F-35 Maneuverability Woes

The JSF program was envisioned to create a multi-role combat aircraft capable of both air-to-ground and air interdiction missions, a "strike fighter". This emphasis in dual role capabilities is directly reflected in the F-35's airframe. The F-35 lacks the maneuverability of a purebred fighter such as the F-22A or F-15C. To judge the effectiveness of the F-35 in air-to-air combat, examples from history provide insight.

The aircraft most similar to the F-35 in service with the USAF today is the General Dynamics F-16 Fighting Falcon. The F-16 has been used to great effect in air-to-ground missions during Operation Dessert Storm, Operation Enduring Freedom, and Operation Iraqi Freedom. While the USAF has drawn blood for F-16, most of the 67 kills achieved the F-16 have been done under the command of skilled Israeli pilots. The F-16 has achieved an impressive 47-0 kill ratio under the IAF. Many of these kills were achieved because of the F-16's dazzling maneuverability. This is a key difference between the F-16 and F-35.



Although the F-16 was intended to be a dual role aircraft, one of the stringent requirements of the F-XX program was for the new aircraft to feature high trust-to-weight ratio. This resulted in the F-16 being one of the earliest fighter aircraft to enter service with a thrust-to-weight ratio exceeding 1.0. The F-16's already spectacular maneuverability was enhanced further with the implication of revolutionary fly-by-wire technology. This degree of maneuverability provides the Falcon with lethal visual range combat capabilities. In contrast, the F-35 was rated as "Double Inferior" in regards to both vertical and horizontal maneuvering capabilities relative to modern Russian and Chinese fighter aircraft such as the Su-27, Su-30, Su-35, Mig-29M and Pak Fa. In fact, the RAND report went as far to say the F-35 has "Inferior acceleration,inferior climb,inferior sustained turn capability" relative to the compared aircraft. This lack in maneuverability is not something that incremental upgrades can solve over the F-35's service life. Rather, they are the permanent result of the F-35's design. Airframe design cannot be changed.


Thrust-to-weight ratios of fighter aircraft; 100% fuel followed by 50% internal fuel
All following calculations assume aircraft thrust using afterburner

F-35A .87 -> 1.07
Su-27K 1.07 -> 1.21
PAK FA* 1.19 (exact figures unknown as final version will feature different engines)
F-16C 1.095 -> 1.25
F-22A 1.08 -> 1.26


Instead of giving the F-35 a high thrust-to-weight ratio and high maneuverability, the design team at Lockheed placed their faith in Helmet Mounted Display (HMD) technology. The HMD allows pilots to literally look at a target to achieve missile lock. With the advent of off-boresight capability missiles such as the AIM-9X, pilots can look at aircraft up 90 degrees away, gain missile lock, and score a kill. If the HMD works as advertised  it could revolutionize the dogfight. However, if the HMD is not able to mitigate the extreme maneuverability of its opponents, that the F-35 is at disadvantage. The last time this much faith was placed on new technology without any back up plan was during the Vietnam War.




In the years prior to the Vietnam War the USAF developed a new theory that beyond visual range (bvr) missiles would be the future of the dogfight and that the traditional weapon of air superiority platforms, the gun, was obsolete. (RAND, 2008)It was also believed that aircraft did not need to be maneuverable as the missile would do most of the maneuvering from range.(APA, 2010) As a result, the F-4 Phantom was not maneuverable and did not feature a gun. Two missile designs were fielded by the USAF during the Vietnam War. The radar guided AIM-7 Sparrow which had a range greater than 20 miles was built for bvr engagements. The AIM-9 Sidewinder missile was designed for visual range combat and had a range of 2.5 miles. The USAF put their faith in guided missile technology and did not equip the F-4 Phantom with guns. The Pk (probability kill) of AIM-7 Sparrow missiles during tests was .70 but during combat the Sparrow had a Pk of .08. Thus, Vietnamese Migs were 100 times more likely to get within visual range and initiate a dogfigt than expected. (RAND, 2008)The Sidewinder did not fare much better with a combat Pk of .15. This spectacular lack of foresight lead to pilots being defenseless without any back up. As a result, pilots had gun pods attached to the F-4 latter in the war. In essence, the lesson learned was that new technology and tactics should always be used in conjunction with older proven technology and tactics in the event that Murphy's law comes to fruition.






The counter point to the argument that the F-35 needs maneuverability is that the F-35 is stealth and enemy fighters would not be able to get within visual range. This assumption is unrealistic. The F-35 will be able to destroy 4.5 generation threats from the comfort of bvr in all likelihood. However, the real threat for the F-35 is against other 5th generation stealth fighters such as the Pak Fa. Because of its stealth, the Pak Fa would not be detectable by the F-35 until it was within 30 nautical miles (estimate using frontal rcs) while the Pak Fa would detect the F-35 at 28 nautical miles. (APA, 2009)If both aircraft are speeding towards each other at mach 1.5 they would be on top of each other in just over 50 seconds. Visual range dogfights are MUCH more likely in the event the JSF is faced with a 5th generation opponent. In which case HMD technology better work. It would also not be out of the question for the Pak Fa to feature an HMD of its own, operational Mig-29's and Su-27's already do. The F-35 has the potential to win the fight but its going to be a lot closer than it needs to be. The F-22A has BOTH high maneuverability PLUS it will be upgraded with HMD technology.

A fight with the F-35 vs the Pak Fa will be close and will likely come down to the skills of their respective aircraft. There is one major component that rests in the F-35's favor and that is avionics, specifically the radar arrays. The Pak Fa is in all likelihood going to use a 1,500 TR AESA array. The new array will likely be an improvement of the NIIP Irbis-E or some evolution of the system in conjunction with other secondary radars. The Irbis-E has 1,500 TR nodes effectively meaning it has more "detection power" than the 1,200 TR F-35 AN/APG-81 AESA.  The vulnerability of the Irbis-E is compounded further by the fact that it is not a low-probability-of-intercept radar(LPIR). Russian engineers do not have a comparable the level of experience in designing LIP radar modes using emission control principles. In tests the APG-81 was able to jam and track even the LPIR of the F-22A (AN/APG-77)

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

If an F-22A with LPIR is vulnerable to the F-35 jamming it, essentially greatly reducing detection abilities, than the Pak Fa without LPIR is that much more vulnerable. As for vulnerability to jamming, the AN/APG-81 has an extremely high resistance to being jammed. In fact, the AN/APG-81 won the David Packard Excellence in Acquisition Award because of its performance against jamming. This ability to jam and track a Pak Fa might end up being what gives the F-35 the edge. Either way, it will be too close for comfort.

Further Reading (links)

Canada and the F-35
Murphy's Law: F-35 Development and Performance Concerns




References

1.) http://www.aviationweek.com/aw/generic/story.jsp?channel=awst&id=news/awst/2011/01/17/AW_01_17_2011_p20-281824.xml&headline=null&next=0

2.)http://www.f-16.net/f-16_users_article7.html

3.)http://www.qualitymag.com/Articles/Industry_Headlines/BNP_GUID_9-5-2006_A_10000000000000943597

4.)http://www.ausairpower.net/APA-NOTAM-300309-1.html

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

6.) http://www.ausairpower.net/APA-Flanker-Radars.html#mozTocId533477

7.) http://www.defenseindustrydaily.com/The-F-35s-Air-to-Air-Capability-Controversy-05089/

8.) http://www.globalsecurity.org/military/systems/aircraft/f-35.htm

9.) http://reporter.kro.nl/downloads/rand_pacific_view.pdf