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Description: JA 37 Viggen is a Swedish Fighter-bomber designed and manufactured by SAAB and Volvo.

History: Project 1357 was started in 1954 to replace J 32 Lansen and J-35 Draken that was just then coming in to service. Viggen (Thunderbolt) flew for the first time on february 8:th 1967 and IOC (Initial Operational Capability) was achieved in 1971 for AJS 37 and 1977 for JA 37. Viggen was the first operational aircraft with a canard design, the reason for this being that one of the goal of the projects was to be able to start and land on very short strips (500 meters) and even short stretches of road. The Swedish defense at the time was well aware that airports were a prime target for an invasion force and that they would need some solution to the problem of losing runways. To solve this, small bases were constructed all over the country near suspiciously straight stretches of road. Viggen was also provided with a at the time unique thrust reversal system and a landing gear capable of taking a sink rate of 5 m/s without a hitch. Viggen can be re-armed and re-fueled in less than 10 minutes by only 7 men (6 of which are conscripts).

Version History: Viggen (Thunderbolt) was intended to be a multi-role aircraft from the start and to accomplish this there were several different versions. The most common ones being JA 37, AJ 37, SF 37, SH 37 and SK 37 in that order.

The first version to come in to service was AJ 37 (Attack-Fighter) intended to fulfill primarily strike (especially against ships) and secondarily fighter missions. No gun was provided because it was not thought necessary at the time instead armament was mainly the SAAB 304 anti-ship missile, Bofors 135mm rockets and iron bombs. AGM-65 Mavericks were later added to the inventory. In fighter-missons AJ 37 could carry Sidewinders and two 30mm cannon pods. AJ 37 has the RM8A Volvo (P&W JT8D-22 with Volvo modifications) engine.

Sk 37 (trainer) is the training version of Viggen, all training was intially ittended to be done on Draken but the airforce changed their mind. No radar, less fuel and a taller fin. Some Sk 37s were converted to Sk 37 E standard which added a ECM package. The Sk 37 Es are used for training of pilots and in exercises with the Swedish airdefense.

SH 37 and SF 37 are Recon versions. SH 37 (Sea-Recon) has a radar and a camera mounted on the right fuselage hardpoint but no capability for armament. SF 37 (Photo-Recon) has no radar but several fixed cameras in the nose as well as a nightphotography pod on the left fuselage hardpoint. Almost all SF and SH have been upgraded to AJSH and AJSF standard (see AJS 37).

JA 37 (Fighter-Attack) is the mainstay fighter in Sweden at the moment, it will be replaced in the years to come by JAS 39 Gripen. JA 37 was provided with a gun as the Vietnam conflict had proven that a gun was an absolute necessity. The gun used is one of the most impressive guns ever used in a fighter, the Oerlikon 30mm KCA. In fact it was so accurate that a mechanism was added to make the gun spread its bullets more in order to improve the chance of hitting the target. JA 37 is 13 cm longer then the attack versions to provide space for the longer RM8B engine. It also has the taller fin of the Sk 37 to compensate for the long fuselage. In combat tests against F-16s and F-14s Viggen has come up somewhat short, especially in dogfights. However, the strength of the system is the low maintenance, extremly short runways needed and the short turn-around times. Viggen is certainly not a bad fighter but it was designed around a different concept than the American Air-superiority fighters. Several upgrades to the system have been made including the capability for using AMRAAM missiles and improved avionics.

In 1992 115 AJ, SF and SH 37s were rebuilt to the AJS 37 standard. This conversion was made mainly to accomodate the use of several new weapons. Rb 15f which is a Swedish-built anti-ship missile and the Mjölner bomblet dispenser were added to the inventory as well as the new AIM-9L Sidewinder. All AJS will be retired as soon as Gripen enters service.

Current Status: A total of 257 Viggen are currently in service with the Swedish airforce. All of these will be replaced by JAS 39 Gripen. A small unit named SWEFRAP (Swedish Airforce Rapid Reaction Unit) has been established for rapid deployment to conflict areas in UN service. It consists of a small number of AJS 37s which can be operational 30 days after a decision has been made.

Technical Data: (JA 37)
Length: 16.40 meters
Wing Span: 10.60 meters
Height: 5.90 meters
Thrust: 12750 kp (with AB)
Weight: 9.5 tons (empty)
Speed: Mach 2
Engine: Volvo Aero RM8B (P&W JT8D-22)
Radar: Ericsson PS-46/A

Armament:
Air to Air: Oerlikon 30mm Cannon, Rb 71 (Skyflash), Rb 74 (AIM-9L Sidewinder), Rb 99 (AIM-120 AMRAAM)
Air to Ground: Bofors Rockets

Sources: Flygplankort, Military aviation: Swedish and worldwide (http://www.canit.se/~griffon/aviation/)

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