The 5^th-generation jet fighter  is one of the high-tech equipment that reflects the combat power of the modern air force. With the strong development of military science and technology, a number of powers have been involved in the R&D of this type of aircraft towards invisibility, super maneuverability, automation, and versatility.

The 5^th-generation jet fighter is the most modern generation of aircrafts at present and in the near future. Its indispensable basic features include: (1) Invisibility thanks to its design that minimizes signs of exposure and special materials that make the aircraft invisible to the enemy’s radar; (2). Super-maneuverability thanks to its dynamic design and multi-directional jet propeller system; (3). Cruising ability that reaches supersonic speed without burning auxiliary fuel thanks to the new-generation jet engine; (4). Ability to perform multiple combat tasks, such as air-to-air, air-to-ground, or air-to-ship tasks thanks to the integration of several weapons; and (5). Fully-automatic control thanks to modern avionics system.

F-22 Raptor, one of the 5th generation jet fighters of the U.S (Photo: National Interest)

The develop and staffing of the 5^th-generation fighters in the United States, Russia, and China

The competition to develop modern, new-generation fighters reflects the scientific foundation of the aerospace industry, while it enhances the combat power of the air force in each country. The United States, Russia, and China, therefore, have been competing in the R&D and production of the 5^th-generation fighters. So far, the 5^th-generation fighters that have been successfully researched, developed, and staffed include the US F-22 Raptor and F-35 Lightening, Russian Su-57 and Chinese J-20. Of which, the US F-22 Raptor and F-35 Lightening were used in airstrike operations in Afghanistan and Syria. Meanwhile, Russia used Su-57 to wipe out Islamic state rebels in Syria.

The F-22 Raptor was manufactured by Lockheed Martin under the US Air Force's modern tactical fighter development program since 1990s. However, 15 years later, not until 2005, was F-22 Raptor able to achieve complete combat capabilities to become the world's first 5^th-generation fighter aircraft. This type of aircrafts uses the stealth technology that makes it difficult to be detected and reach the supersonic cruise speed. It is designed to become an air superiority fighter; but it can also be used for air-to-surface missions, electronic warfare, and intelligence. In 2011, the US Air Force completed a program to staff 194 F-22 Raptor fighters.

The second US 5^th-generation fighter, F-35 Lightening II, was announced by the US Air Force to be successfully developed in 2006. It is the first 5^th-generation, supersonic, multipurpose fighter to integrate modern stealth capability with network connection combat and inter-service use. F-35 is designed in three versions, including: F-35A - the regular version, used for the air force; F-35B,  used for the marines, capable of taking off in short runways and vertical landing; and F-35C, used for the navy, staffed for carriers. Currently, F-35 Lightening II continues to be produced by Lockheed Martin under a multi-year contract with the US Air Force.

As for Russia, since the first 5^th-generation fighter named Su-57, manufactured by Sukhoi, was first introduced in 2010, 12 of this type have been put into operation. In May 2019, the Russian Air Force continued to order 76 Su-57s, a record number in the country's purchase of new-generation fighters. Su-57 has many outstanding advantages in the fuselage structure, aerodynamic design, engine type, and radar reflection cross section and signals in tiny optical and infrared wave bandwidth. Another attractive feature of Su-57 is its special stealth feature. Accordingly, different from the traditional stealth technology used by many other new-generation aircrafts that is based on angled structure combined with radiation absorbent materials which reduce the infrared radiation from the engine, Russia develops a completely new stealth technology on Su-57 - the Plasma, aka "active stealth technology". This technology uses ionized gas to reduce radar reflection cross section. Ionized gas will cover the entire space around the aircraft and absorb the electromagnetic energy of radar waves, making it difficult to be detected by enemy air defense systems. When Russia deployed four combat Su-57s in Syria, therefore, the United States and Israel failed to detect their arrival until Moscow announced its effectiveness in air strikes. On the other hand, Su-57 uses two specially designed engines that increase the efficiency of the three-dimensional vector injection funnel, making the fighter control process very flexible, creating the best maneuverability among the current 5^th-generation stealth fighters - which makes the US extremely worried.

