JA 37 Viggen
Encyclopedia
The Saab 37 Viggen (Thunderbolt) was a Swedish
single-seat, single-engine, short-medium range fighter
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 a two-seat trainer.
. Even VTOL
designs were considered.
The aim was to produce a robust aircraft with good short-runway performance that could be operated from numerous specially prepared road
s and highway
s to reduce the vulnerability to attack in the event of war. 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 was also designed from the beginning to be easy to repair and service, even for personnel without much training.
To meet these design goals, Saab
selected a radical configuration: a conventional delta wing
with small, high-set canard wings. Canards have since become common in fighter aircraft, notably with the Eurofighter Typhoon
, Dassault Rafale
, Saab JAS 39 Gripen and the IAI Kfir
, but mainly for agility reasons rather than STOL
capabilities. The final proposal was presented and accepted on 28 September 1962. Construction started in 1964, with a first prototype
maiden flight
on 8 February 1967.
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 the Swedish militarily 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 which made it possible to design and produce the Saab 37 Viggen much faster and cheaper than would otherwise have been possible.
According to the doctoral
research of Nils Bruzelius at the Swedish National Defence College, the reason for this officially unexplained U.S. support was the need to protect U.S. Polaris
submarines deployed just outside the Swedish west coast against the threat of Soviet anti-submarine aircraft.
However, Bruzelius' theory have been thoroughly debunked by Simon Moores and Jerker Widén.
turbofan
. This was 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 airframe also incorporated 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. The Viggen was the first aircraft to feature both afterburners and thrust-reversers. Only the Viggen, Concorde and the Panavia Tornado
featured 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 (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, 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 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's powerplant. Since the engine design had not been completed in 1962 when the airframe vs. engine design size needed to be frozen, the JT8D was chosen as the basis for modification instead. The RM8 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 of 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 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 engine was started via a small gas turbine, itself started by an electric motor. Standby power and cooling air for onboard avionics were supplied via an external cart. An internal battery permitted start of the starter turbine and main engine in absence of the standby power cart.
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 when carrying external stores. Each dogtooth was also used as a fairing for a radar warning receiver (RWR) antenna.
A consequence of 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 canards were positioned behind the inlets and placed slightly higher than the main wing, but were not movable as control surfaces (however, they were equipped with flaps). The purpose of the canard wings were to act as vortex generators for the main wing and therefore provide more lift. An added benefit was that they also improved roll stability in the transonic region around Mach 0.9. The canard flaps were deployed in conjunction with the landing gear to provide even more lift for takeoff and landing.
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 were placed in tandem. While such a layout is common in airliners and cargo aircraft, it is rare in fighters, but allows stowage in a thinner wing.
The tall single vertical stabilizer
(45 degrees sweepback on the leading edge) was foldable to make it easier to store in hangar
s. After prototype testing of the SK variant, reduced longitudinal stability was discovered. To correct this, the vertical stabilizer was extended 10 cm (4 in) and the pitot tube
was moved from the top of the fin leading edge to about midpoint where a sawtooth was also incorporated. The JA model later used the same improvements.
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 was rated 18 mg/Ns 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.
In the early 1960s, it was decided that the Viggen should be a single seat aircraft. A digital central computer and a head-up display
replaced the human navigator. This computer, called CK 37 (centralkalkylator 37), was the world's first airborne computer to use integrated circuits. It utilized the STRIL 60
system to be linked with the Swedish defence systems. The main sensor was an Ericsson
PS 37 X-band monopulse radar
with several functions: air-to-ground and air-to-air telemetry and cartography. A Honeywell
radar altimeter with transmitter and receiver in the canard wings was used to assist low altitude flight. A Decca Type 72 doppler
navigation radar and a series of other electronic sub-systems were also provided. A novel landing-aid device, the TILS (Tactical Instrument Landing System), made by Cutler-Hammer AIL, was used to improve landing accuracy down to 30 m from the threshold on the short highway airbase system. ECM
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. In total, the electronics weighed 600 kg which was a substantial amount for a single-engine, late 1960s fighter.
The SK 37 trainer omitted the radar and CK 37 navigational computer, navigating only using the Decca system and later DME
. The radar warning receiver electronics were also removed.
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 and cockpit camera and tape recorder for mission analysis. "Red Baron" and LOROP camera pods were usually carried on the fuselage pylons. The centerline 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 the photographic SF version, the radar in the nose was omitted in favour of one SKa 24 57 mm, three SKa 24C 120 mm and two SKa 31 600 mm photographic cameras as well as one VKa 702 Infrared
linescan camera. The "Red Baron" and LOROP camera pods could also be carried on the fuselage pylons.
The avionics suite of the JA was a major improvement over the other variants designed a decade earlier. The onboard computer was a Singer-Kearfott
SKC-2037 built under license by Saab as CD 107, a Garrett AiResearch
LD-5 air data computer (also used in the F-14 Tomcat
), a Saab-Honeywell
SA07 automatic flight control systems (which was the first digital variant to enter production) and a KTL-70L inertial navigation system
. In the cockpit, several dial-indicator instruments were replaced by two CRT displays; one target indicator MI (sw: MålIndikator) in the center and one tactical moving- and rotating map indicator TI (sw: Taktisk Indikator) to the right while the head-up display
SI (sw: SiktlinjesIndikator - line-of-sight indicator) was retained.
The radar on the JA 37 was upgraded to a multi-mode, pulse-Doppler
Ericsson PS 46/A unit more optimized for the fighter/interceptor role. It sported lookdown/shootdown capability, range up to 48 km (30 mi), continuous-wave illumination for the Skyflash
missiles as well as the ability to track two targets while scanning. The MTBF was reported as 100 hours, a very high reliability level for that generation of avionics systems.
In 1992, an upgrade program of some of the AJ/SF/SH (with least hours on the airframe) to AJS/AJSF/AJSH was initiated because of delays of the new JAS 39 Gripen
. The modifications were not too extensive and consisted to the major part of a new Ericsson computer processor system, MIL-STD-1553
B databus and MIL-STD-1760
stores interface system to carry the Rb 15F
anti-ship missile and DWS 39 Mjölner submunitions dispenser. An upgraded radar warning receiver system with recording capability as well as a Mission planning system via a portable cartridge were also implemented. The original PS 37/A radar from the AJ 37 was upgraded to the PS 371/A (from the SH 37) allowing the new AJS 37 to perform radar reconnaissance missions. No airframe- and very minor cockpit modifications were made.
The JA 37 was continuously upgraded throughout its lifetime. In 1985, the "fighter link" went into service, permitting 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 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.
In 1990, the PS 46/A was upgraded with higher resistance to jamming and the ability to track several targets at the same time. In 1993, the ability to generate virtual targets in the radar reduced the cost of flying aggressors for training.
Between 1992 and 1997, a major avionics upgrade program to the JA was implemented, given the new designation JA 37D. It consisted of an Ericsson CD207 mission computer, an ANP-37 stores management computer, linked via dual MIL-STD-1553
B databuses permitting use of the Rb 99 AMRAAM
. In the cockpit, a TI 327 color tactical moving-map display (originally intended for the Gripen) and a Synthetic Attitude Heading Reference System
were installed. The ECM
and ECCM
suite were enhanced with improved electronics, upgraded radar warning receivers, a new Ericsson U95 jammer pod as well as the ability to carry BOY-401 chaff/flare dispensers on a separate location from the weapon pylons.
