The F-35 vs. the Russian Su-35 and the PAK FA
The Russians are now developing new air dominance aircraft with a long-range strike capability -- the Su-35 and the Pak FA (frequently called the PAK T-50) – which will pose a significant threat to NATO Europe. The U.S. F-35, the only 5th generation aircraft in production today, is critical to countering these threats.
The F-35 has recently gotten bad publicity over its dogfighting capability despite the fact the last dogfight was in 1988. Since 1988, all air-to-air kills have been by missiles, a type of warfare in which the F-35 is designed to excel. The F-35 is a strike fighter with multirole capabilities, which makes sense because strike missions happen every day and stealth is necessary against advanced air defenses. While the Russian Su-35 and the PAK FA “stealth fighter” are both reportedly suffering from technical problems, the long-term threat is significant. Russia ordered the Su-35 in 2011 for delivery by 2015 but the announced IOC has slipped to 2018. The PAK FA has been scaled back to a single 12 aircraft squadron by 2017 because of reported cost and technical problems. Future production will depend on trial results. Russia constantly brags about the performance of both aircraft but its claims must be taken with caution because Russia seeks to maximize foreign sales of these aircraft.
Setting aside Russian hype, the Su-35 is clearly an improved 4.5 generation fighter aircraft with very high maneuverability (thrust vectoring) and long-range strike potential. It has a very powerful passive phased array radar (PESA) with a claimed (probably exaggerated) detection range of 350-400-km against “fighter sized targets.” The Su-35 can reportedly carry 8,000-kg of weapons externally including a wide variety of bombs and missiles. The Russians say it carries advanced electronic countermeasures Russia boasts a reduced radar cross section (RCS) reportedly to 1 to 3 square meters. Its radar should give it an advantage over most 4th generation fighters, but not necessarily over modern 4.5 generation fighters designed with elements of stealth technology and equipped with active electronically scanned (AESA) radars.
In a rare moment of candor, Colonel-General Alexander Zelin, then-chief of the Russian Air Force, stated that the Su-35’s avionics and integrated defense system are inferior to “American fighters of the same type.” It is not in the F-22 class, but the Su-35s will be deployed in Europe while there are no current plans to deploy the F-22 on a permanent basis because there are not enough of them.
The PAK FA is touted by Russia as a fifth generation fighter. General Zelin said that its mission is air dominance and to “project force over large distances.” It has a large bomb bay and will carry many types of ground attack weapons. Sputnik News, a government owned news agency, recently reported that it will internally carry a stealth cruise missile.
According to the Indian press, the aircraft (the basis for the Indian FGFA under a joint program with Russia) currently has significant problems including engine performance, the reliability of its AESA radar, and poor stealth engineering. Still, if Russia meets its announced IOC date of 2017 for the first squadron, it will be operational before any stealth aircraft are operational in NATO Europe and will enhance Russia’s advantage over its most vulnerable neighbors. As of now, Norway will be the only state in Northern or Eastern Europe to deploy a fifth generation fighter.
The PAK FA is an effort to build a stealth fighter, but Russian and Indian press reports indicate the actual stealth of the first two versions of the fighter will be marginal. In 2010, Moskovskiy Komsomolets Online noted, “For all its undoubted merits, the PAK FA (Advanced Aviation Complex for Frontline Aviation)…cannot yet be called a fifth-generation fighter….The T-50’s low observability remains contentious.” According to Russian journalist Yuriy Krupnov, the PAK FA “is not a fifth-generation aircraft.” When the PAK FA aircraft was rolled out, General Roger Brady, then-Commander of U.S. Air Forces in Europe and Commander of NATO’s Allied Air Command, said, “I don’t know if it’s really a fifth-generation aircraft. What I do know is that it’s very clear that they’re working on a fifth-generation technology.”
In 2010, Alexander Davidenko, chief engineer on the PAK FA project, claimed that the F-22 radar cross section (RCS) was about 0.3 to 0.4 square meters and that the PAK T-50’s RCS should be close to that. The comparison with the F-22 is clearly bogus (it assumes a F-22 RCS that is orders of magnitude less stealthy than any other report on the stealth level of the F-22), but there does not appear to be any reason why the chief designer would understate the stealth level of the PAK FA.
