, ships, submarines and land-based sites". In some armies the term all-arms air defence (AAAD) is used for air defence by nonspecialist troops. Other terms from the late 20th century include "ground based air defence" (GBAD) with related terms " short range air defense " (SHORAD) and man-portable air-defense system (MANPADS). Anti-aircraft missiles are variously called surface-to-air missiles , ("SAMs") and surface-to-air guided weapons (SAGWs). Examples are

408-504: A new 3.6-inch gun, in 1918. In 1928 a 3.7-inch (94 mm) gun became the preferred solution, but it took six years to gain funding. Production of the QF 3.7-inch gun began in 1937; this gun was used on mobile carriages with the field army and transportable guns on fixed mountings for static positions. At the same time the Royal Navy adopted a new 4.5-inch (113 mm) gun in a twin turret, which

476-624: A new field mounting was introduced in 1916. Since most attacks were at night, searchlights were soon used, and acoustic methods of detection and locating were developed. By December 1916 there were 183 AA sections defending Britain (most with the 3-inch), 74 with the BEF in France and 10 in the Middle East. AA gunnery was a difficult business. The problem was of successfully aiming a shell to burst close to its target's future position, with various factors affecting

544-666: A par with the army, navy, or air force. In the Soviet Union, this was called Voyska PVO , and had both fighter aircraft, separate from the air force, and ground-based systems. This was divided into two arms, PVO Strany, the Strategic Air defence Service responsible for Air Defence of the Homeland, created in 1941 and becoming an independent service in 1954, and PVO SV, Air Defence of the Ground Forces. Subsequently, these became part of

612-520: A total of 52,000 shaft horsepower (38,776  kW ) for a designed speed of 33 knots (61 km/h; 38 mph). The ships carried enough fuel oil to give them ranges of 8,300 nautical miles (15,400 km; 9,600 mi) at speeds of 18 knots (33 km/h; 21 mph). The main armament of the Akizuki class consisted of eight 100-millimeter (3.9 in) Type 98 dual-purpose guns in four twin- gun turrets , two superfiring pairs fore and aft of

680-456: A troop convoy to Ormoc , Philippines . She was sunk by aircraft of Task Force 38 in Ormoc Bay , west of Leyte ( 10°50′N 124°35′E  /  10.833°N 124.583°E  / 10.833; 124.583 ). Wakatsuki's wreck was discovered in early December 2017 by Microsoft co-founder Paul Allen 's research vessel RV Petrel 869 ft (265 m) below the surface of Ormoc Bay. She

748-475: Is assisted but not governed by identification friend or foe (IFF) electronic devices originally introduced during the Second World War . While these rules originate at the highest authority, different rules can apply to different types of air defence covering the same area at the same time. AAAD usually operates under the tightest rules. NATO calls these rules "weapon control orders" (WCO), they are: Until

SECTION 10

#1733085047176

816-631: Is deployed in several ways: Air defence has included other elements, although after the Second World War most fell into disuse: Passive air defence is defined by NATO as "Passive measures taken for the physical defence and protection of personnel, essential installations and equipment in order to minimise the effectiveness of air and/or missile attack". It remains a vital activity by ground forces and includes camouflage and concealment to avoid detection by reconnaissance and attacking aircraft. Measures such as camouflaging important buildings were common in

884-454: Is operated by specialists, batteries may have several dozen teams deploying separately in small sections; self-propelled air defence guns may deploy in pairs. Batteries are usually grouped into battalions or equivalent. In the field army, a light gun or SHORAD battalion is often assigned to a manoeuvre division. Heavier guns and long-range missiles may be in air-defence brigades and come under corps or higher command. Homeland air defence may have

952-664: Is the protection of a sovereignty , territory, domestic population, and critical defense infrastructure against external threats and aggression , or other threats as directed by the leader of that nation such as the President of the United States . The United States Department of Defense is partially responsible for the Homeland defense mission of the United States, and therefore leads the HD response, with other departments and agencies in support of DOD efforts." HD strategic threat environment

1020-430: Is the protection of a territory, sovereignty, domestic population, and critical infrastructure against external threats and aggression. (Definition will be incorporated into JP 3-26 upon its approval). Homeland security ( HS ) is a concerted national effort to prevent terrorist attacks, reduce a nation's vulnerability to terrorism, and minimize the damage and recover from attacks that do occur. "Homeland defense (HD)

