The Lockheed Martin F-35A Lightning II was the version of the Joint Srike Fighter (JSF) program that was designed for conventional takeoffs and landings on land-based airfields. The United States is the primary customer and financial backer, with planned procurement of 1,763 F-35As for the USAF. The program has drawn much scrutiny and criticism for its unprecedented size, complexity, ballooning costs, and much-delayed deliveries.
As compared to X-35A, the forward fuselage of the F-35A was lengthened by 5 inches (13 cm) to make room for mission avionics such as the radar in the nose, while the horizontal stabilizers were moved 2 inches (5.1 cm) aft to retain balance and control. The diverterless supersonic inlet changed from a four-sided to a three-sided cowl shape and was moved 30 inches (76 cm) further aft. The fuselage section was fuller, the top surface raised by 1 inch (2.5 cm) along the centerline to accommodate weapons bays in the lower fuselage. The F-35 has a wing-tail configuration with two vertical stabilizers canted for stealth. Flight control surfaces include leading-edge flaps, flaperons, rudders, and a pair of all-moving horizontal tails, as well as leading edge root extensions that also run forwards to the air inlets. The relatively short 35-foot wingspan of the F-35A was dictated by the requirement that the aircraft fit inside USN amphibious assault ship parking areas and elevators. The fixed diverterless supersonic inlets (DSI) use a bumped compression surface and forward-swept cowl to shed the boundary layer of the forebody away from the inlets, which form a Y-duct for the engine. Structurally, the F-35 drew upon lessons from the F-22 Raptor; composites comprise 35% of airframe weight, with the majority being bismaleimide and composite epoxy materials as well as some carbon nanotube-reinforced epoxy in newer production lots.
The single-engine aircraft is powered by the Pratt & Whitney F135 low-bypass augmented turbofan with rated thrust of 43,000 lbst. Derived from the Pratt & Whitney F119 used by the F-22, the F135 has a larger fan and higher bypass ratio to increase subsonic fuel efficiency, and unlike the F119, is not optimized for supercruise. The engine contributes to the F-35’s stealth by having a low-observable augmenter, or afterburner, that incorporates fuel injectors into thick curved vanes; these vanes are covered by ceramic radar-absorbent materials to mask the turbine. The low-observable axisymmetric nozzle consists of 15 partially overlapping flaps that create a sawtooth pattern at the trailing edge, which reduces the radar signature and creates shed vortices that reduce the infrared signature of the exhaust plume
Stealth is a key aspect of the F-35’s design, and radar cross-section (RCS) is minimized through careful shaping of the airframe and the use of radar-absorbent materials (RAM) on the surface of the airframe Visible measures to reduce the RCS include alignment of edges, the serration of skin panels, and the masking of the engine face and turbine. Additionally, the F-35’s diverterless supersonic air inlet (DSI) uses a compression bump and forward-swept cowl rather than a splitter gap or bleed system to divert the boundary layer away from the inlet duct, eliminating the diverter cavity and further reducing the radar signature by keeping radar beams from reaching the engine fan.
The electronics array include the Northrop Grumman AN/APG-81 active electronically scanned array (AESA) radar mounted in the nose, the BAE Systems AN/ASQ-239 Barracuda electronic warfare system, the Northrop Grumman/Raytheon AN/AAQ-37 Distributed Aperture System (DAS) missile warning system, the Lockheed Martin AN/AAQ-40 Electro-Optical Targeting System (EOTS) and the Northrop Grumman AN/ASQ-242 Communications, Navigation, and Identification (CNI) suite.
The APG-81 radar uses electronic scanning for rapid beam agility and incorporates passive and active air-to-air modes, strike modes, and synthetic aperture radar (SAR) capability, with multiple target tracking at ranges in excess of 90 miles. The antenna is tilted backwards for stealth. Complementing the radar is the AAQ-37 DAS, which consists of six infrared sensors that provide all-aspect missile launch warning and target tracking. The DAS acts as a situational awareness infrared search-and-track (SAIRST) and gives the pilot spherical infrared and night-vision imagery on the helmet visor. The ASQ-239 Barracuda electronic warfare system has ten radio frequency antennas embedded into the edges of the wing and tail to provide for all-aspect radar warning receiver (RWR). It also provides sensor fusion of radio frequency and infrared tracking functions, geolocation threat targeting, and multispectral image countermeasures for self-defense against missiles. The electronic warfare system is capable of detecting and jamming hostile radars. The AAQ-40 EOTS is mounted internally behind a faceted low-observable window under the nose and performs laser targeting, forward-looking infrared (FLIR), and long range IRST functions. The ASQ-242 CNI suite uses a half dozen different physical links, including the Multifunction Advanced Data Link (MADL), for covert CNI functions.[Through sensor fusion, information from radio frequency receivers and infrared sensors are combined to form a single tactical picture for the pilot. The all aspect target direction and identification can be shared via MADL to other platforms without compromising low observability. Link 16 is present for communication with legacy systems.
