Northrop F-5

**F-5A/B Freedom Fighter
F-5E/F Tiger II**

 **Primary Users** | United States Navy
Republic of China Air Force
Republic of Korea Air Force
 **Produced** | 1959 - 1987

The **Northrop F-5A/B Freedom Fighter** and the **F-5E/F Tiger II** are part of a supersonic light fighter family, initially designed in the late 1950s by Northrop Corporation. Being smaller and simpler than contemporaries such as the McDonnell Douglas F-4 Phantom II, the F-5 cost less to both procure and operate, making it a popular export aircraft. The F-5 started life as a privately funded light fighter program by Northrop in the 1950s. The design team wrapped a small, highly aerodynamic fighter around two compact and high-thrust General Electric J85 engines, focusing on performance and low cost of maintenance. Though primarily designed for the day air superiority role, the aircraft is also a capable ground-attack platform. The F-5A entered service in the early 1960s. During the Cold War, over 800 were produced through 1972 for U.S. allies. Though the USAF had no acknowledged need for a light fighter, it did procure roughly 1,200 Northrop T-38 Talon trainer aircraft, which were directly based on the F-5A.

After winning the International Fighter Aircraft competition in 1970, a program aimed at providing effective low-cost fighters to American allies, Northrop introduced the second-generation F-5E Tiger II in 1972. This upgrade included more powerful engines, higher fuel capacity, greater wing area and improved leading edge extensions for a better turn rate, optional air-to-air refueling, and improved avionics including air-to-air radar. Primarily used by American allies, it remains in US service to support training exercises. It has served in a wide array of roles, being able to perform both air and ground attack duties; the type was used extensively in Vietnam. A total of 1,400 Tiger IIs were built before production ended in 1987. More than 3,800 F-5 and T-38 aircraft were produced in Hawthorne, California.

## Design and Development

### Origins

The design effort was led by Northrop vice president of engineering and aircraft designer Edgar Schmued, who previously at North American Aviation had been the chief designer of the successful North American P-51 Mustang and F-86 Sabre fighters. Schmued recruited a strong engineering team to Northrop and assigned them the goal of reversing the trend in fighter development towards greater size and weight in order to deliver an aircraft with high performance, enhanced maneuverability, and high reliability, while still delivering a cost advantage over contemporary fighters. Recognizing that expensive jet aircraft could not viably be replaced every few years, he also demanded "engineered growth potential" allowing service longevity in excess of 10 years. Schmued recognized that new jet engine and aerodynamic technology were crucial to these goals, such as the compact but high thrust-to-weight ratio General Electric J85 turbojet engine, and the recently discovered transonic area rule to reduce drag. The J85 engine had been developed to power McDonnell's ADM-20 Quail decoy employed upon the Boeing B-52 Stratofortress. This engine with thrust-to-weight ratios of 6.25 to 7.5 over various versions had a notable thrust per lb. advantage over contemporaries, such as the 4.7 thrust-to-weight ratio of the J79 engine used in the F-4 Phantom.

Another highly influential figure was chief engineer Welko Gasich, who convinced Schmued that the engines must be located within the fuselage for maximum performance. Gasich also for the first time introduced the concept of "life cycle cost" into fighter design, which provided the foundation for the F-5's low operating cost and long service life. The low costs involved has been recognized as an important element of the aircraft's effectiveness; defense analyst and combat aircraft architect Pierre Sprey stated in a 1982 U.S. Department of Defense report that: "Increases in cost and complexity that were unnecessary to enhance air-to-air effectiveness have decreased today's effective force size per constant dollar by factors of 25 to 75, relative to the F-86's 2000 sorties/day per billion dollars. The only exception to this strikingly adverse trend is the F-5E, which manages to produce 500 sorties/day per billion dollars." The total cost of an F-5 sortie is approximately 20% that of an F-16 sortie.

The F-5 development effort was formally started in the mid-1950s by Northrop Corporation for a low-cost, low-maintenance fighter. The company designation for the first design as the N-156, intended partly to meet a U.S. Navy requirement for a jet fighter to operate from its escort carriers, which were too small to operate the Navy's existing jet fighters. That requirement disappeared when the Navy decided to withdraw the escort carriers; however Northrop continued development of the N-156, both as a two-seat advanced trainer, designated as N-156T, and a single-seat fighter, designated as N-156F.

The N-156T was quickly selected by the United States Air Force as a replacement for the T-33 in July 1956. On 12 June 1959, the first prototype aircraft, which was subsequently designated as YT-38 Talon, performed its first flight. By the time production had ended in January 1972, a total of 1,158 Talons were produced. Development of the N-156F continued at a lower priority as a private venture by Northrop; on 25 February 1958, an order for three prototypes was issued for a prospective low-cost fighter that could be supplied under the Military Assistance Program for distribution to less-developed nations. The first N-156F flew at Edwards Air Force Base on 30 July 1959, exceeding the speed of sound on its first flight.

