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Tuesday, June 12, 2012

Threat Analysis of Foreign Stealth Fighters Part II: Sukhoi PAK FA

Image 1: Sukhoi PAK FA T-50 prototype undergoing early flight testing in 2010.

On January 29th 2010, Russia unveiled the fruits of its decade long initiative to end the American 5th generation stealth fighter monopoly. Western intelligence officials were initially stunned with the reality that Russia would possess a stealth fighter this early within the decade. Since its public debut in 2010, more information about the illusive jet has gradually seeped into the public domain. Although more information is publicly available regarding the PAK FA than its Chinese counterpart, the J-20, there are still many lingering unknowns. How did Russia manage to develop a stealth fighter? How Stealthy is the PAK FA?  How does the PAK FA compare to existing 5th generation designs? This article will seek to compile existing information from reputable sources with the goal of assessing the aforementioned questions. Following these questions will be an analysis of the ramifications a mass deployment of the PAK FA for will pose the United States and its allies. Recommendations will be made to address these new security concerns.

Image 2: PAK FA in new paint scheme. Note the thorough use of planform alignment on flight surfaces

How did Russia Manage to Develop a Stealth Fighter?

Much of the initial shock regarding the emergence of a stealth aircraft outside the United States is largely unfounded. The concept of stealth aircraft dates back to the 1960s with the work of Russian mathematician Petr Ufimtsev. It was only a matter of time before another country besides the United States utilized the technology. Ultimately, it was the crack team of aerospace engineers at Lockheed's Skunk Works that first capitalized and improved upon Ufimtsev's stealth concepts and designed the F-117 Nighthawk. After  years of testing over Area 51 throughout the late 1970s, the first Nighthawks entered service in 1983. The lack of any Soviet response to the F-117, e.g. developing its own stealth technology, stemmed from two main reasons. One, it is unlikely that the Soviets knew a great deal about the F-117 prior to its public acknowledgement in 1988. The F-117 program was given the highest level of secrecy attainable within the U.S Government. Secondly, upon having their suspicions confirmed in 1988 or learning about the F-117 for the first time, the Soviet's simply did not take stealth technology as a serious threat until the Gulf War. (Air Power Australia, 2007)  

After the complete vulnerability of Saddam's Russian supplied surface to air missile systems to stealth aircraft was exposed, Russia became more invested in developing both countermeasures to stealth technology and stealth aircraft of its own. These efforts stalled after the collapse of the Soviet Union in 1991 and subsequent decade after. The last decade of the 20th century had not been kind to the new Russian Federation. The once mighty super power was now at the mercy of oil prices to increase state revenues while the economic shock waves sent out by Gorbachev's economic reforms were still winding down. If Russia was to develop its mutli-billion dollar stealth fighter program in the face of its ongoing economic misfortune, it needed the financial backing of another country. According to Global Security, Russia and India signed an agreement to co-produce the PAK FA in 2001. India has a 25% share in development and design. (Air Power Australia, 2010) Official work on the PAK FA's development process began in 2002. (Global Security, 2010) After years of work by the Sukhoi design team, blueprints for the initial PAK FA prototype were completed by 2009. The first prototype made its historic first flight in January of 2010. 

Many intelligence analysts seemed surprised that the Russian's could design and build a stealth aircraft in the first place. A few of those analysts suspected Russia attempted to reverse engineer U.S stealth fighters and used knowledge gained from programs such as the Advanced Tactical Fighter (ATF) competition. Consequently, upon its debut the PAK FA was dubbed  the "raptorski" or F-22-ski by many western analysts much to the ire of Russian observers. Though incredibly amusing to use, the term raptoski is not entirely accurate. At the same time, the notion that the PAK FA is merely the result of a gradual evolution in Flanker designs, completed without any outside influence (e.g lessons learned from American stealth programs), is as equally dubious. The Advanced Tactical Fighter (ATF) program yielded significant advancements in engineering highly maneuverable planform alignment based stealth aircraft. Advancements such as shaping techniques learned from the ATF are utilized in the PAK FA's design. Such a claim is irrefutable. The PAK FA owes its stealth to planform alignment. As a senior American aircraft designer told one of the authors of Air Power Australia: 

"we [Americans] always end up doing the really hard work learning how to build these things, making it easy for the Russians to follow with their designs

Given the budget constraints of the PAK FA program, it makes logical sense not to conduct similar extensive research only to rediscover various techniques in designing stealth aircraft since it has already been done through the ATF. 

At the same time, the PAK FA is clearly not a mirror copy of the F-22A or YF-22. One of the most obvious examples can be found in the rears of each aircraft e.g lack of low observable thrust vectoring nozzles. In many ways, the PAK FA bears many similarities to advanced Flanker variants e.g. Su-35S. For example, the PAK FA design incorporates advanced versions of sensors and avionics utilized on Flankers including an IRST (Infrared Search and Track) system. Given what has been released about the PAK FA, it can be safely said that the avionics and internal systems of the Raptor and PAK FA are completely different. Many on-board sensors and systems share similar capabilities to their American counterparts but they are not  copies . Further similarities to the Su-35 include usage of the AL-31F 117S 3D thrust vectoring engine. 