In 2011, Russian and Indian press reports started attributing even less stealth to the aircraft. Military journalist Dmitriy Litovkin, writing in Izvestya, stated that the PAK T-50’s RCS “will be equal to 0.5 square meters (for the Su-30 MKI it is 20 square meters).” An Indian military publication, Force Online, said the Indian version of the PAK FA “will reportedly have a RCS of 0.5 square meters….By comparison, the Su-30MKI [the Indian version of the Su-30] has a RCS of approximately 20 square metres, while Lockheed Martin’s F/A-22 Raptor has the RCS of a small bird or a bumble bee at between 0.001 and 0.01 square metres.” Indian and Russian press reports are consistently attributing a .5 square meter RCS to both versions of the PAK FA. A report in Combat Aircraft by Russian journalist Piotr Butoswki from the 2011 Moscow Air Show said, “Based on scant Russian data the T-50 has a radar cross section lower than 0.5m2, which is 25 times less than that of a Su-27.” In 2013, Russia behind the Headlines, which is state-owned publication, said that the PAK FA RCS was 5.3 square feet which is almost exactly .5 square meters. In 2014 and 2015, two Russian reports said its RCS was “0.1 to 1 square meter” which implies a central value of about .5 square meter.
By way of comparison Aviation Week reported the F-22 achieved more stealth than was required and, “Pentagon officials have said privately that the desired signature from certain critical angles was -40 dBsm [.0001 square meter], the equivalent radar reflection of a steel ‘marble.’ By comparison, the F-35 Joint Strike Fighter has a signature of -30 dBsm. [.001 square meter], about the size of a golf ball.” The allusions to steel marbles and golf balls represent the official Air Force unclassified descriptions of the stealth level of these aircraft.
Russia has said that the PAK FA will have a supercruise capability of Mach 1.7.-1.8. The supercruise capability of the existing aircraft is reported by Piotr Butoswki to be Mach 1.3. Two recent Russian press reports have indicated it will not have a supercruise capability with the existing engine. By comparison, Aviation Week says the F-22 supercruises at Mach 1.78. Lockheed Martin indicates that the F-35 can supercruise at Mach 1.2.
General Zelin once claimed that the PAK FA was more maneuverable than the F-22. His credibility is tarnished because he simultaneously asserted that the F-22 was less maneuverable than the Mig-23. Still, there is reason to assume that the PAK FA is about in the F-22 class with regard to maneuverability, or that at least it will get there when it gets a 5th generation engine. It should have a significant maneuverability advantage over all 4th generation fighter aircraft and the F-35. When the current problems are resolved, the PAK FA: 1) will outclass all current NATO 4th or 4.5 generation fighters in almost every respect; 2) will likely be able to engage any of them before they can detect the PAK FA; 3) will likely be able to outmaneuver them in a dogfight; and 4) will have better penetration capability against air defenses. However, PAK FA’s capability against advanced air defenses will apparently not nearly match the F-22 or the F-35. Indeed, Russian advertising literature for its advanced air defenses offered for sale claims an ability to intercept aircraft with .01 square meter radar cross section. This implies they can intercept the Su-35 and PAK FA but not the F-22 and the F-35.
The Air Force has recently described the frontal radar cross section of the F-35 as better than the F-22. The F-35, with about a 2020 IOC in NATO Europe, likely has a considerable sensor advantage over the PAK FA, particularly in passive sensor capability. It appears very likely that the F-35 will be able to either evade the PAK FA on a strike mission or engage it before it is detected due to its stealth advantage, its advanced sensors and sensor fusion.
A number of aviation writers have pointed out the potential vulnerability of existing air-to-air missiles to advanced electronic counter measures (ECM). Improved air-to-air missiles will be an important factor in keeping the F-35 competitive but funding is hardly a given in the U.S. However, even one of the strongest critics of the F-35, Dr. Carlos Kopp concludes, “The case against legacy unstealthy fighters in a modern A2/AD IADS [anti-access air defense integrated air defense system] environment is not open to informed dispute—although uniformed dispute will no doubt continue until a real war proves this even to the most ideologically committed.”
In light of the termination and replacement with inferior substitutes of almost all new U.S. air defense systems over the last 10 years and the deployment of advanced defenses by Russia, it may be able to exploit U.S. vulnerabilities despite inferior aircraft. More Western emphasis on 4th generation aircraft would also increase this vulnerability. It is unlikely that just an IR guided long-range air-to-air missile will make 4th generation aircraft the equal of the PAK FA. Stealth remains an important attribute for high intensity conflict.