An attack aircraft , strike aircraft , or attack bomber is a tactical military aircraft that has a primary role of carrying out airstrikes with greater precision than bombers , and is prepared to encounter strong low-level air defenses while pressing the attack. This class of aircraft is designed mostly for close air support and naval air-to-surface missions, overlapping the tactical bomber mission. Designs dedicated to non-naval roles are often known as ground-attack aircraft .
133-662: The Cessna A-37 Dragonfly , or Super Tweet , is a light attack aircraft designed and produced by the American aircraft manufacturer Cessna . It was developed during the Vietnam War in response to military interest in new counter-insurgency (COIN) aircraft to replace aging types such as the Douglas A-1 Skyraider . A formal United States Air Force (USAF) evaluation of the T-37 Tweet basic trainer for
266-466: A Dragunov sniper rifle killed the co-pilot, causing the pilot to eject, and another that was shot down by an SA-7 missile on November 23, 1990. Nine A-37s remained in operational condition by the end of the war. The A-37B was also exported to Latin America, mostly during the 1970s. It was well suited to their needs because of its simplicity, low cost, and effectiveness for insurgent warfare. Most of
399-399: A convergent-divergent nozzle is needed on high-speed aircraft. The engine thrust is highest if the static pressure of the gas reaches the ambient value as it leaves the nozzle. This only happens if the nozzle exit area is the correct value for the nozzle pressure ratio (npr). Since the npr changes with engine thrust setting and flight speed this is seldom the case. Also at supersonic speeds
532-680: A rotating air compressor powered by a turbine , with the leftover power providing thrust through the propelling nozzle —this process is known as the Brayton thermodynamic cycle . Jet aircraft use such engines for long-distance travel. Early jet aircraft used turbojet engines that were relatively inefficient for subsonic flight. Most modern subsonic jet aircraft use more complex high-bypass turbofan engines . They give higher speed and greater fuel efficiency than piston and propeller aeroengines over long distances. A few air-breathing engines made for high-speed applications (ramjets and scramjets ) use
665-603: A 102mm anti-ship cannon, The BK 7,5 was unsurpassed as an aircraft-fitted gun until 1971, when the four-engine Lockheed AC-130 E Spectre; equipped with a 105 mm M102 howitzer , entered service with the US Air Force.) In the immediate post war era the piston-engined ground-attack aircraft remained useful since all of the early jets lacked endurance due to the fuel consumption rates of the jet engines. The higher powered piston engine types that had been too late for World War II were still capable of holding their own against
798-711: A basic trainer aircraft. In late 1962, the United States Air Force 's (USAF) Special Air Warfare Center at Eglin Air Force Base 's Hurlburt Field in Florida evaluated two T-37Cs for the mission. The USAF determined the T-37 to be a promising COIN aircraft and expressed its interest in a prospective improved version that would be able to carry a much larger payload along with greater endurance and better short-field performance. These requirements meant
931-450: A battlefield, their slower speeds made them extremely vulnerable to ground fire, as did the lighter construction of fighters. The survivability of attack aircraft was guaranteed by their speed/power, protection (i.e. armor panels) and strength of construction; Germany was the first country to produce dedicated ground-attack aircraft (designated CL-class and J-class ). They were put into use in autumn 1917, during World War I. Most notable
1064-605: A class of Schlacht ("battle") aircraft, such as the Henschel Hs 123 . Moreover, the experiences of German Condor Legion during the Spanish Civil War , against an enemy with few fighter aircraft, changed ideas about ground attack. Though equipped with generally unsuitable designs such as the Henschel Hs 123 and cannon -armed versions of the Heinkel He 112 , their armament and pilots proved that aircraft were
1197-408: A compressor ( axial , centrifugal , or both), mixing fuel with the compressed air, burning the mixture in the combustor , and then passing the hot, high pressure air through a turbine and a nozzle . The compressor is powered by the turbine, which extracts energy from the expanding gas passing through it. The engine converts internal energy in the fuel to increased momentum of the gas flowing through
1330-483: A few minor changes relative to the prototypes, to be rebuilt from existing T-37Bs. These aircraft were initially designated AT-37D , but the designation was quickly changed to A-37A . The second prototype YAT-37D was pulled out of the USAF Museum and upgraded to A-37A standards as part of the test program. The A-37A had a gross takeoff weight of 12,000 lb (5,400 kg), of which 2,700 lb (1,200 kg)
1463-604: A high altitude bomber escort, but gradually found that role filled by the North American P-51 Mustang (because of its much longer range and greater maneuverability). The P-47 was also heavier and more robust than the P-51 and regarded therefore, as an " energy fighter ": ideal for high-speed dive-and-climb tactics, including strafing attacks. Its armament of eight 0.50 caliber machine guns was effective against Axis infantry and light vehicles in both Europe and
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#17327649879821596-427: A higher priority than fuel efficiency, fans tend to be smaller or absent. Because of these distinctions, turbofan engine designs are often categorized as low-bypass or high-bypass , depending upon the amount of air which bypasses the core of the engine. Low-bypass turbofans have a bypass ratio of around 2:1 or less. The term Advanced technology engine refers to the modern generation of jet engines. The principle
1729-406: A jet of water. The mechanical arrangement may be a ducted propeller with nozzle, or a centrifugal compressor and nozzle. The pump-jet must be driven by a separate engine such as a Diesel or gas turbine . All jet engines are reaction engines that generate thrust by emitting a jet of fluid rearwards at relatively high speed. The forces on the inside of the engine needed to create this jet give
1862-404: A lack of Air Force enthusiasm for the ground-attack role, developed the dedicated attack helicopter . On 17 January 1991, Task Force Normandy began its attack on two Iraqi anti-aircraft missile sites. TF Normandy, under the command of LTC Richard A. "Dick" Cody , consisted of nine AH-64 Apaches , one UH-60 Black Hawk and four Air Force MH-53J Pave Low helicopters. The purpose of this mission
1995-426: A large number of different types of jet engines, all of which achieve forward thrust from the principle of jet propulsion . Commonly aircraft are propelled by airbreathing jet engines. Most airbreathing jet engines that are in use are turbofan jet engines, which give good efficiency at speeds just below the speed of sound. A turbojet engine is a gas turbine engine that works by compressing air with an inlet and
2128-675: A light aircraft mixing all the roles that required extensive communication with land forces: reconnaissance, liaison, artillery spotting , aerial supply, and, last but not least, occasional strikes on the battlefield. The concept was similar to front-line aircraft used in the World War I, which was called the CL class in the German Empire. Eventually the RAF's experience showed types such as Westland Lysander to be unacceptably vulnerable and it
