History
Development
The F-35 originated from the Joint Strike Fighter (JSF) program in 1993–1994, aimed at replacing a wide range of existing fighter, strike, and ground attack aircraft for the United States, the United Kingdom, and other allied nations. The goal was to develop an advanced aircraft equipped with cutting-edge weapons and sensor technology to replace aging platforms like the F-16, F/A-18, and AV-8B.
McDonnell Douglas, Northrop, Lockheed Martin, and Boeing submitted proposals to the Department of Defense. On November 16, 1996, Lockheed Martin and Boeing were awarded contracts to develop prototypes. Each company was required to produce two aircraft: one for Conventional Takeoff and Landing (CTOL) and Carrier Takeoff and Landing (CV), and another for Short Takeoff and Vertical Landing (STOVL).
Lockheed Martin developed the X-35A (later converted to X-35B) and X-35C, while Boeing developed the X-32A and X-32B, all powered by Pratt & Whitney F119 engines. The X-32A first flew on September 18, 2000, for CTOL and CV trials, while the X-35A first flew on October 24, 2000, completing 28 flight tests to evaluate flying qualities and performance. The X-35A was later converted into the X-35B for STOVL testing, successfully demonstrating short takeoff, supersonic flight, and vertical landing in a single test flight. This achievement gave Lockheed Martin a significant edge over Boeing.
On October 26, 2001, Lockheed Martin won the production contract, and Pratt & Whitney secured a contract to develop the F135 engine for the F-35 series.
Production Design
The Joint Strike Fighter (JSF) program transitioned into the System Development and Demonstration phase with the goal of producing F-35 combat aircraft. Lockheed Martin made several modifications to the production F-35 compared to the prototype X-35. These modifications include:
- Extending the forward fuselage by five inches
- Moving the horizontal stabilizers two inches rearward
- Modifying the diverterless supersonic inlet from a four-sided to a three-sided cowl shape and relocating 30 inches rearward
- Raising the top fuselage surface by 1 inch to accommodate the internal weapons bays.
From this point, the production designs diverged into three variants: F-35A, F-35B, and F-35C, each with a service life of 8,000 hours. Lockheed Martin oversees overall system integration, final assembly, and checkout, while Northrop Grumman and BAE Systems supply mission systems and airframe components.
The F-35B is powered by a single Pratt & Whitney F135-PW-600 engine, featuring a Shaft-Driven Lift Fan (SDLF) system that enables Short Take-off and Vertical Landing (STOVL) operations. To accommodate this system, the F-35B sacrifices approximately one-third of the F-35A’s fuel volume. The SDLF, designed by Lockheed Martin and developed by Rolls-Royce, consists of a lift fan, a drive shaft, two roll posts, and a three-bearing swivel module (3BSM). The 3BSM nozzle is a key component of the STOVL system. It features a three-bearing design, resembling a short cylinder with nonparallel bases, allowing it to swivel from a linear alignment with the engine to a perpendicular position. This thrust-vectoring nozzle directs the main engine exhaust downward at the tail. The lift fan, positioned near the front of the aircraft, counterbalances the torque generated by the 3BSM nozzle. It is powered by the low-pressure turbine via a drive shaft, which engages through a clutch. Additionally, the roll post ducts, located under the wings, divert unheated engine bypass air to enhance stability during low-speed and hover flight.
The engine produces 28,000 pounds of thrust at military power and up to 43,000 pounds with afterburner, enabling the F-35 to reach a top speed of Mach 1.6 with a full internal payload. However, the F-35 does not possess supercruise capability. The engine section is coated with radar-absorbent materials to minimize its radar signature and conceal the turbine. It also features a low-observable, axisymmetric nozzle with 15 overlapping flaps arranged in a sawtooth pattern to reduce both radar and infrared signatures. Furthermore, the F-35 integrates power and thermal management, environmental control, auxiliary power, and engine functions into a single system. Its noise levels are comparable to the F-16C and F/A-18E, though the F-35 produces noticeable low-frequency sound.