Image 3: The Su-35S and PAK FA employ many of the same systems including an IRST as denoted by 02. Engines are also the same model for the prototype PAK FA and production Su-35S as seen on 06.  Ignore the 01 comparison, the PAK FA and Su-35S utilize very different intake designs. (Image credit: retrieved from a Croatian web forum, creator unknown. Image also appears on Pakistani forums. Link provided in sources)

"Examination of the publicly displayed PAK-FA prototypes show that this design is a continuation of the highly evolved pedigree of Flanker aerodynamic design." - Air Power Australia, 2010

"First of all, for anyone contemplating the use of the word "Raptorski":  don't. While this is an airplane that could have been the answer to the Advanced Tactical Fighter requirement, way back when, it's not an F-22 in many important ways. In a lot of ways, the T-50 reflects the heritage of the T-10 Flanker series - it's much more like them than Sukhoi's last fighter prototype, the forward-swept-wing Su-47 Berkut, ever was. From the Flanker family, the T-50 gets the massive "centroplane" - a wide central body that blends the fuselage and inner wing - three-surface aerodynamic control and true three-dimensional thrust vectoring. The main weapons bay has been seen on a Flanker model, too." - Bill Sweetman, 2010

Image 4: F-22A compared to PAK FA. Although the PAK FA incorporates planform alignment, the PAK FA  maintains distinctly different airframe shape. Differences in the rear of the aircraft and the positing of the jet intakes are particularly apparent in this illustration

For decades Russian aircraft designers have produced some of the world's best combat aircraft. In many cases, Russian engineers have built either comparable or superior air superiority platforms relative to their Western counterparts. The success of countries allied or affiliated with the United States during several of the proxy wars fought throughout the Cold War can largely be attributed to superior pilot training rather than vastly superior equipment in many cases. For example, during Operation Focus of the Six Day War, Israeli pilots flying the French built Mirage III interceptors were able to routinely dominate the formidable Mig 21's of several Arab air forces. When the pilot training advantage is taken away, dogfights between Western and Soviet/Russian aircraft becomes much closer. In several of the Indo-Pakistan conflicts, the Soviet equipped Indian Air Force kept toe to toe with the American supplied Pakistani Air Force. More recently, in joint exercises held by Germany with the United States in the 1990s, it became clear that with capable pilots flying the Mig 29, it could compete on even footing with the F-15C. In fact, with the use of an early HMD system, the German Migs initially had the advantage in visual range combat against the F-15s. (Federation of American Scientists, 2000) With the above in mind, the fact that Russia was the first country outside of the United States to produce a stealth fighter hardly seems surprising. If the advent of a Russian stealth fighter really came as a monumental surprise to Western intelligence agencies, perhaps its time to retool their methods of assessing the capabilities of the Russians (and Chinese). During the Cold War, Western intelligence agencies were incessantly worrying about the next Russian doomsday device. Ideally, it would seem that a point in between today's ignorance and the Cold War's panic attacks would be optimal. 

How Stealthy is the PAK FA?

Image 5: Planform alignment in PAK FA design. Flight surfaces are of the same angle. 

The PAK FA design makes extensive usage of planform alignment in order to heavily reduce its forward radar cross section (rcs) signature. Other features that reduce the PAK FA's rcs include the incorporation of  a canted tail design, chined nose, internal weapon bays, and engine inlet placement.  

"The low observable design shaping employed in the PAK-FA prototype shows an excellent grasp of the design rules employed by American designers in the development of the F-22A and YF-23 Advanced Tactical Fighter..." - Air Power Australia, 2010

Although the PAK FA incorporates a multitude of low observable features, it is clearly not as stealthy as the all aspect stealth design of the F-22A and even F-35 (assuming the F-35 meets its own desired specifications).

"Where the PAK-FA falls well short of the F-22A and YF-23 is the shaping design of the lower fuselage and side fuselage, where the general configuration, wing/fuselage join angles, and inlet/engine nacelle join angles" - Air Power Australia, 2010

"The aircraft that flew today is a prototype - and it does not show visible features like a frameless canopy and panel alignment that you'd expect on a production aircraft. Other not-very-stealthy-looking features include the gaps around the inlet (compare the YF-23) and a spherical infrared search and track housing in front of the windshield. And, of course, the nozzles are round." - Bill Sweetman, 2010

Estimates put forth by both Air Power Australia and Global Security place the PAK FA's frontal rcs at -20 dBSM or .01m^2. Though Sukhoi has not officially released exact figures pertaining to the PAK FA's stealth performance, Sukhoi has claimed that the rcs of the PAK FA will be 1/40 of the Su-35S. Based on estimates of the Su-35S, this would place the PAK FA's frontal signature at around -13 to -19 dBSM. Therefore, an estimate of -20 dBSM seems reasonable. (Air Power Australia, 2010) To provide some context, the F-22A has an rcs around -40 dBSM or .0001m^2 while the F-35 is intended to have an rcs of .0013m^2. (Global Security, 2012) The figures listed above only pertain to frontal radar signatures. From other aspects such as the rear, the PAK FA design is much less stealthy. However, these design features are intentional in nature. The following is Bill Sweetman's assessment from Aviation Week regarding the weak rear aspect stealth performance of both the J-20 and PAK FA. 

The rear-aspect view of the aircraft is not as stealthy, a feature also seen on the Sukhoi T-50. This is clearly an intentional trade, eliminating the heavy 2D nozzles of the F-22. In this respect, both the T-50 and J-20 reflect the philosophy behind the pre-1986 Advanced Tactical Fighter studies that preceded the F-22, based on the theory that a fast, high-flying, agile aircraft is relatively immune from rear-quarter attacks. - Bill Sweetman, 2012

Given that most Western countries do not feature extensive SAM (Surface to Air Missile) coverage, deep strike capability was not seen as a high priority in the PAK FA's design. (Sweetman, 2010) Thus, all aspect stealth was not required for the PAK FA design. The extent of stealth featured on the PAK FA coupled with its extreme maneuverability likely means it was intended to get in close to other 5th generation fighters e.g. F-35. Using its stealth to deny its opponents beyond visual range (bvr) missile kills, the PAK FA would close in on enemy jets and subsequently initiate visual range combat where the PAK FA is strongest due to extreme maneuverability.  