1088-414: Is to detect hostile aircraft and destroy them. The critical issue is to hit a target moving in three-dimensional space; an attack must not only match these three coordinates, but must do so at the time the target is at that position. This means that projectiles either have to be guided to hit the target, or aimed at the predicted position of the target at the time the projectile reaches it, taking into account

1156-517: Is usually accomplished via the combined use of systems optimized for either short-, medium-, or long-range air defence. In some countries, such as Britain and Germany during the Second World War , the Soviet Union , and modern NATO and the United States, ground-based air defence and air defence aircraft have been under integrated command and control. However, while overall air defence may be for homeland defence (including military facilities), forces in

1224-425: The 13-pr QF 9 cwt and these proved much more satisfactory. However, in general, these ad hoc solutions proved largely useless. With little experience in the role, no means of measuring target, range, height or speed the difficulty of observing their shell bursts relative to the target gunners proved unable to get their fuse setting correct and most rounds burst well below their targets. The exception to this rule

1292-458: The QF 3-inch and QF 4-inch AA guns and also had Vickers 1-pounder quick firing "pom-poms" that could be used in various mountings. The first US anti-aircraft cannon was a 1-pounder concept design by Admiral Twining in 1911 to meet the perceived threat of airships, that eventually was used as the basis for the US Navy's first operational anti-aircraft cannon: the 3-inch/23 caliber gun . On

1360-647: The RIM-66 Standard , Raytheon Standard Missile 6 , or the MBDA Aster missile. Non-English terms for air defence include the German Flak or FlaK ( Fliegerabwehrkanone , 'aircraft defence cannon', also cited as Flugabwehrkanone ), whence English flak , and the Russian term Protivovozdushnaya oborona ( Cyrillic : Противовозду́шная оборо́на), a literal translation of 'anti-air defence', abbreviated as PVO. In Russian,

1428-653: The Royal Naval Volunteer Reserve (RNVR) was manning AA guns and searchlights assembled from various sources at some nine ports. The Royal Garrison Artillery (RGA) was given responsibility for AA defence in the field, using motorised two-gun sections. The first were formally formed in November 1914. Initially they used QF 1-pounder "pom-pom"s (37 mm versions of the Maxim Gun ). All armies soon deployed AA guns often based on their smaller field pieces, notably

SECTION 20

#1733085047176

1496-658: The United States Air Force 's operating bases in the UK. All ground-based air defence was removed from Royal Air Force (RAF) jurisdiction in 2004 . The British Army's Anti-Aircraft Command was disbanded in March 1955, but during the 1960s and 1970s the RAF's Fighter Command operated long-range air-defence missiles to protect key areas in the UK. During World War II, the Royal Marines also provided air defence units; formally part of

1564-434: The superstructure . They each carried a dozen 25-millimeter (1 in) Type 96 anti-aircraft (AA) guns in four triple-gun mounts. The ships were also each armed with four 610-millimeter (24 in) torpedo tubes in a single quadruple rotating mount amidships ; one reload was carried for each tube. The first batch of ships were each equipped with two depth charge throwers for which 54 depth charges were carried. Wakatsuki

1632-649: The 1950s, guns firing ballistic munitions were the standard weapon; guided missiles then became dominant, except at the very shortest ranges. However, the type of shell or warhead and its fuzing and, with missiles, the guidance arrangement were and are varied. Targets are not always easy to destroy; nonetheless, damaged aircraft may be forced to abort their mission and, even if they manage to return and land in friendly territory, may be out of action for days or permanently. Ignoring small arms and smaller machine-guns, ground-based air defence guns have varied in calibre from 20 mm to at least 152 mm. Ground-based air defence

1700-465: The 30th of September, 1915, troops of the Serbian Army observed three enemy aircraft approaching Kragujevac . Soldiers fired at them with shotguns and machine-guns but failed to prevent them from dropping 45 bombs over the city, hitting military installations, the railway station and many other, mostly civilian, targets in the city. During the bombing raid, private Radoje Ljutovac fired his cannon at

