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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


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. 


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


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. 


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)  


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. 


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:

  1. Threat Analysis of Foreign Stealth Fighters Part II: Sukhoi PAK FA (work in progress) 
  2. F-35 Development and Performance Concerns  (work in progress)
  3. What Would an Israeli Strike on Iran Accomplish? 
  4. Keeping America's Eagles in Shape, F-15 Upgrades & Fleet Modernization 
  5. MMRCA Competition: Did India Make the RIght Choice? Part II  (work in progress)
  6. China's Cyber Warfare Capabilities 
  7. PLANAF vs IAF: comparison of capabilities & equipment 
  8. 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. 

Tuesday, May 22, 2012

Threat Analysis of Foreign Stealth Fighters Part I: Chengdu J-20

In early 2011 China shocked the world by unveiling its first stealth aircraft, the Chengdu J-20. From publicly disclosed statements, it became evident that few individuals within U.S intelligence community thought that China would possess a stealth fighter this early in the decade. The debut of the J-20 came only a year after The Russian Federation publicly unveiled its own stealth fighter, the PAK FA T-50, for the first time. The unveiling of the J-20 and PAK FA T-50 speak volumes of the pace of technological advancement within their respective countries in relation to the United States. The United States can no longer take its head start and former monopoly on stealth aircraft for granted. This will be a two part article that will assess the capabilities and the U.S military policy ramifications of the J-20 and PAK FA.

Image 1: Artistic rendering of Chengdu J-20 destroying a Japanese F-2 fighter. Note how the J-20 in the illustration retains the data probe on the nose of the aircraft despite the fact that the aircraft shown is in service. Data probes are only featured on prototypes or test aircraft (Image credit: Chinese Military Review)

In terms of empirical facts, very little is actually known about the Chengdu J-20. Much of the publicly available information on the J-20 is not based on hard evidence. Endless speculation abounds on seemingly basic information: How did the Chinese develop a stealth aircraft so fast?  How stealthy is the J-20? What its intended role of the J-20 as an aircraft? How much of a threat does the J-20 actually pose for U.S fighter aircraft and installations as well as the fighter aircraft of neighboring countries?  This article will seek to answer these questions with FACTS and the very best estimates made by unbiased reputable aviation experts rather than the patriotic musings of Chinese internet fanboys.

Figure 2: Crew inspecting first J-20 prototype

How Did China Obtain a Stealth Fighter So Quickly? 

'Between legal, quasi-legal [diverted], and espionage-based tech transfer, I'm sure that China has obtained most of the data available on how we build our stealthy aircraft structures and the materials involved,' the intelligence official says. 'They also have taken full advantage of our open patent system, our open engineering undergrad and grad schools, our publish-or-perish academic promotion process, and the ease with which an integrated, centralized [government] can thwart artificial, social-democratic distinctions between military, police, civil and commercial data.'” - Anonymous intelligence official reporting to Aviation Week, 2012 

The exact origins of the J-20 are shrouded in secrecy. However, it is likely that at least some aspects of the J-20's design are the result of multiple attempts at reverse engineering U.S stealth technology. China's obsession with reverse engineering has an established historical precedent dating back to the origin of the nation itself. (see blog article: Made in China? A History of Reverse Engineering for examples) In 1999 during the NATO mission within Serbia, a single F-117 Nighthawk was shot down by a surface to air missile. Following the crash, Chinese agents were dispatched to recover parts from the wreckage. 

"At the time, our intelligence reports told of Chinese agents crisscrossing the region where the F-117 disintegrated, buying up parts of the plane from local farmers," - Croatian Adm. Davor Domazet-Loso

With one glance it becomes inherently obvious that the J-20 does not look like the Lockheed built F-117 Nighthawk. The two planes utilize a different method of incorporating stealth within the airframe. (REF. NOTE 1) However, the stealth coatings found on the wreckage of the F-117 would be invaluable in determining the composition of the highly classified RAM (radar absorbent material) coatings. Another source of information regarding stealth technology came from former Northrup Grumman engineer Noshir Gowadia. Gowadia provided information relating to his work on the B-2 Spirit stealth bomber and other classified projects to a host of foreign governments including: Israel, Germany, Switzerland, and China. (ABC News, 2006) Lastly, Lockheed Martin and even the Pentagon itself are the constant victim of highly organized and sophisticated Chinese hacking attempts. It is probable that information regarding American stealth technology was obtained through Chinese cyber attacks. For example, In 2009 information was released that indicated the Pentagon was attacked by hackers from China (Journal for Strategic Security, 2011) During 2007-2008 hackers stole information pertinent to the F-35 Lightening II, the future backbone of America's stealth arsenal. 

