95-457: The Saab 37 Viggen ( The Tufted Duck , ambiguous with The Thunderbolt ) is a single-seat, single-engine multirole combat aircraft designed and produced by the Swedish aircraft manufacturer Saab . It was the first canard -equipped aircraft to be produced in quantity and the first to carry an airborne digital central computer with integrated circuits for its avionics, arguably making it
190-416: A blue-grey bill with gold-yellow eyes, along with a thin crest on the back of its head. It has an obvious head tuft that gives the species its name. The adult female is brown with paler flanks, and is more easily confused with other diving ducks. In particular, some have white around the bill base which resembles the scaup species, although the white is never as extensive as in those ducks . The females' call
285-497: A cockpit air-data camera and tape recorder for mission analysis. "Red Baron" and a SKa 24D 600 mm LOROP camera pods were usually carried on the fuselage pylons. The centreline fuel tank was converted for a short period of time to a camera pod with two Recon/Optical CA-200 1676 mm cameras. In addition to the reconnaissance equipment, the SH 37 could also use all weapons for the AJ 37. For
380-434: A fully variable nozzle. During 1964, construction of the first prototype aircraft commenced; on 8 February 1967, the first of an eventual seven prototypes conducted its maiden flight , which had occurred as per the established development schedule. This first flight, which lasted for 43 minutes, was flown by Erik Dahlström, Saab's chief test pilot, who reported the prototype to have been easy to handle throughout. Writing at
475-457: A low-flying McDonnell Douglas F-4 Phantom II within a single scan and possessed a high level of resistance to interference from ECM. Saab and Honeywell co-developed an automatic digital flight control system for the JA 37 Viggen, which has been claimed to be the first such system in a production aircraft. To assist low altitude flight, a Honeywell radar altimeter with transmitter and receiver in
570-651: A minimum of 450 flight hours performed on an initial mixture of the Saab 105 , the Lansen, and finally the Viggen itself; dedicated Viggen simulators were also used, the latter of which was seen as a decisive factor in the ease of conversion to the type. In October 1973, Skaraborg Wing was reportedly close to achieving full operational effectiveness; by May 1974, the Swedish Air Force had two operational squadrons using
665-616: A more capable and newer version of the Sidewinder missile than employed on earlier Viggen variants. Following the evaluation of several alternative cannons, including the British ADEN cannon , the American M61 Vulcan , and French DEFA cannon , an Oerlikon KCA 30mm cannon was selected for the JA 37. The KCA was carried, along with 126 rounds of ammunition, in a conformal pod under the fuselage. The firing rate of
760-402: A multifunction display. In July 1971, the first production AJ 37 Viggen was delivered to the Swedish Air Force. The Skaraborg Wing (F 7) became the first wing to receive deliveries of both the single-seat AJ 37 attack model and the twin-seat SK 37 training model of the Viggen, where upon the type began to replace their existing Lansen aircraft. Conversion training to pilot the Viggen involved
855-406: A new generation of electronics being adopted, and a revised armament configuration employed; the principal externally visible changes from most earlier variants were a taller tailfin and the underfuselage gunpack arrangement. The JA 37, in addition to its principal aerial combat mission, also retained a secondary ground-attack capability, and was better suited to low-level operations. In November 1977,
950-428: A population of close to one million birds, found in northern Eurasia. They are partially migratory. The scientific name is derived from Ancient Greek aithuia , an unidentified seabird mentioned by authors including Hesychius and Aristotle , and Latin fuligo 'soot' and gula 'throat'. It is a game bird . The tufted duck was formally described in 1758 by the Swedish naturalist Carl Linnaeus in
1045-431: A sole pre-production JA 37 model, to test the control systems, engine, avionics, and armaments respectively. In June 1974, the first of these prototypes conducted its maiden flight; later that year, an initial order for 30 JA 37s was issued by the Swedish government. The JA 37 Viggen featured various changes from its predecessor, including revisions to the design of the airframe, the use of the more powerful RM8B powerplant,
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#17327875978771140-401: A staggered second canopy for an instructor, was delivered to the Swedish Air Force. On 21 May 1973, the first prototype of SF 37 Viggen, a tactical reconnaissance variant featuring a modified nose to accommodate seven sensors, conducted its first flight. While other variants entered production during the 1960s, Saab continued the development of the more capable all-weather interceptor version of