1768-420: The 8.8 cm FlaK 18 in 1933, the 36 and 37 models followed with various improvements, but ballistic performance was unchanged. In the late 1930s the 10.5 cm FlaK 38 appeared, soon followed by the 39; this was designed primarily for static sites but had a mobile mounting, and the unit had 220 V 24 kW generators. In 1938 design started on the 12.8 cm FlaK . Britain had successfully tested

1836-484: The AA systems are called zenitnye (i.e., 'pointing to zenith ') systems. In French, air defence is called Défense contre les aéronefs (DCA) , aéronef meaning 'aircraft'. The maximum distance at which a gun or missile can engage an aircraft is an important figure. However, many different definitions are used and unless the same definition is used, performance of different guns or missiles cannot be compared. For AA guns only

1904-485: The British Isles increased in 1915 and the AA efforts were deemed somewhat ineffective, so a Royal Navy gunnery expert, Admiral Sir Percy Scott , was appointed to make improvements, particularly an integrated AA defence for London. The air defences were expanded with more RNVR AA guns, 75 mm and 3-inch, the pom-poms being ineffective. The naval 3-inch was also adopted by the army, the QF 3-inch 20 cwt (76 mm),

1972-534: The British adopted a new instrument developed by Vickers. It was a mechanical analogue computer - the Predictor AA No 1. Given the target height, its operators tracked the target and the predictor produced bearing, quadrant elevation and fuse setting. These were passed electrically to the guns, where they were displayed on repeater dials to the layers who "matched pointers" (target data and the gun's actual data) to lay

2040-468: The French 75 mm and Russian 76.2 mm, typically simply propped up on some sort of embankment to get the muzzle pointed skyward. The British Army adopted the 13-pounder quickly producing new mountings suitable for AA use, the 13-pdr QF 6 cwt Mk III was issued in 1915. It remained in service throughout the war but 18-pdr guns were lined down to take the 13-pdr shell with a larger cartridge producing

2108-544: The German Flugzeugabwehrkanone ), "ack-ack" (from the spelling alphabet used by the British for voice transmission of "AA"); and "archie" (a World War I British term probably coined by Amyas Borton , and believed to derive via the Royal Flying Corps , from the music-hall comedian George Robey 's line "Archibald, certainly not!" ). NATO defines anti-aircraft warfare (AAW) as "measures taken to defend

Japanese destroyer Wakatsuki - Misplaced Pages Continue

2176-468: The Second World War. During the Cold War the runways and taxiways of some airfields were painted green. While navies are usually responsible for their own air defence—at least for ships at sea—organisational arrangements for land-based air defence vary between nations and over time. The most extreme case was the Soviet Union and this model may still be followed in some countries: it was a separate service, on

2244-606: The United States Army's Balloon Corps to be disbanded mid-war. The Confederates experimented with balloons as well. Turks carried out the first ever anti-airplane operation in history during the Italo-Turkish war . Although lacking anti-aircraft weapons, they were the first to shoot down an airplane by rifle fire. The first aircraft to crash in a war was the one of Lieutenant Piero Manzini, shot down on August 25, 1912. The earliest known use of weapons specifically made for

2312-647: The air force and ground forces respectively. At the other extreme, the United States Army has an Air Defense Artillery Branch that provides ground-based air defence for both homeland and the army in the field; however, it is operationally under the Joint Force Air Component Commander . Many other nations also deploy an air-defence branch in the army. Some, such as Japan or Israel, choose to integrate their ground based air defence systems into their air force. In Britain and some other armies,

2380-413: The altitude at which a gun could deliver a series of shells against a moving target; this could be constrained by maximum fuse running time as well as the gun's capability. By the late 1930s the British definition was "that height at which a directly approaching target at 400 mph [640 km/h] can be engaged for 20 seconds before the gun reaches 70 degrees elevation". The essence of air defence

2448-545: The anti-aircraft role occurred during the Franco-Prussian War of 1870. After the disaster at Sedan , Paris was besieged and French troops outside the city started an attempt at communication via balloon . Gustav Krupp mounted a modified 1-pounder (37 mm) gun – the Ballonabwehrkanone (Balloon defence cannon) or BaK — on top of a horse-drawn carriage for the purpose of shooting down these balloons. By