Between 1998 and 2000, the conversion of ten Sk 37 trainers to Sk 37E electronic aggressors was completed. The fairly substantial upgrade package consisted of the nose-radome mounted G24 jammer inherited from the decommissioned J 32E Lansen, U22/A jammer- and KB chaff/flare pods and radar warning receivers from the AJS 37 and a new U95 jammer pod all linked together with the MIL-STD-1553
B databus. The rear cockpit for the Electronic Warfare Officer
was improved with new displays and controls while retaining the ability to convert back to the original flight training role.
which could be used as a precision landing aid.
Original layout drawings show the forward display area dominated by a central large Horizontal Situation Indicator
(HSI) with its integral altitude warning light. To the left were the attitude indicator, altimeter
and airspeed indicator
/ MACH displays and to the right, twelve smaller displays including a clock, g-meter, destination indicator, standby instruments, R.P.M. indicator, distance indicator, EPR indicator and fuel indicator.
The ejection seat 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. Low speed capability was limited (on the first versions of the rocket chair) to speeds above 75 km/h (47 mph) on the runway. The seat was angled back by 19 degrees to help counter g-forces in flight. The generation 3 of the rocket chair had zero-zero capability, meaning it needed zero forward speed and zero altitude.
The pilot flew with a centre stick
and left side throttle. The hands-on-throttle–and-stick HOTAS
controls included trim, autopilot
disengage, event marker and trigger (on the stick) and ECM
switch and missile seeker un-cage (on the throttle). Adjacent to the throttle
was a separate radar
joystick.
There were dedicated warning caption panels each side of 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.
A detailed schematic diagram of the original cockpit layout may be found in "Control in the Sky" by L.F.E. Coombs. Photographs of the original cockpit may be found at:
s on the inboard wing pylons with an optional third missile on the centerline pylon. An optional load consisted of two RB 05A
air-to-surface missile
s on the fuselage pylons. The RB 05A was later replaced by Rb 75
TV-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. Self-defense was provided with either ECM
or 30 mm ADEN cannon
pods with 150 rounds of ammunition on the inboard wing pylons.
Rockets had 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. T
For the secondary air-to-air role and self defence, the Rb 28
IR-missile was initially selected, but was never used due to poor performance. This left the outboard wing pylons unutilised as the Rb 28 was the only missile integrated there up until the AJS modernisation. Instead, Rb 24
/Rb 24J were used on the fuselage pylons and inboard wing pylons or in combination with optional 30 mm underwing ADEN cannon
pods.
AJ 37 was under consideration as a carrier of both nuclear
and chemical weapons, although no nuclear or chemical weapons were adopted by Sweden.
/Rb 24J for self defense were employed. The chaff and jammer-pods was the most commonly used load.
/Rb 24J for self defense though. The unguided cannon and rocket pods were also an option.
Rb 71
missiles on the fuselage pylons simultaneously in combination with Rb 24J
/Rb 24J air-to-air missiles. Unlike the strike variant a KCA 30mm Oerlikon
internal cannon was carried as well as 126 rounds, in a conformal pod under the fuselage. The firing rate was selectable at 22 or 11 rounds. The KCA cannon fired 50% heavier shells at higher velocity than the older ADENs, giving a much higher kinetic energy. This, in conjunction with the fire control system, allowed air-to-air engagements at longer range than other fighters. The unguided cannon and rocket pods were available in the secondary ground-attack role.
The centerline pylon was almost exclusively carried a semi-permanent fuel tank, which was jettisonable in the event of a dogfight.
In 1987, the more advanced all-aspect Rb 74 air-to-air missile was introduced for the JA 37. With the major upgrade of the JA to JA 37D in 1997 came the ability to carry four Rb 99
on the fuselage- and inner wing pylons. In addition, a U95 ECM pod could now be carried under the right wing in place of an AMRAAM as well as chaff and flare dispensers on a pair of hitherto unused pylons just behind the main landing gear on each wing.
The extensive electronics upgrade of the old AJ/SF/SH in 1992 gave the ability to carry the Sidewinder on the outer wing pylons which had been unused as well as the ability to carry the newer Rb 74. The AJS and AJSH also received the Rb 15F anti-ship missile
and BK 90
stand-off cluster bomb
originally intended for the delayed JAS 39 Gripen
.
A total of 110 original, ground-attack optimized variant, AJ 37 were built, with the first operational squadron
established in 1972 at F 7 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 trainer
s were ordered and delivered in 1973. To make room for the second cockpit, one fuel tank and some avionics were removed. 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 Lansen. Although fitted with radar and weaponry, the SH 37 Viggen could also undertake photographic missions with its single long-range camera, while external pods could carry a photographic day-set, a "Red Baron" IR
set, an ELINT set, and AQ series ECM
(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 having an elongated nose, equipped with six cameras and a VKa 702 infrared linescanner for night reconnaissance. Also, the "Red Baron" pod, with three IR cameras was widely used, as well as 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 27 JA aircraft. The 28th JA was painted in a gray tone that turned out too close to white. All latter JA aircraft were painted in a darker 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 RM8B engine, a new PS 46/A interception radar, new computers, HUD
, ECM and some other subsystems.
Unusually for a 1970s fighter, three multi-purpose CRT
display screens were fitted within the cockpit, in a system called AP-12, that also included a new model of HUD. 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 Oerlikon
KCA 30 mm cannon mounted internally, with 126 rounds of 360 g ammunition.
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. Between 1998 and 2000, ten SK 37 trainers were converted to SK 37E electronic warfare trainers to replace the aging J 32E Lansen.
with the last front line Viggen retired from the Swedish Air Force
in November 2005. A few aircraft were kept flying for electronic warfare training against JAS 39 at F 17M
in Linköping
. The last Viggen flight took place in June 2007.
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. Partially decommissioned in 1998, some upgraded to AJS 37.
SK 37: Two-seat trainer aircraft, first delivery in 1973, serial numbers 37801-37817. No radar. Decommissioned in 2003, some airframes converted to SK 37E.
SF 37: Single-seat photographic reconnaissance aircraft, first delivery in 1975, radar replaced with four cameras, serial numbers 37950-37977. Partially decommissioned in 1998, some upgraded to AJSF 37.
SH 37: Single-seat maritime reconnaissance and strike aircraft, first delivery in 1975, PS-371A radar, serial numbers 37901-37927. Partially decommissioned in 1998, some upgraded to AJSH 37.
Saab 37E Eurofighter: Proposed NATO replacement of F-104 Starfighter in 1975, none built.
Saab 37X: Proposed export version, none built.
JA 37: Primarily a single-seat all-weather interceptor fighter, with a secondary attack role. First delivery in 1979, serial numbers 37301-37449. A 10 cm (4 in) stretch in the shape of a wedge wider at the bottom than on the top of AJ 37 fuselage between canard and main wing. PS 46A LD/SD radar. Partially decommissioned in 1998, some upgraded to JA 37D.
AJS/AJSF/AJSH 37: Upgrade of some AJ/SF/SH 37 between 1993 and 1998. Avionics and software upgrade. Decommissioned in 2005.
JA 37C: Upgrade of older JA 37, avionics and software upgrade.