1235-528: A substantial upgrade. In 1999, a new tactical liquid-crystal display (LCD) system derived from the Saab JAS 39 Gripen, which replaced the CRT-based AP-12 system, began flight tests with the Swedish Air Force. On the twin-seat SK 37 trainer, the rear cockpit used by the instructor is only fitted with conventional instrumentation and lacks a HUD, computer controls and other features. The ejection seat
1330-425: A tailless delta design, such as in the Viggen, is that the elevons, which replace more conventional control surfaces, operate with a small effective moment arm ; their use adds substantial weight to the aircraft at takeoff and landing. Hinged leading edge surfaces can help counteract this, but an even more effective tool is the canard. The canard surfaces were positioned behind the inlets and placed slightly higher than
1425-419: A tandem arrangement. The design requirements imposed by the large anti-ship missiles employed upon the Viggen necessitated that both the undercarriage and vertical stabilizer be quite tall. To accommodate this, and to allow the main landing gear to be stowed outside of the wing root, the undercarriage legs shortened during retraction. The vertical stabilizer could also be folded via an actuator in order that
1520-405: A thrust reverser to use during landings and land manoeuvres, which, combined with the aircraft having flight capabilities approaching a limited STOL-like performance, enabled operations from 500 m airstrips with minimal support. The thrust reverser could be pre-selected in the air to engage when the nose-wheel strut was compressed after touchdown via a pneumatic trigger. The requirements from
1615-404: A very high reliability level for the generation of avionics systems involved. The displays in the original cockpit were all of the traditional analogue/mechanical type with the exception of an electronic head-up display (HUD), which Saab has claimed makes the Viggen easier to fly, especially at low altitudes during air-to-ground strike missions. Unusually for a 1970s fighter, the JA 37 variant of
1710-482: Is 72.1 kN dry and 125.0 kN with afterburner. Owing to the increased length and weight of the RM8B engine over its predecessor, the airframe of the JA 37 was stretched in order to accommodate it. Onboard electrical power was provided by a 60 kVA generator. In the event of an in-flight engine failure, emergency power was provided by an automatically deploying ram air turbine (RAT), capable of generating 6 kVA. In
1805-553: Is a harsh, growling "karr", mostly given in flight. The males are mostly silent but they make whistles during courtship based on a simple "wit-oo". The only ducks which are similar are the greater scaup and lesser scaup , but these species have no tuft and a different call. The tufted duck is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds ( AEWA ) applies. Refer to
1900-416: Is automated, including the removal of the canopy; in the event of a malfunction, a reserve trigger can be activated. A combined parachute and seat harness is used, which features a barometric interlock to appropriately release the occupant and harness from the seat during the ejection sequence, a manual override handle is also provided for this function. There were dedicated warning caption panels each side of
1995-528: The Eurofighter Typhoon , Dassault Rafale , Saab JAS 39 Gripen and the IAI Kfir , but principally for the purposes of providing agility during flight rather than for its STOL capabilities. Further aerodynamic refinements during the later stage of development included the addition of dog-tooth patterns upon the main wing to generate vortices , allowing for the elimination of blown flaps from
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#17327875978772090-475: The Paris Air Show . On 23 February 1971, the first production aircraft, an AJ37 model, conducted its first flight. In July 1971, the first production aircraft was delivered to the Swedish Air Force. As the initial AJ 37 Viggen was being introduced to service, further variants of the Viggen proceeded to complete development and enter production. In 1972, the first SK 37, an operational trainer variant with
2185-513: The Swedish word vigg , which has two meanings. According to Saab, the aircraft's name alluded to both. The first meaning refers to the Swedish name for the tufted duck , a small diving duck common in Sweden. In this sense, it serves as a reference to the aircraft's canard configuration, as "canard" is French for duck. Vigg is also åskvigg , or "thunderbolt" (thunder wedge), stemming from
2280-479: The Swedish Air Force on 21 June 1971. Even as the initial AJ 37 model entered service, Saab was working on further variants of the Viggen. Accordingly, several distinct variants of the Viggen would be produced to perform the roles of fighter bomber / strike fighter (AJ 37), aerial reconnaissance (SF 37), maritime patrol / anti-surface (SH 37) and a two-seat trainer (Sk 37). During the late 1970s,
2375-530: The Swedish National Defence College , the reason for this officially unexplained U.S. support was to protect U.S. Polaris submarines deployed just outside the Swedish east coast against the threat of Soviet anti-submarine aircraft. However, Bruzelius' theory has been discredited by Simon Moores and Jerker Widén. The connection also appears doubtful due to the time scale – the Viggen's strike version only became operational in 1971, and
