Lockheed-Martin F-35 Lightning II: “The future all-purpose fighter”

On October 26, 2001, after four years of fierce competition, the X-35 was declared the winner of the JSF competition against Boeing’s X-32 and the SDD (System Development and Demonstration) contract was signed. It was at this point that the name F-35 for the future fighter was chosen, to the surprise of Lockheed Martin, which had internally referenced its F-24 aircraft; it was on July 7, 2006 that the aircraft was definitively named Lightning II, a name that the F-22 Raptor prototype also bore, and in reference to both the American P-38 Lightning and the British BAC Lightning.

F-35 Lightning II

The JSF program was to result in the production of three variants of the same aircraft, with about 80% of the structure and parts in common and almost 100% in terms of avionics: the F-35A for the USAF, the F-35B for the USMC and the F-35C for the US Navy.

These three versions have the common feature of being stealthy, the aircraft having a weapons bay capable of housing mainly two guided bombs and two AMRAAM air-to-air missiles. It should be noted that the F-35 can receive numerous weapons on 7 external pylons, sacrificing stealth in favor of carrying capacity, which can go up to 9 tons of various loads (tanks, guided bombs, cruise missiles and air-to-air missiles).

The F-35 is designed to be a better fighter jet

The F-35, all versions included, was designed to benefit from significant autonomy, maneuverability comparable to the first generation F-16, to be relatively light (20 tons in combat order) and competitive in price (between 60 and 100 million dollars according to estimates and variants), with production expected to reach more than 3,000 examples for the United States and the United Kingdom alone.

Although it was originally an American program, many foreign countries (especially European ones) are financially and technically involved in its development; these countries are the United Kingdom (the only level 1 partner), Italy and the Netherlands (level 2 partners), Australia, Canada, Denmark, Norway and Turkey (level 3 partners).

The level 1 partnership covers the design and manufacture of the rear fuselage by BAe Systems, as well as the design of part of the onboard electronics. For Italy, the Level 2 partnership covers the assembly of the European F-35s and the construction of half of the wings. This factory, located in Cameri, is planned to build 200 aircraft, but only 127, i.e. the 90 Italian and 37 Dutch aircraft, are currently planned. This factory, which may build the British aircraft, will also be responsible for maintaining the European F-35s. The Level 3 partnership is the financing of the design and participation in testing.

International interest in the program

Israel and Singapore joined the program as cooperators in 2003. Other countries have already ordered them, such as South Korea and Japan, or are interested, such as Saudi Arabia, Belgium, Finland (to replace its F-18s, decision expected in 2015), Poland (from 48 to 64 units) and Romania.

Taiwan and the United Arab Emirates have also expressed interest in the aircraft. But their request seems to have been rejected, for political reasons with regard to China for Taiwan. As for the United Arab Emirates, which has not yet received an answer, it is not known why.

The F-35 was offered to India in the MMRCA tender (126 aircraft), after the failure of the F-16, and rejected because it entered the competition too late. It was presented to Brazil and also rejected. It was proposed to Greece to replace the F-4E and the F-16C Block 30.

The All purpose fighter jet

Although it has air-to-air capabilities, the F-35 is primarily an attack aircraft. Its avionics are based on a central processor with a very high computing capacity, capable of centralizing and rendering information merged from the various sensors (AN/APG-81 AESA radar, laser/FLIR designator/telemetry/EOTS TV camera, AN/AAQ-37 DAS IR detectors, as well as ALQ-214 jammers and other ECMs) via a very large (20 x 51 cm) Rockwell-Collins touch screen (MFDS). The pilot also has a Helmet Mounted Display System (HMDS) with extremely advanced functions, replacing the classic HUD, and allowing him to designate targets, to do without a JVN for navigation, or to literally see “through” the floor of his aircraft (during vertical landing maneuvers for example).

The F-35 is powered by a Pratt & Whitney F135 turbofan engine in the 20-ton thrust class with afterburner, derived from the F119 of the F-22 Raptor, but without vectoring. It should be noted that it was not desired to equip the F-35 with a super-cruise capability.

The development of the Rolls-Royce and General Electric F136 was maintained for a time for political and economic reasons, as this second engine would keep pressure on the F135’s production costs, while offering an alternative to future export customers. It was finally cancelled in February 2011, in order to save $450 million.

In terms of the aircraft’s structure and design, the general shape is reminiscent of an F-22. The F-35 is a single-engine, single-seat aircraft, with a compact, streamlined fuselage. The wing is diamond-shaped, and its span will be larger on the C version, allowing a greater autonomy, while allowing the aircraft to land with a greater number of external loads if necessary.

