The Northrop F-5 was developed during the 1960s to meet the requirements of a number of NATO countries that needed a simple, cheap and easy to maintain multi-role fighter. Its airframe inspired the subsequent introduction of the F-5E Tiger II in the early 1970s. Equipped with two new J85-GE-21 jet engines capable of providing much higher power and thrust than the previous version, it was characterized by a longer and enlarged fuselage. The improved flight performance arising from the new aerodynamic lay-out, the greater operational range and the updated avionics, allowed the Tiger II to be used successfully by numerous air forces. The basic armaments were two 20 mm cannons installed in the nose under the cabin, supported by the capability to deploy a wide set of air-to-air missiles. In addition to its primary fighter role it still however retained extensive ground attack capabilities.