Currently, American-made fifth-genration fighter jet F-35 are fully operational with USAF, RAAF and IAF inventory. The Chinese J-20 was reported to have entered service with the PLAAF. The J-20 even conducted a flyover during a military parade in Inner Mongolia attended by President Xi Jinping. The Chinese J-31 fighter still in development and yet to be adopted by PLAAF.
Key Points of this Article
- Stealth remains an important attribute for high-intensity conflict
- Futuristic and Stealthy F-35 is technologically quite advanced than Su-57
- Improved air-to-air missiles will be an important factor in keeping the F-35 competitive
- Legacy unstealthy fighters in a A2/AD IADS environment will not sustain in a modern warfare
- Russia has cancelled Su-57 Program on July 2018.
For a decade, Russia and India have argued over a fifth-generation fighter aircraft (FGFA) – a variant of Su-57 to be produced in Indian under joint venture. India’s DRDO insists on full access to Russian stealth design, sensor integration, and data fusion, a terrible bargain for a country whose aerospace sector is not very advanced.
Russia claims that it will soon join the very exclusive stealth club with the imminent arrival of its fifth-generation fighter, the Su-57. The Russian news agency Tass quoted an air force general who revealed the first planes would be delivered in 2018. Russia will receive 12 prototype Su-57 fighter jet since the PAK FA program cancelled on July 2018.
The Russian media and Sukhoi Design Bureau never fully disclosed technical specifcation of Su-57. Russian unwillingness to share information with partner nation like India raised many questions about the capabilities and stealth features of so called fifth-gen Su-57.
Before we analyse technical fact on Russian Su-57, let’s define what makes a fighter jet fifth-generation? There is no strict definition of fifth-gen fighter but there are common elements of a fifth-gen fighter which must be presented in a fifth-gen fighter jet.
Lt Gen Jeffrey Harrigian, the director of F-35A Lightning II Integration Office, said “There are many characteristics of fifth-generation aircraft that separate them from older aircraft. These include, primarily, multi-spectral low observable design features such as radar, infrared sensors, and visual situational awareness tools, along with self-protection and radar jamming capabilities that delay or deny enemy systems the ability to detect, track, and engage the aircraft. These aircraft also feature integrated avionics, which autonomously fuses and prioritises the aircraft’s multi-spectral sensors and off-board data, providing an accurate real-time operations picture for the pilot, and the ability to download data for post-mission analysis.”
US congressional report defines that the fifth-generation fighters combine new developments such as thrust vectoring, composite materials, supercruise, stealth technology, advanced radar and sensors, and integrated avionics to improve pilot situational awareness significantly.
To summarise the definition of fifth-gen fighter, the most notable component of a fifth-gen Fighter must have onboard offensive and defence sensor, capability to feed off-board information, networked digital data-presentation to the cockpit, share information automatically with other aircraft, stealth characteristics, advanced handling characteristics, sustained supercruise, AESA Radar, fully integrated computer systems and internal weapons bay.
Origin of Su-57 Fighter Jet
Su-57 is claimed to be production variant of fifth-gen fighter jet derived from T-50 proto type fighter of PAK FA fighter jet program. The Su-57 will feature a new engine and other enhancements near further maintaining the same airframe of T-50 proto type.
Stealth technology allows a pilot to shoot at another aircraft without the enemy having the ability to shoot back because they cannot see them. Stealth refers to the inability of the enemy to detect the aircraft, commonly by radar. The smaller the radar cross-section of an aircraft, the more difficult it is to detect and the more stealthy it is considered to be. Stealth does not mean invisible though; stealth means less visible from a certain distance of an adversary’s aircraft.
In the year 2010, Sukhoi Design Bureau added some exterior stealth characteristics–having a fuselage made of composite materials coated in radar absorbent paint.
Su-57 is a big fighter jet. From the design point of view, Su-57 has larger radar cross section comparing with another operational fighter jet. Su-57 does not match the stealth capability of the F-22 or F-35, nor does it match the price tag of them. I think it will be a very capable platform. I do not think it will match or compete the low-observation parameters of American aircraft. Regarding visibility, Su-57 may out-matched any current fourth-generation fighter jet. In a beyond visual range, Su-57 may be detected by American F-35 and even the Chinese J-20 fighter jet.
The stealth technology of Su-57 is more of advertising technology. The aircraft is still visible to a certain extent, but modern radar technology such as APG/AN 81 radar can detect su-57 aircraft, even at a longer distance. The USAF’s high confidence in stealth technology based on operational experience of F-117 Nighthawk and B-2 Stealth Bomber.
Advanced Handling Characteristics
According to Michael Kofman, a senior research scientist at the think tank CAN, Su-57 will be a step above a fourth-generation aircraft – regarding how manoeuvrable it is, Russian aircraft are always quite capable, very manoeuvrable. However, American F-22 or F-35 negate manoeuvrability by having superior electronics, software, situational awareness, BVR and stealth capability.
The Supercruise is the ability to cruise at supersonic speeds without using engine afterburners. At the core of every plane is the engine – it is all about the engine. Everything else may be interesting, but it is all about the engine says, Michael Kofman.