The first aircraft to fly, the pre-production version of the F-35A (designated AA-1), made its maiden flight on December 15, 2006. In May 2007, it suffered an electrical short circuit that disabled the horizontal stabilization flight controls. In all, 13 prototypes and 8 pre-production aircraft have been built.

However, the program itself suffers from numerous problems and delays. As early as January 2006, the Pentagon was considering cancelling one of the versions in order to finance the war in Iraq. On April 21, 2009, the Wall Street Journal revealed that a hacking had led to the theft of confidential data (onboard electronics and stealth systems).

The entire structure had to be rethought; initially the wings and fuselage were to be one piece, but problems of manufacturing complexity, structural constraints and long-term maintenance got the better of this revolutionary design.

In addition, a vital project has been undertaken in recent years to meet the aircraft’s weight specifications, with more than 1,200 kg saved, sometimes at the cost of major modifications, such as limiting the payload capacity of the F-35 B version.

F-35 Lightning II

Issues with the F-35

The F-35s have been grounded several times: the F-35Bs in November 2009 due to a fuel valve problem, and again in October 2010 due to fuel pumps. The problem reappears in a January 2013 report.

The F-35As were grounded twice between October 2010 and March 2011, first because of a failure of two generators and then because of an oil leak during a test flight.

In January 2012, it was the F-35Cs that were grounded because of… badly packed parachutes.

The entire F-35 fleet was grounded in August 2011 because of the IPP (Integrated Power Package), which combines the function of auxiliary power unit and air management, for cooling electronic systems. This IPP went out for no known reason in the middle of a ground test.

It was grounded a second time in February 2013 due to a cracked blade on an F-35A engine’s F-135 turbine, again in June 2014 due to an oil leak, and again the following month due to a fire in the rear of the aircraft, the cause of which has yet to be identified. Since the crash of an F-35B in September 2018, the global F-35 fleet has been grounded again.

The F-35 has been a source of friction between the United States and the United Kingdom: in addition to the cancellation of the Rolls-Royce-designed engine, there is the U.S. denial of full software access to the British decided in November 2009.

The software itself has caused many problems: in November 2010, 20 million lines of code had to be rewritten. In September 2012, the problem persists. The Pentagon report in January 2013 indicates that Block 1 is insufficient, missing 20% of the code which prevents delivery and testing, and that Block 2A is more than 50% incomplete. The Block 2B version, which should have been delivered in October 2014, was still not delivered in January 2015, making the Marine Corps’ F-35 unreliable and difficult to maintain.

The engine itself has many problems: in December 2010, it was realized that it was too large to be carried on an aircraft carrier at sea. In October 2010, it was found to be noisier than the two F-15 engines at takeoff, which required the design of new noise-cancelling helmets.

The speed dump is shown to be capricious by December 2011, and even defined as dangerous in January 2012.

The helmet sight, supposed to replace a classic HUD, caused problems as early as December 2011: the data display system did not work. In October 2012, the reported problems were more specific: the projected images flickered, and there was a latency when the pilot turned his head too quickly. The Pentagon report in January 2013 mentions a fluctuating and jerky image, as well as a new concern: at night, a green glow, due to the light contamination of the helmet display by the lights of the dashboard screens, pollutes the pilot’s vision. In October 2013, this helmet sight is abandoned. But as early as November, the alternative helmet of BAE System presents a display bug occurring beyond 1000 mph. Too much information would have made the display greenish and blurry.

In October 2012, it was still unclear how the F-35’s composite structure would perform in the face of a lightning strike, and the aircraft was not allowed to come within 35 km of a thunderstorm, or even to fly in rainy weather. In January 2013, we know: the fuel tank could explode if hit by lightning. In June 2014, it was banned from night flight by the FAA, because of …non-regulation position lights. Poorly positioned, they do not represent the full envelope of the aircraft.

The Pentagon report of January 2013 points out that flights at high altitude and high speed induce a greater than expected heating of the horizontal flight surfaces. This erodes the material of these surfaces and shows burn marks.

In December 2014, the USAF discovered that the F-35 had a temperature threshold during refueling beyond which it could not function properly. As a result, it repaints its tankers white to resupply the F-35 with fuel at the correct temperature…

The first doubts about the F-35’s true stealth seem to emerge in December 2011. In April 2014, a USAF colonel estimated that this stealth is not guaranteed, and indeed leaves something to be desired in the face of Russian and Chinese radars.

The armament itself poses many problems for the F-35: in January 2012, it was realized that the payload bay is too small for English missiles! In January 2015, the software managing the F-35A’s gun is not ready and will not be until 2019. This also impacts the other B and C versions. In March 2015, the internal cargo bay of the F-35B is not even big enough to hold the 8 SDB II bombs planned. More generally, in March 2015, the F-35 was unable to deliver its weapons accurately due to its deficient navigation system.