JA 37D: Upgrade of older JA 37 between 1993 and 1998, avionics and software upgrade.
JA 37Di: Upgrade of older JA 37, avionics and software upgrade.
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.
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
single-seat, single-engine, short-medium range fighter
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...
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 a two-seat trainer.
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 Finnish aircraft designer Aarne Lakomaa. Several different concepts were studied involving both single- and twin engines and also with separate lift engines, both simple and double delta wings and also with canard wingsCanard (aeronautics)
In aeronautics, canard is an airframe configuration of fixed-wing aircraft in which the forward surface is smaller than the rearward, the former being known as the "canard", while the latter is the main wing...
. Even VTOL
VTOL
A vertical take-off and landing aircraft is one that can hover, take off and land vertically. This classification includes fixed-wing aircraft as well as helicopters and other aircraft with powered rotors, such as cyclogyros/cyclocopters and tiltrotors...
designs were considered.
The aim was to produce a robust aircraft with good short-runway performance that could be operated from numerous specially prepared road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
s and highway
Highway
A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...
s to reduce the vulnerability to attack in the event of war. Other requirements included supersonic
Supersonic
Supersonic speed is a rate of travel of an object that exceeds the speed of sound . For objects traveling in dry air of a temperature of 20 °C this speed is approximately 343 m/s, 1,125 ft/s, 768 mph or 1,235 km/h. Speeds greater than five times the speed of sound are often...
ability at low level, Mach
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...
2 performance at altitude, and the ability to make short landings at low angles of attack (to avoid damaging improvised runways). The aircraft was also designed from the beginning to be easy to repair and service, even for personnel without much training.
To meet these design goals, Saab
Saab
Saab AB is a Swedish aerospace and defence company, founded in 1937. From 1947 to 1990 it was the parent company of automobile manufacturer Saab Automobile, and between 1968 and 1995 the company was in a merger with commercial vehicle manufacturer Scania, known as Saab-Scania.-History:"Svenska...
selected a radical configuration: a conventional delta wing
Delta wing
The delta wing is a wing planform in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta .-Delta-shaped stabilizers:...
with small, high-set canard wings. Canards have since become common in fighter aircraft, notably with the Eurofighter Typhoon
Eurofighter Typhoon
The Eurofighter Typhoon is a twin-engine, canard-delta wing, multirole combat aircraft, designed and built by a consortium of three companies: EADS, Alenia Aeronautica and BAE Systems; working through a holding company, Eurofighter GmbH, which was formed in 1986...
, Dassault Rafale
Dassault Rafale
The Dassault Rafale is a French twin-engine delta-wing multi-role jet fighter aircraft designed and built by Dassault Aviation. Introduced in 2000, the Rafale is being produced both for land-based use with the French Air Force and for carrier-based operations with the French Navy...
, Saab JAS 39 Gripen and the IAI Kfir
IAI Kfir
The Israel Aircraft Industries Kfir is an Israeli-built all-weather, multirole combat aircraft based on a modified Dassault Mirage 5 airframe, with Israeli avionics and an Israeli-made version of the General Electric J79 turbojet engine.-Background:...
, but mainly for agility reasons rather than STOL
STOL
STOL is an acronym for short take-off and landing, a term used to describe aircraft with very short runway requirements.-Definitions:There is no one accepted definition of STOL and many different definitions have been used by different authorities and nations at various times and for a myriad of...
capabilities. The final proposal was presented and accepted on 28 September 1962. Construction started in 1964, with a first prototype
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
maiden flight
Maiden flight
The maiden flight of an aircraft is the first occasion on which an aircraft leaves the ground of its own accord. This is similar to a ship's maiden voyage....
on 8 February 1967.
In 1960, the U.S. National Security Council, led by President
President of the United States
The President of the United States of America is the head of state and head of government of the United States. The president leads the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces....
Eisenhower
Dwight D. Eisenhower
Dwight David "Ike" Eisenhower was the 34th President of the United States, from 1953 until 1961. He was a five-star general in the United States Army...
, formulated a military security guarantee for Sweden. The U.S. promised to help the Swedish militarily 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 which made it possible to design and produce the Saab 37 Viggen much faster and cheaper than would otherwise have been possible.
According to the doctoral
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
research of Nils Bruzelius at the Swedish National Defence College, the reason for this officially unexplained U.S. support was the need to protect U.S. Polaris
UGM-27 Polaris
The Polaris missile was a two-stage solid-fuel nuclear-armed submarine-launched ballistic missile built during the Cold War by Lockheed Corporation of California for the United States Navy....
submarines deployed just outside the Swedish west coast against the threat of Soviet anti-submarine aircraft.
However, Bruzelius' theory have been thoroughly debunked by Simon Moores and Jerker Widén.
Propulsion
The Viggen was powered by a single Volvo RM8Volvo RM8
|-See also:-External links:*...
turbofan
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
. This was essentially a licence-built
Licence-built
The term licence-built refers to an object manufactured by one organisation with the authorisation of the organisation that owns the intellectual property of the design...
variant of the Pratt & Whitney JT8D engine that powered commercial airliners of the 1960s, with an afterburner
Afterburner (engine)
An afterburner is an additional component added to some jet engines, primarily those on military supersonic aircraft. Its purpose is to provide a temporary increase in thrust, both for supersonic flight and for takeoff...
added for the Viggen. The airframe also incorporated a thrust-reverser
Thrust reversal
Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's exhaust or changing of propeller pitch so that the thrust produced is directed forward, rather than aft. This acts against the forward travel of the aircraft, providing deceleration...
to use during landings and land manoeuvres, which, combined with the aircraft having flight capabilities approaching a limited STOL
STOL
STOL is an acronym for short take-off and landing, a term used to describe aircraft with very short runway requirements.-Definitions:There is no one accepted definition of STOL and many different definitions have been used by different authorities and nations at various times and for a myriad of...
-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. The Viggen was the first aircraft to feature both afterburners and thrust-reversers. Only the Viggen, Concorde and the Panavia Tornado
Panavia Tornado
The Panavia Tornado is a family of twin-engine, variable-sweep wing combat aircraft, which was jointly developed and manufactured by the United Kingdom, West Germany and Italy...
featured both afterburners and thrust-reversers.
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
engines just emerging and indicating better fuel economy for cruise than turbojet engines, 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 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
Tumansky R-15
- External links :* *...
was bigger.
Saab had originally wanted the Pratt & Whitney TF30 as the Viggen's powerplant. Since the engine design had not been completed in 1962 when the airframe vs. engine design size needed to be frozen, the JT8D was chosen as the basis for modification instead. The RM8 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 engine was started via a small gas turbine, itself started by an electric motor. Standby power and cooling air for onboard avionics were supplied via an external cart. An internal battery permitted start of the starter turbine and main engine in absence of the standby power cart.
Wing and airframe
With 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 fuselageFuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...
that was later improved with a "hump" on the dorsal spine for reduced drag according to the area rule
Area rule
The Whitcomb area rule, also called the transonic area rule, is a design technique used to reduce an aircraft's drag at transonic and supersonic speeds, particularly between Mach 0.75 and 1.2....
.
The wing had the shape of a double delta with a dogtooth added to improve longitudinal stability when carrying external stores. Each dogtooth was also used as a fairing for a radar warning receiver (RWR) antenna.
