Light Weight Fighter
Encyclopedia
Fighter mafia
The Fighter Mafia was a group of U.S. Air Force officers and civilian defense analysts who, in the 1970s, advocated the use of John Boyd's Energy-Maneuverability theory to develop fighter aircraft...
". It was spurred by then Major John Boyd
John Boyd (military strategist)
Colonel John Boyd was a United States Air Force fighter pilot and Pentagon consultant of the late 20th century, whose theories have been highly influential in the military, sports, and business.-Biography:...
's Energy-Maneuverability (E-M) theory
Energy-Maneuverability theory
Energy Maneuverability theory is a model of aircraft performance. It was promulgated by Col. John Boyd, and is useful in describing an aircraft's performance as the total of kinetic and potential energies or aircraft specific energy. It relates the thrust, weight, drag, wing area, and other flight...
of maneuverability, which indicated that excessive weight would have severely debilitating consequences on the maneuverability of an aircraft. Boyd's design called for a light-weight fighter with a high thrust-to-weight ratio
Thrust-to-weight ratio
Thrust-to-weight ratio is a ratio of thrust to weight of a rocket, jet engine, propeller engine, or a vehicle propelled by such an engine. It is a dimensionless quantity and is an indicator of the performance of the engine or vehicle....
, a gross weight of less than 20,000 pounds (9,100 kg) (half that of its counterpart, the F-15 Eagle), and high maneuverability. It resulted in the development of the General Dynamics YF-16 and Northrop YF-17. Late in the program, in 1974, with the promise of European sales, the Air Force changed the program name to Air Combat Fighter (ACF), and committed to purchasing 650 models of the YF-16, adopted as the F-16 Fighting Falcon. The U.S. Navy adopted a modified version of the YF-17 as the F/A-18 Hornet.
Missileers
Project Forecast, a 1963 Air Force study, attempted to identify future weapons trends and "certain high-priority areas for research and developmentResearch and development
The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...
(R&D), recommendations based on the greatest potential payoff for the future." The report strongly suggested that future air combat would be carried out primarily by long-range missile fire. Future "fighters" would be designed primarily for long range, high speed, and equipped with extremely large radar systems in order to detect and engage opposing fighters at beyond visual range (BVR). This made them much more like interceptor
Interceptor aircraft
An interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...
s than classic fighter designs, and led to increasingly heavier and more technologically sophisticated designs – and thus costlier.
The US Navy had long ago come to similar conclusions, and had been designing a series of aircraft dedicated to this role. Notable among these was the well named Douglas F6D Missileer, a slow and unmaneuverable design equipped with very powerful missiles and radar. The US Air Force had similar designs, but these had been dedicated to the interceptor
Interceptor
-Vehicles:* Interceptor aircraft , a type of fighter aircraft designed specifically to intercept and destroy enemy aircraft* Ford Crown Victoria Police Interceptor, a police car...
role, where the large size of its targets allowed reasonable radar performance. However, as radar equipment improved, in particular the introduction of Doppler radar
Doppler radar
A Doppler radar is a specialized radar that makes use of the Doppler effect to produce velocity data about objects at a distance. It does this by beaming a microwave signal towards a desired target and listening for its reflection, then analyzing how the frequency of the returned signal has been...
systems, allowed similar range performance against smaller targets. By the early 1960s, even before the release of Forecast, both the Air Force and Navy expected to use the F-111
General Dynamics F-111
The General Dynamics F-111 "Aardvark" was a medium-range interdictor and tactical strike aircraft that also filled the roles of strategic bomber, reconnaissance, and electronic warfare in its various versions. Developed in the 1960s by General Dynamics, it first entered service in 1967 with the...