As for performance, it has been very disappointing: as early as May 2011, its flight performance was similar to that of the F/A-18. The F-35A’s range is 584 nautical miles instead of the 590 requested. In May 2012, the F-35B’s takeoff distance was extended by 50 meters compared to what was planned. The Pentagon’s January 2013 report indicates that the turn load factors are lower than expected. For the F-35A, this is down from 5.3 G to 4.6 G. The acceleration rate to go from Mach 0.8 to Mach 1.2 increases to 43 seconds for the F-35C. Passing the sound barrier is accompanied by heavy roll and vibration on the F-35B and C.

By October 2012, the F-35 is already considered inferior to each of the aircraft it is to replace, in isolation. In April 2014, its performance was even judged inferior to that of the previous generation in terms of range, speed, military load… In June 2014, Pierre Sprey, one of the designers of the F-16, went so far as to judge it inferior to a MiG-21 in close combat, among other criticisms. The Pentagon’s January 2015 report states that for all 3 versions, the aircraft’s suitability for its missions is unsatisfactory. Even the tires are wearing out 3 to 4 times faster than expected.

All this has led to delays in the tests: in January 2010, only 16 flights out of 168 planned had been carried out. In May of the same year, 60 test flights were carried out in 4 months, whereas 42 test flights per month were planned. By October 2010, the F-35B had completed 141 flights out of 181 planned. In January 2015, the OUE (Operationnal Utility Evaluation) tests are purely and simply abandoned in order to avoid too important delays, at the risk that serious problems are revealed only during the mission…

In May 2010, the community between the various versions, which was supposed to be 80%, was only 25%. In December 2011, Lockheed had to make 577 modifications, the equivalent of 18 to 24 months of work, before fixing 8 other major defects and 5 minor design defects (vibration problems, helmet sight, stealth, vacuum, auxiliary power unit, landing stock…).

In 2014, one-third of the 100 F-35s built were capable of flying. In January 2015, the Pentagon report stated that the reliability and maintenance of the F-35s already deployed relied heavily on Lockheed technicians, as well as “unacceptable fiddling.”

This has led to delays in delivery and entry into service, as well as increased costs and reduced orders. The F-35 is increasingly controversial in the United States itself, and has become the most expensive weapons program in history: the GAO (the equivalent of the U.S. Court of Auditors) estimated the program at $950 billion for the purchase and use of the 2,443 aircraft planned over 55 years in March 2008, a figure that had risen to $1,550 billion by April 2012 for the same number of aircraft. Unit costs vary widely from one source to another, ranging from $99 million to twice that amount, or $182 million, for the F-35A.

F-35 Lightning II

The F-35 in combat

The 100th aircraft was built in December 2013. As of September 2018, production has reached 320.

The F-35 completed its first combat mission on September 27, 2018. It was a Marine Corps F-35B, on a mission in Afghanistan. The next day, another example crashed in South Carolina.

It is still too early to judge the true value of the F-35. Perhaps it will solve its teething problems and prove to be a successful aircraft in operations, even if it does not. Many aviation enthusiasts, in France at least, compare the characteristics of the F-35 and the Rafale.

The two aircraft share the same design philosophy: capable of a wide range of missions with a dominant air-to-ground capability, they are intended to replace a wide range of very different aircraft, and they are as close as possible to each other, including at least one navalized version. Until about 2009, the F-35’s supporters saw European aircraft, particularly the Rafale, as mediocre and far inferior to the F-35, which was the ultimate. As for Rafale supporters, they saw (and still see) the F-35 as a Trojan horse designed to reduce any industrial competition in fighter aircraft, especially European ones.

But since then, in 2015, the Rafale has proven itself in combat, while the F-35’s entry into service has been continually delayed.

The Rafale does not seem to have suffered from any major design flaws, and its main problem is rather a budget stagger due to the economic crisis.

The Rafale more than honorably fulfills the missions entrusted to it and replaces its predecessors very advantageously. The F-35 is currently inferior to all the aircraft it is supposed to replace. For example, we cannot imagine it replacing the A-10 in anti-tank missions.

Its advantages over the Rafale are supposed to be stealth, but this is being questioned. Its price, but it is increasingly high and is just starting to come down in March 2015, and official prices remain slightly higher. Its ADAV capability, but it weighs the aircraft down and makes it very complex and unmaneuverable. The knowledge of its environment due to the fusion of data from its sensors, but it is undoubtedly difficult to manage for a single man, not to mention the software problems.

The only real advantage it has left seems to be its future mass production, which will probably end up reducing the price of the device. There is obviously no other solution for the United States than to continue the program.

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