2516-448: The army adopted in simplified single-gun mountings for static positions, mostly around ports where naval ammunition was available. The performance of the new guns was limited by their standard fuse No 199, with a 30-second running time, although a new mechanical time fuse giving 43 seconds was nearing readiness. In 1939 a machine fuse setter was introduced to eliminate manual fuse setting. Homeland defence Homeland defense ( HD )

2584-407: The ascending part of the trajectory can be usefully used. One term is "ceiling", the maximum ceiling being the height a projectile would reach if fired vertically, not practically useful in itself as few AA guns are able to fire vertically, and the maximum fuse duration may be too short, but potentially useful as a standard to compare different weapons. The British adopted "effective ceiling", meaning

2652-457: The battlefield, the AA guns could not be traversed quickly enough at close targets and, being relatively few, were not always in the right place (and were often unpopular with other troops), so changed positions frequently. Soon the forces were adding various machine-gun based weapons mounted on poles. These short-range weapons proved more deadly, and the " Red Baron " is believed to have been shot down by an anti-aircraft Vickers machine gun . When

2720-408: The competition for a share of limited defence budgets. Demobilisation meant that most AA guns were taken out of service, leaving only the most modern. However, there were lessons to be learned. In particular the British, who had had AA guns in most theatres in action in daylight and used them against night attacks at home. Furthermore, they had also formed an Anti-Aircraft Experimental Section during

2788-674: The early 20th century balloon, or airship, guns, for land and naval use were attracting attention. Various types of ammunition were proposed, high explosive, incendiary, bullet-chains, rod bullets and shrapnel. The need for some form of tracer or smoke trail was articulated. Fuzing options were also examined, both impact and time types. Mountings were generally pedestal type but could be on field platforms. Trials were underway in most countries in Europe but only Krupp, Erhardt, Vickers Maxim, and Schneider had published any information by 1910. Krupp's designs included adaptations of their 65 mm 9-pounder,

Japanese destroyer Wakatsuki - Misplaced Pages Continue

2856-482: The enemy aircraft and successfully shot one down. It crashed in the city and both pilots died from their injuries. The cannon Ljutovac used was not designed as an anti-aircraft gun; it was a slightly modified Turkish cannon captured during the First Balkan War in 1912. This was the first occasion in military history that a military aircraft was shot down with ground-to-air artillery fire. The British recognised

2924-654: The field, wherever they are, provide their own defences against airborne threats. Until the 1950s, guns firing ballistic munitions ranging from 7.62 mm (.30 in) to 152.4 mm (6 in) were the standard weapons; guided missiles then became dominant, except at the very shortest ranges (as with close-in weapon systems , which typically use rotary autocannons or, in very modern systems, surface-to-air adaptations of short-range air-to-air missiles , often combined in one system with rotary cannons). It may also be called counter-air , anti-air , AA , flak , layered air defence or air defence forces . The term air defence

2992-578: The ground-based air defence of the British Army's Anti-Aircraft Command , although field-deployed air defence relied on less sophisticated arrangements. NATO later called these arrangements an "air defence ground environment", defined as "the network of ground radar sites and command and control centres within a specific theatre of operations which are used for the tactical control of air defence operations". Rules of engagement are critical to prevent air defences engaging friendly or neutral aircraft. Their use

3060-579: The guns. This system of repeater electrical dials built on the arrangements introduced by British coast artillery in the 1880s, and coast artillery was the background of many AA officers. Similar systems were adopted in other countries and for example the later Sperry M3A3 in the US, was also used by Britain as the Predictor AA No 2. Height finders were also increasing in size; in Britain, the seven-foot optical base World War I Barr & Stroud UB 2 stereoscopic rangefinder

3128-494: The late 1930s for development work on sound-locating acoustic devices to be generally halted, although equipment was retained. Furthermore, in Britain the volunteer Observer Corps formed in 1925 provided a network of observation posts to report hostile aircraft flying over Britain. Initially radar was used for airspace surveillance to detect approaching hostile aircraft. However, the German Würzburg radar put into use in 1940