(then still in development as the TFX) and F-4 Phantom II
F-4 Phantom II
The McDonnell Douglas F-4 Phantom II is a tandem two-seat, twin-engined, all-weather, long-range supersonic jet interceptor fighter/fighter-bomber originally developed for the United States Navy by McDonnell Aircraft. It first entered service in 1960 with the U.S. Navy. Proving highly adaptable,...
for their long- and medium-range needs. The perception of a declining need for close-in "dogfight
Dogfight
A dogfight, or dog fight, is a form of aerial combat between fighter aircraft; in particular, combat of maneuver at short range, where each side is aware of the other's presence. Dogfighting first appeared during World War I, shortly after the invention of the airplane...
ing" capabilities resulted in the original decision to not install internal cannons in the Phantom.
Combat experience and E-M Theory
However, real-world experience in the Vietnam WarVietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
revealed some shortcomings in American fighter capabilities, as early generation Soviet-bloc jet fighters proved to be more of a challenge than expected for U.S. designs. Although U.S. pilots had achieved favorable kill-to-loss ratios, combat had revealed that air-to-air missile
Air-to-air missile
An air-to-air missile is a missile fired from an aircraft for the purpose of destroying another aircraft. AAMs are typically powered by one or more rocket motors, usually solid fuelled but sometimes liquid fuelled...
s (AAM) of this era were significantly less reliable than anticipated. Furthermore, the rules of engagement
Rules of engagement
Rules of Engagement refers to those responses that are permitted in the employment of military personnel during operations or in the course of their duties. These rules of engagement are determined by the legal framework within which these duties are being carried out...
in Vietnam precluded long-range missile attacks in most instances, as visual identification was normally required. Under these conditions, combat invariably closed to short ranges where maneuverability and short-range air-to-air weapons became critical, even for dedicated interceptors like the F-102 Delta Dagger
F-102 Delta Dagger
The Convair F-102 Delta Dagger was a US interceptor aircraft built as part of the backbone of the United States Air Force's air defenses in the late 1950s. Entering service in 1956, its main purpose was to intercept invading Soviet bomber fleets...
.
The need for new air superiority fighters led the USAF to initiate two concept development studies in 1965: the Fighter Experimental (FX) project originally envisioned a 60,000-pound (27,200 kg) class twin-engine design with a variable-geometry wing, and the Advanced Day Fighter (ADF), a lightweight design in the 25,000 lb (11,300 kg) class which would out-perform the MiG-21
Mikoyan-Gurevich MiG-21
The Mikoyan-Gurevich MiG-21 is a supersonic jet fighter aircraft, designed by the Mikoyan-Gurevich Design Bureau in the Soviet Union. It was popularly nicknamed "balalaika", from the aircraft's planform-view resemblance to the Russian stringed musical instrument or ołówek by Polish pilots due to...
by 25%. However, the first appearance of the Mach-3
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...
-capable MiG-25
Mikoyan-Gurevich MiG-25
The Mikoyan-Gurevich MiG-25 is a supersonic interceptor and reconnaissance aircraft that was among the fastest military aircraft to enter service. Designed by the Soviet Union's Mikoyan-Gurevich bureau the first prototype flew in 1964 with entry into service in 1970...
in July 1967 would result in the ADF effort being relaxed in favor of the FX program, which would produce the F-15 Eagle.
Based on his experiences in the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
and as a fighter tactics instructor, in the early 1960s Colonel John Boyd
John Boyd (military strategist)
Colonel John Boyd was a United States Air Force fighter pilot and Pentagon consultant of the late 20th century, whose theories have been highly influential in the military, sports, and business.-Biography:...
and mathematician Thomas Christie developed the Energy-Maneuverability (E-M) theory of the value of aircraft specific energy
Aircraft specific energy
Aircraft specific energy is a form of specific energy applied to aircraft and missile trajectory analysis. It represents the combined kinetic and potential energy of the vehicle at any given time...
maintenance as an advantage in fighter combat. Maneuverability was the means of getting “inside” an adversary’s decision-making cycle, a process Boyd called the "OODA" loop (for "Observation-Orientation-Decision-Action"). This approach emphasized an aircraft design capable of “fast transients” –quick changes in speed, altitude, and direction. A fighter that is superior in its ability to gain or lose energy while out-turning an opponent can initiate and control any engagement opportunity; a fast transient capability allows the pilot to stay inside a hard-turning opponent when on the offensive or to force an overshoot of an opponent when on the defensive.