Of the two foreign stealth fighter prototypes currently undergoing testing, the PAK FA has the potential to be the stealthier of the two. Because of the incorporation of canards in the J-20 design, the PAK FA might be stealthier. If the canards were removed, the J-20 would certainly be stealthier than the PAK FA. The only way to definitively know is to build ultra accurate to scale models, e.g. 1/4 size of the jets (if enough data is available and budget expenses permit, a full scale model is usually used in such tests but can be done with smaller models if required). These models would have to be coated with RAM (radar absorbent materials). For the PAK FA model, RAM coatings at around 80% to 90% of the effectiveness of the Raptor's RAM coatings should be employed. For the J-20, RAM coatings at 70% to 80% effectiveness would likely be employed. Then the model would be taken to a facility capable of administrating extensive radar tests e.g. the Tejon (Northrop Grumman) or Helendale (Lockheed Martin ) facilities located in California. Building and testing a single ultra accurate model would be costly but the data would be invaluable

Lockheed Martin video on stealth. Model process discussed at 2:12-3:00

Image 6: A full scale F-22 model with RAM coatings mounted on a stand undergoing radar testing. The proposed PAK FA and J-20 models would undergo similar testing to determine the extent of their low observable features. I am not on the "inside" thus do not know if such tests are underway. If not, they should be seriously considered. Though it would be hard to create an exact replica of a J-20 and PAK FA (many official specifications not released), a replica of reasonable accuracy would greatly benefit U.S strategic planers. 

Image 7: The Russian Federation operates radar testing facilities similar to Helendale and Tejon. These images are of the 2nd Central Scientific Research and Test Institute of the Ministry of Defense (2 TzNII MO RF) based in the Migalovo Air Force Base within Tver Russia. What appears to be a mock up of a F-117 Nighthawk is undergoing radar tests. (Image Credit: Institute for Defense Analyses, 2010)

Image 8: Four stealthy internal weapon bays shown in between engines and inlets in lower fuselage. Note the unprotected circular engine nozzles at the rear of the aircraft. The lack of protection on these nozzles will make the PAK FA especially vulnerable to both IR guided missiles such as the AIM-9X and radar guided AIM-120D missiles.

How Does The PAK FA Compare to Other 5th Generation Designs?

Image 9: Two of the current three T-50 prototypes flying in formation. 

Arguably the most important question is how much of a threat does the PAK FA pose to the F-22A and F-35 variants? To answer this question, known and detailed estimated performance specifications of the PAK FA will be compared to the F-22A and F-35. The following will be compared: maneuverability, avionics, and armament. Other factors such as which countries would likely acquire the PAK FA and the quantity of PAK FA's produced will will also be examined. 


As discussed within the Murphy's Law at Work: F-35 Development and Performance Concerns article, there are two principle ways of determining an aircraft's maneuverability. The wing loading and thrust to weight ratio. Wing loading of an aircraft is calculated by taking its weight and dividing by its total wing area. In general, the lower the wing loading, the more maneuverable the aircraft is. The second measurement thrust to weight ratio which is calculated by taking the total thrust produced by an aircraft's engine(s) divided by its weight. Naturally, high thrust to weight ratios are indicative of higher vertical maneuverability and overall agility. The following figures are derived from data provided by: Global Security, Air Power Australia, Pratt & Whitney, and Lockheed Martin. All figures feature aircraft with 50% fuel, full afterburner, and full air combat load out e.g. eight R-77 missiles with GSh-30-1 cannon and 150 rounds of ammunition. 

For more details on discrepancy between these figures and the most recent F-35 article's cited figures, see the NOTES section at the conclusion of this article. (Note 2)

From these figures, it is apparent that the PAK FA is on par with the F-22A in terms of maneuverability. In fact, the PAK FA might be slight more maneuverable in certain situations as it features 3D thrust vectoring engines (pitch and yaw) as opposed to only 2D (pitch) engines featured on the F-22A. The F-22A will likely be more maneuverable in vertical oriented maneuvers due to its higher thrust to weight ratio. After examination of these figures, it also becomes apparent that the F-35 is not nearly as maneuverable as the F-22A or PAK FA. Even with the higher end spectrum of thrust figures for the F 135 engine (thrust to weight ratio at 40,000 lbf is .9867 vs 1.065 with 43,000 lbf), the wing loading for the F-35 is much higher. Additionally, the F 135 engine lacks thrust vectoring. Modern F-15 variants can come close to the PAK FA in terms of wing loading and thrust/weight ratios but lack thrust vectoring. Only the Raptor can compete on even ground with the PAK FA in terms of maneuverability. The J-20 almost certainly does not match the PAK FA in terms of maneuverability due to ongoing engine development issues. Furthermore, if the J-20 has a similar role to the F-111, than it will almost certainly have a high wing loading.

Maneuverability Advantage:

PAK FA > F-35
PAK FA = F-22A


Image 10: The highly advanced integrated avionics suite of the Lockheed F-22A Raptor. (Image Credit: USAF) 

"Perhaps the most foolish of the popular misconceptions of Russian basic technology is that which assumes that the US and EU maintain the technological lead of 1-2 decades held at the end of the Cold War. Alas, nearly two decades later, in a globalised, digitised and networked world, the US retains a decisive lead only in top end stealth technologies, and some aspects of networking and highly integrated systems software. The Russians have closed the gap in most other areas, but importantly, have mastered the difficult embedded software technology so critical for radar and electronic warfare systems, as well as sensor fusion, networking and engine and flight controls. The Russians are working very hard at closing the remaing gap, with the planned PAK-FA fighter to be properly shaped for low observable and very low observable stealth capability." - Air Power Australia, 2008

Russian designers have reduced the gap in many important avionic systems. Of particular importance, Russia is now capable of manufacturing high quality AESA radars. No broad consensus on exactly what type of radar the PAK FA will use has been reached. It is likely that the PAK FA will be equipped with upgraded versions of systems featured in the Su-35S. (Air Power Australia, 2010) At a minimum, it is likely that the publicly undisclosed Irbis E AESA variant planned for the PAK FA will feature low probability intercept (LPI) modes to decrease its probability of being detected by enemy radar warning receiver systems. In this area, the United States maintains an clear edge over its Russian counterparts. (Air Power Australia, 2010) Both the AN/APG-77 featured in the F-22A and the AN/APG-81 featured in the F-35 are equipped with low probability intercept modes. Without low probability intercept modes, the aircraft is incredibly vulnerable to being jammed and tracked by enemy radars. Radars equipped with LPI modes are much more difficult to jam and track but are not invulnerable. During testing, the F-35's AN/APG-81 was able to jam and track a F-22A utilizing LPI modes.

