American Innovation

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.

Maneuverability

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

Avionics

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

Armament

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

Thursday, May 31, 2012

Murphy's Law at Work: F-35 Development and Performance Concerns

Image 1: F-35A undergoing flight testing. The conventional take of and landing variant (CTOL) of the F-35, the F-35A will be the backbone of the USAF and several allied nations such as the UK for decades to come. (Image Credit: Lockheed Martin)

Its no secret that Lockheed Martin has encountered numerous design issues with the F-35. In a Quick Look Review (QLR) report written by Defense Department experts in 2011, the full extent of the F-35's troubles become apparent. A total of 13 costly design problems were found ranging from moderate to severe. The five main issues found by the report were with the : HMD system, fuel dump subsystem, integrated power package, arresting tailhook system, and a classified issue which is almost certainly stealth. Other problems included software and reliability issues. In light of these design problems, this article will examine the F-35's airframe and systems in its current state with the goal of determining the true effectiveness of the F-35 as a dogfighter. An excellent dogfighter must exemplify the following qualities: survivability, maneuverability, and lethality. After the current F-35 design is evaluated on the aforementioned qualities, a recommendation of potential design improvements will be made. The goal of these improvements is to enhance existing capabilities in addition to mitigating potential problems with the current design at minimal added cost.

Survivability (Stealth Characteristics of the Current F-35 Design)

The key component of Lockheed's claim that the F-35's has high survivability lies in its all aspect stealth design; electronic jamming and missile countermeasure systems are used in conjunction with its stealthy airframe to further augment the F-35's survivability. However, if the F-35 is not as stealthy as the Lockheed design team assures the U.S Government, then pilots will face the increased risk. The Quick Review analysis seems to come to the conclusion that the F-35 is not as stealthy as promised. Though the word stealth is not technically used in the unclassified version of the report, the wording regarding the "classified" issue clearly indicates stealth is a problem. The following excerpts from the QLR report support the argument that the unmentioned classified issue is related to poor in low observable performance.

The OA OT-IIE report cited unsatisfactory progress towards meeting performance requirement for the air-to-surface (A/S) attack mission capability and survivability. The chief concern cited in the report was the lack of legacy-quality night vision capability…as well as certain classified issues. - page 4

The operational testers cited unsatisfactory progress and the like hood of severe operation impacts for survivability, lethality, air vehicle performance, and employment. These conclusions were driven by certain classified issues… - page 4

The OA report cited specific concerns related to the EA [ electronic attack] performance for suppression and defeat of enemy air defenses as well as classified lethality and survivability issues. - page 5

Arguments regarding the F-35's stealth or lack of stealth capabilities have been long and brutal. The findings of the QLR report have significantly bolstered the argument that the F-35 is not nearly as stealthy as Lockheed claims. Stealth is the cornerstone of the F-35's defense and the defining characteristic of 5th generation fighters. The exact magnitude of how much F-35's stealth qualities have been compromised is omitted from the report. Even a slight increase in a plane's radar cross section (rcs) can make the difference between life or death for a pilot. All aspect stealth is especially vital for deep strike missions within an enemy country equipped with a sophisticated Integrated Air Defense System (IADS).

Example: Detection ranges for following rcs sizes using Russian 55Zh6 Nebo UE Tall Rack Radar. This radar can be utilized in the highly capable SA-21 (S-400) SAM system. (Data from APA, 2012)

10 m^2 Detected at 300 nautical miles

1 m^2 Detected at ~160 nautical miles

.01 m^2 Detected at 100 nautical miles (Estimated rear of F-35)

.001 m ^2 Detected at 50 nautical miles (Estimated Rear of F-22)

.0001 m^2 Detected at ~30 nautical miles

Note: The distance in which an aircraft can penetrate an airspace guarded by an IADS is dictated by its rear rcs rather than its forward stealthier rcs. With swift maneuvering, the side rcs will be exposed for an extremely short duration.

Due to the classified nature of the issue, the non-classified version of the QLR report does not discuss what aspects of the F-35 airframe fail to scatter radar signals away from the source. After reading much of the publicly available literature on possible stealth deficiencies within the F-35's design, I've come to a similar conclusion to Dr. Kopp of Air Power Australia. Although the F-35 makes extensive usage of planform alignment in its design as well as incorporating a number of stealthy features such as diverterless supersonic inlets (DSI), the F-35 design is unusual among previous stealth aircraft because of the curvature featured on its lower fuselage.