These parameters called for a small, lightweight aircraft – which would minimize drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
and increase the thrust-to-weight ratio
Thrust-to-weight ratio
Thrust-to-weight ratio is a ratio of thrust to weight of a rocket, jet engine, propeller engine, or a vehicle propelled by such an engine. It is a dimensionless quantity and is an indicator of the performance of the engine or vehicle....
– but a larger, higher-lift
Lift (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...
wing to minimize wing loading
Wing loading
In aerodynamics, wing loading is the loaded weight of the aircraft divided by the area of the wing. The faster an aircraft flies, the more lift is produced by each unit area of wing, so a smaller wing can carry the same weight in level flight, operating at a higher wing loading. Correspondingly,...
– which tends to reduce top speed while increasing payload, and can lower range (which can be compensated for by increased fuel in the larger wing).
Lightweight Fighter program
A 1965 Air Force study suggested equipping its squadrons with a mix of high and low cost fighters as being the most economical. Boyd’s theories led to requirements for a smaller F-15 in the 40,000-pound (18,100 kg) class. In the late 1960s he gathered around him a group of like-minded innovators that became known as the "Lightweight Fighter Mafia". In 1969, the "Fighter MafiaFighter mafia
The Fighter Mafia was a group of U.S. Air Force officers and civilian defense analysts who, in the 1970s, advocated the use of John Boyd's Energy-Maneuverability theory to develop fighter aircraft...
" was able to secure funds for a "Study to Validate the Integration of Advanced Energy-Maneuverability Theory with Trade-Off Analysis". General Dynamics received $49,000 and Northrop $100,000 study contracts to design concepts that embodied Boyd's E-M theory – a small, low-drag, low-weight, pure fighter with no bomb racks; their work would lead to the YF-16 and YF-17, respectively.
Although the Air Force’s F-X proponents remained hostile to the concept because they perceived it as a threat to the F-15 program, the ADP concept (revamped and renamed as the "F-XX") gained civilian political support under the reform-minded Deputy Secretary of Defense David Packard
David Packard
David Packard was a co-founder of Hewlett-Packard , serving as president , CEO , and Chairman of the Board . He served as U.S. Deputy Secretary of Defense from 1969–1971 during the Nixon administration...
, who favored the idea of competitive prototyping
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
. As a result in May 1971, the Air Force Prototype Study Group was established, with Boyd a key member, and two of its six proposals would be funded, one being the Lightweight Fighter (LWF). The Request for Proposal
Request for Proposal
A request for proposal is issued at an early stage in a procurement process, where an invitation is presented for suppliers, often through a bidding process, to submit a proposal on a specific commodity or service. The RFP process brings structure to the procurement decision and is meant to...
s (RFP) was issued 6 January 1972, and called for a 20,000 lb (9,100 kg) class fighter with a good turn rate, acceleration and range, and optimized for combat at speeds of Mach 0.6–1.6 and altitudes of 30,000–40,000 ft (9,150–12,200 m). This was the region in which the USAF expected most future air combat to occur, based on studies of the Vietnam, Six-Day
Six-Day War
The Six-Day War , also known as the June War, 1967 Arab-Israeli War, or Third Arab-Israeli War, was fought between June 5 and 10, 1967, by Israel and the neighboring states of Egypt , Jordan, and Syria...
, and Indo-Pakistani wars. The anticipated average flyaway cost of a production version was $3 million.
Five manufacturers – Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
, General Dynamics
General Dynamics
General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...