2261-670: A light attack aircraft. The Soviets' similar Sukhoi Su-25 ( Frogfoot ) found success in the "flying artillery" role with many air forces. The UK has completely retired the BAE Harrier II in 2011, and the Panavia Tornado dedicated attack-reconnaissance aircraft in 2019. It obtained the F-35 in 2018 and it retains its fleet of Eurofighter Typhoon multirole fighters. [REDACTED] Media related to Attack aircraft at Wikimedia Commons Jet engine A jet engine
2394-435: A particular engine design that if some bumps in a bypass duct are smoothed out the air will flow more smoothly giving a pressure loss reduction of x% and y% less fuel will be needed to get the take-off thrust, for example. This understanding comes under the engineering discipline Jet engine performance . How efficiency is affected by forward speed and by supplying energy to aircraft systems is mentioned later. The efficiency of
2527-759: A powerplant for the world's first jet- fighter aircraft , the Messerschmitt Me 262 (and later the world's first jet- bomber aircraft, the Arado Ar 234 ). A variety of reasons conspired to delay the engine's availability, causing the fighter to arrive too late to improve Germany's position in World War II , however this was the first jet engine to be used in service. Meanwhile, in Britain the Gloster E28/39 had its maiden flight on 15 May 1941 and
2660-474: A production contract was not immediately forthcoming until an uptick in combat intensity and aircraft losses became apparent. An initial batch of 25 A-37As was deployed to Vietnam under the "Combat Dragon" evaluation program in August 1967, flying from Bien Hoa Air Base on various missions, including close air support , helicopter escort, FAC , and night interdiction . The type proved itself to be effective in
2793-609: A redesigned instrument panel to make the aircraft easier to fly from either seat, an automatic engine inlet de-icing system, and revised landing gear. Like its predecessors, the A-37B was not pressurized. In order to accommodate the increased weight, the A-37B was powered by General Electric J85-GE-17A engines, providing 2,850 lbf (12.7 kN) thrust each. These engines were canted slightly outward and downward to improve single-engine handling. Air commando pilots in Vietnam operating
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#17327649879822926-503: A revival in the USAF's interest in COIN aircraft. The YAT-37D seemed like a promising candidate for the role, yet the USAF felt that the only means of being certain was to evaluate the aircraft in real world combat. At the time, this was a relatively unorthodox approach to military aircraft procurement. The USAF issued a contract to Cessna for a pre-production batch of 39 YAT-37Ds, opting for only
3059-410: A separate attack aircraft category was greatly diminished by the introduction of precision-guided munitions which allowed almost any aircraft to carry out this role while remaining safe at high altitude. Attack helicopters also have overtaken many remaining roles that could only be carried out at lower altitudes. Since the 1960s, only two dedicated attack aircraft designs have been widely introduced,
3192-401: A slight increase in ordnance. In August 1967, 25 A-37As were deployed to Vietnam under the "Combat Dragon" evaluation program, and flew from Bien Hoa Air Base on USAF "air commando" missions, including close air support , helicopter escort, FAC , and night interdiction . Combat loads included high-explosive bombs, cluster munition dispensers, unguided rocket packs, napalm tanks, and
3325-530: A strong thrust on the engine which pushes the craft forwards. Jet engines make their jet from propellant stored in tanks that are attached to the engine (as in a 'rocket') as well as in duct engines (those commonly used on aircraft) by ingesting an external fluid (very typically air) and expelling it at higher speed. A propelling nozzle produces a high velocity exhaust jet . Propelling nozzles turn internal and pressure energy into high velocity kinetic energy. The total pressure and temperature don't change through
3458-439: A substantial initial forward airspeed before it can function. Ramjets are considered the simplest type of air breathing jet engine because they have no moving parts in the engine proper, only in the accessories. Scramjets differ mainly in the fact that the air does not slow to subsonic speeds. Rather, they use supersonic combustion. They are efficient at even higher speed. Very few have been built or flown. The rocket engine uses
3591-421: A supersonic afterburning engine or 2200 K with afterburner lit. The pressure entering the nozzle may vary from 1.5 times the pressure outside the nozzle, for a single stage fan, to 30 times for the fastest manned aircraft at Mach 3+. Convergent nozzles are only able to accelerate the gas up to local sonic (Mach 1) conditions. To reach high flight speeds, even greater exhaust velocities are required, and so
3724-639: A task of converted trainers, like the BAE Systems Hawk or Aero L-39 Albatros , and many trainers are built with this task in mind, like the CASA C-101 or the Aermacchi MB-339 . Such counter-insurgency aircraft are popular with air forces which cannot afford to purchase more expensive multirole aircraft, or do not wish to risk the few such aircraft they have on light ground attack missions. A proliferation of low intensity conflicts in
3857-402: A test stand, sucks in fuel and generates thrust. How well it does this is judged by how much fuel it uses and what force is required to restrain it. This is a measure of its efficiency. If something deteriorates inside the engine (known as performance deterioration ) it will be less efficient and this will show when the fuel produces less thrust. If a change is made to an internal part which allows
3990-674: A time, with the second prototype "put out to pasture" at the National Museum of the United States Air Force at Wright-Patterson Air Force Base in Ohio . The conflict in Southeast Asia continued to escalate during the mid 1960s. Losses of Douglas A-1 Skyraider close-support aircraft in USAF, United States Navy , and Republic of Vietnam Air Force service proved to be greater than anticipated, which led to
4123-461: A two-stage axial compressor feeding a single-sided centrifugal compressor . Practical axial compressors were made possible by ideas from A.A.Griffith in a seminal paper in 1926 ("An Aerodynamic Theory of Turbine Design"). Whittle would later concentrate on the simpler centrifugal compressor only. Whittle was unable to interest the government in his invention, and development continued at a slow pace. In Spain, pilot and engineer Virgilio Leret Ruiz
Cessna A-37 Dragonfly - Misplaced Pages Continue
4256-483: A very effective weapon, even without bombs. This led to some support within the Luftwaffe for the creation of an aircraft dedicated to this role, resulting in tenders for a new "attack aircraft". This led to the introduction (in 1942) of a unique single-seat, twin-engine attack aircraft, the slow-moving but heavily armored and formidably armed Henschel Hs 129 Panzerknacker ("Safecracker" /"Tank Cracker"). In Japan,
4389-467: A wide range of munitions. During October 1964, the first YAT-37D performed its maiden flight , followed one year later by the second prototype. The second prototype was equipped with four stores pylons under each wing as opposed to three, the first prototype was subsequently upgraded to this configuration as well. Test results were good, however, the USAF's interest in counter-insurgency (COIN) aircraft had decreased over time. The program went into limbo for