"The intruders appear to have been interested in data about the design of the plane, its performance statistics and its electronic systems, former officials said. The intruders compromised the system responsible for diagnosing a plane's maintenance problems during flight, according to officials familiar with the matter. However, the plane's most vital systems -- such as flight controls and sensors -- are physically isolated from the publicly accessible Internet, they said… The spies inserted technology that encrypts the data as it's being stolen; as a result, investigators can't tell exactly what data has been taken." - Wall Street Journal, 2009 

"In 2009, there was a forced electronic entry into the Joint Strike Fighter program and large amounts of data were copied.  According to present and former employees at the Pentagon, the attack can be traced to China. This could mean that it would be easy for China to defend itself  against the aircraft (which many western countries expect to acquire) and, assuming the attackers have acquired enough data, they may even be able to copy parts of it.  The American chief of counterintelligence has been reported as saying that "our networks are being mapped" with reference to American flight traffic control, and also as having warned about a situation in which "a fighter pilot can't trust his radar." - Journal of Strategic Security Volume IV Issue 2 2011

China constantly tests the envelope of what qualifies as Casus Belli, an act of war, through its repeated and invasive cyber attacks on the United States. In addition to obtaining information regarding U.S stealth technology, some analysts believe China was able to get information from the Russian Mikoyan 1.42/1.44 Multi Role Fighter (MFI) program. The Mikoyan 1.44 was designed to compete with the winner of the American Advanced Tactical Fighter competition, the YF-22. Although Russia claimed the 1.44 MFI could out preform the YF-22, virtually no foreign observers agreed with that assessment. The claim that the Mikoyan 1.44 was stealthier than the YF-22 was especially dubious.

"The conclusion which can be drawn is that the MFI may outperform the Eurocanards for RCS performance if radar absorbent materials are used generously, the nose chined, the fuselage wing interface and spine blended, and internal weapons carried. It will never be competitive with the edge aligned, faceted, and chined F-22A design (or the chined and blended YF-23 ATF demonstrator). The statements emanating from Russia clearly contradict the technically evident and have been described as a transparent marketing ploy, in the context of the somewhat byzantine post Soviet defence acquisition system." - Air Power Australia, 2005

Despite the MFI's shortcomings, the J-20 bears an uncanny resemblance to the abandoned MFI prototype. Adil Mukashev, an expert on Chinese-Russian ties, asserts that Russia likely sold MFI fighter parts to China. Sources within Russia suggest that China might have gotten access to key information on the MFI design. (The Guardian, 2011)

"It looks like they got access... to documents relating to the Mikoyan - the aircraft that the Ministry of Defense skipped over in its tender to create a stealth fighter" - Anonymous Russian source reporting to The Guardian, 2011

Although both aircraft share a number of design similarities such as the tail, there are important differences between the MFI and J-20. The chined nose employed on the J-20 is characteristic of the F-22A. The trapezoidal engine inlets are also "borrowed" from the F-22A and are utilized in conjunction to the enlarged Diverterless Supersonic Inlet features from the F-35. The flat lower fuselage is also remarkably similar to the F-22A design. (APA, 2011)

Image 3: Mikoyan 1.44 MFI aircraft on debut in 1998

Image 4: The first Chengdu J-20 undergoing flight testing

It is important not to dismiss the J-20 as purely the product of fruitful reverse engineering attempts. While China has no doubt at least obtained some elements or techniques used in the J-20's design from the United States and even Russia, China's ability to create new technological solutions has rapidly improved over the last few decades. Although China's domestic ability to innovate lags behind the United States and Russia, China continues to invest heavily in its science and engineering programs. The theory that China utilized at least some degree of reverse engineering helps answer how China was able to design a stealth fighter quicker than anyone expected.  

How Stealthy is the J-20? 

The hottest point of contention between aviation experts on the J-20 is how stealthy the airframe actually is. Official radar cross section (rcs) figures for the J-20 are impossible to find due to the fact that it is in China's best interest not to release such information. That said, a massive disparity exists between the different rcs estimates for J-20. On the high rcs side estimates, some argue that the J-20 features a merely reduced radar cross section similar to 4.5 generation fighters. Comparatively, some  argue that the J-20 design boasts a very low observable designation similar to the F-22A. In order to understand how stealthy the J-20 airframe is, a better understanding of stealth is required. An aircraft given a stealth designation means that the given airframe will reflect the vast majority of radar waves away from the source and hence has a low radar cross section. It gets more complicated when multiple bands or frequencies utilized in radars are factored into the equation. (e.g. I, J, H, X band radars, etc.) Calculating the rcs of an object is a very complicated and arduous process. 

