Saab 37 Viggen

The Saab 37 Viggen (The Tufted Duck; the word also means The Thunderbolt) is a single-seat, single-engine multirole combat aircraft designed and produced by the Swedish aircraft manufacturer Saab. It was the first canard-equipped aircraft to be produced in quantity and the first to carry an airborne digital central computer with integrated circuits for its avionics, arguably making it the most modern/advanced combat aircraft in Europe at the time of introduction. The digital central computer was the first of its kind in the world, automating and taking over tasks previously requiring a navigator/copilot, facilitating handling in tactical situations where, among other things, high speeds and short decision times determined whether attacks would be successful or not, a system not surpassed until the introduction of the Panavia Tornado into operational service in 1981.

Development work began during the early 1950s to develop a successor to the Saab 32 Lansen in the attack role, as well as to the Saab 35 Draken as a fighter. Saab's design team opted for a relatively radical delta wing configuration, and operation as an integrated weapon system in conjunction with Sweden's STRIL-60 national electronic air defense system. It was also designed to be operated from runways as short as 500 meters. Development work was aided by the "37-annex" under which Sweden could access advanced U.S. aeronautical technology to accelerate both design and production. The aircraft's aerodynamic design was finalised in 1963. The prototype performed its maiden flight on 8 February 1967 and the following year the Swedish government ordered an initial batch of 175 Viggens. The first of these entered service with the Swedish Air Force on 21 June 1971.

Even as the initial AJ 37 model entered service, Saab was working on further variants of the Viggen. Several distinct variants of the Viggen would be produced to perform the roles of fighter bomber/strike fighter (AJ 37), aerial reconnaissance (SF 37), maritime patrol/anti-surface (SH 37) and a two-seat trainer (Sk 37). During the late 1970s, the all-weather interceptor/strike fighter JA 37 variant was introduced. Attempts to export the Viggen to other nations were made, but ultimately proved unsuccessful. In November 2005, the last Viggens were withdrawn from service by the Swedish Air Force, its only operator; by this point, it had been replaced by the newer and more advanced Saab JAS 39 Gripen.

Viggen is the definite form of the Swedish word vigg, which has two meanings. According to Saab, the aircraft's name alluded to both.

The first meaning refers to the Swedish name for the tufted duck, a small diving duck common in Sweden. In this sense, it serves as a reference to the aircraft's canard configuration, as "canard" is French for duck.

Vigg is also åskvigg, or "thunderbolt" (thunder wedge), stemming from the thunderstones of Nordic folklore, called "åskviggar", said to come from the lightning strikes of Norse god Thor when he hunted giants with his war hammer, Mjölnir.

The Viggen was initially developed as an intended replacement for the Saab 32 Lansen in the attack role and later the Saab 35 Draken as a fighter. In 1955, as Saab's prototype Draken, the most aerodynamically advanced fighter in the world at that point, performed its first flight, the Swedish Air Force was already forming a series of requirements for the next generation of combat aircraft; due to the challenging nature of these requirements, a lengthy development time was anticipated, with the first flight intended to be no earlier than the middle of the next decade. Between 1952 and 1957, the first studies towards what would become the Viggen were carried out, involving the Finnish aircraft designer Aarne Lakomaa. Over 100 different concepts were examined in these studies, involving both single- and twin engine configurations, both traditional and double delta wings, and canard wings. Even VTOL designs were considered, with separate lift engines, but were soon identified as being unacceptable.

From the onset, the Viggen was planned as an integrated weapon system, to be operated in conjunction with the newest revision of Sweden's national electronic air defense system, STRIL-60. It was used as the nation's standard platform, capable of being efficiently adapted to perform all tactical mission roles. 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.