Image 2: The curvature elements incorporated on the lower fuselage of the current F-35 design likely hinders its stealth performance. It is probable that these curves are responsible for the poor stealth performance noted in the QLR report. If latter F-35's produced do not feature these curves, it is likely that this was the case. (Image Credit: Air Power Australia, 2009)

The following images and analysis in between them are from Air Power Australia.

"X-35 Dev/Val prototype (above) vs F-35 SDD AA-1 (below). The clean wing fuselage join and flat low curvature lower fuselage of the X-35 had the potential to yield quite good beam/side aspect radar signature, but the revised SDD design discarded this arrangement in favour of a much inferior contoured design, clearly intended to accommodate the larger weapon bays. While the F-35 SDD engine inlet arrangement is superior to the X-35 Dev/Val prototype inlet design, the gains in the forward sector cannot overcome the performance losses incurred in the beam/side aspect sectors" - Air Power Australia, 2009 (Images via Air Force Link)

While I agree with Dr. Kopp's hypothesis regarding the curvature within the lower fuselage compromises the F-35's stealth performance, I disagree on the extent in which these curves hinders the F-35's low observable characteristics e.g. Kopp argues that the F-35 is less stealthy than the three decade old F-117. According to Global Security, the F-35 is supposed to have an estimated rcs of .0013m^2 while the venerable F-117 has an rcs of .025m^2. (F-117 figure: Richardson, 2001) Even if the F-35 has an rcs ten times larger than promised, it would still be twice as stealthy as the venerable F-117. That said, if the F-35's stealth design was compromised to this extent (10 times larger than promised) it would pose a serious risk for F-35 pilots. (REF NOTE 1 below) The F-117 was retired in 2008 because it was no longer stealthy enough to penetrate the airspace of countries utilizing an modern IADS (its stealth coatings were also inefficient and costly to maintain).

Note 1: The usage of ten is an arbitrary number used to prove an argument and is not based on empirical fact. The extent in which the F-35's airframe is compromised compared to promised specifications is unknown to the public. However, such an estimate is within the realm of possibility. Planform alignment is an extremely unforgiving technique of lowering a plane's rcs. If the flight surfaces of the aircraft do not align with one another at the exact intended common angle, the volume of radar signals sent back to the source is increased considerably.

Image 5: An example of planform alignment utilized in the F-35's design. Note how the vertical stabilizers and the fuselage slides are curved at the same angle. The resulting effect of planform alignment is the oriented flight surfaces of the aircraft shape and focus radar energy away from the source. In order to achieve all aspect stealth, all of the flight surfaces within the airframe must be utilized to this effect. (Image Credit: Lockheed Martin, 2004)

Image 6: Planform alignment in use with the Raptor. With the exception of the YF-23 prototype, the Lockheed F-22A is the stealthiest aircraft ever designed due to its extensive usage of planform alignment. The Raptor has an estimated frontal rcs of .0001m^2 (-40 dBSM). Meaning that the Raptor has a radar signature 13 times smaller than the promised rcs of the F-35. (Image Credit: History Channel, 2008)

The QLR indicates that measures to improve the F-35's stealth performance are underway but they specifics are not specified in the unclassified version of the report. Presumably, such details are included in the classified version.

"The QLR team evaluated the classified concerns and determined that while program plans were in place to address those risks the aforementioned concerns with the HMD and aircraft maneuverability still held." -page 5

Maneuverability

A premier dogfighter must have excellent maneuverability. There are several factors that determine an aircraft's maneuverability. In nearly every aspect of measuring maneuverability, the F-35 falls short relative to its peers. An aircraft's thrust to weight ratio is often indicative of the aircraft’s overall agility and how well the aircraft performs in vertical maneuvering. This graph shows the following aircraft with 50% internal fuel on full afterburner and equipped with a full air-to-air load out (for their respective countries e.g. F-15 with 6 AIM-120D missiles and 2 AIM-9X missiles). These calculations also included the weight of the aircraft's cannon and cannon munitions. (e.g. F-35A with 182 PGU-32/U 25 mm cannon rounds that weigh 493g each = 89.729 kg of cannon munitions) Every expense was undertaken for the purpose of these calculations. Data used for these calculations was taken directly from the manufacturer when ever possible.