"The radar cross section (RCS) of a target is defined as the effective area intercepting an amount of incident power which, when scattered isotropically, produces a level of reflected power at the radar equal to that from the target. RCS calculations require broad and extensive technical knowledge, thus many scientists and scholars find the subject challenging and intellectually motivating. This is a very complex field that defies simple explanation, and any short treatment is only a very rough approximation...The units of radar cross section are square meters; however, the radar cross section is NOT the same as the area of the target. Because of the wide range of amplitudes typically encountered on a target, RCS is frequently expressed in dBsm, or decibels relative to one square meter. The RCS is the projected area of a metal sphere that is large compared with the wavelength and that, if substituted for the object, would scatter identically the same power back to the radar." - Global Security, 2011

The radar cross section of an aircraft is different for each side of the airframe facing the radar source. In order to qualify as an all aspect stealth aircraft (e.g. F-22A, B-2) the airframe must not reflect radar waves from all sides of the airframe. The stealth designation is variable and does not mean all stealth aircraft have the same radar cross section. Here are some examples of aircraft and their frontal radar cross section figures and estimates. 

Estimates taken from Global Security (2011 and 2012) and Illinois State University (1997) 

Conventional and reduced radar cross section aircraft 
B-52 radar cross section = 40-50 m^2
B-1B radar cross section = 1m^2
F-15C radar cross section = 5m^2

Stealth aircraft 
B-2 Spirit radar cross section =  .01m^2 (mid range estimate, lowest rcs estimate .0001m^2)
F-35A radar cross section = .0013 m^2
F-22A radar cross section =  .0001 m^2 (-40 dBSM) 

Note: size has nothing to do with an rcs figure. The 51.4 ft long F-35 has an rcs 13 times larger than the highly refined 62ft long design of the F-22A. Yet, both aircraft qualify for the stealth designation. It is also worth noting that there are other components to stealth aside from an aircraft's radar signature. Stealth aircraft also have to reduce their include infrared (IR), radio frequency, and even visual signatures.

Image 5: This image highlights the extensive stealth features Incorporated within the J-20 design. (more details given below)

Now that a better definition of stealth has been provided, an analysis of the J-20's stealth potential can be given. First and foremost it should be noted that the J-20 design features canards. With the exception of the J-20, no verified full aspect stealth aircraft design features canards e.g. F-22A, YF-23, F-35, PAK FA. Russian and American Aerospace companies choose not to incorporate canards for a simple reason, they have terrible stealth characteristics. (Sweetman, 1997) Incorporating canards inherently limits the J-20's stealth qualities from a frontal aspect. Despite the fact that planform alignment is used in regards to the canards and extensive RAM coatings are no doubt utilized, it does not change the fact that canards yield terrible stealth results. Given the usage of the two techniques listed above, the poor rcs qualities of the canards will be mitigated but not completely eliminated. Thus, any estimates that claim the J-20 is stealthier or comparable to the F-22A can be outright eliminated.

Aside from the canards however, the J-20 design retains a stealthy frontal rcs. The design of the engine inlets,  chined  nose, flat lower fuselage, sawtooth design incorporation on internal bays, and extensive use of planform alignment should reduce the airframe's frontal radar signature considerably. It is hard to say if the J-20 design qualifies for the very low observable designation of -30 dBSM or lower because of its incorporation of canards. Dr. Carlo Kopp of the Australian based think tank, Air Power Australia, conducted a very thorough analysis of the J-20. He concluded that the J-20 qualifies as a very low observable aircraft. Other aviation experts such as Bill Sweetman are more reserved. Overall, the frontal aspect of the  J-20 design has a good chance of qualifying for low observable (-20 dBSM or .01m^2) designation. It is unlikely that it is any stealthier than -20 dBSM because of its incorporation of canards.

Although the frontal aspect of the J-20 qualifies as at least for the low observable designation, the rear of the aircraft is a completely different story. The engine nozzles are completely exposed to both radar and IR detection methods. True all aspect stealth aircraft such as the F-22A shield the rear of the aircraft from detection. Unless the J-20 wants an AIM-9X shot strait up its tail pipe, China better remedy this problem.

Image 6: Rear of J-20. Note the exposed engine nozzles.