A consequence of 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
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
; 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
Canard (aeronautics)
In aeronautics, canard is an airframe configuration of fixed-wing aircraft in which the forward surface is smaller than the rearward, the former being known as the "canard", while the latter is the main wing...
. The canards were positioned behind the inlets and placed slightly higher than the main wing, but were not movable as control surfaces (however, they were equipped with flaps). The purpose of the canard wings were to act as vortex generators for the main wing and therefore provide more lift. An added benefit was that they also improved roll stability in the transonic region around Mach 0.9. The canard flaps were deployed in conjunction with the landing gear to provide even more lift for takeoff and landing.
To withstand the stresses of no-flare landings, Saab made extensive use of titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
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 were placed in tandem. While such a layout is common in airliners and cargo aircraft, it is rare in fighters, but allows stowage in a thinner wing.
Vertical stabilizer
The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...
(45 degrees sweepback on the leading edge) was foldable to make it easier to store in hangar
Hangar
A hangar is a closed structure to hold aircraft or spacecraft in protective storage. Most hangars are built of metal, but other materials such as wood and concrete are also sometimes used...
s. After prototype testing of the SK variant, reduced longitudinal stability was discovered. To correct this, the vertical stabilizer was extended 10 cm (4 in) and the pitot tube
Pitot tube
A pitot tube is a pressure measurement instrument used to measure fluid flow velocity. The pitot tube was invented by the French engineer Henri Pitot Ulo in the early 18th century and was modified to its modern form in the mid-19th century by French scientist Henry Darcy...
was moved from the top of the fin leading edge to about midpoint where a sawtooth was also incorporated. The JA model later used the same improvements.
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 was rated 18 mg/Ns 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
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
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
Yakovlev Yak-38
The Yakovlev Yak-38 was Soviet Naval Aviation's first and only operational VTOL strike fighter aircraft, in addition to being its first operational carrier-based fixed-wing aircraft...
were designed for STOL
STOL
STOL is an acronym for short take-off and landing, a term used to describe aircraft with very short runway requirements.-Definitions:There is no one accepted definition of STOL and many different definitions have been used by different authorities and nations at various times and for a myriad of...
or VTOL
VTOL
A vertical take-off and landing aircraft is one that can hover, take off and land vertically. This classification includes fixed-wing aircraft as well as helicopters and other aircraft with powered rotors, such as cyclogyros/cyclocopters and tiltrotors...
capability.
Avionics
Head-Up Display
A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...
replaced the human navigator. This computer, called CK 37 (centralkalkylator 37), was the world's first airborne computer to use integrated circuits. It utilized the STRIL 60
STRIL
STRIL is short for "Stridsledning" which means "combat management" in Swedish. STRIL 50 and STRIL 60 were integrated systems for air combat management including early warning and ground-controlled interception...
system to be linked with the Swedish defence systems. The main sensor was an Ericsson
Ericsson
Ericsson , one of Sweden's largest companies, is a provider of telecommunication and data communication systems, and related services, covering a range of technologies, including especially mobile networks...
PS 37 X-band monopulse radar
Monopulse radar
Monopulse radar is an adaptation of conical scanning radar which sends additional information in the radar signal in order to avoid problems caused by rapid changes in signal strength. The system also makes jamming more difficult...
with several functions: air-to-ground and air-to-air telemetry and cartography. A Honeywell
Honeywell
Honeywell International, Inc. is a major conglomerate company that produces a variety of consumer products, engineering services, and aerospace systems for a wide variety of customers, from private consumers to major corporations and governments....
radar altimeter with transmitter and receiver in the canard wings was used to assist low altitude flight. A Decca Type 72 doppler
Doppler effect
The Doppler effect , named after Austrian physicist Christian Doppler who proposed it in 1842 in Prague, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from...
navigation radar and a series of other electronic sub-systems were also provided. A novel landing-aid device, the TILS (Tactical Instrument Landing System), made by Cutler-Hammer AIL, was used to improve landing accuracy down to 30 m from the threshold on the short highway airbase system. ECM
Electronic countermeasures
An electronic countermeasure is an electrical or electronic device designed to trick or deceive radar, sonar or other detection systems, like infrared or lasers. It may be used both offensively and defensively to deny targeting information to an enemy...
consisted of a Satt Elektronik radar warning receiver
Radar warning receiver
Radar warning receiver systems detect the radio emissions of radar systems. Their primary purpose is to issue a warning when a radar signal that might be a threat is detected. The warning can then be used, manually or automatically, to evade the detected threat...
system in the wings and the tail, an optional Ericsson Erijammer pod and BOZ-100 chaff/flare pod. In total, the electronics weighed 600 kg which was a substantial amount for a single-engine, late 1960s fighter.
The SK 37 trainer omitted the radar and CK 37 navigational computer, navigating only using the Decca system and later DME
Distance Measuring Equipment
Distance measuring equipment is a transponder-based radio navigation technology that measures distance by timing the propagation delay of VHF or UHF radio signals....
. The radar warning receiver electronics were also removed.
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 and cockpit camera and tape recorder for mission analysis. "Red Baron" and LOROP camera pods were usually carried on the fuselage pylons. The centerline 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 the photographic SF version, the radar in the nose was omitted in favour of one SKa 24 57 mm, three SKa 24C 120 mm and two SKa 31 600 mm photographic cameras as well as one VKa 702 Infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
linescan camera. The "Red Baron" and LOROP camera pods could also be carried on the fuselage pylons.
The avionics suite of the JA was a major improvement over the other variants designed a decade earlier. The onboard computer was a Singer-Kearfott
Kearfott Guidance & Navigation
Kearfott was a defense equipment manufacturer founded in 1917. Today the electronics division is part of BAE Systems, while the remaining Kearfott Guidance & Navigation division is a subsidiary of the Astronautics Corporation of America...
SKC-2037 built under license by Saab as CD 107, a Garrett AiResearch
Garrett AiResearch
Garrett AiResearch was a manufacturer of turboprop engines and turbochargers, and a pioneer in numerous aerospace technologies. It was previously known as Aircraft Tool and Supply Company, Garrett Supply Company, AiResearch Manufacturing Company, or simply AiResearch...
LD-5 air data computer (also used in the F-14 Tomcat
F-14 Tomcat
The Grumman F-14 Tomcat is a supersonic, twin-engine, two-seat, variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy's Naval Fighter Experimental program following the collapse of the F-111B project...
), a Saab-Honeywell
Honeywell
Honeywell International, Inc. is a major conglomerate company that produces a variety of consumer products, engineering services, and aerospace systems for a wide variety of customers, from private consumers to major corporations and governments....
SA07 automatic flight control systems (which was the first digital variant to enter production) and a KTL-70L inertial navigation system
Inertial navigation system
An inertial navigation system is a navigation aid that uses a computer, motion sensors and rotation sensors to continuously calculate via dead reckoning the position, orientation, and velocity of a moving object without the need for external references...
. In the cockpit, several dial-indicator instruments were replaced by two CRT displays; one target indicator MI (sw: MålIndikator) in the center and one tactical moving- and rotating map indicator TI (sw: Taktisk Indikator) to the right while the head-up display
Head-Up Display
A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...
SI (sw: SiktlinjesIndikator - line-of-sight indicator) was retained.