Thrust to Weight Ratio of Selected Fighter Aircraft

F-15C = 1.203 [equipped with 940 PGU-20 A/B 20mm cannon rounds with M61B (technically should have been M61A which is 600 pounds heavier), 6 AIM-120D missiles, and 2 AIM-9X missiles)

F-22A =1.26 (equipped with 480 PGU-20 A/B 20mm cannon rounds with M61B cannon, 6 AIM-120 missiles, 2 AIM-9X missiles)

F-35A = .98967 (equipped with internal GAU-22/A cannon, 182 25mm x 137mm PGU-32/U rounds, 4 AIM-120D missiles)

F-35C = .86609 (weight for proposed gun pod unknown thus weight of cannon and ammunition added, and 4 AIM-120D missiles)

Su-30 MIK = 1.208 (equipped with AL-31 M1 standard engines, 6 R-27 missiles, GSh-301 cannon, 150 AP-T 403g shells)

Su-35 BM = 1.136 (equipped with 6 R-27 missiles, GSh-301 cannon, 150 AP-T 403g shells)

The other important determinant of maneuverability is wing loading or the ratio of the weight of an airplane to its wing area. (Princeton, 2012) In this measurement of maneuverability, the F-35 is also deficient relative to its peers. Generally speaking, an aircraft with a high wing loading is not maneuverable as an aircraft with a low wing loading. For example, the highly maneuverable F-22A has a wing loading of 77 lb/ft² (375 kg/m²). In contrast the F-35A has a wing loading of 91.4 lb/ft² (446 kg/m²). In the words of the influential think tank, the RAND corporation, the F-35 is double inferior in the thrust loading (similar to thrust to weight ratio calculated by weight/thrust vs thrust/weight) and wing loading criteria.

"F-35A is 'Double Inferior' relative to modern Russian/Chinese fighter designs in visual range combat. [The F-35 has] Inferior acceleration, inferior climb, inferior sustained turn capability. Also has lower top speed. Can't turn, can't climb, can't run." - RAND, 2004

Image 8: Wing Loading vs Thrust Loading for modern fighter aircraft. (Image Credit: Rand, 2004) NOTE: To any perspective RAND employee I could not find the terms of use for the ppt. Should a valid RAND employee desire the image to be removed it will be. Thus, please don't sue me. Its not worth your time and money! :) Thank you.

Take a deep breath we’re not done with maneuverability issues yet. Keep in mind, the findings of the RAND report merely states the effect of the basic design specifications of the intended airframe. The Lockheed design team knew full well how maneuverable the finished F-35 would be. These inherent design choices such as the total wing area on the F-35 cannot be changed through incremental upgrades. Rather, these design features are permanent and are not liable to change. So what was Lockheed thinking? The JSF program requirement called for a multipurpose aircraft capable of both air to air and air to ground interdiction missions. Due to the nature of the JSF requirements, it became clear from the onset that the F-35 would not be as maneuverable as its purebred dogfighter cousin, the F-22A. Several design compromises were undertaken to give the F-35 added air to ground capabilities at the expense of air to air capabilities e.g. maneuverability.

In essence, the lack of maneuverability was planned. The linchpin of the F-35’s success now lies on a new technology, the Helmet Mounted Display or HMD. Lockheed hopes that the Second Generation HMD will mitigate the lack of maneuverability in the F-35 design. At the moment, First Generation HMD’s are already in use within advanced generation 4 fighters (4.5 gen.) such as the Eurofighter Typhoon. More details on the significance and role of a HMD under lethality section.

However, the less than commendable expected maneuverability standards are not even being met at the moment. The QLR notes extensive maneuverability issues with the current jets undergoing testing. Current F-35 test planes fail to meet even the mediocre promised maneuverability standards. One of the major problems the jets are now experiencing is extensive buffeting.

Aerodynamic buffeting is a vibration (sometimes violent) that is felt in the airframe and controls of an aircraft. It is brought on by the separation of the boundary layer of air that normally flows along the wing or tail. It is usually associated with slow speed and high angle of attacks, but can also be brought on by high (near-supersonic) speeds as well. – (I don’t like referencing Wikipedia and have never done so before. However, they provided the most comprehensible explanation without too much use of verbiage. For more detailed information, NASA has published a number of studies relating to buffeting)

According to the QLR, when the test planes attempt to execute maneuvers beyond 20 degrees angle of attack, buffeting sets in. Buffeting is interfering with the HMD system causing further concerns. Though in initially alarming, buffeting is a fairly typical occurrence that is usually ironed out through extensive testing. Both the F-22A and F/A-18E prototypes experienced higher than anticipated buffeting while undergoing flight testing. The QLR reports that measures are being undertaken to remove the buffeting issue.