4522-493: Is a type of reaction engine , discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion . While this broad definition may include rocket , water jet , and hybrid propulsion, the term jet engine typically refers to an internal combustion air-breathing jet engine such as a turbojet , turbofan , ramjet , pulse jet , or scramjet . In general, jet engines are internal combustion engines . Air-breathing jet engines typically feature
4655-426: Is considered an attack mission . In United States Navy vocabulary, the alternative designation for the same activity is a strike mission . Attack missions are principally divided into two categories: air interdiction and close air support . In the last several decades, the rise of the ubiquitous multi-role fighter has created some confusion about the difference between attack and fighter aircraft. According to
4788-507: Is documented in the story of Ottoman soldier Lagâri Hasan Çelebi , who reportedly achieved flight using a cone-shaped rocket in 1633. The earliest attempts at airbreathing jet engines were hybrid designs in which an external power source first compressed air, which was then mixed with fuel and burned for jet thrust. The Italian Caproni Campini N.1 , and the Japanese Tsu-11 engine intended to power Ohka kamikaze planes towards
4921-443: Is that a turbine engine will function more efficiently if the various sets of turbines can revolve at their individual optimum speeds, instead of at the same speed. The true advanced technology engine has a triple spool, meaning that instead of having a single drive shaft, there are three, in order that the three sets of blades may revolve at different speeds. An interim state is a twin-spool engine, allowing only two different speeds for
5054-400: Is the propellant flow in kg/s, A e {\displaystyle A_{e}} is the cross-sectional area at the exit of the exhaust nozzle, and p {\displaystyle p} is the atmospheric pressure. Combined-cycle engines simultaneously use two or more different principles of jet propulsion. A water jet, or pump-jet, is a marine propulsion system that uses
5187-570: Is used for launching satellites, space exploration and crewed access, and permitted landing on the Moon in 1969. Rocket engines are used for high altitude flights, or anywhere where very high accelerations are needed since rocket engines themselves have a very high thrust-to-weight ratio . However, the high exhaust speed and the heavier, oxidizer-rich propellant results in far more propellant use than turbofans. Even so, at extremely high speeds they become energy-efficient. An approximate equation for
5320-518: The Douglas A-1 Skyraider were less than fully satisfactory, in part because younger pilots, having been trained and used to flying jet aircraft, had difficulties adapting to the A-1's increasingly uncommon features for a frontline combat aircraft, such as a radial engine and a 'taildragger' landing gear arrangement. At the time, the Cessna T-37 Tweet was in widespread use by the military as
5453-659: The F-111 "Aardvark" was designated F despite having only minimal air-to-air capabilities. Only a single aircraft in the USAF's current inventory bears a simple, unmixed "A" designation: the A-10 Thunderbolt II. British designations have included FB for fighter-bomber and more recently "G" for "Ground-attack" as in Harrier GR1 (meaning "Ground-attack/Reconnaissance, Mark 1"). Imperial Japanese Navy designation use "B" to designate carrier attack bomber such as
Cessna A-37 Dragonfly - Misplaced Pages Continue
5586-903: The Gloster Meteor finally entered service with the RAF in July 1944. These were powered by turbojet engines from Power Jets Ltd., set up by Frank Whittle. The first two operational turbojet aircraft, the Messerschmitt Me 262 and then the Gloster Meteor entered service within three months of each other in 1944; the Me 262 in April and the Gloster Meteor in July. The Meteor only saw around 15 aircraft enter World War II action, while up to 1400 Me 262 were produced, with 300 entering combat, delivering
5719-442: The Henschel Hs 123 ). Although not a synonymous class with ground-attack aircraft, fighter-bombers were usually used for the role, and proved to excel at it, even when they were only lightly armored. The Royal Air Force and United States Army Air Forces relegated obsolescent fighters to this role, while cutting-edge fighters would serve as interceptors and establish air superiority . The United States Navy , in distinction to
5852-835: The Imperial Japanese Navy had developed the Aichi D3A dive bomber (based on the Heinkel He 70 ) and the Mitsubishi B5M light attack bomber. Both, like their US counterparts, were lightly armored types, and were critically reliant on surprise attacks and the absence of significant fighter or AA opposition. During the Winter War , the Soviet Air Forces used the Polikarpov R-5 SSS, and Polikarpov R-Z Sh, as attack aircraft. Perhaps
5985-791: The Junkers Ju 87 Stuka greatly outnumbered the Hs 129, while the Petlyakov Pe-2 was used for this role in spite of not being specifically designed for it. In the latter part of World War II, the fighter-bomber began to take over many attack roles, a transition that continued in the post-war era. Jet -powered examples were relatively rare but not unknown, such as the Blackburn Buccaneer . The U.S. Navy continued to introduce new aircraft in their A - series , but these were mostly similar to light and medium bombers . The need for
6118-519: The McDonnell F-101 Voodoo ; a feat was partially due to the convenient placement of multiple access panels at strategic locations. The A-37 did not typically attract attention from the media, unlike many other USAF combat aircraft used in the theatre; one reason for this was that the type was never flown into North Vietnam, where hostile air defenses were proved to be challenging, claiming to have downed almost 200 F-4s and 300 F-105s by
6251-1017: The Nakajima B5N Type-97 bomber although these aircraft are mostly used for torpedo attack and level bombing. They also use "D" to specifically designate carrier dive bomber like the Yokosuka D4Y Suisei . However by the end of the world war II, the IJN introduced the Aichi B7A Ryusei which could performed both torpedo bombing and dive bombing rendering the "D" designation redundant. The NATO reporting names for Soviet/Russian ground-attack aircraft at first started with "B" categorizing them as bombers, as in case of Il-10 'Beast'. But later they were usually classified as fighters ("F")—possibly because (since Sukhoi Su-7 ) they were similar in size and visual appearance to Soviet fighters, or were simply derivatives of such. In
6384-608: The North American B-25G Mitchell and de Havilland Mosquito Tsetse . In Germany and the USSR , where they were known as Schlachtflugzeug ("battle aircraft") or sturmovik ("storm trooper") respectively, this role was carried out by purpose-designed and heavily armored aircraft such as the Henschel Hs 129 and Ilyushin Il-2 . The Germans and Soviets also used light bombers in this role: cannon-armed versions of
6517-667: The PLAAF , ground-attack aircraft are given the designation "Q". So far this has only been given to the Nanchang Q-5 . The attack aircraft as a role was defined by its use during World War I , in support of ground forces on battlefields. Battlefield support is generally divided into close air support and battlefield air interdiction, the first requiring strict and the latter only general cooperation with friendly surface forces. Such aircraft also attacked targets in rear areas. Such missions required flying where light anti-aircraft fire
