What is the Story of the Fighter Aircraft (F-14, F-15, F-16 and F-18) Developed to Overcome the Vietnam Syndrome?

Vietnam Syndrome and F-4 Phantom

The Vietnam syndrome had hit the American people as well as the US Air Force and Navy. The need for more advanced aircraft to compensate for the shortcomings of the F-4 Phantoms, which could not make much of an impact against the MiG-21s, had become more pronounced. Mobilised to meet this need, the American aerospace industry developed a large number of fighter aircraft such as the F-111, F-14, F-15, F-16 and F-18 in a very short period of time in the 1970s, almost exclusively to replace a single aircraft, the F-4 Phantom II. 

The F-4 Phantom II was originally built as a fighter bomber for the US Navy. The F-4s were soon adopted by the US Air Force, and eventually the F-4 Phantoms became a truly joint strike and fighter aircraft in the 1960s. Armed with four AIM-7 Sparrow missiles and four AIM-9 Sidewinders in the air-to-air role, the F-4s had a nose cannon integrated into an optional gun pod in the nose area. The machine gun pod on today's F-35B and Cs was a solution that was implemented on F-4s at some point in the past.

F-4 aircraft were equipped with the capability to fight beyond visibility. However, the avionics on the aircraft were not yet developed enough to distinguish between friend or foe in enemy territory. It was obvious that more sophisticated avionics and an Advanced Identification Friend an Foe (AIFF) system were needed. In Vietnam, the only solution for F-4 pilots, who could not successfully distinguish between friend and foe beyond line of sight, was to accept close engagement against MiG-21s. In short, the F-4s were forced to "dogfight" with the Soviet agile fighter in the area where they were most disadvantaged. During the latter part of the Vietnam War, F-4 pilots, aided by an electronic programme that was partially useful in discriminating between friend or foe beyond line of sight, managed to shoot down MiG-21s beyond line of sight.

A team led by Colonel John Boyd, who closely followed what happened to the 1960s star F-4, developed a formula called the energy manoeuvre theory. Thanks to this formula, they wrote a programme in which you can calculate the flight envelope of an aircraft by entering a few parameters and compare it with other aircraft around the world. In this framework, clues about what kind of fighter aircraft should be developed began to emerge. Meanwhile, the Soviets had developed the MiG-25. As American intelligence penetrated information about this aircraft, the American aerospace industry had to roll up its sleeves to develop early versions of today's 4th generation fighter aircraft.

F-111

The US Navy initially pioneered the development of the F-111 fighter aircraft to replace the F-4s, which were also used on aircraft carriers, in air-to-ground attack missions. This was because the F-111 was designed to be used for bombing missions rather than multi-role missions. It was developed to fly safely at very low altitudes without being visible to enemy radar. After dropping its bomb on the target, it was requested to be an aircraft that could almost crawl away from the target area. The F-111s, which fulfilled this mission with outstanding success, were still no more than a specific-specification aircraft lacking most of the multi-role capabilities of the F-4. It was necessary to develop other fighter aircraft to replace the F-4. Thus, the focus was on developing the F-15 for the US Air Force and the F-14 for the Navy.

Air Force Aircraft F-15

The F-15 was designed primarily for the needs of the US Air Force. It was designed to carry 4 AIM-7s, 4 AIM-9s and other weapons similar to the F-4. Its radar was much more advanced and powerful than that carried by the F-4 Phantom II. Since the F-15 was conceived as an aircraft that could compete with the MiG-25, it was required to have an aerodynamic airframe structure that could reach speeds of Mach 2.5 and above. The F-15 continues to be used today as a large, powerful and specialised Air Superiority fighter with great manoeuvrability, a large and powerful radar and a large number of missiles. Designed to go head-to-head with other fighters and to shoot down bombers and attack aircraft before they reach their targets, the F-15s have been in the skies for 51 years since their first flight in 1972.

Meanwhile, in those years, the Air Force thought that the MiG-25 fighter aircraft was an aircraft that exceeded the capabilities and features they actually had. Instead of seeing the MiG-25 as a high-speed, but low manoeuvrability and heavy fighter aircraft, they perceived it as a core capability, a multi-role aircraft around which almost anything could form a ring. For this reason, they focused on the development of the F-15 and the F-14, which is in a sense the Navy version of the F-15, according to these predictions.