Lethality

Image 9: F-35B testing a weapon bay containing a mock up of a AIM-120 C-5 missile. The current design of the weapons bay featured on the F-35 allows for four of the medium sized AIM-120C or D variants. The F-35 can carry more missile externally at the cost of an unstealthily rcs. (Image Credit: Lockheed Martin via The Aviationist, 2012)

Now that we’ve examined the F-35’s maneuvering capabilities, it is now possible to determine the lethality of the aircraft in terms of air to air capabilities. Two different types of engagements exist between fighter aircraft: beyond visual range engagements (BVR) situations or within visual range (VR) combat situations. With the advent of radar guided missiles in the mid to late 1950s, beyond visual range engagements became possible. Prior to guided missile technology, pilots fought brutal close range engagements decided by positioning with an eventual a gun kill e.g. World War I, World War II, and Korean War. The first conflict to make extensive usage of radar guided missiles was Vietnam. (REF NOTE 3)

It is hoped that the HMD featured on the F-35 will mitigate its lower maneuverability. (Refer to F-35 sensors and avionics below for more information) Ultimately, employment of an HMD will only mitigate the F-35's mediocre maneuverability performance. It does not change the fact that F-35 relies too much on missiles. Despite the advancements made in bvr missiles like the AIM-120D, the counter measures for such missiles has evolved to keep pace with radar guided missiles. (e.g. electronic counter measure systems, towed decoy systems, use of infrared search and track systems to detect incoming missiles, etc.) The following is directly taken from RAND.

Since the advent of BVR missiles, 588 air-to-air kills have been recorded by BVR-equipped forces

– 24 have been BVR

Before “AMRAAM era,” (1991) only four of 527 kills were BVR

Since 1991, 20 of 61 kills have been BVR

U.S. has recorded ten AIM-120 kills

–Four not Beyond Visual Range

–Fired 13 missiles to achieve 6 BVR kills Pk = 0.46*

–Iraqi MiGs were fleeing and non-maneuvering

–Serb J-21 had no radar or Electronic Countermeasures (ECM)

–US Army UH-60 not expecting attack; no radar or ECM

–Serb MiG-29 FULCRUMS had inoperative radars

–No reports of ECM use by any victim

–No victim had comparable BVR weapon

–Fights involved numerical parity or US numerical superiority

Even the most modern bvr missile in the U.S arsenal, the AIM-120D, probably has an actual pk around .5 vs enemy fighters equipped with an advanced missile warning systems and jammer pods like the KNIRTI SAP-518 featured on the Su-30 MKI (keep in mind, the 100 nautical mile capable AIM-120D is arguably the best air to air missile in the world). To take matters worse, the F-35's internal weapons bay holds can only accommodate a total four AMRAAMs (AIM-120's) missiles. In air to ground missions the F-35 only carries two air to air missiles. This is compared to the F-22A which carries eight air to air missiles.

I wake up in a cold sweat at the thought of the F-35 going in with only two air-dominance weapons," -Air Force Major Richard Koch

Now that the doom and gloom bit is over, the F-35A Lightning II has several advantages that put it far ahead of any 4.5 generation fighter. Even if the stealth characteristics are not as good as Lockheed initially promised, its virtually assured that the F-35 will have first look and first kill capability vs any 4.5 generation fighter. F-35 pilots will dictate the terms of engagement as they will see enemy jets with their powerful AN/APG-81 AESA radars long before they are detected. The avionics and sensors alone give the F-35 a tremendous edge as they are an entire generation ahead of their 4.5 generation rivals. (e.g. AN/APG-81 AESA, AN/AAQ-37 Distributed Aperture System (DAS), Electro-Optical Targeting System, HMD, etc.) Because of these advantages, the F-35's can quickly ripple fire their load of four AIM-120D's and leave the engagement zone without heading towards the merge and initiating a visual range dogfight if the pilot desires.