Image 7: Rear of F-22A Raptor. Note the protected 2-D thrust vectoring nozzles that both reduce the raptor's rear rcs signature as well as its IR signature.

Because the current J-20 in flight testing is likely a prototype, it is possible that the airframe will undergo numerous design changes. For example, the YF-22 went through numerous design alterations to become the F-22A. It is possible that the rear of the J-20 will be better protected on the final production version of the J-20.  Sawthooth engine nozzles will better protect the J-20 from enemy radars from the rear aspect but will not provide the same level of protection as the 2-D nozzles mounted on the F-22A.

The biggest uncertainty about the design concerns the engine exhausts, which as seen on the prototype are likely to cause a radar cross-section (RCS) peak from the rear aspect. One possibility is that a stealthier two-dimensional nozzle will be integrated later in the program:  however, the nozzles on the current aircraft show some signs of RCS-reducing saw-tooth treatment, suggesting that the PLA has accepted a rear-aspect RCS penalty rather than the much greater weight and complexity of 2-D nozzles.” - Bill Sweetman and David Fulghum, 2011 

"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

What its intended role of the J-20 as an aircraft? 

The most mysterious questions regarding the J-20 is what is its purpose? China has not provided an answer as to what the J-20's intended role is. The most compelling theory as to what the role of the J-20 will be is provided by Dr. Kopp. Kopp believes that the J-20 will act as a theatre range strike bomber similar to the proposed FB-22 while maintaining the ability to dogfight. The J-20 is an extremely large aircraft relative to other 5th generation fighters. No official spesifications have been released but estimates suggest the aircraft is nearly 70 feet long. (Some estimates put the J-20 at 75 feet long)

"The J-20 is a single-seat, twin-engine aircraft, bigger and heavier than the Sukhoi T-50 and the F-22... which would suggest a takeoff weight in the 75,000-80,000-lb. class with no external load. That in turn implies a generous internal fuel capacity. The overall length is close to that of the 1960s General Dynamics F-111, which carries 34,000 lb. of fuel." -Global Security 2011

Image 9: With such a large supply of internal fuel, the J-20 could have an unrefueled range of 1,000-1,500 nautical miles. If the J-20 features supercruise, in addition to its high fuel capacity, its combat radius will be extensive. According to the DOD, in a war with the United States, China would likely seek to maintain control over areas up to the second island chain shown on the map. An extended range stealth strike aircraft like the J-20 would fit well into this role. The J-20 would penetrate U.S integrated air defense systems (IADS) and hit U.S installations using its stealthy frontal rcs.  (Image credit: Air Power Australia, Kopp, 2011)

Although the J-20 will likely preform bombing missions, it retains the ability to dogfight. The J-20's incorporation of canards suggests that maneuverability was a key requirement of the design. Although canards will damage the J-20's stealth prospects as mentioned earlier, the J-20 will have excellent angle of attack capabilities and turning abilities because of the incorporation of canards.

How much of a threat does the J-20 actually pose for the United States and its allies? 

With the J-20 likely to enter service between 2017-2019, the United States must be prepared. Before possible and active U.S responses are analyzed its worth mentioning several key potential problems Chengdu is likely to face in the development of the J-20. First an foremost the biggest concern with the J-20 lies in its engines, the Russian designed AL-31F. The AL-31F was designed for use in the Su-27. China has struggled to domestically produce capable jet engines for its growing fighter fleet and heavily relies on Russian exports. The second prototype currently undergoing flight testing, the 2002 aircraft, is said to feature the domestically produced WS-10 which is a copy of the AL-31F. Its unclear if the WS-10 is capable of super cruise or produces enough thrust to keep the large J-20 airframe maneuverable. What is clear is that the WS-10 has experienced numerous performance issues. (Axe, 2011)  

Another key problem with the J-20 and Chinese fighters in general lies in the lack of capable avionics. Chinese built avionic systems are woefully far behind their American and Russian counterparts. Its unclear if the Chinese have actually been able to produce a capable active scanned electronic array (AESA) radar. The domestically produced J-10 features a mechanically scanned radar comparable to U.S fighter radars used in the early 1990s. (Sinodefense, 2009). For example, the radar used in the J-10 can track 10 targets while engaging 4 targets vs the F-15's AN/APG-63 (V) 1 radar built in the 1990s can track 14 and engage 6) Although stealth is the primary qualifier for the designation of a 5th generation fighter, other important qualifiers such as avionics matter. Without a capable AESA radar system, sensor fusion, or and HMD the J-20 will not be able to fullly capitalize on its stealth design. With those limitations in mind, a threat analysis of the J-20 will follow. 