Why was the F-16 Needed?

Naturally, the F-14 and F-15 duo emerged as very expensive fighter aircraft for the US military due to the common mission and expectations placed on them. In the meantime, other designs were needed to complement the F-14 and F-15, which were originally intended to be used as air defence and air superiority aircraft. These designs were required to be smaller and cheaper multi-role aircraft. 

The F-15 had too much capability, especially in the air superiority role, and this expensive aircraft should not be risked in other secondary missions. Smaller aircraft could do the other tasks envisaged. In the meantime, some were still saying that the F-15 was too big to fight, too complex to manage, too dependent on electronics and too costly. In a way, in the early 1970s, similar evaluations of the F-22s in the 2000s were being made for the F-15s.

In this context, the US Air Force opened a design competition to develop a light fighter aircraft. The requirements and operational requirements of the new aircraft pointed to an aircraft that corresponded to about half of the F-15. The requirements were deliberately narrow. A cheap and simple solution was sought. The general expectation was that the F-15 would be used beyond visual range and this complementary aircraft would be used within visual range. Unlike the F-15, the new aircraft was expected to be able to perform air-to-air as well as air-to-ground missions. The two new designs that emerged in this context were the YF-16 and YF-17, in a sense, new competing prototype aircraft. Although it was not explicitly stated in the competition, one thing that was desired was that not only the US Air Force should purchase a large number of the aircraft to be developed, but also that it should be an aircraft that could be purchased by US allied countries, as in the F-104 and other fighter aircraft before it.

Air Force Aircraft F-16

The YF-16 won this race as the aircraft that best met the requirements of the Air Force. Meanwhile, the YF-16 also had the advantage of using the same engine as the F-15. This also served the US Air Force's expectations of a common engine pool concept, which would facilitate engine maintenance and thus lower costs.

According to some, the F-16 also served the interests of the Fighter Mafia, as it is commonly called in the US Air Force. Above all, it was light, fast, single-engined, very powerful and had a large, high-visibility cockpit to see what was going on around. The US Air Force decided that the F-16 fighter, along with the F-15, was an absolute necessity to achieve a balanced and versatile air force structure.

Later, the F-16s received better radar, more avionics and other capabilities. This transformed the F-16 into a multi-role, all-weather fighter-bomber. Over time, more advanced engines were integrated into the aircraft for better performance. The F-16, which gradually became a very capable aircraft, took its place in the literature as a brand new fighter, no longer a complement or a patchwork of the F-15. Over the years, the F-16 has performed far above its assigned role, and proved to be a very successful design. 

The main differences and complementary features between the F-15 and F-16

It should be noted that both aircraft have evolved over time with various variants and upgrades, gaining new technologies and capabilities. Today, the F-15EX is quite different from the classic F-15 and the F-16Viper is quite different from the classic F-16 Block 10.

Size and Weight: 

The F-15 is a larger and heavier fighter aircraft than the F-16. It has a longer fuselage and a wider wingspan. With this structure, it can carry more fuel and weapons than the F-16. The F-15 also has a longer operating radius and a greater payload capacity.

Mission Role: 

The F-15 is primarily designed as an air superiority aircraft specialising in air-to-air combat. It was primarily intended to have the capability to engage and destroy enemy aircraft in the air. In this respect, it is considered one of the perfect aircraft. On the other hand, the F-16 is designed as a multi-role fighter capable of performing a variety of missions such as air combat, air-to-ground attacks (including LANTIRN), defensive suppression, tactical reconnaissance, and indeed this little monster is capable of performing these missions with high competence.

Twin Engine versus Single Engine: 

The F-15 has two engines, while the F-16 has a single engine. The twin-engine configuration of the F-15 almost guarantees the aircraft's safe return to base in the event of additional power requirements and engine failures, making the F-15s advantageous. The single-engine design of the F-16 offers advantages such as lower cost, simpler maintenance and better manoeuvrability. On the other hand, the internal redundancy of the F-16 engine (primary power position-PRI, Hybrid position, secondary power position-SEC, respectively) is used as a factor that increases the survivability of the aircraft in terms of flight safety, and contributes to minimising aircraft losses due to engine failure.