The radar on the JA 37 was upgraded to a multi-mode, pulse-Doppler
Pulse-doppler radar
Pulse-Doppler is a 4D radar system capable of detecting both target 3D location as well as measuring radial velocity . It uses the Doppler effect to avoid overloading computers and operators as well as to reduce power consumption...
Ericsson PS 46/A unit more optimized for the fighter/interceptor role. It sported lookdown/shootdown capability, range up to 48 km (30 mi), continuous-wave illumination for the Skyflash
Skyflash
The British Aerospace Skyflash was a medium-range semi-active radar homing air-to-air missile derived from the US AIM-7 Sparrow missile and carried by Royal Air Force F-4 Phantoms and Tornado F3s, Italian Aeronautica Militare and Royal Saudi Air Force Tornados and Swedish Flygvapnet Viggens...
missiles as well as the ability to track two targets while scanning. The MTBF was reported as 100 hours, a very high reliability level for that generation of avionics systems.
In 1992, an upgrade program of some of the AJ/SF/SH (with least hours on the airframe) to AJS/AJSF/AJSH was initiated because of delays of the new JAS 39 Gripen
JAS 39 Gripen
The Saab JAS 39 Gripen is a lightweight single-engine multirole fighter manufactured by the Swedish aerospace company Saab. It was designed to replace the Saab 35 Draken and 37 Viggen in the Swedish Air Force...
. The modifications were not too extensive and consisted to the major part of a new Ericsson computer processor system, MIL-STD-1553
MIL-STD-1553
MIL-STD-1553 is a military standard published by the United States Department of Defense that defines the mechanical, electrical, and functional characteristics of a serial data bus. It was originally designed for use with military avionics, but has also become commonly used in spacecraft on-board...
B databus and MIL-STD-1760
MIL-STD-1760
MIL-STD-1760 Aircraft/Store Electrical Interconnection System defines a standardized electrical interface between a military aircraft and its carriage stores. Carriage stores range from weapons, such as GBU-31 JDAM, to pods, such as AN/AAQ-14 LANTIRN, to external fuel tanks...
stores interface system to carry the Rb 15F
RBS15
The RBS-15 is a long-range fire-and-forget surface-to-surface and air-to-surface, anti-ship missile. The later version Mk. III has the ability to attack land targets as well...
anti-ship missile and DWS 39 Mjölner submunitions dispenser. An upgraded radar warning receiver system with recording capability as well as a Mission planning system via a portable cartridge were also implemented. The original PS 37/A radar from the AJ 37 was upgraded to the PS 371/A (from the SH 37) allowing the new AJS 37 to perform radar reconnaissance missions. No airframe- and very minor cockpit modifications were made.
The JA 37 was continuously upgraded throughout its lifetime. In 1985, the "fighter link" went into service, permitting 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
Skyflash
The British Aerospace Skyflash was a medium-range semi-active radar homing air-to-air missile derived from the US AIM-7 Sparrow missile and carried by Royal Air Force F-4 Phantoms and Tornado F3s, Italian Aeronautica Militare and Royal Saudi Air Force Tornados and Swedish Flygvapnet Viggens...
missiles of 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.
In 1990, the PS 46/A was upgraded with higher resistance to jamming and the ability to track several targets at the same time. In 1993, the ability to generate virtual targets in the radar reduced the cost of flying aggressors for training.
Between 1992 and 1997, a major avionics upgrade program to the JA was implemented, given the new designation JA 37D. It consisted of an Ericsson CD207 mission computer, an ANP-37 stores management computer, linked via dual MIL-STD-1553
MIL-STD-1553
MIL-STD-1553 is a military standard published by the United States Department of Defense that defines the mechanical, electrical, and functional characteristics of a serial data bus. It was originally designed for use with military avionics, but has also become commonly used in spacecraft on-board...
B databuses permitting use of the Rb 99 AMRAAM
AIM-120 AMRAAM
The AIM-120 Advanced Medium-Range Air-to-Air Missile, or AMRAAM , is a modern beyond-visual-range air-to-air missile capable of all-weather day-and-night operations. Designed with the same form-factor as the previous generation of semi-active guided Sparrow missiles, it is a fire-and-forget...
. In the cockpit, a TI 327 color tactical moving-map display (originally intended for the Gripen) and a Synthetic Attitude Heading Reference System
Attitude and Heading Reference Systems
An attitude heading reference system consists of sensors on three axes that provide heading, attitude and yaw information for aircraft. They are designed to replace traditional mechanical gyroscopic flight instruments and provide superior reliability and accuracy.AHRS consist of either solid-state...
were installed. The ECM
Electronic countermeasures
An electronic countermeasure is an electrical or electronic device designed to trick or deceive radar, sonar or other detection systems, like infrared or lasers. It may be used both offensively and defensively to deny targeting information to an enemy...
and ECCM
Electronic counter-countermeasures
Electronic counter-countermeasures is a part of electronic warfare which includes a variety of practices which attempt to reduce or eliminate the effect of electronic countermeasures on electronic sensors aboard vehicles, ships and aircraft and weapons such as missiles. ECCM is also known as...
suite were enhanced with improved electronics, upgraded radar warning receivers, a new Ericsson U95 jammer pod as well as the ability to carry BOY-401 chaff/flare dispensers on a separate location from the weapon pylons.
Between 1998 and 2000, the conversion of ten Sk 37 trainers to Sk 37E electronic aggressors was completed. The fairly substantial upgrade package consisted of the nose-radome mounted G24 jammer inherited from the decommissioned J 32E Lansen, U22/A jammer- and KB chaff/flare pods and radar warning receivers from the AJS 37 and a new U95 jammer pod all linked together with the MIL-STD-1553
MIL-STD-1553
MIL-STD-1553 is a military standard published by the United States Department of Defense that defines the mechanical, electrical, and functional characteristics of a serial data bus. It was originally designed for use with military avionics, but has also become commonly used in spacecraft on-board...
B databus. The rear cockpit for the Electronic Warfare Officer
Electronic Warfare Officer
In the U.S. Air Force, an Electronic Warfare Officer is a trained aerial navigator in the Air Force who has received training in enemy threat systems, electronic warfare principles and overcoming enemy air defense systems...
was improved with new displays and controls while retaining the ability to convert back to the original flight training role.
Cockpit
The displays in the original cockpit were all of the traditional analogue/mechanical type with the exception of an electronic HUDHead-Up Display
A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...
which could be used as a precision landing aid.
Original layout drawings show the forward display area dominated by a central large Horizontal Situation Indicator
Horizontal Situation Indicator
The horizontal situation indicator is an aircraft instrument normally mounted below the artificial horizon in place of a conventional heading indicator. It combines a heading indicator with a VOR/ILS display, reducing pilot workload by lessening the number of elements in the pilot's instrument...
(HSI) with its integral altitude warning light. To the left were the attitude indicator, altimeter
Altimeter
An altimeter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater.-Pressure altimeter:...
and airspeed indicator
Airspeed indicator
The airspeed indicator or airspeed gauge is an instrument used in an aircraft to display the craft's airspeed, typically in knots, to the pilot.- Use :...
/ MACH displays and to the right, twelve smaller displays including a clock, g-meter, destination indicator, standby instruments, R.P.M. indicator, distance indicator, EPR indicator and fuel indicator.