2470-471: The tenth edition of his Systema Naturae under the binomial name Anas fuligula . He cited the Swiss naturalist Conrad Gessner who in 1555 had used the identical name Anas fuligula in his Historiae animalium . Linnaeus specified the type locality as Europe but in 1761 restricted it to Sweden. The tufted duck is now one of 12 species placed in the genus Aythya that was introduced in 1822 by
2565-416: The thunderstones of Nordic folklore , called "åskviggar", said to come from the lightning strikes of Norse god Thor when he hunted giants with his war hammer , Mjölnir . The Viggen was initially developed as an intended replacement for the Saab 32 Lansen in the attack role and later the Saab 35 Draken as a fighter. In 1955, as Saab's prototype Draken, the most aerodynamically advanced fighter in
2660-602: The CK 37 proved to be more reliable than predicted. On later variants of the Viggen, from the JA37 onwards, it was decided to adopt a newer and more powerful Singer-Kearfott SKC-2037 digital central processor, license-manufactured and further developed by Saab as the CD 107. The computing techniques and concepts, such as distributed computing , went beyond use of the Viggen, in addition to civil-orientated derivatives, it directly contributed to
2755-647: The Ericsson PS 46/A radar which was capable of guiding the medium-range semi-active radar homing RB 71 Skyflash air-to-air missiles. Both the RB 71 and the PS 46/A radar were designed to provide the Viggen with a look-down/shoot-down capability and to engage targets at beyond visual range distances. The JA 37 could carry up to two RB 71s on the inner wing pylons; in a typical air defense loadout, these would typically have been combined with four RB 24J air-to-air missiles,
2850-486: The German naturalist Friedrich Boie . The genus name is from Ancient Greek aithuia , an unidentified seabird mentioned by Aristotle , Hesychius and other authors. The specific epithet fuligula combines Latin meaning "soot" and gula meaning "throat". The species is monotypic : no subspecies are recognised. An alternative common name is "tufted pochard". The adult male is all black except for white flanks and
2945-401: The JA 37 fighter-interceptor model of the Viggen was introduced, Bråvalla Wing (F 13) being the first wing of the Swedish Air Force to convert to the new type. The Viggen went on to become Sweden's primary air defense platform for many years. Tufted Duck Anas fuligula Linnaeus, 1758 The tufted duck (or tufted pochard ) ( Aythya fuligula ) is a small diving duck with
Saab 37 Viggen - Misplaced Pages Continue
3040-470: The JA 37 fighter-interceptor model, the PS 37 radar was replaced by the more capable Ericsson PS 46 X-band pulse-doppler radar , which had an all-weather look-down/shoot-down capability reportedly in excess of 50 kilometers and continuous-wave illumination for the Skyflash missiles as well as the ability to track two targets while scanning . According to Ericsson, it had a 50 per cent chance of spotting
3135-580: The Medway engine was cancelled due to the intended launch aircraft, the de Havilland Trident , being downsized during development. In place of the Medway, Saab chose to adopt a licence-production version of the American Pratt & Whitney JT8D engine, the Volvo RM8 , instead. The RM8 was heavily redesigned, using new materials to accommodate flight at Mach-2 speeds, a Swedish-built afterburner, and
3230-516: The Swedish Air Force dictated Mach 2 capability at high altitude and Mach 1 at low altitude. At the same time, short-field take-off and landing performance was also required. Since the Viggen was developed initially as an attack aircraft instead of an interceptor (the Saab 35 Draken fulfilled this role), some emphasis was given to low fuel consumption at high subsonic speeds at low level for good range. With turbofan engines just emerging and indicating better fuel economy for cruise than turbojet engines,
3325-431: The Swedish Air Force, in which it had been envisioned that 800 or more Viggens would be produced, which was in turn intended to allow all other combat aircraft then in service with the Swedish Air Force to be replaced with this single type. However, a combination of inflation and other factors eventually reduced the total number of aircraft manufactured to 329. By 1980, up to 149 JA 37 Viggens were projected to be built, and
3420-522: The U.S. National Security Council , led by President Eisenhower , formulated a security guarantee for Sweden, promising U.S. military help in the event of a Soviet attack against Sweden; both countries signed a military-technology agreement. In what was known as the " 37-annex ", Sweden was allowed access to advanced U.S. aeronautical technology that made it possible to design and produce the Viggen much faster and more cheaply than would otherwise have been possible. According to research by Nils Bruzelius at
3515-415: The Viggen along with a third squadron in the final process of achieving that status. By 1974, the safety and reliability levels of the Viggen were reportedly above expectations, despite the overall complexity and relative newness of the aircraft. In practice, one of the most significant issues encountered with the Viggen during low-level flight, as extensively performed during a typical attack mission profile,