The F-35 is equipped with two internal weapons bays, each containing two stations capable of carrying AIM-120 AMRAAM missiles or Joint Direct Attack Munitions (JDAM). The F-35B features two external outboard weapon stations, each capable of carrying up to 1,500 pounds of ordnance, including JDAM or Paveway bombs. The aircraft also has wingtip pylons—specifically, SUU-96 pylons with LAU-151/152 launcher rails—designed to carry AIM-9X Sidewinder missiles. These pylons are angled outward to help reduce radar cross-section. The latest AIM-9X Block II+ variant features stealth-enhancing coatings and structural improvements, which maintains the F-35’s RCS. A stealth-optimized air-to-air weapons configuration typically includes four AIM-120 missiles in the internal bays and two AIM-9X missiles mounted on the wingtip pylons. Behind the weapons bays, the aircraft has two compartments that house flares, chaff, and towed decoys for defensive countermeasures. Unlike other variants, the F-35B does not have an internal gun. However, it can be equipped with a GAU-22/A 25mm rotary cannon housed in a Terma A/S multi-mission pod mounted on the aircraft’s centerline. The pod is designed with a low-observable shape to minimize its radar cross-section.
The F-35’s fuselage and wings are coated with radar-absorbent materials and designed with continuous curves to minimize radar cross-section. The aircraft’s diverterless supersonic inlet further reduces radar signature by using a compression bump and a forward-swept cowl instead of traditional boundary layer diverters. Reports indicate that the F-35’s radar signature is comparable to that of a metal golf ball, depending on detection frequencies and angles. While low-frequency radars can detect the F-35 due to Rayleigh scattering effects, these radars generally suffer from high levels of interference and lack precision. However, the F-35’s stealth technology is considered an improvement over the F-22’s, as it benefits from advancements and lessons learned from the first-generation stealth features introduced on the F-22.
The F-35 features an advanced glass cockpit designed to enhance pilot situational awareness. The cockpit is equipped with a large, widescreen touchscreen display that provides flight data, weapons management, communication, and navigation information, and system alerts. Instead of a traditional head-up display, the F-35 integrates this information into the pilot’s helmet via a helmet-mounted display system (HMDS). This system projects flight and combat data onto the pilot’s visor, allowing them to view critical information regardless of head position. The Distributed Aperture System (DAS) provides infrared and night vision imagery directly to the HMDS, allowing the pilot to have an unobstructed view of their surroundings. The HMDS also enables high off-boresight targeting, allowing missiles to be fired at extreme angles.
The mission systems of the F-35 are among the most advanced and costly aspects of the aircraft. Digital avionics and sensor fusion are combining with data from multiple sources to enhance battlefield awareness and facilitate network-centric warfare. Key sensors include the AN/APG-81 active electronically scanned array (AESA) radar, the AN/ASQ-239 Barracuda electronic warfare system, the AN/AAQ-37 Electro-Optical Distributed Aperture System, the AN/AAQ-40 Electro-Optical Targeting System (EOTS), and the AN/ASQ-242 Communications, Navigation, and Identification (CNI) system. These systems work together to enable seamless data sharing with allied forces without compromising stealth.
The APG-81 AESA radar provides high-speed electronic scanning and features both passive and active air-to-air and strike capabilities. It also has synthetic aperture radar functionality, allowing it to track and scan multiple targets at ranges of approximately 90 miles. To maintain stealth characteristics, the radar antenna is tilted backward within the fuselage. Complementing the radar, the AAQ-37 DAS consists of six infrared sensors that provide missile launch warnings, target tracking, and spherical infrared imagery, which is projected onto the pilot’s helmet visor. The AAQ-40 EOTS, located beneath the nose, offers laser targeting, forward-looking infrared (FLIR), and long-range infrared search and track (IRST) capabilities.
