F-35 Lightning: The Joint Strike Fighter Program

The $382 billion F-35 Joint Strike fighter program may well be the largest single global defense program in history. This major multinational program is intended to produce an “affordably stealthy” multi-role fighter that will have 3 variants: the F-35A conventional version for the US Air Force et. al.; the F-35B Short Take-Off, Vertical Landing for the US Marines, British Royal Navy, et. al.; and the F-35C conventional carrier-launched version for the US Navy. The aircraft is named after Lockheed’s famous WW2 P-38 Lightning, and the Mach 2, stacked-engine English Electric (now BAE) Lightning jet. Lightning II system development partners included The USA & Britain (Tier 1), Italy and the Netherlands (Tier 2), and Australia, Canada, Denmark, Norway and Turkey (Tier 3), with Singapore and Israel as “Security Cooperation Partners,” and Japan as the 1st export customer.

The big question for Lockheed Martin is whether, and when, many of these partner countries will begin placing purchase orders. This updated article has expanded to feature more detail regarding the F-35 program, including contracts, sub-contracts, and notable events and reports during 2012-2013.

The F-35 Lightning II Fighter Family

F-35 Family Variants: Door A, B, or C?

Figure 1: F-35 Variants.

The above table illustrates the key differences between the baseline F-35A, the Short Take-Off, Vertical Landing (STOVL) capable F-35B, and the catapult-launched F-35C naval variant. Additional explanations follow.

The F-35A CTOL

F-35A, doors open
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The F-35A is sometimes called the CTOL (Conventional Take-Off and Landing) version. It’s the USAF’s version, and is expected to make up most of the plane’s export orders. It’s also expected to be the least expensive F-35, in part because it will have the largest production run. The USAF currently estimates its average flyaway cost after 2017 at $108.3 million, but early production models ordered in FY 2012 will cost over $150 million.
Its main difference from other versions is its wider 9g maneuverability limits, though its air-air combat flight benchmarks are only on par with the F-16. Canard equipped “4+ generation” adversaries like the Eurofighter, and thrust-vectored fighters like the F-22A, MiG-35, SU-35, etc., will still enjoy certain kinetic advantages. The F-35 hopes to mitigate them using its improved stealth to shrink detection ranges, the lack of drag from weapons in its internal bays, and its current electronic superiority.
The second major physical difference between the F-35A and the rest of the Lightning family is its internal 25mm cannon, instead of using a weapons station for a semi-stealthy gun pod option. The USAF removed guns from some of its planes back in the 1960s, and didn’t enjoy the resulting experiences in Vietnam. It has kept guns on all of its fighters ever since, including the stealthy F-22 and F-35. Many allies wanted the 27mm Mauser cannon installed instead, as it’s widely believed to offer the world’s best combination of firing rate and hitting power. In the end, however, ammunition standardization benefits involving 25mm land and sea platforms trumped pure performance.
The 3rd difference is that the F-35A uses a dorsal refueling receptacle that is refueled using an aerial tanker boom, instead of the probe-and-drogue method favored by the US Navy and many American allies.
The F-35A was the first variant to fly, in 2009. Unfortunately, it looks like it won’t reach Initial Operational Capability (IOC) until 2017 or 2018.

The F-35B STOVL (Short Take-Off, Vertical Landing)

F-35B features

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The F-35B is expected to be the most expensive Lightning II fighter variant. According to US Navy documents, even planes bought after 2017 are expected to have an average flyaway cost of $135 million each. It will serve the US Marines, Royal Navy, other navies with ski-ramp equipped LHDs or small carriers, and militaries looking for an “expeditionary airplane” that can take off in short distances and land vertically. To accomplish this, the F-35B has a large fan behind the cockpit, and nozzles that go out to the wing undersides. Unlike the F-35A, it will use a retractable mid-air refueling probe, which is standard for the US Navy and for many American allies.
Those capabilities gives the plane a unique niche, but a unique niche also means unique challenges, and the responses to those challenges have changed the aircraft. In 2005, the JSF program took a 1-year delay because the design was deemed overweight by about 3,000 pounds. The program decided to reduce weight rather than run the engine hotter, because the latter choice would have sharply reduced the durability of engine components and driven life cycle costs higher. Weight cutting became a focus of various engineering teams, with especial focus on the F-35B because the weight was most critical to that design. Those efforts pushed the F-35B’s design, and changed its airframe. The F-35B gives up some range, some bomb load (it cannot carry 2,000 pound weapons internally, and the shape of its bay may make some weapons a challenge to carry), some structural strength (7g maneuvers design maximum), and the 25mm internal gun.
The F-35B completed its Critical Design Review in October 2006, and the 2nd production F-35 was a STOVL variant. Per the revised Sept 16/10 program plan, the USMC’s VMA-332 in Yuma, AZ must have 10 F-35Bs equipped with Block IIB software, with 6 aircraft capable of austere and/or ship-based operations, and all aircraft meeting the 7g and 50-degree angle of attack specifications, in order to declare Initial Operational Capability.
Flight testing began in 2009, and IOC was expected by December 2012, but flight testing fell way behind thanks to a series of technical delays. By 2013, the first operational planes were fielded to the USMC at Yuma, AZ. The USMC is currently aiming for a 2015 IOC, but it would involve just Block 2B software loads that will limit the F-35B’s combat capability. Even then, the Pentagon’s 2012 DOT&E report isn’t grounds for software schedule optimism. Planes with full Block 3 initial combat capability are unlikely to be fielded before 2018.