3610-445: The Viggen ceased and the final aircraft was delivered. In May 1991, a SEK 300-million program to upgrade 11 AJ37, SF37 and SH37 Viggens to a common multirole variant, designated AJS37, was announced. Amongst the changes involved, interchangeable armaments and sensor payloads were implemented in addition to the adoption of new mission planning and threat analysis computer systems. The onboard ECM systems were also improved. Specifically,
3705-458: The Viggen featured three multi-purpose cathode-ray tube (CRT) display screens were fitted within the cockpit, in a system called AP-12, developed by Saab and Ericsson. These displays would be used to display processed radar information, computer-generated maps, flight and weapons data, along with steering cues during precision landings. Between 1989 and 1992, the AP-12 display system was subject to
3800-520: The Viggen had the first version of the RM8A engine with uprated internal components from the JT8D that it was based on. Thrust was 65.6 kN dry and 115.6 kN with afterburner. For the JA 37, the RM8A was developed into the RM8B, achieved by adding a third low-pressure compressor stage over the preceding model, increasing the turbine inlet temperature and fuel diffusion within the combustion chamber. Thrust
3895-460: The Viggen were carried out, involving the Finnish aircraft designer Aarne Lakomaa . Over 100 different concepts were examined in these studies, involving both single- and twin engine configurations, both traditional and double delta wings, and canard wings . Even VTOL designs were considered, with separate lift engines, but were soon identified as being unacceptable. From the onset, the Viggen
Saab 37 Viggen - Misplaced Pages Continue
3990-498: The aerodynamic configuration was radical: it combined an aft-mounted double delta wing with a small, high-set canard foreplane, equipped with powered trailing flaps mounted ahead of and slightly above the main wing; this would be judged to be the best means to satisfy the conflicting demands for STOL performance, supersonic speed, low turbulence sensitivity at low level flight, and efficient lift for subsonic flight. Canard aircraft have since become common in fighter aircraft, notably with
4085-426: The aircraft could be stored in smaller hangars, hardened aircraft shelters , and underground hangars , the latter of which were employed by the Swedish military to limit the damage of preemptive attacks. The six tanks in the fuselage and wings held approximately 5,000 litres of fuel with an additional 1,500 litres in an external drop tank. The specific fuel consumption was only 0.63 for cruise speeds (fuel consumption
4180-454: The aircraft, the JA 37. In 1970, Sweden's air defenses had been closely inspected and it was determined that the prospective JA 37 Viggen was highly suited to the role. In 1972, the Swedish government authorized the development of the fighter-interceptor variant to proceed, which was followed by several major contracts for the JA 37's further development. A total of five prototypes would be produced, four of which being modified AJ 37s and one being
4275-406: The all-weather interceptor / strike fighter JA 37 variant was introduced. Attempts to export the Viggen to other nations were made, but ultimately proved unsuccessful. In November 2005, the last Viggens were withdrawn from service by the Swedish Air Force, its only operator; by this point, it had been replaced by the newer and more advanced Saab JAS 39 Gripen . Viggen is the definite form of
4370-428: The canard wings was used. The aircraft was also fitted with a Decca Type 72 Doppler navigation radar . TILS (Tactical Instrument Landing System ), a landing-aid system made by Cutler-Hammer AIL, improved landing accuracy to 30 m from the threshold on the short highway airbase system. In order to effectively enforce Sweden's air space, the Viggen was integrated with STRIL 60 national defence system. The JA 37 Viggen
4465-501: The canard. The use of a thrust reverser enabled the sought short landing performance. During development, Saab had opted to power the type using a single large turbofan engine. Originally, the British Rolls-Royce Medway engine had been selected to power the Viggen, which was then considered to be ideal for the basis for a supersonic engine equipped with a fully modulated afterburner ; however, development of
4560-507: The cannon was selectable at 22 or 11 rounds per second. It fired the same cartridge as the GAU-8 , reportedly 50% heavier shells at a higher velocity than the ADEN cannon, resulting in six and a half times the kinetic energy on impact, and was effective up to 2,000 meters. This, in conjunction with the fire control system, allowed air-to-air engagements at longer range than other fighters. Perhaps
4655-460: The case of the earlier Draken, in addition to accuracy issues. The computer, called CK 37 [ sv ] (short for Centralkalkylator 37 , "central calculator 37"), was the world's first airborne computer to use integrated circuits . Developed by Datasaab , the CK 37 was the integrating unit for all electronic equipment to support the pilot, performing functions such as navigation, flight control, and weapon-aiming calculations. In practice,
