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-35A is powered by a single Pratt & Whitney F135-PW-100 low-bypass augmented turbofan. This engine is based on the Pratt & Whitney F119 used in the F-22A Raptor but features a larger fan for improved subsonic thrust and fuel efficiency. Unlike the F-22, however, the F-35 does not have supercruise capability. The engine produces 28,000 pounds of thrust at military power and up to 43,000 pounds with afterburner, allowing the aircraft to reach a top speed of Mach 1.6 with a full internal payload. The engine section is enclosed with radar-absorbent materials to reduce its radar signature. Additionally, the engine features an axisymmetric nozzle with 15 overlapping flaps, creating a sawtooth pattern to help lower both radar and infrared signatures. The aircraft’s power and thermal management, environmental control, auxiliary power unit, and engine functions are all integrated into a single system. Noise levels from the F-35 are comparable to those of the F-16C and F/A-18E, though its low-frequency sound is particularly noticeable.
The F-35 is equipped with two internal weapons bays, each housing two stations capable of carrying AIM-120 AMRAAM missiles or Joint Direct Attack Munitions (JDAM). In addition, it features four external weapons stations, each capable of carrying up to 2,500 pounds of ordnance, including JDAMs, Paveway laser-guided bombs, and Joint Standoff Weapons. 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 maintain the F-35’s RCS. A stealth-oriented air-to-air loadout consists of four AIM-120s in the internal bays and two AIM-9Xs on the wingtip pylons, while a non-stealth loadout could include up to eight AIM-120s and two AIM-9Xs. Located behind the weapons bays are compartments housing countermeasure dispensers for flares, chaff, and towed decoys. The F-35A is fitted with a 25mm GAU-22/A rotary cannon, mounted internally near the left wing root, with a capacity of 182 rounds and a firing rate of up to 3,300 rounds per minute.
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 Air Force Service
The first F-35A was built and rolled out in Fort Worth, Texas, on February 19, 2006, approximately five years after Lockheed Martin began developing the aircraft from the X-35. It underwent its first engine test in September 2006 and completed its maiden flight on December 15, 2006. The aircraft was officially named “Lightning II.”
The initial batch of six F-35As, including the first prototype, was designated for flight testing to evaluate performance and mission systems. These tests uncovered several issues, particularly in the F-35B and F-35C variants, which required costly redesigns and led to multiple fleet-wide groundings, delaying further production. Lockheed Martin spent years addressing these defects, leading to significant cost overruns.
In early 2012, the F-35A was approved for flight training, and the first USAF training units at Eglin Air Force Base, Florida, received their aircraft alongside the USMC’s F-35Bs and the USN’s F-35Cs. With the F-35A, the USAF added its second fifth-generation supersonic stealth multirole fighter to its inventory. Over time, the fleet expanded to additional Air Force bases.
On August 2, 2016, the USAF’s 34th Fighter Squadron at Hill Air Force Base, Utah, received the Block 3i configuration, which introduced new hardware. This milestone marked the aircraft’s Initial Operational Capability, declaring it combat-ready. The F-35A participated in its first Red Flag exercise in 2017, achieving a 15:1 kill ratio against an F-16 aggressor squadron, demonstrating its advanced stealth capabilities and superiority of its mission systems. The aircraft was later deployed to Al Dhafra Air Base, UAE, on April 15, 2019, where it conducted its first combat operations, striking Islamic State targets in northern Iraq.
Throughout its service life, the F-35A has undergone continuous upgrades to enhance its software and combat capabilities. The first combat-capable configuration, Block 2B, was introduced in July 2015, enabling air-to-air and strike capabilities. This was followed by incremental upgrades with Blocks 3i and 3F, which brought additional software and hardware improvements. The final Block 3F configuration marked the completion of the System Development and Demonstration phase, spanning from December 2018 to March 2024.
The first major upgrade following this phase is the Block 4 configuration, which entered development in 2019. This upgrade includes integration of additional weapons, the AN/APG-85 AESA radar, new avionics hardware, and an improved F135 engine. Initially expected to enter service in the late 2020s to early 2030s, Block 4 has faced delays due to hardware development challenges, postponing aircraft deliveries from 2023 to 2024. This upgrade also introduces a new weapon rack, allowing the F-35A to carry six AIM-120 missiles internally, enhancing its air-to-air combat capabilities.
To date, more than 300 F-35As have been delivered to the USAF, with approximately 1,000 F-35s planned for production and delivery. The aircraft has also been exported to multiple allied nations, including Australia, Israel, Italy, Japan, the Netherlands, Norway, and South Korea, with additional international customers awaiting delivery.