3196-601: The main effort has tended to be homeland defence . Missile defence is an extension of air defence, as are initiatives to adapt air defence to the task of intercepting any projectile in flight. Most modern anti-aircraft (AA) weapons systems are optimized for short-, medium-, or long-range air defence, although some systems may incorporate multiple weapons (such as both autocannons and surface-to-air missiles ). ‘Layered air defence’ usually refers to multiple ‘tiers’ of air defence systems which, when combined, an airborne threat must penetrate in order to reach its target; This defence

3264-513: The mobile naval base defence organisation, they were handled as an integral part of the army-commanded ground based air defences. The basic air defence unit is typically a battery with 2 to 12 guns or missile launchers and fire control elements. These batteries, particularly with guns, usually deploy in a small area, although batteries may be split; this is usual for some missile systems. SHORAD missile batteries often deploy across an area with individual launchers several kilometres apart. When MANPADS

3332-487: The need for anti-aircraft capability a few weeks before World War I broke out; on 8 July 1914, the New York Times reported that the British government had decided to "dot the coasts of the British Isles with a series of towers, each armed with two quick-firing guns of special design," while "a complete circle of towers" was to be built around "naval installations" and "at other especially vulnerable points". By December 1914

3400-461: The shells' predicted trajectory. This was called deflection gun-laying, where "off-set" angles for range and elevation were set on the gunsight and updated as their target moved. In this method, when the sights were on the target, the barrel was pointed at the target's future position. Range and height of the target determined fuse length. The difficulties increased as aircraft performance improved. The British dealt with range measurement first, when it

3468-621: The single artillery branch has been responsible for both home and overseas ground-based air defence, although there was divided responsibility with the Royal Navy for air defence of the British Isles in World War I . However, during the Second World War , the RAF Regiment was formed to protect airfields everywhere, and this included light air defences. In the later decades of the Cold War this included

SECTION 50

#1733085047176

3536-477: The speed and direction of both the target and the projectile. Throughout the 20th century, air defence was one of the fastest-evolving areas of military technology, responding to the evolution of aircraft and exploiting technology such as radar, guided missiles and computing (initially electromechanical analogue computing from the 1930s on, as with equipment described below). Improvements were made to sensors, technical fire control, weapons, and command and control. At

3604-422: The start of the 20th century these were either very primitive or non-existent. Initially sensors were optical and acoustic devices developed during World War I and continued into the 1930s, but were quickly superseded by radar, which in turn was supplemented by optoelectronics in the 1980s. Command and control remained primitive until the late 1930s, when Britain created an integrated system for ADGB that linked

3672-463: The target and having its height. Second, that the target would maintain a steady course, speed and height. This HAA was to engage targets up to 24,000 ft (7.3 km). Mechanical time fuses were required because the speed of powder burning varied with height, so fuse length was not a simple function of time of flight. Automated fire ensured a constant rate of fire that made it easier to predict where each shell should be individually aimed. In 1925

3740-409: The war and accumulated large amounts of data that was subjected to extensive analysis. As a result, they published the two-volume Textbook of Anti-Aircraft Gunnery in 1924–1925. It included five key recommendations for HAA equipment: Two assumptions underpinned the British approach to HAA fire; first, aimed fire was the primary method and this was enabled by predicting gun data from visually tracking

3808-437: The war ended, it was clear that the increasing capabilities of aircraft would require better means of acquiring targets and aiming at them. Nevertheless, a pattern had been set: anti-aircraft warfare would employ heavy weapons to attack high-altitude targets and lighter weapons for use when aircraft came to lower altitudes. World War I demonstrated that aircraft could be an important part of the battlefield, but in some nations it

3876-440: The years immediately after World War I, the prospect of another major war seemed remote, particularly in Europe, where the most militarily capable nations were, and little financing was available. Four years of war had seen the creation of a new and technically demanding branch of military activity. Air defence had made huge advances, albeit from a very low starting point. However, it was new and often lacked influential 'friends' in

3944-571: Was capable of providing data suitable for controlling AA guns, and the British Radar, Gun Laying, Mark I , was designed to be used on AA gun positions and was in use by 1939. The Treaty of Versailles prevented Germany having AA weapons, and for example, the Krupps designers joined Bofors in Sweden. Some World War I guns were retained and some covert AA training started in the late 1920s. Germany introduced