4750-444: The computers used on board the Viggen's replacement, the Saab JAS 39 Gripen. Various electronic countermeasures (ECM) were installed upon the Viggen, these were typically provided by Satt Elektronik. The ECM systems consisted of a Satt Elektronik radar warning receiver system in the wings and the tail, an optional Ericsson Erijammer pod and BOZ-100 chaff / flare pod. Infrared warning receivers were also later installed. In total,
4845-441: The early 1960s, it was decided that the Viggen should be a single seat aircraft, Saab having recognized that advanced avionics such as a digital central computer and a head-up display could perform the workload of a human navigator and entirely replace the need for a second crew member. A use of a digital computer would reduce or entirely replace analogue systems, which had proven to be expensive to maintain and alter, as had been
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#17327875978774940-412: The electronics weighed 600 kg, a substantial amount for a single-engine fighter of the era. The aircraft's principal sensor was an Ericsson PS 37 X-band monopulse radar , which used a mechanically steered parabolic reflector housed in a radome . This radar performed several functions, including air-to-ground and air-to-air telemetry , search , track , terrain-avoidance and cartography . On
5035-412: The end of July. They are not colonial but sometimes the nests can be in a loose group. Most nests are placed beside water; an island site is preferred. The nest is built by the female and consists of depression in the ground that is lined with grass, reeds and down. The clutch consists of 8–11 greenish-grey eggs that measure 59 mm × 41 mm (2.3 in × 1.6 in). They are incubated by
5130-548: The female starting after the clutch is complete so that they hatch synchronously. The female covers the eggs with down when she is away from the nest. The eggs hatch after around 25 days (range 23–28 days). The young are precocial and nidifugous . They can feed themselves and are cared for by the female who broods them when they are small. They typically fledge when aged between 45 and 50 days. Tufted ducks usually first breed at one year but occasionally at 2 years. These birds feed mainly by diving, but they will sometimes upend from
5225-513: The fighter version in 1978, by which time Polaris had already been retired. In December 1961, the Swedish government gave its approval for the development of Aircraft System 37 , which would ultimately become the Viggen. By 1962, all elements for the project either existed or were close to fully developed; these included the aircraft itself, the powerplant, ejector seat, armaments, reconnaissance systems, ground servicing equipment, and training equipment such as simulators. In February 1962, approval of
5320-439: The first production JA 37 Viggen conducted its maiden flight. Operational trials for the new variant were conducted between January and December 1979, which resulted in the type being introduced to operational service that year. According to Flight International , at the time of the JA 37's introduction, it was the most advanced European fighter then in service. In April 1964, the Swedish government revealed its budget proposal for
5415-547: The following table for measurements of the tufted duck: The tufted duck breeds throughout temperate and northern Eurasia . It occasionally can be found as a winter visitor along both coasts of the United States and Canada . It is believed to have expanded its traditional range with the increased availability of open water due to gravel extraction, and the spread of freshwater mussels , a favourite food. These ducks are migratory in most of their range, and overwinter in
5510-429: The former was favoured, since the latter were mainly limited by metallurgy development resulting from limitations in turbine temperature . Mechanical simplicity was also favoured, so the air intakes were simple D-section types with boundary layer splitter plates , while the fixed inlet had no adjustable geometry for improved pressure recovery. The disadvantage was that the required engine would be very large. In fact, at
5605-414: The fuselage pylons. The fighter-interceptor version of the Viggen, the JA 37, featured various avionics changes, including the extensive use of digital electronics alongside mechanical technology. In 1985, the "fighter link" went into service, permitting encrypted data communication between four fighters; this enabled one fighter to "paint" an airborne enemy with guidance radar for the Skyflash missiles of
5700-530: The implementation of a new stores management system and MIL-STD-1553 serial data bus , similar to that used on the newer JAS 39 Gripen, allowed for the integration of the AIM-120 AMRAAM air-to-air missile; an upgraded Ericsson PS-46A radar was installed, and a new tactical radio. On 4 June 1996, the first upgraded prototype JA37 Viggen performed its first flight. In 1996, according to Swedish air force material-department chief General Steffan Nasstrom,