The ejection seat was the Raketstol 37 (literally; Rocket chair 37) and was the last Saab designed seat in service. A derivative of the Saab 105
Saab 105
-See also:-Bibliography:* Hewson, Robert. "Saab 105/Sk60 Variant Briefing". World Air Power Journal, Volume 23 Winter 1995. London:Aerospace Publishing. ISBN 1 874023 64 6. ISSN 0959-7050. pp. 40—49....
trainer seat, the seat was optimized for low altitude, high speed ejections. Low speed capability was limited (on the first versions of the rocket chair) to speeds above 75 km/h (47 mph) on the runway. The seat was angled back by 19 degrees to help counter g-forces in flight. The generation 3 of the rocket chair had zero-zero capability, meaning it needed zero forward speed and zero altitude.
The pilot flew with a centre stick
Centre stick
A centre stick , or simply control stick is an aircraft cockpit arrangement where the control column is located conventionally in the centre of the cockpit between the pilot's legs...
and left side throttle. The hands-on-throttle–and-stick HOTAS
HOTAS
HOTAS, an abbreviation for Hands On Throttle-And-Stick, is the name given to the concept of placing buttons and switches on the throttle stick and flight control stick in an aircraft's cockpit, allowing the pilot to access vital cockpit functions and fly the aircraft without having to remove his...
controls included trim, autopilot
Autopilot
An autopilot is a mechanical, electrical, or hydraulic system used to guide a vehicle without assistance from a human being. An autopilot can refer specifically to aircraft, self-steering gear for boats, or auto guidance of space craft and missiles...
disengage, event marker and trigger (on the stick) and ECM
Electronic countermeasures
An electronic countermeasure is an electrical or electronic device designed to trick or deceive radar, sonar or other detection systems, like infrared or lasers. It may be used both offensively and defensively to deny targeting information to an enemy...
switch and missile seeker un-cage (on the throttle). Adjacent to the throttle
Throttle
A throttle is the mechanism by which the flow of a fluid is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases , but usually decreased. The term throttle has come to refer, informally and incorrectly, to any mechanism by which...
was a separate radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
joystick.
There were dedicated warning caption panels each side of 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
IFF
IFF, Iff or iff may refer to:Technology/Science:* Identification friend or foe, an electronic radio-based identification system using transponders...
control, lighting controls. Situated on the left console panel were radar controls, canopy handle, landing gear handle, radio controls and the cabin pressure indicator.
A detailed schematic diagram of the original cockpit layout may be found in "Control in the Sky" by L.F.E. Coombs. Photographs of the original cockpit may be found at:
Armament
A weapons load of up to 7,000 kg could be accommodated on seven hardpoints; one centerline pylon, two fuselage pylons, two inner and two outer wing pylons. The centerline pylon was the only wet pylon and was usually occupied by an external fuel tank. The outboard wing pylons were never used in peacetime since aerodynamic flutter loads would structurally fatigue the wing.AJ 37
The AJ 37 was designed to carry two RB 04E anti-ship missileAnti-ship missile
Anti-ship missiles are guided missiles that are designed for use against ships and large boats. Most anti-ship missiles are of the sea-skimming type, many use a combination of inertial guidance and radar homing...
s on the inboard wing pylons with an optional third missile on the centerline pylon. An optional load consisted of two RB 05A
Rb 05
The Rb 05A is a short-range air-to-surface missile that was developed in the 1960s by the Swedish company Saab-Scania, Missiles and Electronics.-History:...
air-to-surface missile
Air-to-surface missile
An air-to-surface missile is a missile designed to be launched from military aircraft and strike ground targets on land, at sea, or both...
s on the fuselage pylons. The RB 05A was later replaced by Rb 75
AGM-65 Maverick
The AGM-65 Maverick is an air-to-ground tactical missile designed for close-air support. It is effective against a wide range of tactical targets, including armor, air defenses, ships, ground transportation and fuel storage facilities....
TV-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. Self-defense was provided with either ECM
Electronic countermeasures
An electronic countermeasure is an electrical or electronic device designed to trick or deceive radar, sonar or other detection systems, like infrared or lasers. It may be used both offensively and defensively to deny targeting information to an enemy...
or 30 mm ADEN cannon
ADEN cannon
The Royal Small Arms Factory ADEN is a 30 mm revolver cannon used on many military aircraft, particularly those of the British Royal Air Force and Fleet Air Arm...
pods with 150 rounds of ammunition on the inboard wing pylons.
Rockets had 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
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
warhead. T
For the secondary air-to-air role and self defence, the Rb 28
AIM-4 Falcon
The Hughes AIM-4 Falcon was the first operational guided air-to-air missile of the United States Air Force.-Development:Development of a guided air-to-air missile began in 1946. Hughes Aircraft was awarded a contract for a subsonic missile under the project designation MX-798, which soon gave way...
IR-missile was initially selected, but was never used due to poor performance. This left the outboard wing pylons unutilised as the Rb 28 was the only missile integrated there up until the AJS modernisation. Instead, Rb 24
AIM-9 Sidewinder
The AIM-9 Sidewinder is a heat-seeking, short-range, air-to-air missile carried mostly by fighter aircraft and recently, certain gunship helicopters. The missile entered service with United States Air Force in the early 1950s, and variants and upgrades remain in active service with many air forces...
/Rb 24J were used on the fuselage pylons and inboard wing pylons or in combination with optional 30 mm underwing ADEN cannon
ADEN cannon
The Royal Small Arms Factory ADEN is a 30 mm revolver cannon used on many military aircraft, particularly those of the British Royal Air Force and Fleet Air Arm...
pods.
AJ 37 was under consideration as a carrier of both nuclear
Swedish nuclear weapon program
During the 20th century Sweden had programs for both Nuclear and Chemical weapons. During the first decades of the Cold War a nuclear weapon program was active...
and chemical weapons, although no nuclear or chemical weapons were adopted by Sweden.
SH 37
The SH 37 was capable of carrying the same configuration of weapons as the AJ 37. However, since it was only used in the maritime role, only the RB 04E in combination with Rb 24AIM-9 Sidewinder
The AIM-9 Sidewinder is a heat-seeking, short-range, air-to-air missile carried mostly by fighter aircraft and recently, certain gunship helicopters. The missile entered service with United States Air Force in the early 1950s, and variants and upgrades remain in active service with many air forces...
/Rb 24J for self defense were employed. The chaff and jammer-pods was the most commonly used load.
SF/SK 37
Both the SF and SK variants lacked the radar and could not carry the guided air-to-surface missiles as the AJ and SH. The SF could carry Rb 24AIM-9 Sidewinder
The AIM-9 Sidewinder is a heat-seeking, short-range, air-to-air missile carried mostly by fighter aircraft and recently, certain gunship helicopters. The missile entered service with United States Air Force in the early 1950s, and variants and upgrades remain in active service with many air forces...
/Rb 24J for self defense though. The unguided cannon and rocket pods were also an option.
JA 37
With the introduction of the JA 37 in 1979 came the Ericsson PS 46/A radar capable of guiding the two semi-active radar homingSemi-active radar homing
Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer-range air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is only a passive detector of a radar signal – provided by an external ...
