The large-area wing surface served to provide six underwing/under fuselage hardpoints for the carrying of air-to-air and air-to-surface ordnance. A single 30mm Oerlikon KCA cannon was fitted for close-in work and allotted 150 rounds of ammunition. A typical weapons load became 2 x RB71 "Skyflash" short-range air-to-air missiles and 4 x AIM-120 AMRAAM medium-range air-to-air missiles.
The RM8 engine outputted at 16,200lbf on dry thrust and 28,110lbf with afterburning. This provided the aircraft with a maximum speed of Mach 2.1 - or 1,385 miles per hour - when running at an altitude of 36,100 feet. Range was out to 1,245 miles and the aircraft sported a service ceiling of 59,100 feet. Rate-of-climb was an impressive 40,025 feet per minute - a good quality for an interceptor-minded airframe.
The initial production version of the Viggen was the AJ 37 which served in the single-seat ground attack role while retaining fighter capabilities. The aircraft were delivered from 1971 onwards and fitted the RM8A engine with Ericsson PS-37/A series radar in the nose. Saab provided the navigation/attack computer hardware and software for this model as well as the HUD system. The SK 37 served as a two-seat trainer and appeared from 1973 onwards while lacking the radar seen in the AJ 37 mount. The SF 37 was a single-seater and used in the photographic-reconnaissance role which saw the radar system in the nose replaced by a battery of cameras. The SH 37 was used for the maritime patrol role with over-water strike capabilities built in. These aircraft appeared from 1975 onwards.
The JA 37 became the definitive (and final) Viggen production form. These were single-seat interceptors retaining their strike capabilities and first appeared in 1979. The model carried the Ericsson PS-46/A "Look Down/Shoot Down" Doppler multimode radar suite supporting missile armament. The RM8B engine was an uprated design and there proved a slight revision of the canard foreplanes. The last of these was delivered during 1990. The JA 37C were JA 37 models upgraded with new flight software and avionics for multirole service. Similarly, the JA 37D, numbering 35 aircraft, were JA 37s upgraded with new avionics and software and some 20 JA 37Ds followed, upgraded to the JA 37DI standard featuring more modern PS-46/A radar systems and AIM-120 missile support. The AJS model line were earlier upgraded (AJ 37, SF 37, and SH 37) Viggens to a new standard that introduced modern avionics and software. The modernization took place from 1993 to 1998 and numbered 86 existing airframes.
There also proved some lesser-known models of the Viggen including the SK 37E which served as an Electronic Warfare Aircraft (EWA) trainer platform. This stock was made up of 10 outgoing SK 37 trainer types and were modified from 1998 into 2000. The Saab 37X was to become an export-minded variant of the mainline JA 37 but the initiative fell to naught. The Saab 37E "Eurofighter" was a proposed interceptor competitor for NATO intended to replace outgoing stocks of Lockheed F-104 Starfighters then in service. This project was not furthered into anything tangible.
Total production of Viggens numbered 329 aircraft, a far cry from the original 800+ once envisioned. Production spanned from 1970 to 1990 and the type gave excellent service that spanned some 34 years of the critical and tumultuous Cold War decades. The product was never exported due to strict exportation rules followed by Sweden but the Saab aircraft served 25 total Swedish Air Force squadrons internally during its long, storied tenure. The line was eventually retired on November 25th, 2005 and succeeded directly by the new Saab "Gripen" multirole, lightweight fighter detailed elsewhere on this site.
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