5795-544: The in-development AJ 37 Viggen would be both cheaper than and superior to the McDonnell Douglas F-4 Phantom II . In April 1968, the Swedish government formally issued the authorization for manufacturing of the Viggen to proceed, issuing an order for 175 Viggens that year. Also in 1968, Saab began work on the Viggen's maritime reconnaissance and photo reconnaissance variants. In May 1969, the Viggen made its first public appearance outside of Sweden at
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#17327875978775890-543: The inboard wing pylons. Self-defence measures included various ECM systems, as well as either the AIM-4 Falcon (Swedish designation "RB 28") or AIM-9 Sidewinder (Swedish designation "RB 24") air-to-air missiles. At one point, the AJ 37 Viggen was under consideration as a carrier of both a Swedish nuclear weapon and chemical weapons , although no nuclear or chemical weapons were ultimately adopted by Sweden. The JA 37 fighter interceptor, introduced in 1979, featured
5985-543: The introduction of the Panavia Tornado into operational service in 1981. Development work begun during the early 1950s to develop a successor to the Saab 32 Lansen in the attack role, as well as to the Saab 35 Draken as a fighter. Saab's design team opted for a relatively radical delta wing configuration, as well as to produce the aircraft as an integrated weapon system that operated in conjunction with Sweden's STRIL -6 national electronic air defense system. It
6080-405: The line to be closed within the decade as the Swedish aerospace industry changed focus to the impending Saab JAS 39 Gripen, the Viggen's eventual replacement. Over time, advances in computing, such as the microprocessor , had enabled greater flexibility than the physical configuration of the Viggen, so further development of the Viggen platform was not viewed as cost-effective. In 1990, production of
6175-409: The main wing, with a higher stall angle than the wing, and were equipped with flaps. The lifting canard surfaces act as a vortex generator for the main wing and therefore provide more lift. An added benefit was that they also improved roll stability in the transonic region. The canard flaps were deployed in conjunction with the landing gear to provide even more lift for takeoff and landing. To withstand
6270-518: The milder south and west of Europe , southern Asia and all year in the British Isles . One individual has been reported as far south as Melbourne , Australia . They form large flocks on open water in winter. Their breeding habitat is close to marshes and lakes with plenty of vegetation to conceal the nest. They are also found on coastal lagoons , shorelines and sheltered ponds. In northern Europe breeding takes place between mid May and
6365-509: The most important improvement was the expanded STRIL datalink which entered service in 1982–85. It allowed not only ground control-aircraft communication, but also between up to four aircraft simultaneously regardless if airborne or on the ground. Datalink information was displayed on the Horizontal Situation Display and a tactical display, the latter using link symbology that could be overlaid with an electronic map on
6460-471: The most modern/advanced combat aircraft in Europe at the time of introduction. The digital central computer was the first of its kind in the world, automating and taking over tasks previously requiring a navigator/copilot, facilitating handling in tactical situations where, among other things, high speeds and short decision times determined whether attacks would be successful or not, a system not surpassed until
6555-407: The munitions fitted into the aircraft's central computer using a load-selector panel, which would automatically choose the correct values for fire control, fuel consumption, and other calculations. The AJ 37 was typically equipped with a total of seven hardpoints , three underneath the fuselage and two under each wing, a further two wing-mounted hardpoints could be optionally fitted but this facility
6650-477: The original Hispano-Suiza 12Y 31 liquid-cooled V-12 rated at 860 hp with a 1,100 hp Soviet engine— the Klimov M-105P—which was a war booty. This engine was installed under the cover of a more aerodynamic cowling and fitted with a different pitch propeller. The French M.S.406's airframe was strengthened, and an oil cooler from a Messerschmitt-109 replaced the old one. In this way over-heating problems
6745-460: The overall configuration was given and was followed by a development contract in October 1962. According to aviation authors Bill Gunston and Peter Gilchrist, the project was "by far the largest industrial development task ever attempted in Sweden". During the 1960s, the Viggen accounted for 10 per cent of all Swedish R&D funding. In 1963, Saab finalized the aerodynamic design of the aircraft;
6840-493: The performance requirements to a large extent dictating the choice of the engine, the airframe turned out to be quite bulky compared to contemporary slimmer designs with turbojet engines. The first prototypes had a straight midsection fuselage that was later improved with a "hump" on the dorsal spine for reduced drag according to the area rule . The wing had the shape of a double delta with a dogtooth added to improve longitudinal stability at high incidence angles. A consequence of
