Saab 37 Viggen

See also the Saab 9-3 Viggen automobile

Template:Infobox Aircraft The Saab 37 Viggen (Thunderbolt) was a Swedish single-seat, single-engine, short-medium range fighter aircraft and attack aircraft, manufactured between 1970 and 1990. Several variants were produced to perform the roles of all-weather fighter-interceptor, ground attack, and photo-reconnaissance, as well as two-seat trainer variants.

Design and development

The Viggen was initially developed as a replacement for the Saab 32 Lansen in the attack role and later the Saab 35 Draken as a fighter. The first studies were carried out between 1952 and 1957 involving the legendary Finnish aircraft designer Aarne Lakomaa. Construction started in 1964, with a first prototype maiden flight on 8 February 1967. The aim was to produce a robust single-engined aircraft with performance that could be operated from improvised facilities such as roads and highways in the event of nuclear attacks on major installations. 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 cockpit and air intake of JA 37 Viggen

To meet these design goals, Saab selected a radical canard configuration: a conventional delta wing with small, high-set canard wings. Canards have since become common in fighter aircraft, notably with the Eurofighter Typhoon and the IAI Kfir, but mainly for agility reasons rather than STOL capabilities. The air intakes are simple D-section types with boundary layer splitter plates, while the fixed inlet has no adjustable geometry for improved pressure recovery.

The canards are positioned behind the inlets and placed slightly higher than the main wing, but are not movable as control surfaces; however the canard flaps are deployed in conjunction with the landing gear to provide more lift. To withstand the stresses of no-flare landings, Saab made extensive use of titanium in the construction of the Viggen, especially in the fuselage; and incorporated an unusual arrangement for the main landing gear, in which the two wheels on each leg are placed in tandem. While such a layout is common in airliners and cargo planes, it is rare in fighters, but allows stowage in a thinner wing. The tall single tail fin (45 degrees in the leading edge) is foldable to make it easier to store in hangars. The plane was designed from the beginning to be easy to repair and service, even for personnel without much training.

In 1960 the U.S. National Security Council, led by President Eisenhower, formulated a military security guarantee for Sweden. The U.S. promised to help Sweden militarily in case of a Soviet attack against Sweden. As a consequence of this Sweden and the U.S. signed a military-technology agreement. In what was known as the "37-annex", Sweden was allowed access to advanced U.S. aeronautical technology which made it possible to design and produce the Saab 37 Viggen much faster and cheaper than would otherwise have been possible.

The reason for this officially unexplained U.S. support was, according to the doctoral research of Nils Bruzelius at the Swedish National Defence College, the need to protect U.S. Polaris submarines deployed just outside the Swedish west coast against the threat of Soviet anti-submarine aircraft.

Propulsion

The Viggen is powered by a single Svenska Flygmotor RM 8 turbofan. This is essentially a licence-built variant of the Pratt & Whitney JT8D engine that powered commercial airliners of the 1960s, with an afterburner added for the Viggen. The engine also incorporates a thrust-reverser to use during landings and land manoeuvers, which, combined with the aircraft having flight capabilities approaching a limited STOL-like performance, enable operations from 500 m airstrips with minimal support. The thrust reverser can be pre-selected in air to engage when the nose-wheel strut is compressed after touchdown. Only the Viggen and the Panavia Tornado carry both afterburners and thrust-reversers.

The requirements from the Swedish Air Force dictated Mach 2 capability at high altitude and Mach 1 at low altitude. At the same time, short-field takeoff and landing performance was also required. Since the Viggen was developed initially as an attack aircraft instead of an interceptor (which role the Saab 35 Draken fulfilled), 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, the former was favored, since the latter were mainly limited by metallurgy development resulting from limitations in turbine temperature. Mechanical simplicity with no Swing-wing or adjustable inlets were also favored. The disadvantage was that the required engine would be very large. In fact, at 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 Pratt & Whitney TF30 as the Viggen powerplant. Since the engine was not finished at the time when the airframe vs. engine design size needed to be frozen, the civilian variant of the TF30 - the JT8D was chosen as the basis for a Volvo Aero modification instead. The RM 8 became the second operational afterburning turbofan in the world, and also the first equipped with 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 AJ, SF, SH and SK 37 models had the first version RM 8A engine with uprated internal components from the JT8D it was based on. Thrust is 65.6 kN dry and 115.6 kN with afterburner. For the JA 37, the RM 8A was modified to an 8B by replacing one LP compressor stage with a fan stage and improved combustor, turbine and afterburner. Thrust is 72.1 kN dry and 125.0 kN with afterburner.