The glass cockpit was designed to give the pilot good situational awareness. The main display is a 20- by 8-inch (50 by 20 cm) panoramic touchscreen, which shows flight instruments, stores management, CNI information, and integrated caution and warnings; the pilot can customize the arrangement of the information. Below the main display is a smaller stand-by display.[143] The cockpit has a speech-recognition system developed by Adacel. The F-35 does not have a heads-up display; instead, flight and combat information is displayed on the visor of the pilot’s helmet in a helmet-mounted display system (HMDS). The one-piece tinted canopy is hinged at the front and has an internal frame for structural strength. The Martin-Baker US16E ejection seat is launched by a twin-catapult system housed on side rails. There is a right-hand side stick and throttle hands-on throttle-and-stick system. For life support, an onboard oxygen-generation system (OBOGS) is fitted and powered by the Integrated Power Package (IPP), with an auxiliary oxygen bottle and backup oxygen system for emergencies.
To preserve its stealth shaping, the F-35 has two internal weapons bays with four weapons stations. The outboard weapons stations can carry air-to-ground ordinance, whereas the two inboard stations can carry air-to-air missiles. The aircraft can also use six external weapons stations underneath the wings for missions that do not require stealth. The F-35A is armed with a 25 mm GAU-22/A rotary cannon mounted internally near the left wing root with 182 rounds carried; The F-35A is the only JSF version to carry an internal cannon.
The F-35A uses a boom-type aerial refuelling system, with a recepticle in the upper fuselage behind the cockpit.
The first F-35A test aircraft, designated AA-1, was rolled out in Fort Worth, Texas, on 19 February 2006 and first flew on 15 December 2006. The aircraft was given the name “Lightning II” in 2006. The Air Force took delivery of its first production F-35A at Eglin AFB in 2001 to begin pilot and maintainer training. On September 12, 2012, the USAF began an operational utility evaluation of the F-35A. In January 2013, training began at Eglin AFB. In 2014, the 58th Fighter Squadron became the first complete F-35A squadron. In January 2015, two USAF F-35A squadrons were based at RAF Lakenheath in the UK. Air Combat Command declared the F-35A “combat ready” in August of 2016. In the spring of 2017, USAF F-35As particated in Red Flag exercises held at Nellis AFB. By 2018, the Air Force units operating the F-35A included the 461st Flight Test Squadron and the 31st Test and Evaluation Squadron at Edwards AFB in California, the Integrated Training Cener at Eglin AFB, the 388th FW and 419th FW at Hill AFB in Utah, the 56th FW wing at Luke AFB in Arizona, and the 422nd Test and Evaluation Squatron at Nellis AFB in Nevada. USAF F-35As completed their first combat mission on Apr 27, 2019 in an airstrike on an Islamic State tunnel network in northern Iraw.
Specifications of the F-35A: Length: 51.4 ft Wingspan: 35 ft Height: 14.4 ft Wing area: 460 sq ft Empty weight: 29,300 lb Gross weight: 49,540 lb Max takeoff weight: 70,000 lb Fuel capacity: 18,250 lb internal Powerplant: 1 × Pratt & Whitney F135-PW-100 afterburning turbofan, 28,000 lbf thrust dry, 43,000 lbf with afterburner Performance Maximum speed: Mach 1.6 at altitude 806 mph at sea level Range: 1,700 mi, Combat range: 770 mi on internal fuel 870 mi oninterdiction mission on internal fuel, for internal air to air configuration Service ceiling: 50,000 ft g limits: +9.0 Armament Guns: 1 GAU-22/A 4-barrel rotary cannon, 180 rounds Hardpoints: 4 internal stations, 6 external stations on wings with a capacity of 5,700 pounds internal, 15,000 pounds external, 18,000 pounds total weapons payload.
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