Today, fighter jets are the backbone of the world’s air forces. However, they can be separated into one of five different categories, known as “generations” based on their age, tactical configuration and the technology found onboard.
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Indeed, the notion of a “generation” fighter isn’t even that old: it was coined in the 1990s and is generally associated with the US aviation industry by the international community as a whole.
Unlike the terms “fighter plane” and “fighter aircraft” which are incredibly broad terms used to describe any fixed-wing aircraft designed for air-to-air combat missions, a “generation” fighter can only be used to refer to a jet-powered fighter (fighter jet).
Although the term and corresponding classifications were born out of necessity from within the industry itself, it should be noted that not everyone shares the same classifications.
Depending on who you talk to, you may find that they class different aircraft in different generations (especially if those aircraft were produced near the end or start of a “generation” and there’s some overlap) or that there are only four generations rather than five (mainly by the Chinese).
For the purposes of this article, we will be using the most widely used and accepted consensus regarding which aircraft are in which generation and the notion of five generations over four.
The idea of using aviation for warfare predates even the Wright Brothers’ first flight.
But aerial warfare didn’t truly become widespread until WWI, leading to the first so-called “fighter” aircraft, like the Fokker Eindecker and Sopwith Camel, which were specifically designed for aerial combat. As the war progressed, so did the sophistication of fighter aircraft.
With the end of war in 1918 saw the end of this progress. With no war to fight, few new fighters were put into production during the 1920s and manufacturers ceased research into developing new ones.
The 1930s were much different due to the looming threat of war, which convinced aircraft manufacturers across the world to ramp up research into fighter aircraft technology once more.
For the most part, this was done independently by aircraft manufacturers on an ad hoc (and rather limited) basis.
Direct government involvement was spared for those manufacturers located in countries like Germany and Japan, whose leaders had embarked on projects of aggressive military expansionism and needed brand new, state-of-the-art fighter aircraft to do this.
With the official declaration of war in September 1939, development of new fighters increased considerably on both sides, and in non-aligned countries like the US.
Developments in fighter jet technology included making them faster, more maneuverable and extending their range and payload capabilities among others.
In the quest for increasing speed, aircraft and engine manufacturers soon discovered the limitations of piston engine technology; after all, a propeller can only spin so fast before it becomes ineffective. So they began searching for another way to power their aircraft: jet propulsion.
First Generation – 1940s to 1953
By mid-WWII, both Allied and Axis engineers had built working jet engines and the aircraft they’d power.
Many of these aircraft, like the Messerschmitt Me 262 and Gloster Meteor, saw active (albeit limited) combat during the war. Development of jet-powered fighters continued following the war’s end, leading to new aircraft like the Lockheed P-80, MiG-15 and F-86 Sabre.
Aside from being powered by a jet powerplant, rather than a piston one, these first generation fighters were little different to their contemporaries, featuring minor sweep or unswept wings, manually controlled guns and little in the way of modern avionics.
The edge – aside from having a more reliable powerplant – first generation fighters had over their piston counterparts was their speed. With only a few exceptions, most first gen fighters were considerably faster than the pistons they replaced.
Most were even capable of supersonic flight, though this was usually limited to controlled drives rather than level flying. The Korean War was the first conflict where jets were used on a mass scale by both sides, with first generation fighters now being a symbol of the conflict.
Due to their advanced age, first generation fighters have been retired for a considerable length of time, now finding themselves primarily as museum exhibits, whilst a few remain in airworthy condition as warbirds.
Second Generation – 1953 to 1960
By most accounts, Korea was the point of no return for first generation fighters. Their wide-scale use revealed the immense shortfalls of first gen fighters; they’d advanced so much but still had a long way to go.
WWII-style manual guns weren’t particularly effective at the speeds most first gen fighters flew at, necessitating the need for much faster air-to-air missiles.
To improve accuracy of these, second generation fighters were fitted with rudimentary avionics, including a supersonic radar.
As speed was now the aim of the game, engineers made every effort to incorporate then-cutting edge aerodynamic advances such as swept wings (or in some cases, blended wings!) and integrated engines.
Coupled with the introduction of more powerful engines and afterburners (on a mass scale), second gen fighters were able to fly supersonically during level flight – instantly making them much more deadly in a dogfight.
Though most were originally designed expressly as fighters, many air forces used them in multirole capacities, particularly as fighter-bombers, interceptors and night fighters (by virtue of their advanced onboard radars).
The US-produced Century Series, Mirage III, English Electric Lightning and MiG-21 are all quintessential second generation fighters.
Whilst most third gen fighters have been retired from active military service, a select few remain in service, such as the Mirage III with the Pakistani Air Force.
Third Generation – 1960 to 1970
With many air forces using their second gen fighters in roles beyond aerial superiority, third generation fighters were designed for multirole capabilities.
Due to the widely varying missions third gen fighters would be used in, third gen fighters were given a wide range of new avionics systems, including beyond visual range radars, terrain-warning systems and electronic countermeasures (ECMs) for fooling enemy radars.
