The goal was to develop a multi-role aircraft that could manage fighter, attack and surveillance missions. The unit price per plane became increasingly expensive. There were major benefits to be gained if everything could be combined in a single aircraft type, which led to many lengthy discussions. Among other things, an attack version of the Draken called the Saab 36 was studied. This “super” version, however, was unpopular and the project was terminated.
The engineers at Saab created and discarded many designs. About 200 design drafts were prepared before a concept was produced that seemed to measure up. The decisive decisions for what would become the new Saab 37 Viggen were made in late 1961 and early 1962.
In December of 1961, Saab was informed that the Swedish Defence Procurement Authority had chosen a military version of a new American engine originally designed for civilian planes, the Pratt & Whitney JT8D, for the new multi-role aircraft. A consequence of this was that the aircraft would be delta-winged and with canards.