U.S Military Recommendation I: Harden Pacific Airbases 

With a stealthy frontal rcs of around -20 dBSM (.01m^2), the J-20 will likely be able to avoid detection long enough for it to come into weapons range of U.S bases. Given its range and considerable payload capacity, the J-20 could pose a major threat to U.S airbases. If the J-20 is outfitted with long range low observable air to surface missiles the J-20 could pose an even greater security risk.  At the moment, few U.S airbases within the area are hardened (with the exception of Kadena AFB which has limited protection of 30 hardened aircraft shelters). This means that U.S airbases are vulnerable to attack if U.S fighters on patrol fail to intercept an incoming J-20 strike force. The largest U.S airbase in the Pacific region, Anderson AFB, is particularly noteworthy. Anderson AFB is barren in terms of hardened aircraft shelters and runways. Although it's more than 1,500 nautical miles from China, it is no longer safe from attack due to the extended range of the J-20. If flight operations are no longer possible from Anderson AFB, any war effort with China would be severely crippled from the U.S perspective. Due to its poor rear stealth characteristics, the J-20 might be open to reprisal after striking U.S bases but by that point the damage has already been done. 

The United States MUST harden the runways and install hardened aircraft shelters on all of its airbases within the Pacific region: Osan (SK), Kunsan (SK), Misawa (Japan), Yokota (Japan), Iwakuni (Japan), Kadena (Japan), and Anderson (Guam). Hardening U.S airbases in the region would not only mitigate the damage from a J-20 strike force, but also it would make U.S airbases more resistant to the hundreds of medium range and theatre range ballistic missiles China is deploying in the region. GPS jamming equipment is also suggested to deny usage of China's GPS system as to reduce the effectiveness of Chinese GPS precision guided munitions

Image 10: B-2 Spirit escorted by F-22A raptors from Anderson AFB Guam 

U.S Military Recommendation II: Improve IADS systems in Pacific Region

The United States must continue to upgrade and deploy Patriot missile batteries and other capable surface to air missiles in the Pacific region to protect its land based assets. Upgrades to enhance the Patriot PAC-2 system's effectiveness towards low observable targets are already underway with the GEM-T upgrades (Raytheon, 2011). Further upgrades to assist in the targeting of low observable aircraft should be considered for the PAC-2 system. PAC-3 Patriot batteries should be deployed in conjunction with the upgraded PAC-2 systems to protect U.S Pacific airbases from Chinese deployed medium range ballistic missiles.

Image 11: The MIM-104 Patriot PAC-2 is the principle surface to air missile system of choice for several western nations. Over the years the Patriot has undergone several upgrades and modifications to keep the system relevant and increase its lethality. Current PAC-2 Patriot missiles have a range of 160 km (100 miles). However, keep in mind the J-20 has a lower frontal rcs, its unlikely that the PAC-2 would be able to detect and engage the J-20 until it was a great deal closer e.g. ~30-40 miles out. The system would have a better chance in shooting down a J-20 once its rear faces the Patriot's radar array. (Image Credit: Global Security)

U.S Military Recommendation III: Deploy more Raptors to the Pacific 

Image 12: The most lethal fighter aircraft ever produced, the Lockheed F-22A Raptor.

Arguably the best defense against the Chengdu J-20 is the Lockheed F-22A Raptor. From what we know of the J-20 in terms of its stealth capabilities, avionics, engine troubles, available surface to air munitions, and Chinese pilot training programs, using the technical term, the J-20 is "toast" against the Raptor. It is also worth noting that only the very best USAF pilots are selected to fly F-22A. In every category comparable, the Raptor exceeds the J-20. [Onboard oxegen generating (OBGS) issues aside of course; OBGS problems should be remedied upon the installation of back-up onboard oxygen generating systems. The entire F-22A fleet will be upgraded with the new system by 2014 at the cost of $44 million USD] - Daily Press, 2012

Currently the United States operates 184 Lockheed F-22A Raptors in active duty. A sizable portion of America's available Raptors should be permanently based in the Pacific region. From time to time Raptors train at Kadena AFB and Anderson AFB but arrangements should be made to increase the number of permanently stationed Raptors in the Pacific. I believe the 36th Operations group based at Anderson AFB fly's Raptor's but I'm not entirely certain. Raptors should be given priority for the proposed hardened aircraft shelters due to their high unit cost and low numbers.