6650-721: The Pacific . While machine guns and cannon were initially sufficient, the evolution of well-armored tanks required heavier weapons. To augment bombs, high explosive rockets were introduced, although these unguided projectiles were still "barely adequate" because of their inaccuracy. For the British RP3 , one hit per sortie was considered acceptable. However, even a near miss with rockets could cause damage or injuries to "soft targets," and patrols by Allied rocket-armed aircraft over Normandy disrupted or even completely paralyzed German road traffic. They also affected morale, because even
6783-475: The Peruvian Air Force . On 10 February 1983, a Peruvian A-37 was shot down by an Ecuadorian Air Force IAI Kfir over a border dispute. On 20 April 2001, a Peruvian A-37B shot down a civilian Cessna A185E floatplane with a minigun under surveillance by CIA controllers who advised against engaging. The Peruvian controller had the final authority in this situation, and he believed that the flight
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#17327649879826916-527: The SUU-11/A Minigun pod. For the majority of missions, the aircraft also carried two additional external fuel tanks on the inner stores pylons. During this period, the A-37As flew thousands of sorties; none were lost to enemy fire, although two were wrecked in landing accidents. While the aircraft was formally named the "Dragonfly", many pilots called it the "Super Tweet". The Combat Dragon program
7049-692: The Salvadoran Civil War , supplied by the United States in 1983 as a replacement for the Salvadoran Air Force's Dassault Ouragans , several of which had been destroyed on the ground by the FMLN . A-37Bs were used to bomb rebel bases, columns, towns, provided close air support, and flew interdiction missions. A total of 21 A-37Bs and 9 OA-37Bs were supplied during the war, one of which was lost on November 18, 1989 when fire from
7182-605: The United States occupation of Haiti and Nicaragua . The United States Army Air Corps was notable for its creation of a separate "A-" designation for attack types, distinct from and alongside "B-" for bomber types and "P-" for pursuit (later replaced by "F-" for fighter) aircraft. The first designated attack type to be operational with the USAAC was the Curtiss A-2 Falcon . Nevertheless, such aircraft, including
7315-500: The aeolipile , a device described by Hero of Alexandria in 1st-century Egypt . This device directed steam power through two nozzles to cause a sphere to spin rapidly on its axis. It was seen as a curiosity. Meanwhile, practical applications of the turbine can be seen in the water wheel and the windmill . Historians have further traced the theoretical origin of the principles of jet engines to traditional Chinese firework and rocket propulsion systems. Such devices' use for flight
7448-564: The carrier-based nuclear strike Douglas A-3 Skywarrior and North American A-5 Vigilante , while the Grumman A-6 Intruder , F-105 Thunderchief , F-111 , F-117 Nighthawk , LTV A-7 Corsair II , Sukhoi Su-25 , A-10 Thunderbolt II , Panavia Tornado , AMX , Dassault Étendard , Super Étendard and others were designed specifically for ground-attack, strike , close support and anti-armor work, with little or no air-to-air capability. Ground attack has increasingly become
7581-664: The gasoline -fuelled HeS 3 of 5 kN (1,100 lbf), which was fitted to Heinkel's simple and compact He 178 airframe and flown by Erich Warsitz in the early morning of August 27, 1939, from Rostock -Marienehe aerodrome , an impressively short time for development. The He 178 was the world's first jet plane. Heinkel applied for a US patent covering the Aircraft Power Plant by Hans Joachim Pabst von Ohain on May 31, 1939; patent number US2256198, with M Hahn referenced as inventor. Von Ohain's design, an axial-flow engine, as opposed to Whittle's centrifugal flow engine,
7714-558: The interdiction and tactical bombing roles. Today it remains the only dedicated fixed-wing ground-attack aircraft in any U.S. military service. Overall U.S. experience in the Gulf War , Kosovo War , Afghanistan War , and Iraq War has resulted in renewed interest in such aircraft. The U.S. Air Force is currently researching a replacement for the A-10 and started the OA-X program to procure
7847-402: The ram effect of the vehicle's speed instead of a mechanical compressor. The thrust of a typical jetliner engine went from 5,000 lbf (22 kN) ( de Havilland Ghost turbojet) in the 1950s to 115,000 lbf (510 kN) ( General Electric GE90 turbofan) in the 1990s, and their reliability went from 40 in-flight shutdowns per 100,000 engine flight hours to less than 1 per 100,000 in
7980-481: The " Night Witches " utilised an obsolescent, wooden light trainer biplane type, the Polikarpov Po-2 and small anti-personnel bombs in "harassment bombing" attacks that proved difficult to counter. Wartime experience showed that poorly armored and/or lightly built, pre-war types were unacceptably vulnerable, especially to fighters. Nevertheless, skilled crews could be highly successful in those types, such as
8113-591: The 1,420 maritime strike variants of the North American B-25 Mitchell G/H, which mounted either a M4 cannon , or light-weight T13E1 or M5 versions of the same gun. These weapons, however, were hand-loaded, had shorter barrels and/or a lower muzzle velocity than the BK 7,5 and, therefore, poorer armor penetration, accuracy and rate of fire. (Except for versions of the Piaggio P.108 armed with
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#17327649879828246-537: The 1950s, the jet engine was almost universal in combat aircraft, with the exception of cargo, liaison and other specialty types. By this point, some of the British designs were already cleared for civilian use, and had appeared on early models like the de Havilland Comet and Avro Canada Jetliner . By the 1960s, all large civilian aircraft were also jet powered, leaving the piston engine in low-cost niche roles such as cargo flights. The efficiency of turbojet engines
8379-588: The A-2's replacement, the Curtiss A-12 Shrike , were unarmored and highly vulnerable to AA fire. The British Royal Air Force focused primarily on strategic bombing, rather than ground attack. However, like most air arms of the period it did operate attack aircraft, named Army Cooperation in RAF parlance, which included the Hawker Hector , Westland Lysander and others. Aviation played a role in
8512-618: The A-37 on only one active engine, an uncommon practice outside of emergency situations at that time. The 20 mm (0.787 in) GPU-2/A and AMD 30 mm (1.18 in) cannon pods were tested with favorable results on the A-37B, but reports indicate that such pods were either seldom or never used in operation. The A-37 proved to excel at the close air support mission. It was able to engage targets at speeds roughly 100 miles per hour slower than swept-wing fighters and by doing so improve its bombing accuracy; pilots were reportedly able to achieve an average accuracy of 45 feet (14 m). While
8645-413: The A-37. In anticipation of a need for additional combat aircraft, the service subsequently procured A-37s from the United States as well. The Guatemalan Air Force flew the A-37 in extensive counter-insurgency operations throughout the 1970s-1990s, losing one aircraft in action in 1985. The type has also been widely used for counter-narcotics operations. During the mid-1970s, 36 A-37Bs were procured for
8778-438: The A-37; it saw active use during the Salvadoran Civil War . Over 200 aircraft were also supplied to the Republic of Vietnam Air Force (RVNAF), and numerous A-37Bs would be captured by North Vietnamese forces near the conflict's end. During the early 1960s, American military involvement in Vietnam was growing, leading to strong interest from military officials in counter-insurgency (COIN) aircraft . Existing platforms such as
