The Northrop F-20 Tigershark (initially F-5G) was a privately financed light fighter, designed and built by Northrop. Its development began in 1975 as a further evolution of Northrop's F-5E Tiger II, featuring a new engine that greatly improved overall performance, and a modern avionics suite including a powerful and flexible radar. Compared with the F-5E, the F-20 was much faster, gained beyond-visual-range air-to-air capability, and had a full suite of air-to-ground modes capable of firing most U.S. weapons. With these improved capabilities, the F-20 became competitive with contemporary fighter designs such as the General Dynamics F-16 Fighting Falcon, but was much less expensive to purchase and operate.
Much of the F-20's development was carried out under a US Department of Defense (DoD) project called "FX". FX sought to develop fighters that would be capable in combat with the latest Soviet aircraft, but excluding sensitive front-line technologies used by the United States Air Force's own aircraft. FX was a product of the Carter administration's military export policies, which aimed to provide foreign nations with high quality equipment without the risk of US front-line technology falling into Soviet hands. Northrop had high hopes for the F-20 in the international market, but policy changes following Ronald Reagan's election meant the F-20 had to compete for sales against aircraft like the F-16, the USAF's latest fighter design. The development program was abandoned in 1986 after three prototypes had been built and a fourth partially completed.
The United States Military Aircraft Designation System was first designed in 1919 when the US Army's Aeronautical Division became the United States Army Air Service. Before this aircraft were put into service under their manufacturers' designations.
During this period Type Designations used by the United States Army Air Service were allotted, using two or three letters, which were an abbreviation of the aircraft's purpose. Examples include GA for Ground Attack aircraft; NO for Night Observation aircraft and NBS for Night Bombardment, Short Distance aircraft.
From 1924 to 1947 the Air Service, United States Army Air Corps, United States Army Air Forces and United States Air Force used a designation system based on mission category, with each model in a category numbered sequentially. In 1947, the designation system was extensively overhauled, with several categories being dispensed with, and others renamed For instance, the Lockheed P-80 Shooting Star (Pursuit) was redesignated as F-80 (Fighter), while the A-26 medium bomber/attack aircraft was redesignated as the B-26, reusing the designation, the Martin B-26 having retired in the meantime.
F20, F-20, F.XX, or F-XX may refer to: