In November 1970, the F-5E was selected by the US government as the winner of a competition to determine the single-seat International Fighter Aircraft (IFA) which was to succeed Northrop's F-5A. The two-seat F-5F was developed subsequently. The F-5E design places particular emphasis on manoeuvrability rather than high speed, notably by the incorporation of auto-manoeuvring flaps. Its full-span leading-edge flaps work in conjunction with conventional trailing-edge flaps, and are operated automatically in response to airspeed and angle of attack.
Wing loading of the F-5E is maintained at approximately the same value as on the F-5A, as the result of an increase in wing area to 186 sq ft. This is due principally to the widened fuselage, which also increases wingspan. The tapered wing leading-edge extension, between the inboard leading-edge and fuselage, was refined to increase the wing area and maximise the lift coefficient of the wing.
The F-5E incorporates other features developed for the Canadian, Dutch and Norwegian F-5s, including a two-position nosewheel gear, which increases the wing angle of attack on the ground by approximately 3.1 degrees. Together with the more powerful engines, this improves the F-5E's take-off performance by some 30 per cent compared with earlier F-5s. The aircraft is qualified to carry two 275 US gallon drop tanks, and up to nine 500 lb Mk 82 bombs, following the addition of a multiple ejector rack (MER) on the centreline stores station.
The first F-5E was presented on 23 June 1972 and took-off for the first time on 11 August 1972. First deliveries followed quite rapidly in the Spring of 1973 with the delivery of the first aircraft to the US Air Force's 425th Tactical Fighter Squadron. Deliveries to foreign countries started later that same year in September 1973.
Besides being a tactical fighter, the F-5Es are operated by the US Air Force and US Navy in the 'aggressor' role, to simulate enemy aircraft at major air combat training schools in the USA, England and the Philippines.