8911-496: The A-37A had found single-engine cruise an effective means of improving their flight endurance. Modifications were made to control surfaces to improve handling. To improve aircraft and crew survivability, the A-37B was fitted with redundant elevator control runs that were placed as far apart as possible. The ejection seats were armored, the cockpit was lined with nylon flak curtains, and foam-filled self-sealing fuel tanks were installed. To extend endurance, pilots were authorized to fly
9044-399: The A-37Bs exported south had the refueling probe shortened to act as a single-point ground refueling probe, or deleted completely. During the late 1970s, amid rising tensions between Argentina and Chile over conflicting territorial claims, commonly referred to be as the Beagle conflict , the Chilean Air Force retrofitted their T-37s into an armed configuration near identical to that of
9177-461: The American Fairchild Republic A-10 Thunderbolt II and the Soviet/Russian Sukhoi Su-25 Frogfoot. A variety of light attack aircraft has also been introduced in the post-World War II era, usually based on adapted trainers or other light fixed-wing aircraft. These have been used in counter-insurgency operations. U.S. attack aircraft are currently identified by the prefix A- , as in " A-6 Intruder " and " A-10 Thunderbolt II ". However, until
9310-432: The Brazilian Constitutionalist Revolution of 1932 , although both sides had few aircraft. The federal government had approximately 58 aircraft divided between the Navy and the Army , as the Air Force at this time did not constitute an independent branch. In contrast, the rebels had only two Potez 25 planes and two Waco CSO , plus a small number of private aircraft. During the 1930s, Nazi Germany had begun to field
9443-413: The British embassy in Madrid a few years later by his wife, Carlota O'Neill , upon her release from prison. In 1935, Hans von Ohain started work on a similar design to Whittle's in Germany, both compressor and turbine being radial, on opposite sides of the same disc, initially unaware of Whittle's work. Von Ohain's first device was strictly experimental and could run only under external power, but he
9576-492: The COIN mission was conducted in late 1962, after which it was concluded that it could be modified to effectively perform the role. The attack-orientated A-37 was directly derived from the T-37, roughly doubling in both all-up weight and engine thrust to permit considerable quantities of munitions to be carried along with extended flight endurance and additional mission avionics. The prototype YAT-37D performed its maiden flight during October 1964. While test results were positive,
9709-694: The German Focke-Wulf Fw 190 , the British Hawker Typhoon and the US Republic P-47 Thunderbolt . The Typhoon, which was disappointing as a fighter, due to poor high altitude performance, was very fast at low altitudes and thus became the RAF's premier ground attack fighter. It was armed with four 20mm cannon , augmented first with bombs, then rockets. Likewise the P-47 was designed and intended for use as
9842-852: The North Vietnamese to attack Tan Son Nhut Air Base , still held by the South Vietnamese. Approximately 187 A-37Bs are believed to have been in RVNAF service by the Fall of Saigon in April 1975. Ninety-two of these were recovered by the US, while the other 95 aircraft would be operated by the Vietnam People's Air Force in missions over Cambodia and during the China conflict in 1979 . These "renegade" aircraft were phased out of service in
9975-534: The Pratt & Whitney J57 and J75 models. There is also a derivative of the P&;W JT8D low-bypass turbofan that creates up to 35,000 horsepower (HP) . Jet engines are also sometimes developed into, or share certain components such as engine cores, with turboshaft and turboprop engines, which are forms of gas turbine engines that are typically used to power helicopters and some propeller-driven aircraft. There are
10108-583: The T-37C; a remarkable fraction of the loaded weight, 5,800 lb (2,600 kg), could be external stores. In practice, the A-37B usually operated with at least two and sometimes four underwing fuel tanks to improve combat endurance. The A-37B added a refueling probe to the nose, leading to pipes wrapped around the lower lip of the canopy, for probe-and-drogue aerial refueling . This was an unusual fit for USAF aircraft, which traditionally are configured for boom refueling. Other improvements included updated avionics,
10241-597: The U.S. Marine Corps has noted similar problems. In the late 1960s the United States Air Force requested a dedicated close air support (CAS) plane that became the Fairchild Republic A-10 Thunderbolt II . The A-10 was originally conceived as an anti-armor weapon (the A-X program requirements specifically called for an aircraft mounting a large rotary cannon to destroy massed Warsaw Pact armored forces) with limited secondary capability in
10374-602: The USAAF, preferred the older term "Scout-Bomber", under a "SB-" designation, such as the Curtiss SB2C Helldiver . The Junkers Ju 87s of the German Luftwaffe became virtually synonymous with close air support during the early months of World War II. The British Commonwealth's Desert Air Force , led by Arthur Tedder, became the first Allied tactical formation to emphasize the attack role, usually in
10507-685: The USAAF. It was not until 1946, when the US Navy and US Marine Corps started using the "attack" (A) designation, when it renamed BT2D Skyraider and BTM Mauler to, respectively, AD Skyraider and AM Mauler. As with many aircraft classifications, the definition of attack aircraft is somewhat vague and has tended to change over time. Current U.S. military doctrine defines it as an aircraft which most likely performs an attack mission , more than any other kind of mission. Attack mission means, in turn, specifically tactical air-to-ground action—in other words, neither air-to-air action nor strategic bombing
10640-531: The USAF awarded a contract to Cessna to produce two prototype aircraft, designated YAT-37D ; these were essentially heavily modified T-37s. Specific alterations made for the YAT-37D included the adoption of strengthened wings, the use of larger wingtip fuel tanks of 360 litres (95 US gal) capacity, additional avionics suitable for battlefield communications, navigation, and targeting, toughened landing gear that were suitable for rough-field operation, and
10773-400: The air/combustion gases to flow more smoothly the engine will be more efficient and use less fuel. A standard definition is used to assess how different things change engine efficiency and also to allow comparisons to be made between different engines. This definition is called specific fuel consumption , or how much fuel is needed to produce one unit of thrust. For example, it will be known for
10906-520: The aircraft would have to be considerably heavier and thus necessitate the use of more powerful engines . As to account for the drastic increase in airframe weight along with the need to a significant payload as well, Cessna opted to double the aircraft's engine power by replacing its twin Continental J-69 engines with General Electric J85 -J2/5 turbojet engines, each capable of generating up to 2,400 lbf (11 kN) of thrust. During 1963,
11039-464: The aircraft's slow speed was feared to make it more vulnerable to hostile ground fire, the A-37's relatively small size, atypical speeds, and relatively low altitudes combined to make it somewhat hard to effectively hit with gunfire. The A-37 required a relatively low amount of maintenance compared to contemporary fighters—only two hours of maintenance for each hour of flight time, six times less than that of