"In a series of tests at Edwards AFB, Calif., in 2009, Lockheed Martin’s CATbird avionics testbed—a Boeing 737 that carries the F-35 Joint Strike Fighter’s entire avionics system—engaged a mixed force of F-22s and Boeing F-15s and was able to locate and jam F-22 radars, according to researchers." - Aviation Week, 2011

Considering the edge maintained by U.S radars in LPI, the PAK FA will be vulnerable to the Raptor and Lightning radars. Furthermore, Russian designers have experienced difficulties in cooling their AESA systems as to avoid an increased the aircraft's IR signature. U.S designers have more experience designing AESA liquid cooling systems than Russian designers. (Air Power Australia, 2010)

In terms of sheer processing and detection power, the edge varies from system to system. The amount of transmit receiver (TR) modules within an array is generally indicative of its detection power. High end fighter based radars typically feature around 1,500 TR modules. Both the AN/APG-77 and Tikhomirov NIIP designed PAK FA radar will feature 1,500 TR modules. (Air Power Australia, 2009) With its smaller nose cone, the F-35's radar will only feature 1,200 TR modules. (Department of Defense, 2001) The following figures are from Air Power Australia.

Raptor detects PAK FA with .01m^2 at ~40 nautical miles
PAK FA detects Raptor with .0001m^2 at ~15 nautical miles 

Lightning II detects PAK FA with .01m^2 at ~30 nautical miles
PAK FA detects Lightning II with .001m^2 at ~28 nautical miles  

With its extensive all aspect stealth design coupled with its powerful AESA radar, the Raptor will achieve first look and first shoot capability against stealthy opponents including the PAK FA. This will give the Raptor a tremendous advantage against the PAK FA and other future stealthy opponents. The less powerful AN/APG-81 will not be able to detect low observable targets until much closer ranges. Despite its lower TR module count, the stealthier F-35 will barely detect the PAK FA before being seen. However, with its only 2 nautical mile advantage, at high speed this advantage is limited.

Although a powerful radar is the core avionic system in 5th generation aircraft, other systems such as IRST, radar warning receivers, and electronic counter measure systems are also important. It is critical to note that radar is not the only method of detecting enemy aircraft. Aside from radar, IRST systems are the main method of detecting enemy aircraft at shorter ranges. Both the PAK FA and F-35 feature IRST systems. The F-22A was planned to feature an IRST system but it was removed to lower costs. (Air Power Australia, 2010) The F-35 will be able to easily detect the PAK FA using its IRST system due to the lack of IR reduction features in the PAK FA design. Russian sources claim the PAK FA is IR shielded but it is clear that the current design is very exposed to IR detection methods. (Air Power Australia, 2010) Unlike the PAK FA, both the F-35 and F-22A designs incorporate IR reduction methods. (Lockheed Martin, 2012)
As long as the F-35 does not go to afterburner, it should be able to remain undetected in the IR spectrum. The F-22A does not have to worry a great deal about speed constraints in regards to IR detection due to its 1.82 mach super cruise capability. The PAK FA will be vulnerable to IR detection as long as its engine is active.

Image 11: Above, technicians performing testing on an electro-optical sensor developed for the AIRST originally featured in the F-22A design. (Image Credit: USAF)

Image 12: The spherical bulb mounted on the nose of the PAK FA is its electro-optical sensor which grants the PAK FA IRST capabilities. Unlike the proposed electro-optical sensor mounted on the F-22A and the current electro-optical sensor on the F-35, the system employed on the PAK FA is not well shielded from radar signatures. (Image Credit Sukhoi, 2010)

Image 13: F-35C undergoing catapult testing. Note the  electro-optical targeting system (EOTS) mounted underneath the nose of the F-35. The positioning and shaping of the EOTS prevents the F-35's stealth outline from being compromised. The EOTS will be instrumental in aiding the Lightning against 5th generation threats in visual range combat. (Image Credit: Lockheed Martin, 2012)

Avionics Advantage:

PAK FA < F-35
PAK FA < F-22A


All 5th generation aircraft feature internal weapon bays in order to minimize their radar signature. This is the case for the F-22A, PAK FA, and F-35. The differences between these aircraft is the capacity of  their internal weapon bays. Although there is no complete consensus on the exact number of missiles the PAK FA can carry within its four internal bays, eight air to air missiles is the most broadly made estimate. (Global Security, 2010) The Raptor was designed as the premier air dominance weapon of the USAF and subsequently carries eight air to air missiles internally. The multirole F-35 carries a meager four air to air missiles even in its dedicated air to air load out. The planned Block 5 upgrade will grant the F-35 the ability to carry six missiles internally but it is unclear when the entire F-35 fleet will be upgraded to the Block 5 standard (sometime after 2017). As mentioned in previous articles, the probability kill (pk) of advanced radar guided air to air missiles has been around 50% since Desert Storm. Modern electronic countermeasure systems, chaff, and AESA radars capable of jamming missile guidance systems have kept the pk of radar guided missiles relatively low. A similar trend has occurred with IR guided missiles. In the Falklands War, British Harriers used the IR guided AIM-9 Sidewinder to great effect and achieved a pk over 70%. By the time of Desert Storm, new countermeasures reduced the pk of the Sidewinder to 25%. (RAND, 2008) Both Russia and the United States have made modifications to their newest IR guided missiles to increase their resistance to IR countermeasures such as flares. Even with these improved seeker heads, it is unlikely that modern IR guided missiles with achieve pk's much higher than 50%. Essentially, multiple missiles are going to be required to achieve a single kill from either side. Until the Block 5 upgrade is complete, F-35's will be at a severe disadvantage relative to the PAK FA. (See proposed low observable missile pod in Murphy's Law at Work: F-35 Development and Performance Concerns article.)