The Saturn/Lyulka 117/AL-41F1 engine that has powered Su-57 has many maintenance issues. Indian Air Force always complaint about Russian manufactured engines. Russian engines have been smoky and require many hours of maintenance. Su-57 has not designed modular aircraft for an engine to be replaced quickly without attention from a skilled engineer from MRO facilities.
In addition to offering a higher thrust rating than the Lyulka 117 model engine it is replacing, it has a lower specific fuel consumption, fewer parts overall in its design and a more considerable projected number of flight hours in its service life. While writing this article, Su-57 was not capable of supercruise. Su-57 used its afterburner when required.
On the other hand, American F-35 which has cutting-edge engines which are capable of Short Take Off and Vertical Landing (STOVL) and can direct up to 18,000 pounds of heated thrust from the engine exhaust. The F-35B, a vertical take-off and landing (VTOL) variant has also grown as an attractive option for American Marine and British Royal Navy.
Advanced Radar and Sensor
Su-57 does not house a single AESA radar and sensor to support the pilot rather than a single radar installed on its nose cone; there’s an L-band active phased antenna array housed in it. There are two more arrays on either side of the cockpit and an additional pair on the wings. Russian media claim these sensors allow the Su-57 to detect as many as 60 targets 400 km away. This, of course, might be an exaggeration. It is worthwhile to point out that the beyond visual range (BVR) sensors for both the F-22 and F-35 are better than the Su-57. The F-22 and F-35 are also supported by off-board and onboard sensors, datalinks and digital information systems which the Russian Su-57 lacks.
The APG/AN 81 radar is designed to enable F-35 pilots to efficiently engage air and ground targets at long range, while also providing outstanding situational awareness for enhanced survivability. The system will provide F-35 pilots with a unique protective sphere around the aircraft for missile warning, navigation support and night operations. The radar system also features a “replaceable assemblies” design for faster, easier repairs or upgrades to hardware and software modules.
For some time, the Su-57 program had been criticised as being the same engine, radar, avionics as the Su-35, but installed in a stealthy-looking airframe.
Digital Data presentation
Raytheon and Northrop Grumman have developed a new line of GaN-based airborne radars suitable for the F-22 and F-35. GaN technology impacts radar performance as much as these common metrics but the radars used by the F-22 of course use GaAs based T/R modules and cannot merely be upgraded with GaN modules.
Gallium Nitride (GaN) is a new semiconductor compound that can amplify higher power radio frequency signals than GaAs at microwave frequencies. It is expected to have more significant output power compared to GaAs; theoretically, if GaAs module can transmit 10 watts, a GaN sibling module can transmit 50 watts.
The American F-35 has been built with superior datalink networking or sensor fusion to fully incorporate present state of the art technology which includes improved detection, tracking and acquisition range, resistant to electronic countermeasures, higher radar resolution, improved terminal guidance performance against agile fighters, reduces the effectiveness MAWS, faster and more reliable datalink networking.
Some people are claiming Su-57 has GaN radars. The manufacturer of Radar, NIIP product brochure mentions GaAs* T/R modules being used for Su-57’s primary radar. Su-57 is yet to be proved any off-board digital data exchange and sharing with other su-57 or su-35 aircraft. Information sharing capability of Su-57 falls behind current 4.5 Generation fighter like Gripen E.
All stealth fighters are still vulnerable to infrared guided missiles. Both Russian and American Fighter jets have IRST. The Russian Airfract carry more armament than American Aircraft. In WVR combat, Su-57 has slightly edge over American F-35 Fighter Jet but in a BVR combat, very stealthy F-35 has the upper hand and capable of engaging enemy fighter jet before it can detect F-35. Operationally, F-35 will work with an extensive network of supporting sensors and electronic warfare platforms, both at sea and in the air.
The greater range of the Russian K-77M may be an advantage, but not against a low-observable stealth fighter but superior ramjet-powered missiles with AESA seeker such as the Meteor are already being fielded by American and NATO ally. Su-57 will operate closer to ground-based positions, which may be acceptable given Russia’s security posture and supported air defence systems such as S-400.
IAF Assesment of Su-57
A preliminary development agreement was signed in 2010 between Russia’s United Aircraft Corporation and India’s Hindustan Aeronautics Limited, or HAL when India paid its 50 percent share of $250 million toward initial development cost. If the final agreement is reached, then India will release over $5 billion toward India’s share to develop the FGFA.
India could be about to re-examine its decision to acquire fifth-generation fighters from Russia, after the Indian Air Force (IAF) produced a report questioning the reasoning behind the program includes higher maintenance costs, lack of modular design, Saturn 117S/AL-41F1 engine, compromised designed, use of radar absorbent materials and not a stealthy airframe.
The first flight of the Su-57 is considered to be proof positive that Russia’s military aircraft industry is capable of fielding a new aircraft that has a some complement of fifth-generation subsystems.
In other words, said one Russian aerospace analyst, “It looked like a next-generation aircraft, but below the surface, it was less than what it appeared.”
In short, the Su-57 is a work in progress, its final capabilities unclear. And it’s very expensive work, leaving large question marks on how many will actually be produced.
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