In a visual range engagement with a 4.5 generation fighter, the F-35 still maintains the edge. Although the Lightning does possess exceptional maneuverability, its sensors provide an excellent spherical all aspect missile defense. Given its already difficult to detect radar signature (would be weak radar and IR signature for missiles), these countermeasures should make short work of any missiles have have managed to achieve lock on to the F-35. Utilizing off-boresight missiles will reduce the F-35's deficiency stemming from a lack of maneuverability. (Ideally high maneuverability should be utilized in conjunction with off boresight missiles e.g. F-22A) The only trouble the F-35 would face in a dogfight with a 4.5 generation fighter would be positioning itself for a gun shot due to its lower maneuverability. USAF pilot training is arguably the best in the world with the possible exception of the Israeli Air Force. For example, the Air National Guard requires F-16 to fly 247.2 hours per year (Global Security, 2012) This is fairly typical as the average logged flight hours for USAF fighter pilots lies between 250-300 hours. (19th Air Force, 2012). In contrast, Russian Air Force pilots typically log slightly more than 100 hours each year. (Fighter Pilot Academy, 2003). Chinese fighter pilots in the PLANAF fly 200 hours per year. (RAND, 2011) Historically, excellent pilots who know how to position their aircraft, even if its a far less maneuverable than their opponent's aircraft, win consistently in visual range gun engagements.

The increased emphasis put on comparisons between the JSF and 4.5 generation fighters stems from the fact that despite the increased proliferation of 5th generation fighter designs, the 4.5 generation fighter will still be the principle adversary the F-35 is likely to encounter en mass for the next two decades. The only other countries with 5th generation designs currently undergoing flight testing outside of the United States, China and Russia, will still have the bulk of their Air Forces comprised of 4th or 4.5 generation fighters. An in depth look at how the F-35 compares to the PAK FA will be out next week. Generally speaking, the current F-35 design will face much more difficulty from other 5th generation threats. Due to their lower radar cross sections, the PAK FA and J-20 will be able to get much closer to the F-35 before being detected. The F-35 will have less time to react vs 5th generation threats and subsequently might be forced into a visual range engagement as its lower agility prevents it from fleeing. The F-22A would not experience these difficulties due to its increased stealth, high agility, and superior maneuverability.

Principle F-35 Sensors and Avionic Systems

AN/APG-81

Image 10: Although not as capable as the AN/APG-77 utilized in the Raptor, the AN/APG-81 AESA radar will still grant the F-35 first look capability against its opponents in addition to mapping ground targets. Due to the F-35's smaller nose, a total of 1,200 transmit receiver nodes (TR) will be featured in the array as opposed to the F-22A's estimated 1,500 TR nodes. (DoD, 2001) Generally speaking, the more TR nodes featured in a radar, the detection range it has. The AN/APG-81 will also help the Lightning jam and track other aircraft's radars. "Because AESA radars have high power, speed and sensitivity, they are also ideal tools for electronic warfare. Threat jamming, protection and countermeasures can be an integral part of the AESA mission suite, rather than a separate system provided by the host platform." - (Northrop Grumman, 2006) The AN/APG-81 has already been able to jam and track the F-22A's radar even when set to low probability intercept modes.

AN/AAQ-37 Distributed Aperture System (DAS)

The DAS coverage will greatly assist F-35 pilots in threat identification and targeting information.

Electro-Optical Targeting System

Image 11: The EOTS is a technological marvel that will greatly enhance the F-35's capabilities by providing FILR and IRST capabilities. The IRST system will be especially useful in countering 5th generation threats like the PAK FA and J-20 due to their poor IR shielding qualities of their rear aspects. You can see the faceted glass covering of the EOTS mounted below the nose on the F-35. "The low-drag, stealthy EOTS is integrated into the Lightning II's fuselage with a durable sapphire window and is linked to the aircraft's integrated central computer through a high-speed fiber-optic interface...The EOTS uses a staring mid-wave 3rd-generation forward-looking infrared that provides superior target detection and identification at greatly increased standoff ranges. EOTS also provides high-resolution imagery, automatic tracking, infrared search and track, laser designation and rangefinding and laser spot tracking. As the world’s first and only system that shares a Sniper Advanced Targeting Pod and IRST systems legacy, it provides high reliability and efficient two-level maintenance." - (Lockheed Martin, 2012)

Second Generation HMD

Image 12: If the technical problems are fixed and the second generation HMD works as per specifications, the F-35 will be significantly more lethal in visual range engagements. Pilots will use the HMD featured on the F-35 to gain missile lock by simply looking at targets. Use of the GAU-22/A 25mm cannon also becomes easier as the gun sight can be linked to the HMD display. Relevant flight data will also be easily accessible via the HMD meaning the pilot can spend less time interacting with consoles within the cockpit. In effect, the situational awareness of the pilot is greatly increased due to the use of an HMD. With the use of these added capabilities, it is hoped the F-35 would be able to defend itself in a VR engagement with an enemy fighter despite its lower maneuverability.