Third gen fighters were also designed to host an equally wide range of weapons, from air-to-air missiles, to air-to-surface missiles and laser guided bombs (LGBs).
Beginning in the mid-1960s, third gen fighters were installed with externally mounted targeting pods for precision-guided munitions (PGMs) further increasing their effectiveness as fighter-bombers particularly.
As third gen fighters would no longer just be flying quick sorties, and instead needed much longer in the air to complete their missions, manufacturers put an even greater emphasis on increasing range and speed.
To do this, brand new turbofan engines were installed on third gen fighters, which were more fuel efficient than the turbojets used up until then, thus extending range.
Similarly, new aerodynamic inventions such as swing wings and/or variable thrust were used on many third gen fighters, helping increase both speed and range as well.
The concept of a third generation fighter is perhaps best exemplified by the F-4 Phantom, an aircraft synonymous with the Vietnam War. Other famous third generation fighters include the Dassault Mirage F1, Hawker Siddeley Harrier, and MiG-23.
Fourth Generation – 1970 to 1990
Yet whilst the war in Vietnam made the F-4 a household name on both sides of the Iron Curtain, it also revealed the fundamental flaws in third generation aircraft technology just as the Korean War had done for first generation fighters a decade earlier.
No matter what the public thought of and praised third generation fighters like the F-4, they were no longer fit for purpose.
Vietnam had been a war that didn’t just need multirole fighter-bombers, but aircraft that were as maneuverable as they fast. Indeed, fourth gen fighters are among the fastest aircraft ever built – even faster than their fifth gen counterparts.
Coupled with inventions and advances in other technologies like fly-by-wire, composite materials and digital avionics, fourth generation fighters were designed to be fighters first and foremost but adaptable enough that air forces could use them in the same multirole capacities their third generation forebearers had.
Fourth generation fighters were also the first aircraft to be consciously designed with stealth (albeit rather limited) capabilities and experimented with new aerodynamic features like canards on a mass scale.
Among the most famous fourth gen fighters are the Saab Viggen, F-16, Panavia Tornado, Su-27 and Harrier II.
Whilst many air forces maintain fourth generation fighters in their arsenal, most are beginning to move away from them as they are increasingly becoming obsolete in modern military aviation.
4.5 Generation – 1990 to 2000
Recognizing the increased obsolescence of fourth generation fighters, but also the lack of funding for new fighters nearing and following the end of the Cold War, aircraft manufacturers began developing what are sometimes called 4.5 generation fighters.
Combining many of the developments originally designed for fifth generation fighters with the technology on already-proven fourth generation fighters, 4.5 gen fighters aren’t distinct enough to be their own separate “generation” but are unique enough to not fit into the classification of either fourth or fifth generation fighters.
Many of these fighters incorporate elements of stealth technology and modern avionics, albeit not to the extent of fifth generation fighters. Alternatively, 4.5 generation fighters are also called 4+ generation fighters.
Perhaps the most famous 4.5 generation fighters include the Eurofighter Typhoon, Dassault Rafale, MiG-35, F/A-18 Hornet and Saab Gripen.
Due to the delay of and recent integration issues with fifth generation fighters, 4.5 generation fighters are the premier fighters of many air forces around the world.
Fifth Generation – 2000 to Present
So far, almost every aspect of 21st century life has been defined by increased digitization. Military aviation is no different.
Almost all avionics on these aircraft are digital, with the aircraft being programmed through millions of lines of code. Many also have new types of avionics such as synthetic aperture radar (SAR) and/or infra-red search and tracking (IRST).
To increase situational awareness and coordination, most fifth gen fighters have networked data fusion, allowing fifth gen fighters to “talk” to other allied fifth gen fighters nearby. A few even have varying degrees of AI installed to assist the pilot during flight, especially in a dogfight!
As much a computer as they are an aircraft, it is expected that fifth gen fighters will adapt to future changes in aerial combat, not through new variants, but through software updates, thus saving air forces around the world millions of dollars in the long run.
Fifth gen fighters have inherited the maneuverability of their fourth and 4.5 gen predecessors (and are arguably more so) but have lost some of the speed associated with these generations due to more pressing operational requirements.
But perhaps the defining feature of fifth generation fighters is their stealth.
With more reliable and longer-range radars becoming more and more widespread, manufacturers have had to design fifth gen fighters to have as minimal radar cross-sections (how much it reflects radar signals) as possible.
This is why many fifth gen fighters have much straighter lines than fighters from previous generations: it’s about reflecting those signals in any direction that’s not directly back at the radar.
In addition to this, many are painted with radar-absorbing paint, so that those radar signals that do get reflected back at the radar (remember: “stealth” doesn’t mean “invisible” it just means “less visible”) are considerably weaker, and thus “spoof” the radar.
A few famous (or should I say infamous?) fifth gen fighters include the F-35 Lightning, Sukhoi Su-57, Shenyang FC-31, F-22 Raptor and Chengdu J-20. There are presently several fifth generation fighters under development, such as the TAI TFX in Turkey and Sukhoi Su-75 in Russia.