Rb 71
Skyflash
The British Aerospace Skyflash was a medium-range semi-active radar homing air-to-air missile derived from the US AIM-7 Sparrow missile and carried by Royal Air Force F-4 Phantoms and Tornado F3s, Italian Aeronautica Militare and Royal Saudi Air Force Tornados and Swedish Flygvapnet Viggens...
missiles on the fuselage pylons simultaneously in combination with Rb 24J
AIM-9 Sidewinder
The AIM-9 Sidewinder is a heat-seeking, short-range, air-to-air missile carried mostly by fighter aircraft and recently, certain gunship helicopters. The missile entered service with United States Air Force in the early 1950s, and variants and upgrades remain in active service with many air forces...
/Rb 24J air-to-air missiles. Unlike the strike variant a KCA 30mm Oerlikon
Oerlikon Contraves
Rheinmetall Air Defence AG is a division of German armament manufacturer Rheinmetall, created when the company's Oerlikon Contraves unit was renamed on 1 January 2009 and integrated with Rheinmetall's other air-defence products...
internal cannon was carried as well as 126 rounds, in a conformal pod under the fuselage. The firing rate was selectable at 22 or 11 rounds. The KCA cannon fired 50% heavier shells at higher velocity than the older ADENs, giving a much higher kinetic energy. This, in conjunction with the fire control system, allowed air-to-air engagements at longer range than other fighters. The unguided cannon and rocket pods were available in the secondary ground-attack role.
The centerline pylon was almost exclusively carried a semi-permanent fuel tank, which was jettisonable in the event of a dogfight.
In 1987, the more advanced all-aspect Rb 74 air-to-air missile was introduced for the JA 37. With the major upgrade of the JA to JA 37D in 1997 came the ability to carry four Rb 99
AIM-120 AMRAAM
The AIM-120 Advanced Medium-Range Air-to-Air Missile, or AMRAAM , is a modern beyond-visual-range air-to-air missile capable of all-weather day-and-night operations. Designed with the same form-factor as the previous generation of semi-active guided Sparrow missiles, it is a fire-and-forget...
on the fuselage- and inner wing pylons. In addition, a U95 ECM pod could now be carried under the right wing in place of an AMRAAM as well as chaff and flare dispensers on a pair of hitherto unused pylons just behind the main landing gear on each wing.
AJS/AJSF/AJSH 37
With a need arisning to carry the new RBS-15 anti ship missile the onboard computer was inadequate. Instead of installing a computer in the misile pylon it was considered more effective to upgrade the onboard electronics.The extensive electronics upgrade of the old AJ/SF/SH in 1992 gave the ability to carry the Sidewinder on the outer wing pylons which had been unused as well as the ability to carry the newer Rb 74. The AJS and AJSH also received the Rb 15F anti-ship missile
Anti-ship missile
Anti-ship missiles are guided missiles that are designed for use against ships and large boats. Most anti-ship missiles are of the sea-skimming type, many use a combination of inertial guidance and radar homing...
and BK 90
Bombkapsel 90
Bombkapsel 90 is the Swedish Air Force's nomenclature for a gliding stand-off submunitions dispenser, or cluster bomb, with 72 submunitions. It is manufactured by DaimlerChrysler Aerospace in Germany by the name of DWS 24 - Dispenser Weapon System 24 barrels. The BK90 is also commonly known as...
stand-off cluster bomb
Cluster bomb
A cluster munition is a form of air-dropped or ground-launched explosive weapon that releases or ejects smaller sub-munitions. Commonly, this is a cluster bomb that ejects explosive bomblets that are designed to kill enemy personnel and destroy vehicles...
originally intended for the delayed JAS 39 Gripen
JAS 39 Gripen
The Saab JAS 39 Gripen is a lightweight single-engine multirole fighter manufactured by the Swedish aerospace company Saab. It was designed to replace the Saab 35 Draken and 37 Viggen in the Swedish Air Force...
.
Operational history
Squadron (aviation)
A squadron in air force, army aviation or naval aviation is mainly a unit comprising a number of military aircraft, usually of the same type, typically with 12 to 24 aircraft, sometimes divided into three or four flights, depending on aircraft type and air force...
established in 1972 at F 7 Såtenäs
F 7 Såtenäs
F 7 Såtenäs, Skaraborgs Flygflottilj, Skaraborg Air Force Wing, or simply "F 7", is a Swedish Air Force wing with the main base located near Lidköping in south-central Sweden.- History of the airbase :...
.
A two-seat trainer was not initially planned since it was considered that new pilots could get enough experience with delta-winged
Delta wing
The delta wing is a wing planform in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta .-Delta-shaped stabilizers:...
aircraft on the SK 35 Draken trainer. Eventually, however, 18 SK 37 two-seat trainer
Trainer (aircraft)
A trainer is a class of aircraft designed specifically to facilitate in-flight training of pilots and aircrews. The use of a dedicated trainer aircraft with additional safety features—such as tandem flight controls, forgiving flight characteristics and a simplified cockpit arrangement—allows...
s were ordered and delivered in 1973. To make room for the second cockpit, one fuel tank and some avionics were removed. 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 Lansen. Although fitted with radar and weaponry, the SH 37 Viggen could also undertake photographic missions with its single long-range camera, while external pods could carry a photographic day-set, a "Red Baron" IR
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
set, an ELINT set, and AQ series ECM
Electronic countermeasures
An electronic countermeasure is an electrical or electronic device designed to trick or deceive radar, sonar or other detection systems, like infrared or lasers. It may be used both offensively and defensively to deny targeting information to an enemy...
(made by SATT).
A further 26 of the SF 37 reconnaissance
Reconnaissance
Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....
variant were also delivered to replace the S 35 Draken in 1975. These were recognizable by having an elongated nose, equipped with six cameras and a VKa 702 infrared linescanner for night reconnaissance. Also, the "Red Baron" pod, with three IR cameras was widely used, as well as 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
Dictatorship
A dictatorship is defined as an autocratic form of government in which the government is ruled by an individual, the dictator. It has three possible meanings:...
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
SEPECAT Jaguar
The SEPECAT Jaguar is an Anglo-French jet ground attack aircraft, originally used by the British Royal Air Force and the French Armée de l'Air in the close air support and nuclear strike role, and still in service with several export customers, notably the Indian Air Force and the Royal Air Force...
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 27 JA aircraft. The 28th JA was painted in a gray tone that turned out too close to white. All latter JA aircraft were painted in a darker light/dark gray, appropriate for a high altitude fighter.
The final Viggen production variant was the JA 37 interceptor
Interceptor aircraft
An interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...
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 RM8B engine, a new PS 46/A interception radar, new computers, HUD
Head-Up Display
A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...
, ECM and some other subsystems.
Unusually for a 1970s fighter, three multi-purpose CRT
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
display screens were fitted within the cockpit, in a system called AP-12, that also included a new model of HUD. The new radar was compatible with the Skyflash
Skyflash
The British Aerospace Skyflash was a medium-range semi-active radar homing air-to-air missile derived from the US AIM-7 Sparrow missile and carried by Royal Air Force F-4 Phantoms and Tornado F3s, Italian Aeronautica Militare and Royal Saudi Air Force Tornados and Swedish Flygvapnet Viggens...
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 Oerlikon
Oerlikon Contraves
Rheinmetall Air Defence AG is a division of German armament manufacturer Rheinmetall, created when the company's Oerlikon Contraves unit was renamed on 1 January 2009 and integrated with Rheinmetall's other air-defence products...