The Chinese J-20 fighter jet was first tested in 2011. Although J-20 has stealth capability, using dual engines and officially being staffed in the Chinese Air Force since February 2018, so far, there have been only 20 fighters staffed for a training and testing brigade. China will not staff J-20s in combat units until the installation of the WS-15 vector jet turbine engine is completed (currently being researched). According to international aerospace experts, if Chinese designers achieve a comprehensive level of both materials and detailed techniques, J-20 will have much better stealth capability from the front and the two sides than the US F-35 and can be equal to F-22. The design of J-20, however, has two weaknesses: the curves on the flanks causing more reflexes than necessary and the round air exhaust (this is the common weakness of both F-35 and Su -57).

The trend of combining procurement  and self-sufficiency in the R&D of the 5^th-generation fighter aircraft

According to military experts, it costs a country around 100 billion USD to develop, manufacture, and deploy a few dozens of 5^th-generation fighters. Evidence is that the US has spent USD 70 billion to develop and manufacture 194 F-22s and replenish billions of dollars to use them since 2005. The Pentagon is also expected to spend no less than 1,500 billion USD to acquire 2,300 F-35s (excluding operational costs). As a result, many countries choose to buy US or Russian 5^th-generation fighters. In the Asia-Pacific region, the US F-35A is chosen by many countries, among which, Japan, Korea, and Australia have acquired dozens of US F-35As to modernize their air forces. Singapore has also expressed its intention to purchase F-35A fighters to replace its F-16C/D fleet.

Russia's Su-57 is of great interest to India as the 4^th-generation Plus Su-30 MKI fighters are key players in the country air force. Technical issues, costs, and delivery time are being discussed by both parties. Besides, India is also willing to consider the cooperation for developing of this type of aircraft if the cost-sharing problem is acceptable to both. Russia has also promoted Su-57 aircraft to Chinese customers. As Moscow has realized that J-20 still needs time to complete, the supplementation of Su-57 to complete interceptor and long-range airstrike capabilities is necessary. Turkey, after deciding to staff Russia's long-range S-400 air defense system, could be removed from the F-35 program by the US. Accordingly, in the coming time, Turkey may choose to purchase Russian Su-57 instead.

However, in addition to procurement, self-developing the 5^th-generation fighters is still a "dream" of many countries, especially those with economic and technological potentials. Specifically, Japan has launched a new future fighter program to replace the F-2 Air Self-Defense fleet. In April 2016, the pilot ATD-X stealth fighter jet had its first test flight. Information obtained from these flights will be applied to future fighter projects, designated as F-3. This will be a heavy-duty single-seated aircraft that is very similar to the US F-22, using two XF9-1 jet rear-burning turbines. To accelerate the progress, Japan has sought an international partner to cooperate with Mitsubishi Heavy Industries in the future fighter program. In July 2018, Japan affirmed that it had joined with the UK to "exchange views" on the Tempest fighter future project.

Korea, a Northeast Asian country, is also developing the 5^th-generation KF-X fighter project. In 2001, Korea announced the concept of KF-X outlined by the country's Committee on Defense Procurement Programs. In April 2011, Korea and Indonesia signed an agreement to develop the new-generation KF-X fighter. Accordingly, Indonesia will bear 20% of development costs to have 80 KF-Xs to replace F-16s and Su-27s, while Korea will have 120 KF-Xs to replace F-16s. As the US refused to export some key technologies for Korea for self-production, including active electronically scanned array (AESA) network, infrared search and track (IRST) system, electronic photovoltaic system, and the new-generation radio frequency jammer, the development of KF-X has been prolonged to at least until 2025.

In the coming time, the 5^th-generation jet fighters  will continue to be developed with new features, including (1). Using the engine system that can transform the operation cycle, take the thrust vector engine as the basis, and ensure the high maneuverability and expansion of the flight speed from subsonic to beyond-sonic, and supersonic; (2). The fuselage using adaptive structure and materials, ensuring high aerodynamic features in any flight status; (3). Staffing new weapons: laser and super high frequency weapons that cannot only attack but also defend; and (4). Using radio equipment and integrated optical - electric aiming system to increase the target detection range.

Development of the 5^th-generation fighter jets will contribute to enhancing the air superiority, day and night assaults with precisely guided weapons, interceptor airstrike, air defense attack, sea attack, reconnaissance, and aerial control. According to military experts, the trend of developing the 5^th-generation fighter aircraft will demonstrate the progress of humanity in aerospace technology. On the other hand, it will also make the arms race, especially the high-tech weapons and equipment, among the major powers more intense, potentially threatening the regional and global security.

Senior Colonel Dang Dong Tien, General Department of Techniques