Avionics and Sensors: 

Both aircraft have advanced avionics and sensor packages, but certain systems differ. The F-15 has a more powerful radar system that provides superior long-range target detection and tracking capabilities. The F-16 has a capable radar, but focuses on a lighter design and carries advanced electronic warfare and targeting systems. 

Speed and Performance: 

The F-15 has higher speed and altitude capabilities than the F-16. Its powerful engines and aerodynamic design allow it to reach higher speeds and operate safely at higher altitudes. However, the F-16 has become an agile fighter known for its exceptional manoeuvrability, superior turn rate, and the ability to easily outmanoeuvre its enemies, allowing it to excel in close dogfights. 

Cost: 

The F-16 is much cheaper to procure and maintain than the F-15. Its single-engine design and smaller size allow the aircraft to be flown with lower operation, maintenance and repair costs. In this respect, it has been the aircraft of choice for many countries.

Aircraft of the Navy F-14

This jet was also produced for the US Navy in the early 70s. In those years, it became famous as one of the most successful combat aircraft of all time. The Tomcat's primary mission was to defend US Navy fleets against Soviet bombers carrying long-range anti-ship missiles. At the time of its development, it was considered one of the most dangerous fighter jets. The main reason for this was that this aircraft was much better than its counterparts in terms of speed and radius of action, which were considered valid at that time.

The Tomcat became known as the largest and heaviest fighter aircraft launched from an aircraft carrier at the time. Despite being the heaviest, we need not think of the Tomcat as a slow jet. The F-14 Tomcat, which could reach a speed of 2.35 mach or 1803.082 miles per hour, could fly much faster than the F-16, F-17, F-18, F-22, F-35, F-4, F-5 and many other fighters. Its speed rivals were the F-15 (2.5 mach), MiG-25 (3.2 mach, a speed it could reach at the cost of partially melting its engines) and MiG-31 (3.2 mach, but limited to 2.8 mach).

An important difference between the Tomcat and many similar fighters was that it could also use the AIM-54 "Phoenix" missile. This missile was the longest-range air-to-air missile of its era, making the F-14 Tomcat one of the most capable fighters of almost all time. The long-range AIM-54 Phoenix was originally designed to intercept bombers carrying anti-ship missiles that threatened US carrier groups, not manoeuvrable fighters. In addition, the F-14s could carry AIM-9 Sidewinder, AIM-7 Sparrow and, in later years, AIM-120 AMRAAM air-to-air missiles.

Navy F-18

The Northrop-built YF-16s, which lost the race against the YF-17s, did not go to waste either. It was initially in competition with the F-16. It was a twin-engined aircraft, slightly larger than the F-16. Although twin-engined, it had a narrower fuselage design than the F-15 and F-14. It was small, agile, and the amount of bomb load it carried was quite high for its size. It was also not very expensive despite its capabilities. Realising this, the US Navy and Marine Corps later developed the YF-17 into the F-18. 

The F-18 was primarily redesigned to replace the A-4, A-7 and also as a complement to the F-14. The F-18s replaced the F-4s on the Midway-class aircraft carriers because the larger F-14 could not be used on these carriers at the time.

Eventually, F-18s, like F-15s and F-16s, emerged as a fighter aircraft that is still in use and has a place in the inventory.

Conclusion

The F-111 was never intended to replace the F-4. Initially the F-111B was supposed to replace the F-4 in the fleet defence role, but this was not fully achieved by this aircraft. The F-14 and F-15 were ultimately the only aircraft truly designed as a one-for-one replacement for the F-4. Later, the F-16 and F/A-18 were developed to complement the F-15 and F-14, respectively. 

We know that the F-4 Phantom II is a multi-role fighter aircraft. In the early years, the first F-16s lacked the capability to launch missiles at beyond visual range. The F-15s also lacked the bombing capability for air-to-ground attack. Under these conditions, only the F-15 and F-16 could operate together in a multi-role role, like the F-4. Incidentally, it is said that the US Marine Corps, unlike the Navy, never adopted the F-14. Nevertheless, the F-14 and F/A-18 duo continued to play key roles in the Army's naval aviation for many years.