Recommendations

Although capable, the current F-35 design will encounter difficulty when facing 5th generation opponents. (Even footing is not acceptable, U.S must work to be ahead of potential adversaries) As mentioned previously, 5th generation fighters will not be as common as 4.5 generation fighters but the potential threat still exists. A few hundred 5th generation fighters will likely be fielded outside of the United States in the coming decade. It is important to understand no amount of upgrades will make the F-35 equal to the Raptor. Inherent design features will constrain certain growth paths of future modifications. However, with the right modifications, the F-35 can maintain a sizable edge vs other 5th generation fighters. At the moment three rectifiable factors will weaken the F-35s performance against other stealth fighters: low missile capacity, low agility, and HMD issues. The following will seek to rectify these issues.

(1) If HMD difficulties persevere, U.S designers should consider contracting technical advisers from Elbit systems, the first Western based designers of high quality HMD's. The Israeli based Elbit systems has had more experience in designing and producing HMD systems than any U.S based corporation. Given that the Israeli's are already scheduled to receive the F-35, any technology transfer or classified system issues shouldn't be a major hindrance. It might be prudent to keep a potential contract from Elbit systems low key to avoid public relations difficulties (e.g. loss of faith in domestic ability to produce high end technological systems).

(2) Conventional installation of missiles on hardpoints outside of internal bays will compromise the F-35's stealth outline. The internal weapons bays have a finite amount of space. Block 5 standard F-35's will be capable of holding a total of 6 AIM-120D missiles internally instead of 4 due to new optimized reconfiguration of internal missile racks. The entire F-35 fleet will be of the Block 3 standard in 2017 according to the QLR report. However, it did not specify when the entire fleet would be of the Block 5 standard (presumably after 2017). In the mean time, a short term low cost solution needs to be explored to bridge the gap. Development of an conformal low observable externally mounted enclosed missile pod should be considered. Ideally, the proposed weapons pods would not significantly jeopardize the F-35's low observable rcs and would allow the platform to carry more missiles. The development of such a pod should not be cost intensive. A low observable gun pod has already been developed for the F-35B and F-35C variants. Planned upgrades for the F/A-18E Super Hornet include a missile pod similar in nature to this proposal.

(3) In terms of solutions to rectify maneuverability issues, low cost options are insufficient to mitigate the problem. Wing loading issues cannot be fixed by upgrades as they are part of the aircraft's fundamental design. The only way to improve wing loading on the F-35 is to increase its wing area (which is not going to happen) or to reduce its weight. Currently, the QLR report notes that the Lockheed design team is fighting to keep the weight down to specifications. Any significant reduction in weight seems unlikely at this point. The only path forward is to develop an even more powerful engine for the F-35. Although the current F135 engine is the most powerful engine ever mounted on a fighter aircraft, the engine is insufficiently powerful for the F-35's needs. Adding a second engine into the design is not practicable at this point in development. An upgraded engine would increase the F-35's thrust to weight ratio and thrust loading characteristics. This would translate to increased vertical maneuverability and increased agility for the airframe. Any upgrade to the F135 is likely to be cost intensive but will be worth pursuing. Against a 5th generation threat, the F-35 is likely to enter VR combat situations, history has repeatedly shown maneuverability will play a pivotal role in this situation regardless of new technology such as the HMD. Exceptionally powerful engines have made the difference between success and failure for fighter aircraft. This truth is especially profound for single engine fighters like the F-35. (e.g. F-8 Crusader, a single engine fighter renown for its excellent maneuverability stemming from its powerful engine relative to its opponents.)

In conclusion, the USAF must make due with what it is currently scheduled to procure. The production line of the F-22A has ended. For better or for worse the future USAF will be largely comprised of F-35's for the next three decades. It is projected that Defense spending will decline over the next several years making any new sizable procurement programs unlikely. With certainty, it can be said that the F-35 will experience at least some of the budget cuts to come (which will likely result in the loss of a few hundred planes). It is of national imperative that the remaining fleet of F-35's are as capable as possible. The funding the DoD is scheduled to receive must be used intelligently e.g. pursuit of low cost but effective solutions. If the aforementioned proposals are put into place, the F-35 has a good chance of securing U.S interests even in the face of 5th generation threats.