The F-35C carrier-based fighter

USN F-35C

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The F-35C is instantly recognizable. It features 30% more wing area than other designs, with larger tails and control surfaces, plus wingtip ailerons. These changes provide the precise slow-speed handling required for carrier approaches, and extend range a bit. The F-35C’s internal structure is strengthened to withstand the punishment dished out by the catapult launches and controlled crashes of carrier launch and recovery, an arrester hook is added to the airframe, and the fighter gets a retractable refueling probe. According to US Navy documents, average flyaway costs for F-35Cs bought after 2017 will be $125.9 million each.
The US Navy gave up the internal gun, and the aircraft will be restricted to 7.5g maneuvers. That’s only slightly lower than the existing F/A-18E Super Hornet’s 7.6g, but significantly lower than the 9g limit for Dassault’s carrier-capable Rafale-M.
The F-35C is expected to be the US Navy’s high-end fighter, as well as its high-end strike aircraft. This means that any performance or survivability issues will have a disproportionate effect on the US Navy’s future ability to project power around the world.
The F-35C will be the last variant designed; it passed its Critical Design Review in June 2007, and the first production version was scheduled to fly in January 2009. The F-35C’s rollout did not take place until July 2009, however, and first flight didn’t take place until June 2010. Initial Operational Capability was scheduled for 2014, but looks set to slip to 2019.

F-35s: Key Features

F-35 Variants

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Stealth. The F-35 is designed as an ‘affordable stealth’ counterpart to the F-22 Raptor air dominance fighter, one that can share “first day of the war” duties against defended targets but can’t perform air-air or air-ground missions to the same standard. The F-35 has a larger single engine instead of the Raptor’s twin thrust-vectoring F119s, removing both supercruise (sustained flight above Mach 1) and super-maneuverability options. The F-22A is also a much stealthier aircraft from all angles, and independent analysis & modeling has concluded that the F-35’s stealth will be weaker from the sides and the rear. Even so, the F-35 is an improvement over existing ‘teen series’ fighters and even beats Generation 4+ options like the Eurofighter, Rafale, and JAS-39 Gripen.
Engine. The F-35 was set to offer interchangeable engine options. That has been an important feature for global F-16 and F-15 customers, improving both costs and performance, and providing added readiness insurance for dual-engine fleets. Pratt & Whitney’s lobbying eventually forced GE & Rolls-Royce’s F136 out of the F-35 program, and made their F135-PW-100 engine the only choice for global F-35 fleets. A special F-135-PW-600 version with Rolls Royce’s LiftFan add-on, and a nozzle that can rotate to point down, will power the vertical-landing F-35B.
The US military had better hope that an engine design problem never grounds all of their fighters. While they’re at it, they should hope that maintenance contracts somehow remain reasonable in the absence of any competitive alternative.

F-35’s APG-81
AESA Radar
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Sensors. The Lightning II will equipped to levels that would once have defined a high-end reconnaissance aircraft. Its advanced APG-81 AESA (Active Electronically Scanned Array) radar is smaller and less powerful than the F-22A’s APG-77v1; but still offers the strong AESA advantages of simultaneous air-air and air-ground capabilities, major maintenance & availability improvements, and secure, high-bandwidth communications benefits. The F-35 also shares a “sensor fusion” design advance with the F-22, based on sensors of various types embedded all around the airframe. This sensor set is even more extensive than the F-22’s. Both planes will be able to perform as reconnaissance aircraft, though the F-35 will have superior infrared and ground-looking sensors. Both aircraft will also have the potential to act as electronic warfare aircraft.
These sensors are connected to a lot of computing power, in order to create single-picture view that lets the pilot see everything on one big 20″ LCD screen and just fly the plane, rather than pushing buttons to switch from one view to another and trying to figure it all out. As part of that sensor fusion, the F-35 will be the first plane is several decades to fly without a heads-up display. Instead, pilots will wear Elbit/Rockwell’s JHMDS helmet or BAE’s HMSS, and have all of that information projected wherever they look.
Maintenance. The F-35 has a large number of design features that aim to simplify maintenance and keep life cycle costs down. Since operations and maintenance are usually about 65% or more of a fighter’s lifetime cost, this is one the most important and overlooked aspects of fighter selection.
Stealth aircraft have always had much higher maintenance costs, but the F-35’s designers hope that new measures can reverse that trend. Some of the plane’s stealth coatings are being baked into composite airplane parts, for instance, in the hope that customers will need fewer “Martians” (Materials Application and Repair Specialists) around to apply stealth tapes and putties before each mission. Technical innovations like self-diagnosing aircraft wiring aim to eliminate one of the toughest problems for any mechanic, and the fleet-wide ALIS information and diagnostic system is designed to shift the fleet from scheduled maintenance to maintenance only as needed.
Despite these measure, March 2012 operations and maintenance projections have the F-35 at 142% O&M cost, relative to any F-16s they’ll replace. It remains to be seen if the advantages of F-35 innovations manage to fulfill their promise, or if projections that they’ll be outweighed in the end by increased internal complexity, and by the proliferation of fault-prone electronics, come true. That has certainly been the general trend over the last 50 years of fighter development, with a very few notable exceptions like the F-16, A-10, and JAS-39.

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