, Lockheed
Lockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
, Northrop
Northrop Corporation
Northrop Corporation was a leading United States aircraft manufacturer from its formation in 1939 until its merger with Grumman to form Northrop Grumman in 1994. The company is known for its development of the flying wing design, although only a few of these have entered service.-History:Jack...
, and Vought
Vought
Vought is the name of several related aerospace firms. These have included, in the past, Lewis and Vought Corporation, Chance Vought, Vought Sikorsky, LTV Aerospace , Vought Aircraft Companies, and the current Vought Aircraft Industries. The first incarnation of Vought was established by Chance M...
– submitted proposals. Vought's V-1100 and Lockheed's CL-1200 Lancer were eliminated in March 1972. Though the Boeing Model 908-909 was initially most favored, it was quite similar in technology and appearance to the cheaper General Dynamics Model 401-16B. Since one of the goals of the program was to validate emerging technologies, Secretary of the Air Force Robert Seamans chose to select the General Dynamics and Northrop entries.
The first YF-16 had its "official" maiden flight
Maiden flight
The maiden flight of an aircraft is the first occasion on which an aircraft leaves the ground of its own accord. This is similar to a ship's maiden voyage....
on 2 February 1974. The second YF-16 prototype first flew on 9 May 1974. This was followed by the first flights of the Northrop’s YF-17 prototypes, which were achieved on 9 June and 21 August 1974, respectively. The fly-off commenced in 1974 as both prototypes were delivered. The YF-16s would complete 330 sorties during the flyoff, accumulating a total of 417 flight hours; the YF-17s would accomplish 268 sorties.
Air Combat Fighter competition
Three factors would converge to turn the LWF into a serious acquisition program. First, four North Atlantic Treaty Organization (NATO) members – BelgiumBelgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
, Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
, the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, and Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
– were looking to replace their F-104G fighter-bomber
Fighter-bomber
A fighter-bomber is a fixed-wing aircraft with an intended primary role of light tactical bombing and also incorporating certain performance characteristics of a fighter aircraft. This term, although still used, has less significance since the introduction of rockets and guided missiles into aerial...
variants of the F-104 Starfighter
F-104 Starfighter
The Lockheed F-104 Starfighter is a single-engine, high-performance, supersonic interceptor aircraft originally developed for the United States Air Force by Lockheed. One of the Century Series of aircraft, it served with the USAF from 1958 until 1969, and continued with Air National Guard units...
interceptor; furthermore, they were seeking an aircraft that their own aerospace industries could manufacture under license, as they had the F-104G. In early 1974, they reached an agreement with the U.S. that if the USAF placed orders for the aircraft winning the LWF flyoff, they would consider ordering it as well. Secondly, while the USAF was not particularly interested in a complementary air superiority fighter, it did need to begin replacing its F-4 and F-105 Thunderchief
F-105 Thunderchief
The Republic F-105 Thunderchief, was a supersonic fighter-bomber used by the United States Air Force. The Mach 2 capable F-105 conducted the majority of strike bombing missions during the early years of the Vietnam War; it has the dubious distinction of being the only US aircraft to have been...
fighter-bombers. To reflect this new, more serious intent to procure a new aircraft, along with its reorientation toward a fighter-bomber design, the LWF program was rolled into a new Air Combat Fighter (ACF) competition in an announcement by U.S. Secretary of Defense
United States Secretary of Defense
The Secretary of Defense is the head and chief executive officer of the Department of Defense of the United States of America. This position corresponds to what is generally known as a Defense Minister in other countries...
