Staff Writer (Updated: 5/17/2016):
The F-5 was born out of a 1950s US Navy requirement calling for a small, lightweight, jet-powered fighter to operate from the decks of its Escort Carriers. Escort Carriers received their own birth in ocean-going fighting during World War 2. However, Escort Carriers were not designed for the newer, larger types of fighters then entering USN service. Northrop, therefore, responded with their in-house "N-156" lightweight, twin-engine jet fighter proposal. The project was to make use of the General Electric J85 turbojet engine - the same powerplant as used in the Boeing B-52 Stratofortress-launched McDonnell ADM-20 "Quail" subsonic decoy cruise missile - and this installation proved ideal for use in such a small airframe design for the engine outputted a strong thrust-to-weight ratio for its size. However, US Navy interest soon waned after the retirement of her Escort Carrier classes, leaving the future of the N-156 in doubt. Regardless, Northrop engineers forged ahead and spawned the N-156 into two distinct aircraft forms - the single-seat "N-156F" fighter and the two-seat "N-156T" combat trainer.
The USAF took notice of the N-156T twin-seat design. While not looking directly to purchase a new frontline fighter at the time, it did seek a direct replacement for its aging line of Lockheed T-33 "Shooting Star" jet trainers whose own origins traced as far back as the 1940s. The USAF formally selected the N-156T to become the basis of its next -generation jet trainer and the design eventually evolved to become the YT-38 "Talon" and, ultimately, becoming the well-known Northrop T-38 "Talon" production model. This aircraft was built in 1,187 examples and began USAF service in 1961.
While the government-funded two-seat N-156T was now finding a respectable existence in the inventory of the USAF, the single-seat N-156F was not an entirely forgotten endeavor for Northrop. Instead, she was moved along in development at a slower pace as a privately funded venture by Northrop. Fate ultimately came to knock on the door of the N-156F during the height of the Cold War. In an effort to keep pace with the Soviet military reach across the world, the "Military Assistance Program" (MAP) was enacted by the United States to help those budget conscious American-allies field capable military hardware. The promising low-cost, easy-to-use nature of the N-156F seem to fit the proverbial bill and Northrop received a government contract to produce three working prototypes for official USAF evaluation. The first of these achieved initial flight on July 30th, 1959 out of Edwards AFB. Of note during this first run was the prototype exceeding the sound barrier without issue - proving the design inherently sound and efficient. The N-156F prototypes furthermore showcased strong qualities that would be pertinent to the air-to-air and ground attack roles making her a truly multi-role platform.
The New Northrop Fighter Gets Named
Despite the promising early showing, the USAF exerted a lackadaisical response in pushing the N-156F program further into 1960. It was not until 1961 that the project gained some slight interest from the US Army looking for close-support and reconnaissance platform but the move was derailed to keep the USAF as the only "true" fixed-wing, air combat arm in the US military. The N-156F was once again in limbo for a time longer until an initiative by then-President John F. Kennedy brought about a new requirement for a budget export fighter under the "F-X" program to serve American allies worldwide.
On April 23rd, 1962, the N-156F was formally declared the winner of F-X and, on August 9th, 1962, she was removed of her N-156F prototype designation and officially labeled as the "F-5" in accordance with the revamped USAF designation system of September 1962 (the old system ended with the General Dynamics F-111 Aardvark, so the new Northrop fighter was christened with the smaller-value "F-5" designator). As such, her first production models were known as "F-5A". To go along with her export-minded existence, the F-5A was nicknamed the "Freedom Fighter" and production was slated to begin in October of 1962 with the first flight of a production-quality F-5A example was recorded in May of 1963. Production of F-5A models ran to 1972.
The F-5A "Freedom Fighter" and the Two-Seat F-5B
The F-5A was a basic aircraft design that was optimized for air-to-ground operations with limited air-to-air serviceability. This was mostly due to the lack of any onboard fire control radar system to help identify, track and engage aerial targets with guided/homing missiles all her own. The F-5A was powered by a pair of General Electric J85-GE-13 turbojet engines featuring 2,720lbs of standard thrust and 4,080lbs of thrust with afterburning (raw fuel pumped into the engine to produce a short burst of power and, therefore, heightened speed and performance). Maximum speed was Mach 1.4 / 925mph (36,000 feet) with a service ceiling up to 50,500 feet. Maximum range on internal fuel was around 1,387 miles. Standard armament included 2 x M39 20mm cannons on either side of the nose assembly. Two AIM-9 Sidewinders were exclusively fitted to the wingtips. There were four underwing and a single underfuselage hardpoint for the carrying of bombs, rocket pods and missiles - up to 6,200lbs of ordnance. External fuel stores could replace some of the weapons stations.
The F-5B development stemmed from the F-5A before it and was nothing more than two-seat "combat trainer" with the purpose of training future F-5 pilots while also retaining some of her inherent combat value. With the addition of the second instructor's cockpit came the loss of one of the M39 cannons and some internal space while introducing a new, revised longer nose assembly.