11172-407: The broad concept of an attack aircraft. The dedicated attack aircraft as a separate class existed primarily during and after World War II . The precise implementation varied from country to country, and was handled by a wide variety of designs. In the United States and Britain , attack aircraft were generally light bombers or medium bombers , sometimes carrying heavier forward-firing weapons like
11305-595: The conflict's end, the USAF opted to transfer their A-37Bs from the USAF Tactical Air Command (TAC) to TAC-gained units in the Air National Guard and Air Force Reserve . During the early 1980s, these aircraft were assigned to the FAC (Forward Air Control) role and given the designation OA-37B . The OA-37Bs were eventually phased out in the 1980s and 1990s and replaced in the FAC mission by
11438-414: The conflict's end. Instead, A-37s operated in the south, as well as in neighboring Laos and Cambodia , where it was typically used to support US ground forces. A total of 577 A-37Bs were constructed, 254 of which being delivered to the RVNAF. By the war's end, the A-37 had flown over 160,000 combat sorties, during which only 22 USAF aircraft were recorded as lost due to combat. The type remained active in
11571-666: The current U.S. designation system, an attack aircraft ( A ) is designed primarily for air-to-surface (Attack: Aircraft designed to find, attack, and destroy land or sea targets) missions (also known as "attack missions"), while a fighter category F incorporates not only aircraft designed primarily for air-to-air combat , but additionally multipurpose aircraft designed also for ground-attack missions. "F" - Fighter Aircraft were designed to intercept and destroy other aircraft or missiles. This includes multipurpose aircraft also designed for ground support missions such as interdiction and close air support. Just to mention one example amongst many,
11704-599: The divergent area is less than required to give complete internal expansion to ambient pressure as a trade-off with external body drag. Whitford gives the F-16 as an example. Other underexpanded examples were the XB-70 and SR-71. The nozzle size, together with the area of the turbine nozzles, determines the operating pressure of the compressor. This overview highlights where energy losses occur in complete jet aircraft powerplants or engine installations. A jet engine at rest, as on
11837-458: The end of World War II the A- designation was shared between attack planes and light bombers for USAAF aircraft (as opposed to B- prefix for medium or heavy bombers). The US Navy used a separate designation system and at the time preferred to call similar aircraft scout bombers (SB) or torpedo bombers (TB or BT). For example, Douglas SBD Dauntless scout bomber was designated A-24 when used by
11970-405: The end of World War II were unsuccessful. Even before the start of World War II, engineers were beginning to realize that engines driving propellers were approaching limits due to issues related to propeller efficiency, which declined as blade tips approached the speed of sound . If aircraft performance were to increase beyond such a barrier, a different propulsion mechanism was necessary. This
12103-617: The end of the conflict, the USAF's A-37Bs were transferred from the Tactical Air Command (TAC) to TAC-gained units in the Air National Guard and Air Force Reserve . The type was assigned to the FAC (Forward Air Control) role and given the designation OA-37B . The type were eventually phased out in the 1980s and 1990s, having been replaced in the FAC mission by the more formidable Fairchild Republic A-10 Thunderbolt II in American service. Various international operators, many of which being South American countries, also operated
12236-425: The engine is controlled primarily by the operating conditions inside the engine which are the pressure produced by the compressor and the temperature of the combustion gases at the first set of rotating turbine blades. The pressure is the highest air pressure in the engine. The turbine rotor temperature is not the highest in the engine but is the highest at which energy transfer takes place ( higher temperatures occur in
12369-650: The engine, producing thrust. All the air entering the compressor is passed through the combustor, and turbine, unlike the turbofan engine described below. Turbofans differ from turbojets in that they have an additional fan at the front of the engine, which accelerates air in a duct bypassing the core gas turbine engine. Turbofans are the dominant engine type for medium and long-range airliners . Turbofans are usually more efficient than turbojets at subsonic speeds, but at high speeds their large frontal area generates more drag . Therefore, in supersonic flight, and in military and other aircraft where other considerations have
12502-467: The first ground attacks and air combat victories of jet planes. Following the end of the war the German jet aircraft and jet engines were extensively studied by the victorious allies and contributed to work on early Soviet and US jet fighters. The legacy of the axial-flow engine is seen in the fact that practically all jet engines on fixed-wing aircraft have had some inspiration from this design. By
12635-446: The fitting of a General Electric -supplied GAU-2B/A 7.62 mm (0.300 in) "Minigun" Gatling-style machine gun capable of a rate of fire of 3,000 rounds/minute and 1,500 rounds of ammunition that was installed in the right side of the aircraft's nose behind a large access panel along with an accompanying gunsight and gun camera . Perhaps most importantly, three stores pylons were installed on each wing that were compatible with
12768-712: The form of rocket engines they power model rocketry , spaceflight , and military missiles . Jet engines have propelled high speed cars, particularly drag racers , with the all-time record held by a rocket car . A turbofan powered car, ThrustSSC , currently holds the land speed record . Jet engine designs are frequently modified for non-aircraft applications, as industrial gas turbines or marine powerplants . These are used in electrical power generation, for powering water, natural gas, or oil pumps, and providing propulsion for ships and locomotives. Industrial gas turbines can create up to 50,000 shaft horsepower. Many of these engines are derived from older military turbojets such as
12901-614: The form of single-engine Hawker Hurricane and Curtiss P-40 fighter-bombers or specialized "tank-busters", such as the Hurricane Mk IID, armed with two 40 mm Vickers S guns (notably No. 6 Squadron RAF ). At around the same time, a massive invasion by Axis forces had forced the Soviet air forces to quickly expand their army support capacity, such as the Ilyushin Il-2 Sturmovik. The women pilots known as
13034-543: The jets as they were able to both out accelerate and out maneuver the jets. The Royal Navy Hawker Sea Fury fighters and the U.S. Vought F4U Corsair and Douglas A-1 Skyraider were operated during the Korean War while the latter continued to be used throughout the Vietnam War . Many post-World War II era air forces have been reluctant to adopt fixed-wing jet aircraft developed specifically for ground attack. Although close air support and interdiction remain crucial to
13167-540: The late 1970s or early 1980s, likely due to the lack of spare parts. Some of these captured A-37s were shipped to Vietnam's then- Communist allies such as Czechoslovakia , Poland , the Soviet Union and East Germany . Others were sold to private foreign owners; six A-37B became the property of American warbird fans while four A-37Bs became privately owned by individuals in Australia and New Zealand . Following
13300-458: The late 1990s. This, combined with greatly decreased fuel consumption, permitted routine transatlantic flight by twin-engined airliners by the turn of the century, where previously a similar journey would have required multiple fuel stops. The principle of the jet engine is not new; however, the technical advances necessary to make the idea work did not come to fruition until the 20th century. A rudimentary demonstration of jet power dates back to
13433-487: The leading Stuka ace, Hans-Ulrich Rudel , who claimed 500 tanks, a battleship, a cruiser, and two destroyers in 2,300 combat missions. The Bristol Beaufighter , based on an obsolescent RAF bomber, became a versatile twin-engine attack aircraft and served in almost every theatre of the war, in the maritime strike and ground attack roles as well as that of night fighter. Conversely, some mid-war attack types emerged as adaptations of fighters, including several versions of
13566-462: The modern battlefield, attack aircraft are less glamorous than fighters, while air force pilots and military planners have a certain well-cultivated contempt for "mud-movers". More practically, the cost of operating a specialized ground-attack aircraft is harder to justify when compared with multirole combat aircraft . Jet attack aircraft were designed and employed during the Cold War era, such as
13699-574: The most notable attack type to emerge during the late 1930s was the Soviet Ilyushin Il-2 Sturmovik , which became the most-produced military aircraft type in history. As World War II approached, the concept of an attack aircraft was not well defined, and various air services used many different names for widely differing types, all performing similar roles (sometimes in tandem with non-attack roles of bombers, fighters, reconnaissance and other roles. The British concept of
13832-531: The much more formidable Fairchild Republic A-10 Thunderbolt II in USAF, Air National Guard, and USAF Reserve service. OA-37s from the 24th Composite Wing 's (later 24th Wing 's) 24th Tactical Air Support Squadron ( 24 TASS ) also saw service during Operation Just Cause , the United States invasion of Panama in December 1989. A-37Bs were used extensively by the Salvadoran Air Force during
13965-394: The net thrust of a rocket engine is: Where F N {\displaystyle F_{N}} is the net thrust, I sp,vac {\displaystyle I_{\text{sp,vac}}} is the specific impulse , g 0 {\displaystyle g_{0}} is a standard gravity , m ˙ {\displaystyle {\dot {m}}}
14098-404: The nozzle but their static values drop as the gas speeds up. The velocity of the air entering the nozzle is low, about Mach 0.4, a prerequisite for minimizing pressure losses in the duct leading to the nozzle. The temperature entering the nozzle may be as low as sea level ambient for a fan nozzle in the cold air at cruise altitudes. It may be as high as the 1000 Kelvin exhaust gas temperature for
14231-635: The pilot's view. The USAF signed a contract with Cessna in early 1967 for an improved Super Tweet, designated the "A-37B". The initial order was for 57 aircraft, but this was quickly increased to 127; the unit cost of these aircraft were roughly one quarter of the McDonnell Douglas F-4 Phantom II all-weather fighter aircraft. The A-37Bs were primarily intended to be supplied to the Republic of Vietnam Air Force (RVNAF) as replacements for their A-1 Skyraiders . The A-37B prototype
14364-518: The post-World War II era has also expanded need for these types of aircraft to conduct counter-insurgency and light ground attack operations. A primary distinction of post-World War II aviation between the U.S. Army and the U.S. Air Force was that latter had generally been allocated all fixed-wing aircraft , while helicopters were under control of the former; this was governed by the 1948 Key West Agreement . The Army, wishing to have its own resources to support its troops in combat and faced with
14497-512: The prospect of a rocket attack was unnerving. The ultimate development of the cannon-armed light attack aircraft was the small production run in 1944 of the Henschel Hs 129 B-3, armed with a modified PAK 40 75 mm anti-tank gun. This weapon, the Bordkanone BK 7,5 , was the most powerful forward-firing weapon fitted to a production military aircraft during World War II. The only other aircraft to be factory-equipped with similar guns were
14630-424: The same basic physical principles of thrust as a form of reaction engine , but is distinct from the jet engine in that it does not require atmospheric air to provide oxygen; the rocket carries all components of the reaction mass. However some definitions treat it as a form of jet propulsion . Because rockets do not breathe air, this allows them to operate at arbitrary altitudes and in space. This type of engine
14763-509: The specification was dropped before an aircraft went into production. In some air services, dive bombers did not equip ground-attack units, but were treated as a separate class. In Nazi Germany, the Luftwaffe distinguished between the Stuka ( Sturzkampf- , "dive bombing") units, equipped with Junkers Ju 87 from Schlacht ("battle") units, using strafing/low-level bombing types such as
14896-539: The state of the art in compressors. Alan Arnold Griffith published An Aerodynamic Theory of Turbine Design in 1926 leading to experimental work at the RAE . In 1928, RAF College Cranwell cadet Frank Whittle formally submitted his ideas for a turbojet to his superiors. In October 1929, he developed his ideas further. On 16 January 1930, in England, Whittle submitted his first patent (granted in 1932). The patent showed
15029-471: The theater, leading to the USAF issuing a contract to Cessna for an improved Super Tweet, designated the A-37B , in early 1967. It was largely operated over South Vietnam, as well as in neighboring Laos and Cambodia , typically flying close air support missions in coordination with US ground forces. The A-37 proved to be relatively low-maintenance, accurate, and suffered relatively few combat losses. Following
15162-465: The theatre right up until the Fall of Saigon , shortly prior to which efforts were made to retrieve as many as possible before they fell into North Vietnamese hands. As a consequence of the North Vietnamese capture of Da Nang Air Base at the end of March 1975, their forces captured large amounts of stores and equipment, including 33 intact A-37s. On 28 April 1975, several of these captured A-37s were used by
15295-432: The turbines. Ram compression jet engines are airbreathing engines similar to gas turbine engines in so far as they both use the Brayton cycle . Gas turbine and ram compression engines differ, however, in how they compress the incoming airflow. Whereas gas turbine engines use axial or centrifugal compressors to compress incoming air, ram engines rely only on air compressed in the inlet or diffuser. A ram engine thus requires
15428-484: Was carrying drugs out of the country, and so ordered the A-37 pilot to open fire. As a result a US missionary and her daughter were killed. The Cessna A185E crash landed in a river where locals in their boats helped the passengers. Data from Jane's Civil and Military Aircraft Upgrades General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era The initial version of this article
15561-621: Was a part of the Allied armies' strength in holding German attacks and supporting Allied counter-attacks and offensives. Admittedly, the cost to the Allies was high, with the Royal Flying Corps sustaining a loss rate approaching 30% among ground-attack aircraft. After World War I, it was widely believed that using aircraft against tactical targets was of little use other than in harassing and undermining enemy morale; attacking combatants