James R. Schlesinger
James R. Schlesinger
Dr. James Rodney Schlesinger is an American politician. He is best known for serving as Secretary of Defense from 1973 to 1975 under Presidents Richard Nixon and Gerald Ford...
in April 1974. Schlesinger also made it clear that ACF, as a multirole fighter, would be only an addition to the air-superiority F-15, which essentially ended opposition to the LWF. Third, the U.S. Congress was seeking to achieve greater commonality in fighter procurements by the Air Force and Navy. The Congress, in August 1974, redirected funds for the Navy’s VFAX
VFAX
VFAX for Naval Fighter Attack Experimental was actually two specifications for two US Naval fighter projects. The first was for a low cost lightweight complement for the F-111B which could replace the F-4 Phantom II for air superiority, escort, and ground attack missions in the early 1960s. This...
program to a new Navy Air Combat Fighter (NACF) program that would essentially be a navalized fighter-bomber variant of ACF. These requirements meshed relatively well, but the timing of the procurement was driven by the timeframe needs of the four allies, who had formed a "Multinational Fighter Program Group" (MFPG) and were pressing for a U.S. decision by December 1974. The U.S. Air Force had planned to announce the ACF winner in May 1975, but the decision was advanced to the beginning of the year, and accelerated testing.
ACF also raised the stakes for GD and Northrop because it brought in further competitors intent on securing the lucrative order that was touted at the time as “the arms deal of the century”. These included the Dassault-Breguet’s
Dassault Aviation
Dassault Aviation is a French aircraft manufacturer of military, regional and business jets, a subsidiary of Dassault Group.It was founded in 1930 by Marcel Bloch as Société des Avions Marcel Bloch or "MB". After World War II, Marcel Bloch changed his name to Marcel Dassault, and the name of the...
Mirage F1 E (E for Europe) powered by a Snecma M53 engine and utilizing a fly-by-wire system similar to the one used in Dassault Mirage 2000 series. Only two prototypes were built for the ACF program. the SEPECAT Jaguar
SEPECAT Jaguar
The SEPECAT Jaguar is an Anglo-French jet ground attack aircraft, originally used by the British Royal Air Force and the French Armée de l'Air in the close air support and nuclear strike role, and still in service with several export customers, notably the Indian Air Force and the Royal Air Force...
, and a proposed derivative of the Saab 37 Viggen named the “Saab 37E Eurofighter” (which is not to be confused with the later and unrelated Eurofighter Typhoon
Eurofighter Typhoon
The Eurofighter Typhoon is a twin-engine, canard-delta wing, multirole combat aircraft, designed and built by a consortium of three companies: EADS, Alenia Aeronautica and BAE Systems; working through a holding company, Eurofighter GmbH, which was formed in 1986...
). Northrop also offered their earlier design, the P-530 Cobra, which looked very similar to its YF-17. The Jaguar and Cobra were dropped by the MFPG early on, leaving two European and the two U.S. LWF designs as candidates. On 11 September 1974, the U.S. Air Force confirmed firm plans to place an order for of the winning ACF design sufficient to equip five tactical fighter wings. On 13 January 1975, Secretary of the Air Force John L. McLucas
John L. McLucas
John Luther McLucas was United States Secretary of the Air Force from 1973 to 1975, becoming Secretary of the Air Force on July 19, 1973. He had been Acting Secretary of the Air Force since May 15, 1973, and Under Secretary of the Air Force since March 1969...
announced that the YF-16 had been selected as the winner of the ACF competition.
The chief reasons given by the Secretary for the decision were the YF-16's lower operating costs; greater range; and maneuver performance that was "significantly better" than that of the YF-17, especially at near-supersonic and supersonic speeds. The flight test program revealed that the YF-16 had superior acceleration, climb rates, endurance, and (except around Mach 0.7) turn rates. Another advantage was the fact that the YF-16 – unlike the YF-17 – employed the Pratt & Whitney F100
Pratt & Whitney F100
-External links:* * *...
turbofan engine, which was the same powerplant
Aircraft engine
An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines...
used by the F-15; such commonality would lower the unit costs of the engines for both programs. However in the Navy Air Combat Fighter (NACF) competition, the Navy announced on 2 May 1975 that it selected the YF-17 as the basis for what would become the McDonnell Douglas F/A-18 Hornet.