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 was rated 18 mg/N dry and 71 with afterburner. The Viggen's consumption was around 15 kg/sec at maximum afterburner, which meant that the internal fuel was exhausted in just seven minutes due to the relative inefficiency of the turbofan over a turbojet at full afterburner. Performance comparisons with other aircraft from the same age are however slightly difficult, since no other fighter- or attack aircraft aside from the Harrier and Yak-38 were designed for STOL or VTOL capability.

Armament and avionics

The CK37 computer

The Viggen featured a Datasaab navigational computer, which by Swedish standards was a significant technological achievement for the time. It utilized the STRIL 60 system to be linked with the Swedish defence systems. The main sensor was an Ericcson PS-37 radar (I/J band) with several functions: air-to-ground and air-to-air telemetry, terrain avoidance, cartography, and radar navigation. There was also an RWR SATT system in the wings and the tail, a Decca Type 72 doppler navigation radar , a series of electronic sub-systems, a landing-aid device (TILS) made by AIL, and a 200 MHz combat computer derived from the F-14 Tomcat. Externally there was also provision for BOZ and AQ series of ECM pods. In total, the electronics weighed 600 kg which was an impressive amount for a single-engine, late 1960s fighter.

A weapon load of up to 6,000 kg can be accommodated on seven hardpoints; including Rb 24, Rb 24J, Rb 28, Rb 71, Rb 74, Rb 99 air-to-air missiles and Rb 75, Rb 04, Rb 05 and Rb 15F air-to-ground missiles, four tube launchers for 135 mm rockets, and bombs included the 120 kg Virgo fragmentation type. Rockets are one of the more characteristic weapons of Flygvapnet and have warheads of several types: the 50 mm M56GP 4 kg armour-piercing, the M56B with 6.9 kg of HE, and the M70 with a 4.7 kg HEAT warhead. Since a fighter variant was not initially considered, there was no internal gun on the first variants but external gun pods could be carried housing ADEN 30 mm cannon. The later JA 37 fighter variant was equipped with an Oerlikon KCA 30mm internal cannon (150 rounds), in a conformal pod under the fuselage.

Operational history

One hundred and ten of the original, ground attack optimized variant, AJ 37 were built with the first operational squadron established in 1972 at Såtenäs.

A two-seat trainer was not initially planned since it was considered that new pilots could get enough experience with delta-winged aircraft on the SK 35 Draken trainer. Eventually, however, 18 SK 37 two-seat trainers were ordered and delivered in 1973. To make room for the second cockpit, one fuel tank and some avionics were deleted. The radar was also omitted limiting the weapons load to gun pods and unguided rockets.

A total of 26 of the SH 37 maritime reconnaissance and strike variant were built in 1974, replacing the S 32C Saab Lansen. Although fitted with radar and weaponry, the SH 37 Viggen could undertake long-range photographic missions with only one long range camera, while external pode are: a photographic day-set, a RED baron IR set, an ELINT and finally an ECM AQ series (made by SATT).

A further 26 of the SF 37 reconnaissance variant were also delivered to replace the S 35 Draken in 1975. These were recognizable by an elongated nose, equipped with 6 cameras: two vertical for long for long-range acquisitions, four for low level use, an IR VKA 702 for night reconnissance. Also RED BARON pod, with 3 IR machines was widely used, as well an ELINT set.

Although the Viggen was offered for sale worldwide, and regarded as a very competent aircraft, no export sales occurred. Reasons to explain Saab's failure to sell a competitively priced, highly advanced and well-respected aircraft include the Swedish government's relatively strict controls on arms exports to undemocratic countries, potential customers' doubts about continuity of support and supply of spare parts in the event of a conflict disapproved of by Sweden, and strong diplomatic pressure of larger nations. The United States blocked an export of Viggens to India in 1978 by not issuing an export license for the RM8/JT8D engine, forcing India to choose the SEPECAT Jaguar instead.

The Viggen saw initial service in natural metal, later receiving an extremely elaborate disruptive camouflage scheme for the AJ/SF/SH/SK variants and the first couple of JA aircraft. The latter JA aircraft were painted light/dark gray, appropriate for a high altitude fighter.