4012-581: Was determined by time of flight, but the burning rate of the gunpowder was affected by altitude. The British pom-poms had only contact-fused ammunition. Zeppelins , being hydrogen-filled balloons, were targets for incendiary shells and the British introduced these with airburst fuses, both shrapnel type-forward projection of incendiary "pot" and base ejection of an incendiary stream. The British also fitted tracers to their shells for use at night. Smoke shells were also available for some AA guns, these bursts were used as targets during training. German air attacks on

4080-404: Was electrical; the operator entered the target range and had displays at guns; it was used with their 75 mm. The British Wilson-Dalby gun director used a pair of trackers and mechanical tachymetry; the operator entered the fuse length, and deflection angles were read from the instruments. By the start of World War I , the 77 mm had become the standard German weapon, and came mounted on

4148-399: Was equipped with a Type 21 early-warning radar on her foremast . The ship was commissioned on 31 May 1943 into the 11th Destroyer Squadron. Wakatsuki participated in rescuing sailors from Shōkaku (June 1944) and Zuikaku (October 1944) when each was sunk by US forces. Both of these carriers participated in the attack on Pearl Harbor. On 11 November 1944, Wakatsuki was escorting

SECTION 60

#1733085047176

4216-639: Was found to be heavily damaged from both her sinking and impact with the seafloor, resting on her starboard side. Anti-aircraft warfare Anti-aircraft warfare is the counter to aerial warfare and includes "all measures designed to nullify or reduce the effectiveness of hostile air action". It encompasses surface-based, subsurface ( submarine-launched ), and air-based weapon systems, in addition to associated sensor systems, command and control arrangements, and passive measures (e.g. barrage balloons ). It may be used to protect naval , ground , and air forces in any location. However, for most countries,

4284-575: Was probably first used by the UK when Air Defence of Great Britain (ADGB) was created as a Royal Air Force command in 1925. However, arrangements in the UK were also called "anti-aircraft", abbreviated as AA , a term that remained in general use into the 1950s. After the First World War it was sometimes prefixed by "light" or "heavy" (LAA or HAA) to classify a type of gun or unit. Nicknames for anti-aircraft guns include "AA", "AAA" or "triple-A" (abbreviations of "anti-aircraft artillery"), "flak" (from

4352-472: Was realised that range was the key to producing a better fuse setting. This led to the height/range finder (HRF), the first model being the Barr & Stroud UB2, a two-metre optical coincident rangefinder mounted on a tripod. It measured the distance to the target and the elevation angle, which together gave the height of the aircraft. These were complex instruments and various other methods were also used. The HRF

4420-572: Was replaced by the nine-foot optical base UB 7 and the eighteen-foot optical base UB 10 (only used on static AA sites). Goertz in Germany and Levallois in France produced five m (16 ft) instruments. However, in most countries the main effort in HAA guns until the mid-1930s was improving existing ones, although various new designs were on drawing boards. From the early 1930s eight countries developed radar ; these developments were sufficiently advanced by

4488-551: Was soon joined by the height/fuse indicator (HFI), this was marked with elevation angles and height lines overlaid with fuse length curves, using the height reported by the HRF operator, the necessary fuse length could be read off. However, the problem of deflection settings — "aim-off" — required knowing the rate of change in the target's position. Both France and the UK introduced tachymetric devices to track targets and produce vertical and horizontal deflection angles. The French Brocq system

4556-501: Was the guns protecting spotting balloons, in which case the altitude could be accurately measured from the length of the cable holding the balloon. The first issue was ammunition. Before the war it was recognised that ammunition needed to explode in the air. Both high explosive (HE) and shrapnel were used, mostly the former. Airburst fuses were either igniferious (based on a burning fuse) or mechanical (clockwork). Igniferious fuses were not well suited for anti-aircraft use. The fuse length

4624-496: Was the prospect of strategic air attack that was the main issue, presenting both a threat and an opportunity. The experience of four years of air attacks on London by Zeppelins and Gotha G.V bombers had particularly influenced the British and was one of if not the main driver for forming an independent air force. As the capabilities of aircraft and their engines improved it was clear that their role in future war would be even more critical as their range and weapon load grew. However, in

#175824