15694-604: Was able to demonstrate the basic concept. Ohain was then introduced to Ernst Heinkel , one of the larger aircraft industrialists of the day, who immediately saw the promise of the design. Heinkel had recently purchased the Hirth engine company, and Ohain and his master machinist Max Hahn were set up there as a new division of the Hirth company. They had their first HeS 1 centrifugal engine running by September 1937. Unlike Whittle's design, Ohain used hydrogen as fuel, supplied under external pressure. Their subsequent designs culminated in
15827-499: Was an armored twin-engine triplane for ground strafing with eight machine guns and about a ton of armor plate, and the 1922 Aeromarine PG-1 was a combined pursuit (fighter) and ground attack design with a 37mm gun. The United States Marine Corps Aviation applied close air support tactics in the Banana Wars . While they did not pioneer dive bombing tactics, Marine aviators were the first to include it in their doctrine during
15960-431: Was based on a public domain article from Greg Goebel's Vectorsite . Attack aircraft Fighter aircraft often carry out the attack role, although they would not be considered attack aircraft per se ; fighter-bomber conversions of those same aircraft would be considered part of the class. Strike fighters , which have effectively replaced the fighter-bomber and light bomber concepts, also differ little from
16093-406: Was built in 1903 by Norwegian engineer Ægidius Elling . Such engines did not reach manufacture due to issues of safety, reliability, weight and, especially, sustained operation. The first patent for using a gas turbine to power an aircraft was filed in 1921 by Maxime Guillaume . His engine was an axial-flow turbojet, but was never constructed, as it would have required considerable advances over
16226-578: Was eventually adopted by most manufacturers by the 1950s. Austrian Anselm Franz of Junkers ' engine division ( Junkers Motoren or "Jumo") introduced the axial-flow compressor in their jet engine. Jumo was assigned the next engine number in the RLM 109-0xx numbering sequence for gas turbine aircraft powerplants, "004", and the result was the Jumo 004 engine. After many lesser technical difficulties were solved, mass production of this engine started in 1944 as
16359-475: Was expected and operating at low altitudes to precisely identify targets. Other roles, including those of light bombers , medium bombers , dive bombers , reconnaissance , fighters , fighter-bombers , could and did perform air strikes on battlefields. All these types could significantly damage ground targets from a low level flight, either by bombing, machine guns, or both. Attack aircraft came to diverge from bombers and fighters. While bombers could be used on
16492-641: Was generally much more dangerous to aircrews than their targets, a problem that was continually becoming more acute with the ongoing refinement of anti-aircraft weapons . Within the range of types serving attack roles, dive bombers were increasingly being seen as more effective than aircraft designed for strafing with machine guns or cannons . Nevertheless, during the 1920s, the US military, in particular, procured specialized "Attack" aircraft and formed dedicated units, that were trained primarily for that role. The US Army Engineering Division became involved in designing ground attack aircraft. The 1920 Boeing GA-1
16625-579: Was granted a patent for a jet engine design in March 1935. Republican president Manuel Azaña arranged for initial construction at the Hispano-Suiza aircraft factory in Madrid in 1936, but Leret was executed months later by Francoist Moroccan troops after unsuccessfully defending his seaplane base on the first days of the Spanish Civil War . His plans, hidden from Francoists, were secretly given to
16758-448: Was ordnance. It was a relatively uncomplex aircraft, avoiding any advanced weapon systems or the need for a complex training program to operate. The A-37A retained the dual controls of its T-37B ancestor, allowing it to be used as an operational trainer. In combat " forward air control (FAC)" operations, the second seat was occupied by an observer. Only a single crewman normally flew in the aircraft for close support missions, which permitted
16891-530: Was replaced by faster fighter types for photo-reconnaissance, and light aircraft for artillery spotting. During the inter-war period, the British flew the Fairey Battle , a light bomber which originated in a 1932 specification. Designs in 1938 for a replacement were adapted as a target tug. The last British specification issued for a light bomber was B.20/40 described as a "Close Army Support Bomber" capable of dive bombing and photo-reconnaissance. However,
17024-541: Was rolled out in September 1967, with deliveries to the South Vietnamese beginning in 1968. The A-37Bs were all newly built airframes that were considerably stronger than those of the A-37A, capable of pulling six g instead of five, and were built to have a longer fatigue life of 4,000 hours. Field experience would demonstrate that 7,000 hours between overhauls could be tolerated. The A-37B weighed almost twice as much as
17157-427: Was still rather worse than piston engines, but by the 1970s, with the advent of high-bypass turbofan jet engines (an innovation not foreseen by the early commentators such as Edgar Buckingham , at high speeds and high altitudes that seemed absurd to them), fuel efficiency was about the same as the best piston and propeller engines. Jet engines power jet aircraft , cruise missiles and unmanned aerial vehicles . In
17290-450: Was successful, but unsurprisingly the combat evaluation revealed some of the deficiencies of the A-37A. The most noticeable problem was that the aircraft lacked range and endurance. Other concerns were heavy control response during attack runs (the flight controls were not power-boosted) and the vulnerability of the aircraft's non-redundant flight control system. Some pilots also criticised the machine gun as ineffective and negatively impacting
17423-780: Was the Junkers J.I , which pioneered the idea of an armored "bathtub", that was both fuselage structure and protection for engine and crew. The British experimented with the Sopwith TF series (termed "trench fighters"), although these did not see combat. The last battles of 1918 on the Western Front demonstrated that ground-attacking aircraft were a valuable component of all-arms tactics. Close support ground strafing ( machine-gunning ) and tactical bombing of infantry (especially when moving between trenches and along roads), machine gun posts , artillery , and supply formations
17556-409: Was the motivation behind the development of the gas turbine engine, the most common form of jet engine. The key to a practical jet engine was the gas turbine , extracting power from the engine itself to drive the compressor . The gas turbine was not a new idea: the patent for a stationary turbine was granted to John Barber in England in 1791. The first gas turbine to successfully run self-sustaining
17689-852: Was to create a safe corridor through the Iraqi air defense system. The attack was a huge success and cleared the way for the beginning of the Allied bombing campaign of Operation Desert Storm . One concern involving the Apache arose when a unit of these helicopters was very slow to deploy during U.S. military involvement in Kosovo. According to the Army Times , the Army is shifting its doctrine to favor ground-attack aircraft over attack helicopters for deep strike attack missions because ground-attack helicopters have proved to be highly vulnerable to small-arms fire;
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