The final Viggen production variant was the JA 37 interceptor entering service in 1980. The last of 149 JA 37s was delivered in 1990. Differences from the previous models included an improved and more powerful engine, a new interception radar, new computers, HUD (Head-Up Display), ECM (Electronic CounterMeasures) and some other subsystems were also fitted. The aircraft was also equipped with a new PS-46 interception radar (X band), with lookdown/shootdown capability up to 50 kilometres. It had many features, included CW illuminator and many modes like TWS (Track While Scan). The MTBF is reported as 100 hours, a very high reliability level for that generation of avionic systems.

Unusually for a 1970s fighter, three multi-purpose CRT (Cathode Ray Tube) display screens were fitted within the cockpit, in a system called AP-12, that included also an HUD of new model.

The new radar was compatible with the Skyflash medium-range missiles, for the first time in a Swedish fighter. Two Skyflash missiles could be carried under the wings on hardpoints, as well as four Sidewinder J or L models. Another improvement was the addition of an an Oerlikon KCA 30 mm cannon mounted internally, with 150 rounds of 360 g ammunition. The firing rate was selectable at 22 or 11 rounds/s, and the autopilot was slaved to the radar control to obtain the best precision when firing the cannon.

The structural strength was also improved, especially for the multi-sparred wings (initially Viggens had a high loss rate, with 21 aircraft lost in the early years).

Various upgrades have been performed over the years, mainly to cockpit equipment, weapons and sensor fit. In 1985, the "fighter link" went into service which permitted encrypted data communication between four fighters and ground radar based fighter command. This enabled one fighter to "paint" an airborne enemy with guidance radar for the Skyflash missiles of the three other fighters in the group while they had their search and guidance radar switched off. This system was operational ten years before any other country's.

Between 1998 and 2000, ten SK 37 trainers were converted to SK 37E electronic warfare trainers to replace the aging J 32E Lansen.

The Viggen has been phased out in favor of the advanced later generation JAS 39 Gripen.

Variants

AJ 37

Primarily a single-seat ground-attack fighter aircraft, with a secondary fighter role. First delivery in 1971, serial numbers 37001-37108, RM 8A powerplant, PS 37A radar, Decommissioned in 2000.

JA 37

Primarily a single-seat all-weather interceptor fighter, with a secondary attack role. First delivery in 1979, serial numbers 37301-37449, 10cm (4in.) stretch of AJ 37 fuselage between canard and main wing, PS 46A LD/SD radar.

SF 37

Single-seat photographic reconnaissance aircraft, first delivery in 1975, radar replaced with four cameras, serial numbers 37950-37977.

SH 37

Single-seat maritime reconnaissance and strike aircraft, first delivery in 1975, PS-371A radar, serial numbers 37901-37927.

SK 37

Two-seat trainer aircraft, first delivery in 1973, no radar, able to carry unguided weapons, serial numbers 37801-37817.

SK 37E

Electronic warfare trainer, conversion of ten obsolete SK 37 trainers from 1998 to 2000, serial numbers 37807-37811 & 37813-37817, decommissioned in 2007.

AJS/AJSF/AJSH 37

Upgrade of some AJ/SF/SH 37 between 1993 and 1998. Avionics and software upgrade including MIL-STB 1553B databus for carrying RBS-15F, DWS 39 Mjölner and Rb 74.

JA 37D

Upgrade of older JA 37 between 1993 and 1998, avionics and software upgrade to permit use of Rb 99.

SAAB 37E Eurofighter

Proposed NATO replacement of F-104 Starfighter in 1975, none built.

Saab 37X

Proposed export version, none built.

SAAB 37 8 prototypes, built to various

• AJ 37 109 (initial) attack variant
• SF 37 28 photo-reconnaissance variant
• SH 37 27 maritime surveillance / combat variant
• Sk 37 17 two-seat trainer
• JA 37 149 interceptor variant
• AJS 37 - 48 upgraded AJ 37
• AJSF 37 - 25 upgraded SF 37
• AJSH 37 - 25 upgraded SH 37
• JA 37D - 34 upgraded JA 37
• Sk 37E Stoer - 10 SK 37 countermeasures upgrade

Latest update

• Viggens in service were given a continuous stream of mostly minor upgrades, generally in the form of improved avionics and software upgrades. One of the more important enhancements, performed in the late 1980s, was carriage on the AJ 37 of the US-designed AGM-65A Maverick ASM, license built in Sweden as the "Rb75". This generally replaced the less sophisticated Rb05 ASM. A comparable upgrade, also performed in the late 1980s, provided support for the much improved AIM-9L Sidewinder "all aspect" AAM, built in Sweden as the "Rb74".