6935-449: The photographic SF version, the radar in the nose was omitted in favour of four SKa 24C 120 mm and two SKa 31 570 mm photographic cameras as well as one 57 mm VKa 702 Infrared linescan camera and air-data camera; all of which were integrated with and controlled by the aircraft's central computer. Additional equipment, such as more camera pods, fuel tanks, ECM pods, and self-defense air-to-air missiles could also be carried upon
7030-482: The pilot's legs. On the right console panel were numerous dedicated controls and indicators, including weapons and missile controls, nav panel, oxygen on/off, windshield de-fogging, IFF control, lighting controls. Situated on the left console panel were radar controls, canopy handle, landing gear handle, radio controls and the cabin pressure indicator. As per then-standard practice within the Swedish Air Force, all cockpit instrumentation and labeling were in Swedish. With
7125-458: The stresses of no-flare landings, Saab made extensive use of aluminium in the airframe of the Viggen, which was constructed using a bonded metal honeycomb structure ; the entire rear section of the fuselage, downstream of the engine nozzle, formed a heat-resistant ring composed of titanium . The main landing gear, manufactured by Motala Verkstad, was highly strengthened as well; each leg held two small wheels fitted with anti-skid brakes placed in
7220-567: The surface. They eat molluscs , aquatic insects and some plants and sometimes feed at night. They are hunted as sport in the UK, Italy, Iran, Finland and Denmark, and commercially in Iran. Eggs used to be (and maybe continue to be) gathered in Iceland. Because it feeds on the water bottom, it can taste "muddy" and is considered a less tasty duck. Aarne Lakomaa Aarne Lakomaa (1914–2001)
7315-415: The three other fighters in a group while they had their search and guidance radar switched off. This system was operational ten years before any other country's. The autopilot was also slaved to the radar control to obtain better precision firing the cannon. Once in service, the Viggen's software was regularly updated every 18 months. In 1983, the mean time between failures (MTBF) was reported as 100 hours,
7410-533: The time of introduction, it was the second-largest fighter engine, with a length of 6.1 m and 1.35 m diameter; only the Tumansky R-15 was bigger. Saab had originally wanted the Rolls-Royce Medway as the Viggen's powerplant. Owing to the cancellation of the Medway, the JT8D was instead chosen as the basis for modification. The RM8 became the second operational afterburning turbofan in
7505-536: The time, aerospace publication Flight International described the flight as having been "Sweden's astonishing unilateral stand in the front rank of advanced aircraft-building nations…" Each of the seven prototypes were assigned different roles, although the initial aircraft were focused on supporting the development of the initial production variant, the AJ37. In 1967, the Swedish Government concluded that
7600-458: The various upgrades performed to the Viggen since its introduction had "doubled the effectiveness of the overall system". The Viggen was powered by a single Volvo RM8 turbofan. This was essentially a heavily modified licence-built variant of the Pratt & Whitney JT8D engine that powered commercial airliners of the 1960s, with an afterburner added for the Viggen. The airframe also incorporated
7695-443: The wing landing gear. The centreline pylon was the only pylon plumbed for carrying an external fuel tank, and was usually so occupied. A pair of air-to-air missiles were intended to be placed on the outboard wing pylons, which were more lightweight than the other attachment points. The pylons behind the landing gear were not used until the JA 37D modification when BOL countermeasure dispensers were fitted to them. Ground crew would enter
7790-411: The world at that point, performed its first flight, the Swedish Air Force was already forming a series of requirements for the next generation of combat aircraft; due to the challenging nature of these requirements, a lengthy development time was anticipated, with the first flight intended to be no earlier than the middle of the next decade. Between 1952 and 1957, the first studies towards what would become
7885-465: The world, and also the first equipped with a thrust reverser. According to aviation author Christopher Chant, the RM8 has the distinction of being the first engine to be fitted with both an afterburner and a thrust reverser. It had a bypass ratio of around 1.07:1 in the RM8A, which reduced to 0.97:1 in the RM8B. The RM8A was the most powerful fighter engine in the late 1960s. The AJ, SF, SH and SK 37 models of
7980-792: Was a Finnish aircraft designer. Born in Finland , Lakomaa graduated from Helsinki Polytechnics . He fought as an Army Lieutenant in the Winter War (1939–40) and the Continuation War (1941–44) against the Soviet Union . There he became famous for fitting captured Russian engines to the obsolete French fighter Morane-Saulnier M.S.406 , thereby creating a first rate fighter, the Mörkö-Morane ("mörkö" being Finnish roughly for "bogeyman" or "hobgoblin"). Aarne Lakomaa first replaced