In terms of the quality of American air to air missiles relative to Russian air to air missiles, both are very similar in terms of capabilities. At the moment, the 100 + nautical mile capable AIM-120D has a longer range than the latest R-77 variants missiles employed by Russian equipped forces. However, in a dogfight between stealth aircraft, standoff ranges are heavily reduced. Thus, extreme range isn't much of a concern in these situations. What remains a concern is if current missiles are even capable of acquiring low observable targets. Most literature on the subject automatically assumes that stealthy targets can be engaged despite their faint radar signature. From multiple accounts given by pilots in training exercises against the F-22A, its clear that their instruments are not even capable of detecting the Raptor let alone getting off a missile shot even when pilots can visually detect the Raptor. (Note 3)

"I can’t see the [expletive deleted] thing,” said RAAF Squadron Leader Stephen Chappell, exchange F-15 pilot in the 65th Aggressor Squadron. “It won’t let me put a weapons system on it, even when I can see it visually through the canopy. [Flying against the F-22] annoys the hell out of me."

USAF Colonel describes dogfighting an F-22A from the perspective of an F-15 and F-16 from 7:58-9:10.

Regardless, in terms of IR guided missiles, the American AIM-9X is marginally better than its Russian counterpart the R-73 Archer missile due to its higher off boresight capacity. Both missiles are very similar in capabilities. The major difference is the F-35 and F-22A employ extensive IR reduction methods. The following is from Lockheed Martin regarding IR reduction features in the F-35.

"F-35 Engine Nozzles Employ Specially Designed Shaping, Ceramic Shielding, and Other Coatings To Effectively Reduce IR Emissions" - Lockheed Martin, 2012

Once again,the importance of the lack of IR protection on the PAK FA design cannot be overstated. Although the F-35 will be carrying less missiles than the PAK FA, the few IR guided missiles launched from the F-35 have a higher pk against PAK FA than the PAK FA's missiles against the F-35. The F-22A will not only possess this advantage, but also the Raptor will carry more missiles and further capitalize on the PAK FA's lack of IR reduction.

Image 14: Raptor deploying flares from stealthy internal bays. (Image Credit: USAF)

Lastly, all aircraft in the comparision feature a cannon. It is of great importance not to dismiss the gun as a relic of the past which is no longer relevant in a dogfight. The effectiveness of guns and cannons employed by fighter aircraft is determined by the lethality equation. The equation stipulates the destructive power of an aircraft mounted cannon is determined by the weight of fire (weight of total rounds fired in one minute) times the muzzle velocity squared. (Shaw, 1985) Using the lethality equation, the effectiveness of the cannons can be gauged. The lethality equation is not perfect as it does not factor in the damage done by special types of ammunition (e.g. high explosive rounds) but the equation does provide a fairly accurate comparison.

It should be noted that the T-50 prototype currently undergoing testing is not equipped with a cannon. It is highly probable that the production version of the PAK FA will use a GSh-30-1 30mm cannon. All notable Russian fighters produced in the last three decades are equipped with a GSh-30-1. Although the GSh-30-1 uses 30mm rounds, its slow rate of fire and low muzzle velocity means it falls short of lower caliber high muzzle velocity American Gatling cannons such as the M61A2 and GAU-22/A. Furthermore, the GSh-30-1 uses amuntion developed in the 1970s and the gun itself is prone to overheat because of its use of a single barrel. In fact, the GSh-30-1 must be used in bursts of 40-50 rounds otherwise the gun will overheat so badly it cannot be safety used again. Because Gatling guns utilize multiple barrels to distribute heat, overheating the gun is not generally a concern. Another advantage to the Gatling cannons is its rate of fire which is critical in high speed dogfights. The opportunity for a cannon shot is often measured in fractions of a second. Thus, the more rounds fired, the better chance a pilot has of hitting a maneuvering supersonic target. Despite the fact that the F-35 employs a much more effective cannon than the PAK FA, positioning to get the cannon kill will be problematic due to its lower maneuverability. Effective pilot training and maneuvering coupled with the HMD will help F-35 pilots position for a cannon kill but the F-35 is still at a disadvantage against the PAK FA.

Armament Advantage:

PAK FA > F-35
PAK FA < F-22A

Potential Export Customers of the PAK FA

Image 15: Russian "Premier" Vladimir Putin next to T-50 prototype. 

For the last half century, Russia has been the principle supplier of relatively low cost highly effective weapon systems throughout Africa, the Middle East, Asia, and South America. This trend has continued into the 21st century and shows no signs of weakening. India is scheduled to receive its own version of the PAK FA, the Sukohi/HAL FGFA. In total, India and Russia will possess a total of around 400 planes at around $100 million dollars each. Sukhoi hopes to export between 500-650 PAK FA's over the next few decades. (Global Security, 2010) If past Russian fighter export sales are any indication, it is almost certain that many nations within Africa and east Asia will receive the new jet. A Russian based think tank as determined that Vietnam is also likely to acquire the PAK FA (Jane's Defense Weekly, 2010) China and Vietnam's ongoing territorial disputes will become quite intriguing if Vietnam deploys stealth fighters. China has also managed to aggravate the Philippines with its ludicrous territorial claims in the South China Sea. If the Philippine Government amasses enough funds, its possible they will acquire the jet in the future if tensions with China rise. The Philippine Department of National Defense has already requested 15-18 new fighter aircraft. (Defense Update, 2012) Though it is unlikely that this recent requirement for aircraft will be the PAK FA. 