The ASQ-239 Barracuda electronic warfare system features ten radio frequency antennas embedded in the edges of the wings and tail, providing 360-degree radar warning coverage. This system fuses radio frequency and infrared sensor data for enhanced situational awareness, geolocation of threats, and multi-spectrum electronic countermeasures. It is reported that the Barracuda system is capable of detecting and jamming enemy radar systems.
The F-35’s systems were designed to require less maintenance than previous stealth aircraft, such as the F-22, making it a more cost-effective and operationally sustainable platform.
United States Marine Corps Service
The first F-35B was built and flew on June 11, 2008, with its first hover occurring on March 17, 2010. Following this, other F-35Bs participated in flight sciences testing to assess flight performance, flight loads, store separation, and mission systems. During testing, several issues were identified with the F-35B and F-35C that led to costly redesigns and fleet-wide groundings, delaying further production of the aircraft. For example, premature cracks were discovered in the F-35B during fatigue testing, necessitating a redesign of the structure. Additionally, problems with the horizontal tails were identified, caused by heat damage from prolonged afterburner use. Lockheed Martin spent years addressing these defects, which resulted in cost overruns.
In October 2011, at-sea testing for the F-35B was approved, and two aircraft boarded the USS Wasp for three weeks of initial sea trials under Development Test I. By August 2013, Development Test II began, with the F-35Bs conducting nighttime operations, including 19 vertical landings using Distributed Aperture System (DAS) imagery. In May 2015, six F-35Bs participated in operational tests aboard the USS Wasp, and later, more were tested aboard the USS America in high sea states in late 2016 under Development Test III.
The F-35B was approved for flight training in early 2012, and the USMC training unit received its fleet of F-35Bs at Eglin Air Force Base, Florida, alongside USAF F-35As and USN F-35Cs. This marked the USMC’s acquisition of the first operational supersonic, stealth STOVL fighter, replacing the AV-8B Harrier. The F-35B fleet was then expanded to other Marine Corps Air Stations across the United States.
The VMFA-121 squadron at MCAS Yuma became the first USMC operational unit to receive the F-35Bs on November 16, 2012. The USMC declared Initial Operational Capability (IOC) for the F-35B in the Block 2B configuration on July 31, 2015, after several operational trials. The F-35B participated in its first Red Flag exercise in July 2016, followed by its first overseas deployment to MCAS Iwakuni, Japan, in 2017.
The F-35B made its first known combat deployment to Afghanistan in July 2018. The aircraft launched from the USS Essex to conduct an airstrike against Taliban targets, marking the F-35B’s first combat mission on September 27, 2018. The USMC was the first to deploy the F-35 Joint Strike Fighter (JSF) abroad and use it in combat.
As the F-35B fleet matured, it received several software and combat capability upgrades. The Block 2B configuration, introduced in July 2015, made the aircraft combat-capable with air-to-air and strike capabilities. Incremental upgrades included Blocks 3i and 3F, which provided additional software and hardware enhancements. The F-35s that received the final Block 3F configuration concluded the System Development and Demonstration (SDD) phase from December 2018 to March 2024.
The Block 4 configuration represents the first major upgrade after the SDD phase and began development in 2019. It integrates new weapons, the AN/APG-85 AESA radar, updated avionics hardware, and an improved F135 engine. Block 4 is expected to enter service between the late 2020s and early 2030s, though delays caused by issues with new hardware have postponed aircraft deliveries from 2023 to 2024. Under this upgrade, the F-35B will feature a reworked hydraulic line and bracket, allowing it to carry four Small Diameter Bombs (SDBs) per internal outboard station (instead of three). However, it will not receive an increase in internal air-to-air missile capacity.
Over 100 F-35Bs have been delivered to the USMC, and around 300 are planned for future production and delivery. The F-35B has also been exported to Italy and the United Kingdom, with other international customers awaiting their deliveries in the coming years.
