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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



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. 

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2 comments:

  1. During Vietnam the USAF scored 2:1 kill ratios, even after fielding the F-4E with internal gun, the USN on the other hand went from 2:1 to 13:1 after instituting Top Gun, the USN never used the F-4E and rarely used gun pods. So obviously it was a training issue and had nothing to do with having a Gun, the question is what was the PK% for missiles used by Top Gun graduates.

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    1. Training is certainly a seldom discussed issue with respect to the relative effectiveness of a nation's fighter force. In my own experience, much of the debates online only refer to technical discussions between aircraft specifications and capabilities. I would certainly agree that rigorous pilot training is extremely important to maintaining air to air capabilities.

      "Know and use all the capabilities in your airplane. If you don't, sooner or later, some guy who does use them all will kick your ***." - Lieutenant Dave "Preacher" Pace, USN

      I have written about the importance of pilot training and the lessons from Vietnam here: http://manglermuldoon.blogspot.com/2014/06/divergent-thinking-how-best-to-employ_15.html

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