Image 13: F-35B equipped with low observable missionized gun pod. Note the pod's triangular nose that allows it to fit in between the openings of the weapon bay doors. (Image Credit: Lockheed Martin, 2012)

Image 14: Planned enclosed weapons pod for F/A-18E. The missile pod mentioned in this proposal would be similar. Because the F-35A does not require a cannon pod (internally mounted GAU-22/A), an enclosed missile pod could be fitted between the weapon bay doors. It might be possible to mount an enclosed weapon pod on the wings of the F-35 should the space between the bay doors prove to be insufficient. (Image Credit: Boeing, 2010)

NOTES

NOTE 2: Advanced IR guided missiles such as the AIM-9X will be used to achieve spectacular 90 degree off-boresight shots. The AIM-9X missile can even be launched prior to engaging the target and guided to the target via the HMD. In addition to these features, AIM-9X also utilizes thrust vectoring (jet vane control) granting it exceptional maneuverability. With the addition of a new IR seeker system more resistant to jamming than its predecessors, the AIM-9X is likely the deadliest air launched IR guided missile in the world. (AIM-9X pictured below)

NOTE 3: Prior to this point, U.S strategic planners hypothesized the days of close in visual range gun engagements were largely over. The gun was obsolete. Thus, aircraft no longer needed manuverabity to position themselves for a gun kill as long as they were equipped with a healthy load of air to air missiles such as the AIM-7 Sparrow and the AIM-9 Sidewinder missile. Even if a few enemy aircraft survived the barrage of beyond visual range missiles, they would be engaged by short range IR guided missiles such as the AIM-9. Aircraft such as the F-4 Phantom embodied this new theory of aerial combat. The F-4 carried a load of 8 missiles without any guns. On paper, the plan adopted by American engineers and strategists seemed sound.

However, as with most intricate plans made for a combat situation, Murphy’s Law goes into effect. During testing, the AIM-7 Sparrow had a demonstrated probability kill (pk) of 70% against target drones. In the tropical weather of Vietnam, the AIM-7 had an actual pk of 8% against the highly maneuverable Soviet built Mig 17 and Mig 21. The reliability issues of the AIM-7 meant that Vietnamese Migs were 100 times more likely to reach gun range and initiate visual range combat that expected. (RAND, 2004) The only defense left to Phantom pilots at close range was the IR guided AIM-9 missile. Though the AIM-9 preformed better than its radar guided counterpart, the AIM-9 had a demonstrated combat pk of .15 during the Vietnam War as opposed to .65 against target drones. The situation became so bleak that gunpods for the F-4 were eventually rushed into service to compensate for poor performance of the new missiles. The lives of many brave airmen were needlessly lost due to poor foresight on behalf of U.S strategic planers. U.S pilot training programs underwent major revisions following Vietnam. A new emphasis stressing the importance of utilizing maneuverability and positioning emerged in both pilot training programs and U.S Aerospace defense companies. The lesson learned was that new technology such as air to air missiles should be utilized in conjunction with older proven technologies such as the gun. The result of these reform efforts spawned the highly maneuverable F-15. The now famous F-15 is generally regarded as the finest fighter aircraft ever built with a demonstrated 104-0 kill to loss ratio. The highest of any fighter aircraft in history. The teen series of U.S fighter aircraft followed the example of the F-15.

Image 15: A USAF F-15C pictured above. The design team at McDonnell Douglas took the hard learned lessons from Vietnam and subsequently built the greatest dogfighter of the 20th century. The F-15C was the unmatched lord of the skies upon its service debut in 1976. The plane featured an ultra low wing loading, high thrust to weight ratio, and the capacity to carry eight air to air missiles in conjunction with the 6,000 round per minute 20mm M61 Vulcan gating cannon.