In 1992 the Swedish government approved a program to upgrade a total of 115 AJ 37s, SF 37s, and SH 37s to a multirole "AJS 37" configuration, with "AJS" standing for "Attack / Jakt / Spaning". The follow-on SAAB 39 Gripen was already flying by that time, but development was proving troublesome, with defense cutbacks following the end of the Cold War also promoting delays. Viggens needed to be upgraded to keep them current and capable until the Gripen could enter squadron service.

The specific drivers for the upgrade was the development of new weapons for the Gripen, such as the DWS 39 gliding submunitions dispenser, and in particular the Rb15F antiship missile -- a vastly improved derivative of the old Rb04 fitted with a turbojet engine and new, much smarter seeker. The Rb15F was developed for the Gripen but was ready for service well in advance of the SAAB 39. As long as the weapon was available, there was absolutely no reason not to field it, and fitting such kit to the Viggen would give Flygvapnet pilots useful systems familiarization for when they upgraded to the Gripen. It was determined that the old AJ 37 could carry themissile if the aircraft was fitted with a new Ericsson processor system and a MIL-STD 1553B digital databus. A little further thought showed that the same fit could be performed on the reconnaissance Viggens, and the result was the AJS 37.

Early press releases on the program gave the impression that the AJS 37 was to be a major upgrade, and that the aircraft upgraded would end up with a common configuration. This was reading too much into it, and the announced total of 115 upgrades was also something of an exaggeration, with only 98 conversions actually being performed. Basically this was a middling sort of avionics and software upgrade that did not change the external appearance of any of the upgraded aircraft in any significant way, the major changes being to permit them to carry new stores. Changes to the cockpit control layout were modest and certainly did not involve fit of a true glass cockpit. There was no airframe service life extension program (SLEP).

The upgraded AJ 37, SF 37, and SH 37 machines acquired the new designations of "AJS 37", "AJSF 37", and "AJSH 37" respectively. All had the new processor and the MIL-STB 1553B databus; a MIL-STD 1760 "universal" stores interface system; an improved RWR system that also had a data recording function, giving it a bit of electronic intelligence capability; and a new mission planning system in which a cartridge storing a mission plan could be plugged into the aircraft, and then yanked out after the mission storing data on the flight that could be reviewed on a mission computer.

Beyond that, the capabilities of the three types of machines retained considerable differences:

• The AJS 37 could carry the DWS 39 and the Rb15F, and it could also carry up to six Sidewinders, instead of the two carried previously. Its radar was also upgraded to a similar or identical specification to that of the PS-371/A on the SH 37, allowing the AJS 37 to perform radar reconnaissance flights. However, it could not carry external reconnaissance pods. There were 48 AJS 37 upgrades.

The only really significant improvements in the AJSF 37 over the SF 37 were the mission planning system and the ability to carry six Sidewinders. It still couldn't carry offensive stores. Although there was an impression early on that the upgrade would refit the SF 37 with aradar nose, it didn't happen, and it retained the camera nose with no radar. There were 25 AJSF 37 upgrades.

The AJSH 37 had the same armament options as the AJS 37, but it could carry the Red Baron and LOROP pods. There were 25 AJS 37 upgrades. Re-deliveries of upgraded aircraft began in 1993 and were completed in 1996. Dedicated reconnaissance squadrons were phased out and reconnaissance machines incorporated into regular attack squadrons. However, a special reconnaissance squadron of AJSF 37 Viggens was set up late in the decade to provide support for international peacekeeping missions, the Swedes having become a little more assertive in foreign military operations following the end of the Cold War.

The "Swedish Air Force Rapid Reaction (SWAFRAP)" unit was set up in 2000, with the aircraft repainted in a two-tone gray color scheme, and quickly refitted with a NATO-compatible radio (revealed by a blade antenna on the spine) and a Global Positioning System (GPS) navigation system receiver. The original navigation system was also modified to support wide-ranging deployments with NATO forces. The SWAFRAP Viggens took part in some exercises but were never operationally deployed before they were withdrawn in 2003. A new SWAFRAP squadron flying Gripens was set up in 2004.