8075-589: Was also designed from the beginning to be easy to repair and service, even for personnel without much training. One radical requirement of the proposed aircraft was the ability for it to be operated from relatively short runways only 500 meters long; this was part of the Bas 60 air base system that had been introduced by the Swedish Air Force in the late 1950s. Bas 60 revolved around force dispersal of aircraft across many wartime air bases, including road runways acting as backup runways. Utilizing partially destroyed runways
8170-465: Was also designed to be operated from runways as short as 500 meters. Work was aided by the " 37-annex " under which Sweden could access advanced U.S. aeronautical technology to accelerate both design and production. The aircraft's aerodynamic design was finalised in 1963. The prototype performed its maiden flight on 8 February 1967 and the following year the Swedish government ordered an initial batch of 175 Viggens. The first of these entered service with
8265-507: Was also equipped with a Garrett AiResearch digital Central Air Data Computer , modified from the unit used upon the Grumman F-14 Tomcat . Initially, only a single reconnaissance (S) variant was considered, but fitting cameras as well as a radar proved to be impossible. The SH 37 maritime strike and reconnaissance variant was very similar to the AJ 37 and differed mainly in a maritime-optimized PS 371/A radar with longer range,
8360-428: Was another factor that motivated STOL capability. Bas 60 was developed into Bas 90 in the 1970s and 1980s, and included short runways only 800 meters in length. Enabling such operations imposed several critical demands upon the design, including a modest landing speed, no-flare touchdown, powerful post-landing deceleration, accurate steering even in crosswinds on icy surfaces, and high acceleration on take-off. In 1960,
8455-460: Was finally solved. As a result of these modifications, the improved version of Morane had a 36-mph speed advantage over all previous versions. Lakomaa was recruited to Saab in 1944 as an aircraft designer. He was involved in the development of the fighters Saab 35 Draken and Saab 37 Viggen , and later headed R&D at Saab where he designed a number of prototypes, including a rocket propelled interceptor, nuclear weapon carriers, replacements for
8550-561: Was further developed to become the more capable RBS-15 , also integrated on the Viggen. An optional load consisted of two Rb 05 air-to-surface missiles on the fuselage pylons. The RB 05 was later replaced by AGM-65 Maverick (Swedish designation "RB 75") television-guided missiles. In a ground-attack role, a combination of unguided 135 mm rockets in sextuple pods and 120 kg fragmentation bombs on quadruple-mounts could be used. Other armaments include explosive mines , and 30 mm ADEN cannon pods with 150 rounds of ammunition on
8645-498: Was planned as an integrated weapon system, to be operated in conjunction with the newest revision of Sweden's national electronic air defense system, STRIL -60. It was used as the nation's standard platform, capable of being efficiently adapted to perform all tactical mission roles. Other requirements included supersonic ability at low level, Mach 2 performance at altitude, and the ability to make short landings at low angles of attack (to avoid damaging improvised runways). The aircraft
8740-535: Was rarely used. Various munitions could be carried, such as several types of rockets: the 135 mm M56GP 4 kg armour-piercing, the M56B with 6.9 kg of high explosives , and the M70 with a 4.7 kg HEAT warhead. The AJ 37 was designed to carry two RB 04 E anti-ship missiles on the inboard wing pylons with an optional third missile on the centreline pylon. The RB-04 was a relatively simple cruise missile that
8835-558: Was rated 18 mg/Ns dry and 71 with afterburner). The Viggen's consumption was around 15 kg/s at maximum afterburner. A pair of inlets placed alongside the cockpit feed air to the engine; simple fixed-geometry inlets were adopted, similar to the Draken, except for being larger and standing clear of the fuselage. A weapons load of up to 7,000 kg could be accommodated on nine hardpoints: one centreline pylon, two fuselage pylons, two inner and two outer wing pylons and two pylons behind
8930-465: Was the Raketstol 37 (literally; Rocket chair 37) and was the last Saab designed seat in service. A derivative of the Saab 105 trainer seat, the seat was optimized for low altitude, high speed ejections. Once activated by the pilot via triggers built into the armrests (on twin-seat models, the occupant of the forward cockpit position is able to initiate the ejection of both seats), the ejection sequence
9025-567: Was the threat posed by birds; thus, the Swedish Air Force paid close attention to their migratory patterns. During the later half of the 1970s and into the 1980s, the introduction of various variants of the Viggen proceeded; these included the SK 37, a two-seat operational-conversion trainer, introduced in 1972, the SF 37, an overland reconnaissance model, introduced in 1977, and the SH 37, a maritime reconnaissance version, introduced in 1975. By September 1980,
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