The Asian nations listed above are on fairly good terms with the United States at the moment and if either Vietnam or the Philippines acquires the PAK FA it shouldn't be of much concern. The caveat being a nation's outlook on the United States can quickly change e.g. Iran during 1979. I am not an expert in geopolitical ties between nations. From the limited knowledge I do have, the only major potential problematic recipient of the PAK FA that comes to mind is Venezuela. The possibly of Iran acquiring the new jet is remote. Former Russian President Dmitry Medvedev made it abundantly clear that no further sales of weaponry to Iran are planned pending the cancellation of the S-300 SAM system. Should Putin reverse this decision, he would face international condemnation and ultimately, the added revenue would not outweigh the costs for Russia. 

Image 16: Artistic rendering of Indian FGFA variant of PAK FA. The Indian Air Force is scheduled to receive 166 single seat and 48 twin seat versions. It is probable that the FGFA will not be deployed until 2019.

Conclusion and Recommendations

Though the J-20 may look the part of a stealth fighter, it lacks the internal sensors, avionics, and systems that  compose a true 5th generation fighter. It will likely be at least another ten years before Chinese engineers are able to close the gap with U.S systems (most pessimistic estimate, other estimates are 20+ years). Make no mistake, the PAK FA is not a third rate design and is not hindered by the same problems as its Chinese counterpart. The systems employed on the PAK FA are upgraded versions of advanced proven systems employed on tested Flanker designs. The PAK FA will pose a serious risk to all fighter aircraft employed by the USAF and its allies. By every dimension, the PAK FA is a 5th generation dedicated dogfighter. Though the F-22A is more capable than the current PAK FA design, by in large the F-35 is not. Public statements made by the USAF do not reflect this reality.

"I didn’t see anything … that would cause me to rethink plans for the F-22 or F-35,” Air Force Secretary Michael Donley, 2010

Without support from Raptors, the F-35 will be at a disadvantage. Updated versions of legacy fighters such as the F-16C Block 50/52+, F-15C, and even the F/A-18E Super Hornet are simply outclassed. Relying solely on pilot training advantages to carry the F-35 and legacy fighters to victory is not responsible nor practicable. It is very likely that the PAK FA will only be flown by the very best pilots within the respective Air Forces operating the aircraft (NOTE 1). The United States must give its pilots the tools they need to succeed, anything less is simply unacceptable. 

There is only one tool in the American arsenal that will be able to consistently defeat the PAK FA without higher than acceptable losses. This is not a recommendation to end the F-35 program and halt planned production altogether. Such a plan would be impracticable on many levels. The F-35 has a very useful air to ground niche in the USAF and consequently will be instrumental in future USAF operations. However, dogfighting advanced 5th generation jets such as the PAK FA is not the F-35's strength. The F-35 can handle advanced 4.5 generation fighters and even low quality 5th generation designs such as the J-20. But the Lightning cannot comfortably handle the super maneuverable PAK FA. In two out of three of the critical core criteria of this assessment, the F-35 was at a disadvantage relative to the PAK FA. Upgrades to the F-35 could close the gap but in some aspects the F-35 will never be on equal footing with PAK FA due to inherent design features that largely cannot be changed e.g. wing loading. Keep in mind, the PAK FA and J-20 are only the first of many foreign developed 5th generation fighters to come. With this degree of uncertainty, America needs more Raptors, even if it means cutting a few hundred of the F-35A variant for less than half the number of new Raptors would be acceptable.

The groundwork to restart F-22 production has already begun. As always, RAND produced a thorough and comprehensive analysis of how to restart F-22 production and how much the process would cost to the United States Government. Rand concluded that it would cost $513 million dollars to restart F-22 production with an average unit cost of $227 million dollars per aircraft if a total of 75 were produced (reopen and production costs factored in). The cost of producing Raptors would decrease over time if the decision was made to purchase more aircraft. To put this in perspective, before Raptor production halted in 2012, the average flyaway cost was $150 million dollars. (Defense Industry Daily, 2012) The current cost of an F-35A is $197 million dollars. (Department of Defense, 2012) The F-35A will become less expensive as development issues are fixed and production expands but expect a flyway cost in upwards of $120-$150 million dollars.

Pending the deployment of the new emergency on-board oxygen generating system in 2014, the decision to produce more Raptors should be made if the new system is effective (e.g. hypoxia reports drop considerably). The author recommends that the U.S Government grants the USAF its originally requested 300 Raptors at a minimum. This would add 113 new F-22s to the USAF at the cost of sacrificing around 200-250 F-35As. Ideally, these new proposed F-22B Raptors should be built to the increment 3.2 standard with additional upgrades to ensure the F-22's dominance over future 5th generation fighters (e.g. originally planned electro-optical system). Given that the USAF is scheduled to receive in upwards of 1,700 F-35's, such a proposal would not detract much from the USAF's air to ground capabilities. Furthermore, considering that Lockheed Martin produces both aircraft, the powerful aerospace giant should not protest a great deal against this production order reversal.

The United States needs an credible insurance policy against future advanced 5th generation threats such as the PAK FA. The F-35 has a place in future USAF operations and the program must not be terminated. Rather, it is important to realize the inherent strengths and weaknesses of the F-35 design. The decision to end Raptor production was made before the debut of a credible foreign produced 5th generation threat and consequently should be reversed. The arguments against the F-22 are in large part made by politicians and pundits who have no understanding of military systems, doctrines, and the extent of the deteriorating edge currently maintained by U.S forces technologically. Of course it is best to let diplomacy take its course and avoid conflict when possible but, at the end of the day, it is best to have Raptors and not use them rather than to need Raptors and not have them.