Although testing of the N-156F was successful, demonstrating unprecedented reliability and proving superior in the ground-attack role to the USAF's existing North American F-100 Super Sabres, official interest in the Northrop type waned, and by 1960 it looked as if the program was a failure. Interest revived in 1961 when the United States Army tested it, (along with the Douglas A-4 Skyhawk and Fiat G.91) for reconnaissance and close-support. Although all three types proved capable during Army testing, operating fixed-wing combat aircraft was legally the responsibility of the Air Force, which would not agree to operate the N-156 or allow the Army to operate fixed-wing combat aircraft, a situation repeated with the C-7 Caribou.

In 1962, however, the Kennedy Administration revived the requirement for a low-cost export fighter, selecting the N-156F as winner of the F-X competition on 23 April 1962 subsequently becoming the "F-5A", being ordered into production in October that year. It was named under the 1962 United States Tri-Service aircraft designation system, which included a re-set of the fighter number series (the General Dynamics F-111 was the highest sequentially numbered P/F-aircraft to enter service under the old number sequence). Northrop manufactured a total of 624 F-5As, including three YF-5A prototypes, before production ended in 1972. A further 200 F-5B two-seat trainer aircraft, lacking a nose-mounted cannon but otherwise combat-capable, and 86 RF-5A reconnaissance aircraft, fitted with a four-camera nose, were also built. In addition, Canadair built 240 first generation F-5s under license, CASA in Spain built 70 more aircraft.

### F-5E and F-5F Tiger II

In 1970, Northrop won the International Fighter Aircraft (IFA) competition to replace the F-5A, with better air-to-air performance against aircraft like the Soviet MiG-21. The resultant aircraft, initially known as F-5A-21, subsequently became the F-5E. It had more powerful (5,000 lbf) General Electric J85-21 engines, and had a lengthened and enlarged fuselage, accommodating more fuel. Its wings were fitted with enlarged leading edge extensions, giving an increased wing area and improved maneuverability. The aircraft's avionics were more sophisticated, crucially including a radar (initially the Emerson Electric AN/APQ-153) (the F-5A and B had no radar). It retained the gun armament of two M39 cannon, one on either side of the nose of the F-5A. Various specific avionics fits could be accommodated at customer request, including an inertial navigation system, TACAN and ECM equipment.

The first F-5E flew on 11 August 1972. A two-seat combat-capable trainer, the F-5F, was offered, first flying on 25 September 1974, with a new, longer nose, which, unlike the F-5B that did not mount a gun, allowed it to retain a single M39 cannon, albeit with a reduced ammunition capacity. The two-seater was equipped with the Emerson AN/APQ-157 radar, which is a derivative of the AN/APQ-153 radar, with dual control and display systems to accommodate the two-men crew, and the radar has the same range of AN/APQ-153, around 10 nmi. On 6 April 1973, the 425th TFS at Williams Air Force Base, Ariz. received the first F-5E Tiger II.

A reconnaissance version, the RF-5E Tigereye, with a sensor package in the nose displacing the radar and one cannon, was also offered. The F-5E eventually received the official name Tiger II; 792 F-5Es, 146 F-5Fs and 12 RF-5Es were eventually built by Northrop. More were built under license overseas: 91 F-5Es and -Fs in Switzerland, 68 by Korean Air in South Korea, and 308 in Taiwan.

According to Pierre Sprey, the F-5 was perhaps the most effective U.S. air-to-air fighter in the 1960s and early 1970s based on cost and performance. A small visual and radar cross section size and consequent detection difficulty often conferred the F-5 the advantage of surprise. The aircraft also has a high sortie rate, low accident rate, high maneuverability, and is armed with a combination of 20mm cannon and heat seeking missiles. The flying qualities of the F-5 are often highly rated, comparable to the North American F-86 Sabre and the General Dynamics F-16 Fighting Falcon.

The F-5 proved to be a successful combat aircraft for U.S. allies, but had no combat service with the U.S. Air Force. The F-5E evolved into the single-engine F-5G, which was rebranded the F-20 Tigershark. It lost out on export sales to the F-16 in the 1980s.

## Operators

**Operators of the F-5:**

* Austria
* Bahrain
* Botswana
* Brazil
* Canada
* Chile
* Ethiopia
* Greece
* Honduras
* Indonesia
* Iran
* Jordan
* Template:Country data Kenya Kenya
* Libya
* Mexico
* Morocco
* Malaysia
* Netherlands
* Norway
* Philippines
* Saudi Arabia
* Singapore
* South Korea
* Spain
* Template:Country data Sudan Sudan
* Switzerland
* Template:Country data Taiwan Taiwan
* Tunisia
* Turkey
* United States
* Venezuela
* Vietnam
* Yemen