Viggen is a multi-role fighter, through upgrades still modern and with some almost unique features, in service with the Swedish air force in several versions, since 1971 and until after 2006. The name Viggen means The Thunderbolt, especially those resulting from the Norse god Thor's war hammer Mjölner.
In 1952 studies were started to design a replacement for Saab Draken. "Project 1357" in 1954, was the first to have a canard layout (lots of other layouts were studied as well). I n 1961, P&W JT8D-22 was the chosen engine to be locally built, with a locally designed afterburner and lots of material changes in the rest. In 1962 the design was frozen, and the prototype first flew in Feb 8:th 1967. During the 1960's, it was foreseen that the Swedish air force would purchase 800+ Viggens, but the final figure ended up at 329. In order to make the airframe smaller, it was early decided to replace the navigator with a good navigational computer. It's designed to withstand 12 G, but the limit in operation is 7 G. Emergency power is supplied by a ram air turbine just before the left wing leading edge, which extends automatically on hydraulic power failure, and just before touch down. (Earlier, it was also always deployed whenever the landing gear was down.) The canard doesn't contribute much lift in itself during normal flight, it acts more as a gigantic vortex generator for the main wing. During low speed flight, its rear edge flap can be lowered to increase lift and permit a high nose angle. The requirement was that the aircraft would be able to operate from 500 m runways. A short take-off run is possible due to the powerful engine (then, it was the most powerful installed in a fighter). Landing distance is reduced by several means: The HUD is used as a precision landing aid, making it
possible to aim just 30 m in from the threshold; The landing gear thinks a landing sink rate of 5 m/s is normal, so landings are done without any flare; The thrust reverser is interconnected with the nose gear link, so it can be selected in the air and will operate when the nose is lowered. (It is not intended to be used in the air.) The aircraft must be serviceable very quickly by conscripts with relatively short training. Re-fueling and re-arming by 7 men, of which 6 are conscripts, must take less than 10 min for the JA 37 Viggen. The time limits for reconnaissance and attack configured aircraft are 15 and 20 minutes. It is said that attack squadrons expect to fly 11 missions per aircraft and 24-hour period.
Sk, Skol = Training
SF, Spaning Foto = Reconnaissance Photo
SH, Spaning Havsövervakning = Reconnaissance Maritime surveillance
J, Jakt = Fighter
When two or more designations are combined, the first denotes primary role.
All of the remaining AJ-37's and SF-37's are reconstructed to a type of multirole aircraft, designated AJS-37 Viggen (Not to be mixed with the JAS-39 Gripen).
Length: 16.43 m
Wingspan: 10.6 m
Height: 5.93 m
Max t-o weight: 18600 Kg
Max speed: Mach 2+
Ceiling: 18000 m
Range: 2000 Km
Armament: One 30mm Oerlikon canon; 1700 Kg on 7 hardpionts, including RB04E Anti Ship missile, RB24 (AIM-9 Sidewinder) AAM, Rb-71 (Sky Flash) AAM, Rb-99 (AIM-120 AMRAAM), Mk 81 Bombs, Rocket Pods (6 x 13.5 cm) and Gun Pods.