More than any other secretary of defense, I have been a strong advocate of ‘soft’ power—of the critical importance of diplomacy and development as fundamental components of our foreign policy and national security... But make no mistake: the ultimate guarantee against the success of aggressors, dictators, and terrorists in the 21st century, as in the 20th, is ‘hard’ power—the size, strength, and global reach of the United States military.” - Venerable former Defense Secretary Robert Gates, 2011

SIMILAR ARTICLES (Links Provided) 

J-20 threat analysis
Canada and the F-35


Note 1: As the price of oil per barrel increases, so has the revenue poured into flight training programs for the Russians. After the collapse of the Soviet Union, Russian pilots could only fly a pitiful 30 hours per year. Now Russian pilots fly in upwards of 100 hours per year (Ref. source 34). It is likely that this trend will emerge in other oil rich nations. With its immense economic gains, China has been able to increase the required flight time for its pilots from 24 hours per year during the Cultural Revolution to 200 hours as of 2010. (RAND, 2011) 

Note 2: Engines used in prototype of PAK FA might change. Current engine in use is an AL-31F 117S (also known as a AL-41F1A for marketing reasons). Production engine may feature 34,000 lbf of thrust vs the current 32,000 lbf hence the difference in thrust to weight ratio indicated on the chart. An astute and frequent reader may note the figures on this chart are different from the specifications cited in the previous article featuring the F-35 specifications. The reason for this discrepancy stems from the fact that Lockheed Martin sources put the max thrust of its engine at 40,000 lbf vs Prat & Whitney cites the F 135 engine at 43,000 lbf capable. I have been unable to find the cause of this difference and elected to use the engine rating directly from the Lockheed.

Further more, wing loading figures are different as in last weeks article I made a slight error. Wing loading figures from the most recent F-35 article did not take into account the 50% fuel and were calculated with the 100% fuel within the aircraft. This can be a large difference in some aircraft e.g. some are 9,000 lb lighter with 50% fuel. Most available sources cite thrust to weight ratio's at 50% fuel but do not do the same for wing loading which is odd. Wing loading will lighten as the aircraft uses more fuel. It is not accurate to change one figure but not the other if a variable changes. If 50% fuel is to be used, than both wing loading and thrust to weight must reflect this reality.  (50% fuel is a better indicator for thrust to weigh ratios and wing loading than 100% as they only situation in which an aircraft will dogfight with 100% fuel is if it is taking off from its base and directly engaging the enemy.) Raptor stats have also changed to reflect the 50% wing loading. Analysis featured in the previous F-35 article is still valid however. Though the figures change slightly, the basic underlying point remains; the F-35 has a high wing loading relative to other fighter aircraft. 

Note 3: I am vehemently opposed to making huge assumptions with so much on the line. However, I was unable to find much information on whether or not modern radar guided air to air missiles could acquire low observable targets. I do know that certain missiles are equipped to target low observable cruise missiles such as the ground launched PAC-3 Patriot, but I was unable to find information on the R-77 and AIM-120D in terms of targeting low observable aircraft. Thus without any alternatives, it will be assumed that current missiles can target low observable aircraft.




  1. Thanks for this thorough piece. I hope one day we'll not only restart production of F-22s, but also be able to sell them to our allies, else they'll be forced to develop their own 5th gen fighters at this late stage.

    I also hope we gain stronger military relations with India. Doing so could tip the sliding power of the world's democratic nations.

    1. As much as I'd like to see restart of F-22 Raptor production, I doubt it will happen. I think the best course of action would be to reduce the USAF's dependence of the F-35 and produce new upgraded Raptors. The price of the Raptor can be lowered though mass production (e.g. making "watered down" variants to American allies). Rand published a fascinating article on restarting Raptor production if you want more info. I believe its in my sources somewhere in one of my articles.

      As for India, I agree but its not so simple. America has been directly aiding Pakistan's military for much of the last decade (e.g. new equipment and funds) with the futile hope Pakistan would fight insurgents and aid with intelligence gathering. India is distrustful of the United States at the moment for this reason. It will take time to gain their trust. Though China's increasing territorial belligerence may accelerate this process. India would also not want to come across as China's direct military competitor if possible so building up military ties will take time.

    2. Good point about the Pakistan issue. I'm amazed with our 'strategy' involving a country with suspicious ties to China and the coincidental location of Osama's compound.

  2. The apg77 has over 2000 TR modules, check globalsecurity Apg77.

    1. The estimate varies depending upon sources. This US GOV report cites 1,500. Air Power Australia also cites 1,500. I have seen TR figures for the APG-77 ranging from 1,500-2,500. I went with 1,500 because its directly from the Government. Source:,

    2. The figure* varies depending upon sources.

    3. Yeah, but I would say that the US government does not reveal the full capabilities of the F-22.

    4. That is true. However, most of the time when the U.S omits information that is classified, it is simply labeled classified or some range is give e.g. mach 2+. The report on the AN/APG-77 is listed as 1,500 without any ranges or other indications. Other modern AESA systems have around 1,200-1,500 TR modules. So the 1,500 TR figure makes sense. Furthermore, I would guess the shaping of the F-22 nose inhibits a massive AESA system of the 2,500 TR range. Due to planform alignment, space is very limited inside the F-22.

  3. What do you think of the claiming that the Su-35BM is able to track a 0.01 m2 target at 90 km, how would the APG-77 perform?

    1. Its hard to say for sure. The only source I know who has information that specific would be Air Power Australia. Ideally, you would want multiple sources to validate that type of claim. APA detection ranges F-22 & Su-35 radars:

      APA puts F-22A detection range for .01m^2 target at 40 nautical miles or 74.08km. Here the N011M on the Su-35 detects the target at 30 nautical miles or 56.56km. Thus, I doubt the 90km figure is accurate.