Sources

1) http://s3.documentcloud.org/documents/274217/dod-quick-look-ahern-report.pdf

2) http://www.acq.osd.mil/dsb/reports/ADA391893.pdf

3) http://www.rand.org/content/dam/rand/pubs/monographs/2010/RAND_MG797.pdf

4) http://www.rand.org/content/dam/rand/pubs/monographs/2011/RAND_MG915.pdf

5) http://www.ausairpower.net/APA-2009-01.html

6) http://www.ausairpower.net/APA-Rus-Low-Band-Radars.html

7) http://www.ausairpower.net/APA-2009-02.html

8) http://www.ausairpower.net/APA-2008-04.html

9) http://www.ausairpower.net/APA-JSF-Analysis.html

10) https://docs.google.com/viewer?a=v&q=cache:nEn_l-1-Y_QJ:www.aph.gov.au/Parliamentary_Business/Committees/House_of_Representatives_Committees?url%3Djfadt/defenceannualreport_2002_2003/subs/sub2.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEEShogdbc-Rg1xJ-0frXFf2pSkn-lNpEdre4tLav2kRwl1Tuflxp_g10EGHJqldaRi9dkZnSkT49PaqMYCaTpp_0ar9D7B-RsD4CyVutzoSmutus_ahlBfDuU21Guro_cRUxowfeb&sig=AHIEtbRFIbVhX1hCChoce0uBLA-rUW-iEA&pli=1

11) http://s3.documentcloud.org/documents/274217/dod-quick-look-ahern-report.pdf

12) http://www.scribd.com/doc/67289275/20mm-PGU-28-A-B-SAPHEI

13) http://www.gdatp.com/factsheets/A118_GAU-22.pdf

14) http://www.atk.com/Products/documents/108104_04_25mm%20ds.pdf

15) http://www.dtic.mil/ndia/2006garm/thursday/maher.pdf

16) http://www.lockheedmartin.com/us/products/f35/f-35a-ctol-variant.html

17) http://www.f-16.net/f-16_armament_article5.html

18) http://www.defensenews.com/article/20100826/DEFSECT01/8260301/P-W-Parries-GE-s-F-35-Thrust-Claims

19) http://www.rfidjournal.com/article/articleview/8478/1/1/

20) http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%253a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%253a261f21c4-19ea-40e0-a756-ed0491972939&plckScript=blogScript&plckElementId=blogDest

21) http://www.flightglobal.com/news/articles/aero-india-video-boeing-reveals-advanced-super-hornet-options-352926/

22) http://theaviationist.com/tag/conformal-fuel-tanks/

23) http://www.sukhoi.org/eng/planes/military/su30mk/lth/

24) http://www.sukhoi.org/eng/planes/military/Su-35/

25) http://www.flightglobal.com/blogs/the-dewline/2008/11/usaf-pilot-describes-iaf-su30m.html

26) http://www.flightglobal.com/news/articles/video-us-red-flag-pilot-candidly-assesses-su-30mkis-limits-rafales-dirty-tricks-318506/

27) http://articles.janes.com/articles/Janes-Electronic-Mission-Aircraft/N011M-Bars-Russian-Federation.html

28) http://theaviationist.com/2012/02/23/f-35-gun-pod/

29) http://theaviationist.com/2012/03/28/f35b-aim-120b/

30) http://theaviationist.com/2012/02/23/progress-report-f-35/

31) http://www.wired.com/dangerroom/2011/12/joint-strike-fighter-13-flaws/

32) http://evangelidis.gr/embry/F35LO-ShortReport-HTML.htm

33) http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA450990

34) http://www.randolph.af.mil/library/factsheets/factsheet.asp?id=6428

35) http://www.airforce-magazine.com/MagazineArchive/Pages/2012/February%202012/0212china.aspx

36) http://www.gao.gov/archive/1999/ns99165.pdf

37) http://www.sci.fi/~fta/ruaf-3-4.htm

38) http://www.es.northropgrumman.com/solutions/f35targeting/

39) http://www.northropgrumman.com/review/assets/review_issue_two_2006.pdf

Sunday, May 27, 2012

Upcoming/Possible Articles Summer 2012

Image 1: India's highly capable Russian built Su-30 MKI 4.5 generation fighter.

I plan to write on at least a few of the following topics:

Threat Analysis of Foreign Stealth Fighters Part II: Sukhoi PAK FA (work in progress)
F-35 Development and Performance Concerns (work in progress)
What Would an Israeli Strike on Iran Accomplish?
Keeping America's Eagles in Shape, F-15 Upgrades & Fleet Modernization
MMRCA Competition: Did India Make the RIght Choice? Part II (work in progress)
China's Cyber Warfare Capabilities
PLANAF vs IAF: comparison of capabilities & equipment
Oversized: Russia's Obsession with Massive Military Equipment (work in progress)

Please direct suggestions, concerns, and constructive criticism to either the comments section or the email address provided on my blogger profile, thank you.