• As with other Viggens, the JA 37 interceptor Viggens were continuously upgraded, in particular by being fitted with a datalink system in the mid-1980s. The Flygvapnet had developed the sophisticated STRIC ground-based defense datalink system; STRIC allowed Viggens to be vectored onto targets without using their own radar, giving them an element of surprise. STRIC also allowed ground controllers to read basic aircraft system status, and let pilots trade simple messages through the ground network.

Other useful upgrades added:

• A ground-collision warning system (1986).
• Flare dispensers (1987).
• Support for the AIM-9L / Rb74 Sidewinder (1987).
• Multiple-target tracking to the PS-46A radar (1990).
• A automatic gunsight mode for the radar system that allowed the Oerlikon cannon to be used in collision-course, as opposed to simple tail-chase, attacks (1992).
• Chaff dispensers (1995).

The datalink and Rb74 upgrades required addition of switches to the control stick that eliminated the airbrake control, with the airbrakes wired shut. There were few complaints, since like most other delta-winged aircraft, the Viggen lost speed rapidly under sharp maneuvers and the airbrakes had rarely been used in the first place.

• In the late 1990s, a major upgrade program was implemented to convert surviving JA 37s to the "JA 37D" standard. Updates included:

Carriage of the advanced Hughes AIM-120B Advanced Medium Range AAM (AMRAAM), a substantially improved follow-on to the Sparrow / Skyflash family with greater range -- up to 50 kilometers (31 miles) in optimum conditions -- and a vastly improved seeker system. Sweden was the first non-NATO nation to receive AMRAAM. The weapon is known as the "Rb99" in Flygvapnet service. The JA 37D could carry four AMRAAMs, as opposed to the original load of two Skyflash AAMs.

A new Ericsson SAAB CD207 mission computer, as well as a new ANP-37 stores management computer, supported by dual digital MIL-STD 1553B databuses.

Radar updates to support AMRAAM and provide other capabilities.

• A "Synthetic Attitude Heading Reference System (SAHRS)" to provide better navigation capabilities.
• A new TI 327 15 x 20 centimeter (6 x 8 inch) flat-panel color tactical cockpit display, originally implemented for the Gripen. Dashpanel coloring was also changed to a light gray that was easier on the eyes.
• Improved countermeasures and counter-countermeasures, including an RWR update, fit of BOY 401 chaff-flare dispensers into the inner wing pylons, and carriage of the advanced Ericsson-SAAB U95 jamming pod.

A slightly improved version of the mission planning system implemented on the AJS 37 upgrades. A TARAS encrypted digital tactical radio system was considered but not implemented. With the improved avionics plus all-aspect Sidewinders and AMRAAM, nobody would have considered the JA 37D to be either out-of-date or a pushover. The JA 37D upgrade program was initiated in 1992, with the conversions beginning in the late 1990s. A total of 34 JaktViggens was converted.

The Swedes really like to get their money's worth out of their aircraft, and when the Flygvapnet's J 32E Lansen electronic warfare (EW) machines were phased out in 1997, a decision was made to update ten of the fourteen surviving Sk 37s to the "Sk 37E Stoer (Jammer) Viggen" EW configuration. This was actually a fairly substantial upgrade, including:

• A MIL-STD 1553B digital databus and a GPS receiver.
• A new rear cockpit instrument layout for the "electronic warfare officer (EWO)" in the back seat, featuring a flat-panel display system and jammer controls. The back-seater also got his own radio to allow him to communicate independently of the pilot, with a new radio antenna on the spine for the radio. The original back-seat control panel could be restored with a few days' work.
• A G24 radar jammer inherited from the J 32E Lansen, fitted in a new nose radome with a "window" that did not attenuate jamming power. The window was marked by a yellow ring on the top of the radome, which provided a recognition feature for the Sk 37E.
• The U95 jammer pod.

Carriage of U22/A deception jammer pod and a KB chaff-flare dispenser pod, both inherited from phased-out AJS 37 Viggens. The Sk 37E also inherited an RWR from retired AJ 37s. Work on the first of the ten "Erik" conversions began in late 1997, with an initial conversion flying in early 1998 and the last conversion performed in 2000. There was some thought to giving the Sk 37Es the same two-tone gray color scheme as the JA 37, but though one Erik was painted in this scheme, the decision was made that the old splinter camouflage scheme was fine.