Despite the Raptor's remarkable abilities, the USAF only has 184 Raptors and production of the Raptor has ended. Until the political motivation and financial situation changes, the U.S military will have to make due with what it has already procured. That means ingratiating and improving current 4th generation platforms such as the F-15C and F-16C into operation with 5th generation aircraft e.g. F-22A. Arrangements to upgrade the F-15C and F-15E are already underway with the installation of the new APG-63 (V) 4 radars. Because of its usage of planform alignment, the Raptor has a finite space available in its nose cone for radar upgrades. (Axe, 2012) The non-stealthy F-15C and F-15E is favorable to the F-22A in upgrade mod-ability. These new and improved F-15C's and F-15E's will work in teams with the stealthier F-22A to secure U.S interests in the region.

As currently envisioned, the F-15s would fly with extra fuel tanks and AMRAAM missiles and with radars blaring, while the F-22s, carrying less gas and fewer missiles, would turn off their radar and sneak up on the enemy for ninja-style jabs. 'Our objective is to fly in front with the F-22s, and have the persistence to stay there while the [F-22s] are conducting their [low-observable] attack,' Maj. Todd Giggy, an F-15 pilot, told  ." - Axe, 2012

Note: The reason the Raptors would turn off their radars is to insure that they cannot be jammed and tracked by enemy planes. Even with low probability intercept modes featured on the AN/APG-77 AESA radar (utilized by the Raptor), it does not provide complete protection from jamming and detection. By utilizing this innovative method, Raptor pilots can take full advantage of the stealthiness of the F-22A airframe and remain completely undetectable while F-15E and F-15C pilots with upgraded radars provide targeting information for the Raptors.

Image 13: F-15E flying in formation with F-22A at Anderson AFB.

Military Recommendation to U.S Allies: Purchase the F-35

Image 14: F-35A roll out ceremony at Eglin AFB Flordia. (Image Credit: Samuel King Jr, retrieved from Defense Media Network 2012) 

The United States Government has banned the possibly of exporting the F-22A Raptor. The next best aircraft available to U.S allies is the F-35 Lightning II. Despite the whole host of problems Lockheed is experiencing in the development of the jet, F-35 remains the best bet for U.S allies. Japan has already announced that it plans to acquire 42 F-35A's in its F-X competition. Japan might seek to order more than 100 F-35's if the jet wins its J-XX competition to replace Japan's aging fleet of F-15J's. In terms of standing on even footing with the J-20, no other aircraft currently in the competition even comes close to the F-35A. Given what we know about the J-20, a full production J-20 would likely make short work of 4 and 4.5 generation fighters without the aid of 5th generation fighters. A dogfight between the F-35 and the J-20 would be closer than a dogfight between the F-22A and the J-20. However, the F-35 is still stealthier and features better avionics and sensors than the J-20. Though it is likely less maneuverable than the J-20 (assuming China gets a capable engine for the J-20). It would be prudent of South Korea to order the F-35 for its F-X phase 3 competition. If the F-35A won, South Korea would likely order dozens of jets to supplement its F-15K "Slam Eagles" (upgraded derivative of F-15E Strike Eagle).

In conclusion, the United States and its allies should not fear the deployment of the J-20 a great deal. If the proposed U.S Military recommendations are put into effect,  the United States and its allies will be in a good position to deny Beijing  air control over the Pacific region.

RELATED READING: Threat Analysis of Foreign Stealth Fighters Part II: Sukohi PAK FA 




Note 1: The F-117 utilized first generation stealth technology composed of flat geometrically arranged panels to deflect radar waves. This method was effective in reducing the F-117's radar signature but resulted in an aerodynamically unstable airframe. The J-20 utilizes the planform alignment method of reducing an aircraft's radar signature.  Planform alignment is a more advanced method of stealth technology that allows one to construct an aerodynamically feasible airframe while deflecting radar waves. Planform alignment is achieved through arranging the flight surfaces of the aircraft in such a way that they have identical angles that reflect incoming radar waves away from the source. This technique was pioneered on the YF-22 and YF-23 designs in the Advanced Tactical Fighter competition of the 1990s. 

Image 15: F-35A with F-22A flying behind. The USAF plans to acquire a total of 1,763 F-35A aircraft to supplement its force of 187 F-22A Raptors. The USAF will maintain the largest fleet of highly capable 5th generation aircraft in the world even if a few hundred F-35A's are cancelled due to budget cuts. (Image Credit: Darin Russel, retrieved from Defense Media Network 2012)