KCA 30 mm cannon mounted internally, with 126 rounds of 360 g ammunition.
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. Between 1998 and 2000, ten SK 37 trainers were converted to SK 37E electronic warfare trainers to replace the aging J 32E Lansen.
Retirement
The Viggen has been phased out in favour of the advanced later generation JAS 39 GripenJAS 39 Gripen
The Saab JAS 39 Gripen is a lightweight single-engine multirole fighter manufactured by the Swedish aerospace company Saab. It was designed to replace the Saab 35 Draken and 37 Viggen in the Swedish Air Force...
with the last front line Viggen retired from the Swedish Air Force
Swedish Air Force
The Swedish Air Force is the air force branch of the Swedish Armed Forces.-History:The Swedish Air Force was created on July 1, 1926 when the aircraft units of the Army and Navy were merged. Because of the escalating international tension during the 1930s the Air Force was reorganized and expanded...
in November 2005. A few aircraft were kept flying for electronic warfare training against JAS 39 at F 17M
F 3 Malmslätt
F 3 Malmslätt, Kungliga Östgöta Flygflottilj, Royal Östgöta Air Force Wing, or simply "F 3", is a former Swedish Air Force wing with the main base located at Malmen air base near Linköping in south-eastern Sweden.- History of the airbase :...
in Linköping
Linköping
Linköping is a city in southern middle Sweden, with 104 232 inhabitants in 2010. It is the seat of Linköping Municipality with 146 736 inhabitants and the capital of Östergötland County...
. The last Viggen flight took place in June 2007.
Variants
in chronological orderAJ 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. Partially decommissioned in 1998, some upgraded to AJS 37.
SK 37: Two-seat trainer aircraft, first delivery in 1973, serial numbers 37801-37817. No radar. Decommissioned in 2003, some airframes converted to SK 37E.
SF 37: Single-seat photographic reconnaissance aircraft, first delivery in 1975, radar replaced with four cameras, serial numbers 37950-37977. Partially decommissioned in 1998, some upgraded to AJSF 37.
SH 37: Single-seat maritime reconnaissance and strike aircraft, first delivery in 1975, PS-371A radar, serial numbers 37901-37927. Partially decommissioned in 1998, some upgraded to AJSH 37.
Saab 37E Eurofighter: Proposed NATO replacement of F-104 Starfighter in 1975, none built.
Saab 37X: Proposed export version, none built.
JA 37: Primarily a single-seat all-weather interceptor fighter, with a secondary attack role. First delivery in 1979, serial numbers 37301-37449. A 10 cm (4 in) stretch in the shape of a wedge wider at the bottom than on the top of AJ 37 fuselage between canard and main wing. PS 46A LD/SD radar. Partially decommissioned in 1998, some upgraded to JA 37D.
AJS/AJSF/AJSH 37: Upgrade of some AJ/SF/SH 37 between 1993 and 1998. Avionics and software upgrade. Decommissioned in 2005.
JA 37C: Upgrade of older JA 37, avionics and software upgrade.
JA 37D: Upgrade of older JA 37 between 1993 and 1998, avionics and software upgrade.
JA 37Di: Upgrade of older JA 37, avionics and software upgrade.
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.
Operational units
- F 4 FrösönF 4 FrösönF 4 Frösön, Kungliga Jämtlands Flygflottilj, Royal Jämtland Air Force Wing, or simply "F 4", is a former Swedish Air Force wing with the main base located at Åre Östersund Airport outside Östersund on Frösön in the middle of Sweden....
- 2 squadrons JA 37 1983-2003
- 1 squadron SK 37 1999-2003
- 1 squadron SK 37E 1999-2003
- F 6 KarlsborgF 6 KarlsborgF 6 Karlsborg, Kungliga Västgöta Flygflottilj, Royal Västergötland Air Force Wing, or simply "F 6", is a former Swedish Air Force wing with the main base located near Karlsborg in south-central Sweden.dotabyte- History of the airbase :...
- 2 squadrons AJ 37 1978-1993
- F 7 SåtenäsF 7 SåtenäsF 7 Såtenäs, Skaraborgs Flygflottilj, Skaraborg Air Force Wing, or simply "F 7", is a Swedish Air Force wing with the main base located near Lidköping in south-central Sweden.- History of the airbase :...
- 3 squadrons AJ 37 1972-1998
- 1 squadron SK 37 1972-1974
- F 10 ÄngelholmF 10 ÄngelholmF 10 Ängelholm, Skånska Flygflottiljen, Scania Air Force Wing, or simply "F 10", is a former Swedish Air Force wing with the main base located in southernmost Sweden.- History of the airbase :...
- 1 squadron AJ/SF/SH 37 (combined) 1993-2001
- F 13 NorrköpingF 13 NorrköpingF 13 Norrköping, Bråvalla Flygflottilj, Bråvalla Air Force Wing, or simply "F 13", is a former Swedish Air Force wing with the main base located near Norrköping in south-eastern Sweden.- History of the airbase :...
- 1 squadron SF/SH 37 (combined) 1977-1993
- 1 squadron JA 37 1980-1993
- F 15 SöderhamnF 15 SöderhamnF 15 Söderhamn, Hälsinge Flygflottilj, Royal Hälsinge Air Force Wing, or simply "F 15", is a former Swedish Air Force wing with the main base located near Söderhamn in northern Sweden.- See also :* Swedish Armed Forces* Swedish Air Force...
- 2 squadrons AJ 37 1974-1998
- 1 squadron SK 37 1974-1998
- F 16 UppsalaF 16 UppsalaF 16 Uppsala, Upplands Flygflottilj, Uppland Air Force Wing or simply "F 16" is a Swedish air force base located just north of Uppsala on the east coast of Sweden...
- 2 squadrons JA 37 1986-2003
- F 17 KallingeF 17 KallingeF 17 Kallinge, Blekinge Flygflottilj, Blekinge Air Force Wing, or simply "F 17", is a Swedish Air Force wing with the main base located near Ronneby in southern Sweden. It is one of the three remaining wings in Sweden and currently has two squadrons of multirole aircraft. F17 in the south and F21...
- 1 squadron JA 37 1981-2002
- 1 squadron SF/SH 37 (combined) 1979-1993
- 1 squadron JA 37 1993-2002
- F 21 LuleåF 21 LuleåF 21 Luleå, Norrbottens flygflottilj, Norrbotten Air Force Wing, or simply "F 21", is a Swedish Air Force wing with the main base located in Luleå in northern Sweden.-External links:*...
- 2 squadrons JA 37 1983-2004
- 1 squadron SF/SH 37 1979-2002
- 1 squadron SK 37E (combined) 2003-2007
Specifications (JA 37 Viggen)
See also
External links
- Interview with Viggen pilot
- Saab 37 Viggen webpage
- Detailed photos of cockpit and weapons
- Saab 37 Viggen webpage
- Information on Viggen in public-domain
- Saab 37 Viggen webpage (in Dutch)
- Vigg, The Tufted Duck (in SwedishSwedish languageSwedish is a North Germanic language, spoken by approximately 10 million people, predominantly in Sweden and parts of Finland, especially along its coast and on the Åland islands. It is largely mutually intelligible with Norwegian and Danish...
) - Flug Revue test flight report (in German)