The Stoer Viggen's primary mission was EW training, acting as an "electronic aggressor" for Swedish forces in training exercises. It could be fitted with laser reflector pods on the outer wing pylons for scoring purposes. The Sk 37E was capable of being operated as an operational platform, but since a dedicated jammer aircraft tends to be more useful for offense than defense, that aspect of the Erik was downplayed.

• In the 21st century, the SAAB 39 Gripen rapidly displaced the Viggen from front-line service. Although the Viggen's predecessors had long service lives, and with upgrades the type was clearly still effective, defense cutbacks meant the Viggen was redundant and that its days were numbered. The last operational flight of the Viggen for the Flygvapnet was on 25 November 2005.

The future career of the Viggen seems likely to be restricted to the role of museum display piece, though one or two are being kept on flight status for airshows and the like.

Trivia

• Burt Rutan named his VariViggen kit aircraft after the Saab Viggen.
• Viggen, or a "Vigg" is also a tufted duck (Aythya fuligula), which is found in Sweden. Coincidentally, "Canard" is French for duck.
• The name "Viggen" has a mythological background: it is the clap of Mjolnir, Thor's hammer.
• A high performance model of the SAAB 9-3 car was named the Viggen after the aircraft.

Operators

• Sweden
  • Swedish Air Force

Operational Units

• F 4 Östersund
  • 2 squadrons JA 37 1983-2003
  • 1 squadron SK 37 1999-2003
  • 1 squadron SK 37E 1999-2003
• F 6 Karlsborg
  • 2 squadrons AJ 37 1978-1993
• F 7 Såtenas
  • 3 squadrons AJ 37 1972-1998
  • 1 squadron SK 37 1972-1974
• F 10 Ängelholm
  • 1 squadron AJ/SF/SH 37 (combined) 1993-2001
• F 13 Norrköping
  • 1 squadron SF/SH 37 (combined) 1977-1993
  • 1 squadron JA 37 1980-1993
• F 15 Söderhamn
  • 2 squadrons AJ 37 1974-1998
  • 1 squadron SK 37 1974-1998
• F 16 Uppsala
  • 2 squadrons JA 37 1986-2003
• F 17 Kallinge
  • 1 squadron JA 37 1981-2002
  • 1 squadron SF/SH 37 (combined) 1979-1993
  • 1 squadron JA 37 1993-2002
• F 21 Luleå
  • 2 squadrons JA 37 1983-2004
  • 1 squadron SF/SH 37 1979-2002
  • 1 squadron SK 37E (combined) 2003-2007

Specifications (JA 37 Viggen)

Orthographically projected diagram of the Saab JA 37 Viggen.

General characteristics

• Crew: One

Performance Armament

• 1x 30 mm Oerlikon KCA cannon with 150 rounds
• Six missile stations for two Skyflash, four AIM-120 AMRAAM (JA 37D), or six AIM-9 Sidewinder or four 135 mm (5.4 in) rocket pods.

References

• Donald, David and Lake, Jon, eds. Encyclopedia of World Military Aircraft (Single Volume Edition). London: Aerospace Publishing, 1996. ISBN 1-874023-95-6.
• Nativi, Andrea. "Viggen, Il Caccia Venuto dal Freddo." (in Italian) RID magazine, June 1993, p. 20-36.
• ____________. "Il Cacciabombardiere Su-24 Fencer." (in Italian) RID magazine, October 1996.
• Taylor, John W.R., ed. Jane's All the World's Aircraft, 1988-1989. London: Jane's Information Group, 1988. ISBN 0-7106-0867-5.
• Gunston, Bill Modern combat aircrafts, Salamander book 1983, Peruzzo pubblicazioni 1988 -Not known ISBN but it was a part of an enciclopedia called 'Great modern weapons encyclopedia' traduced by italian, but formerly made by Salamander books as well.

External links

• Website with links to Two Pages of Viggen Pictures
• [2]
• SAAB 37 Viggen webpage
• Vigg, The Tufted Duck (in Swedish)
• Detailed photos of cockpit and weapons
• SAAB 37 Viggen webpage in Dutch
• SAAB 37 Viggen webpage
• Greg Goebel Vectorsite about Viggen-Public domain About the latest developement of Viggens, from which public dominion text is extrapolated

Related content

• Comparison of 21st century fighter aircraft
• Swedish Air Force

Aircraft of comparable role, configuration, and era

• Dassault Mirage F1
• F-4 Phantom
• MiG-23
• MiG-27

Related lists

• List of fighter aircraft
• List of military aircraft of Sweden