    2. If we knew the exact detection range of the APG-77 vs a 3m² target it would be much easier to compare. And according to German Wikipedia, the detection range of the Irbis-e vs a 1m² target is 182 km (they calculated it with the radar equation, however they didn't made it clear how they did it exactly), giving the F-22 a clear edge over the Irbis-E,as the Raptor's detection range vs a 1m2 target is about 200-240 km.

    3. It can be said with certainty the AN/APG-77 is superior. The vast majority of trustworthy sources give APG-77 an edge over the Irbis-e. I'd be careful what you take from a wiki if its anything like the American wiki. They could be right but here is APA's chart of the Irbis-e detection ranges.

  4. What if we take into account, the body lifting charactaristics of these 5th Gen aircraft? ,this would substantially lower the wing loading right? Also most F-35s will have a 45,000lbs thrust engine when full rate production starts, this should atlest close the gap with the maneuverability disadvantage of the f-35

  5. At what distance do you think the PAK-FA would detect the F-22 using its IRST?

    1. Karlo Kopp claims the OLS-35 used on the Su-35 has a cited maximum detection range of 50 km or 27 nautical miles which gives some general idea of where the Raptor would be detected. Its reasonable to expect the Raptor would not be detected right at the 27 nautical mile mark as it does employ some IR reduction measures. In either event, it would be near visual range anyway. I suspect the Raptor pilot would have detected the PAK FA with his/her AN/ALR-94 RWR long before the Raptor is able to be seen by the OLS-35.

  6. Some figures given are:
    Range for rear hemisphere target (flying away) = <90km
    Range for forward aspect target (flying towards you) = <35km
    Laser range finder (airborne target) = < 20km

    Weather and clouds will reduce figures down to <1 in some cases

    taken from FDA Moscow advert for OLS-35:

    1. Thank you for the new information, I'll look into making updates regarding the IRST.

  7. You mention the AIM-9X is marginally better than the R-73 above. The AIM-9X/AIM-2000/AIM-132 all use a 4th gen seeker head with imaging (Focal Plane Array ) - i.e. it can see the entire aircraft and shape. The R-74 was supposed to be the upgrade that would bring the older R-73 up to that standard but have seen no evidence it was ever upgraded or is operational.

  8. Una cochina y asquerosa página pro-yankee

  9. Thanks for precious and remarkable info. but F-35 is better anyway :). Here you can take a look at some great F-35 JSF photos:

    F-35 Joint Strike Fighter Pictures

  10. This comment has been removed by the author.

  11. some data in this comparison are not very accurate ( or at least they are not fully explained/lack some details ),so i'd like to add them.

    in maneuverability part after comparing wing loading and thrust to weight writer said :

    "In fact, the PAK FA might be slight more maneuverable in certain situations as it features 3D thrust vectoring engines (pitch and yaw) as opposed to only 2D (pitch) engines featured on the F-22A. The F-22A will likely be more maneuverable in vertical oriented maneuvers due to its higher thrust to weight ratio".

    now i'd like to explain 1) wing loading,2) thrust to weight and 3) thrust vectoring.

    1) wing loading.
    in one of APA analyses of modern flankers,dr.carlo kopp was explaining how aerodynamic configuration of flankers ( fuselage blended wing ) helps them to produce unprecedented amount of lift among all fighters.
    the same aerodynamic configuration was used in PAK FA design.

    so while wing loading is easy to calculate for all other fighters ,for "blended wing" that calculation is not representative,because in that case fuselage itself carries up to 40% of weight ( carlo kopp is referring to that as "effective wing loading" ).
    the best example of that is SU-27 which performs a cobra maneuver not with help of TVC ( like raptor ),but exclusively by lift that it produces.

    therefore PAK FAs "effective wing loading" is lot less than what numbers are showing ( or at least body lift needs to be calculated in ).

    2) trust to weight
    raptor has slightly better trust to weight ratio ,but both aircrafts have thrust to weight "better than one" (which provides the ability to speed up even when flying vertically).

    the advantage of better trust to weight would be lot more rellevant if one of them had it "lower than one",or if both aircrafts had same aerodynamic qualities with different thrust to weight.

    in this case my opinion is that it won't provide raptor with any significant agility compared to sukhoi ,especially having in mind great aerodynamic choices which seam to resolve lots of problems that in the past were resolved by higher trust to weight.

    3) trust vectoring.
    raptor and PAK FA will have very similar loaded weight ( somewhat less than 29,5 tons ). raptor will have engines of 16 tons of propulsion each while PAK FA 14,5 tons each.both "better than 1".
    raptors 2D TVC nozzles will have 20 degree pitch VS 3D 16 degrees of PAK FA.

    from this appears that raptor would have some advantage in kinetic performance ( and to some extent stronger engines will impact raptors performance )
    but,it is quite certain that PAK FA ( as all flankers ) will produce lot more lift than raptor ( due to his aerodynamic configuration which i've already explained above ).
    an aircraft that produces less lift will sustain the turn with more difficulty ( with TVC it will bleed).

    combining that to higher pitch degrees could mean that raptor will have some bleeding problems in maneuvering.
    SU-35 is very similar to PAK FA ( in numbers ),and with all lift that it produces his TVC nozzles are supporting 16 degree pitch ( everything beyond that would make him bleed ).

    but there are 2 important advantages of PAK FA over SU-35.

    1) it has wider body ( fuselage ) which is likely to produce even more lift and therefore impact all other characteristics ( when it comes to maneuverability ).
    2) it's fitted with movable leading edge root extensions ( LERX ) which will probably give him ability to change direction very quickly and sustain the turn even better.

    if we count in all these characteristics it's very likely that when it comes to maneuverability PAK FA will probably have a class of it's own rather than just be better than others.

  12. es una buena noticia que existan aviones como el pak-fa que puedan combatir los cazas imperiales como el f-22 y la basura de el f-35