The Northrop F-20 Tigershark lightweight fighter was one of six American fourth generation fighter designs developed during the Cold wᴀʀ, was the smallest and least expensive of all of them in terms of both manufacturing and operational costs. Where the F-15 and even larger F-14 occupied the very high end of the American inventory, with the F-18 and F-18E in the middle and the F-16 at the bottom, the F-20 was even lighter and cheaper than the F-16.

Primarily geared towards the export market, the F-20 represented a further evolution of a series of fighters originating with the T-38 trainer from the late 1950s and its derivatives the F-5, which first flew in 1959, and the F-5E which began flying 13 years later. The F-20’s airframe’s most conspicuous change from the F-5E, a successful third generation fighter, was its use of a single F404 engine in the place of much smaller twin J85 engines in twin configuration, with the new powerplant providing 60% more thrust than the two older ones as well as lower maintenance requirements.

Compared to the F-5, the newer fighter’s superior flight performance was supplemented by major improvements to beyond visual range air to air capabilities, avionics and sensors. Able to reach Mach 2, it was significantly faster than both the F-18 designs and on par with the F-16’s speed.

F-5s Lead F-16 and F-18 Fighters in Formation

While the F-20’s ability to go head to head with high or medium end enemy fighter jets such as MiG-29s or even MiG-23s was questionable, the aircraft benefited from a very low operational cost and very easy maintenance which meant that it could be kept at much higher availability rates than heavier more complex fighters, requiring many less hours of work on the ground for every hour they spent flying.

The light aircraft’s strengths were comparable to later those of later programs pursued outside the United States – namely the Swedish Gripen and the Sino-Pakistani JF-17 which came from a similar weight range. While such very light fighters have become popular in the 21st century, however, as avionics and missiles have become increasingly central to a fighter’s performance, the F-20 itself may have been ahead of its time.

The F-20 was notably self funded by Northrop, and saw its first flight in 1982. By 1986 over a billion dollars had been invested in the program, with the aircraft marketed to training programs such as the U.S. Navy’s ‘Top Gun’ Fighter weᴀponѕ  School as well as to export clients which the Jimmy Carter administration had intended to deny high end aircraft to. As the Air Force and Navy favoured the more expensive F-16 and F-18, and the Ronald Reagan administration from 1981 moved to ease export restrictions on the F-16, the F-20 would fail to gain any clients.

F-5TH Lightweight Fighter

The F-20 was proposed as a new fighter for American air defence units, which after an extensive study had concluded that the F-14 would be the ideal fighter for the service but were prohibited by costs from fielding it. The lighter jet was considered highly unsuitable for such a role which required squadrons to fly interception missions over particularly long distances, with its small radar and relatively low endurance prohibiting this.

As part of efforts to export the F-20, Northrop hired retired general Chuck Yeager to become the program’s spokesman, with the former officer flying and personally endorsing the jet. Promotional efforts centred around the F-20’s primary attraction – that it could do a great deal without a large logistical footprint and with a fraction of the operating costs of rival fighter designs.

While the program failed, the philosophy behind it proved successful as seen not only in the Gripen E and JF-17 Block 3 today, but also the Thai-Israeli F-5TH – an extensive modernisation of the F-5E with state of the art avionics and sensors leading it to be considered most capable than most fourth generation fighters. To some extent even the F-35, which has an inferior flight performance than the aircraft it was designed to replace and was intended, albeit unsuccessfully, to prioritise low operational costs and superiority in avionics, also represented a part of this trend.