The F-35 Lightning II joint strike fighter (JSF), is being developed by Lockheed Martin Aeronautics Company for the US Air Force, Navy and Marine Corps and the UK Royal Navy.
The stealthy, supersonic multirole fighter was designated the F-35 Lightning II in July 2006. The JSF is being built in three variants: a conventional take-off and landing aircraft (CTOL) for the US Air Force; a carrier variant (CV) for the US Navy; and a short take-off and vertical landing (STOVL) aircraft for the US Marine Corps and the Royal Navy. A 70%-90% commonality is required for all variants.
The requirement is for: USAF F-35A air-to-ground strike aircraft, replacing F-16 and A-10, complementing F-22 (1763); USMC F-35B – STOVL strike fighter to replace F/A-18B/C and AV-8B (480); UK RN F-35C – STOVL strike fighter to replace Sea Harriers (60); US Navy F-35C – first-day-of-war strike fighter to replace F/A-18B/C and A-6, complementing the F/A-18E/F (480 aircraft).
Lightning II Joint Strike Fighter (JSF) development
The Lockheed Martin JSF team includes Northrop Grumman, BAE Systems, Pratt and Whitney and Rolls-Royce. Final assembly of the aircraft took place at Lockheed Martin’s Fort Worth plant in Texas.
Major subassemblies were produced by Northrop Grumman Integrated Systems at El Segundo, California and BAE Systems at Samlesbury, Lancashire, England. BAE Systems is responsible for the design and integration of the aft fuselage, horizontal and vertical tails and the wing-fold mechanism for the CV variant, using experience from the Harrier STOVL programme. Terma of Denmark and Turkish Aerospace Industries of Turkey are supplying sub-assemblies for the centre fuselage.
In January 2001, the UK MoD signed a memorandum of understanding to co-operate in the SDD (system development and demonstration) phase of JSF and, in September 2002, selected the STOVL variant to fulfil the future joint combat aircraft (FJCA) requirement. Following the contract award, other nations signed up to the SDD phase are: Australia, Canada, Denmark, Italy, Netherlands, Norway, Singapore and Turkey.
The development of the centre fuselage for the first international F-35 joint strike fighter began on 30 October 2009. It is being developed by Northrop Grumman, principally for the UK. The centre fuselage including composite air inlet ducts were supplied by Turkish Aerospace Industries (TAI).
The F-35B short take-off and vertical landing (STOVL) variant, designated BK-1, completed its assembly in November 2011. It will be delivered to the UK Ministry of Defence by 2012. The variant is being developed as part of the low-rate initial production (LRIP) 3 and is expected to produce 138 F-35Bs for the UK.
Training centre at Elgin Air Force Base and F-35 operational bases
An integrated training centre for the F-35 fighter programme has been set up at Elgin Air Force Base in the US. The training centre was inaugurated in November 2010 and will be fully operational by 2013.
A total of 11 base locations were unveiled for the F-35 Lightning joint strike fighter. Of the 11, six were selected to carry out operations and five to be training bases.
The six bases implementing F-35 operations are Burlington International Airport Guard Station, Vermont; Hill AFB, Utah; Jacksonville International Airport Air Guard Station, Florida; Mountain Home AFB, Idaho; Shaw AFB, South Carolina; and McEntire Air Guard Base, South Carolina. The five bases for training purposes are Boise Air Terminal Air Guard Station, Idaho; Eglin Air Force Base, Florida; Holloman Air Force Base, New Mexico; Luke AFB, Arizona; and Tucson International Airport Air Guard Station, Arizona.
The selected locations will be finalised after implementing environmental impact analysis.
Concept demonstration phase led by Boeing and Lockheed
The concept demonstration phase of the programme began in November 1996 with the award of contracts to two consortia, led by Boeing Aerospace and Lockheed Martin. The contracts involved the building of demonstrator aircraft for three different configurations of JSF, with one of the two consortia to be selected for the development and manufacture of all three variants.
In October 2001, an international team led by Lockheed Martin was awarded the contract to build JSF. An initial 22 aircraft (13 flying test aircraft and eight ground-test aircraft) will be built in the programme’s system development and demonstration (SDD) phase. Flight testing will be carried out at Edwards Air Force Base, California, and Naval Air Station, Patuxent River, Maryland.
In April 2003, JSF completed a successful preliminary design review (PDR). The critical design review (CDR) for the F-35A was completed in February 2006, for the F-35B in October 2006 and for the F-35C in June 2007. The first flight of the CTOL F-35A took place on 15 December 2006.
Low-rate initial production (LRIP) for the F-35A/B was approved in April 2007 with an order for two CTOL aircraft. An LRIP 2 contract for six CTOL aircraft was placed in July 2007. The STOVL F-35B was rolled out in December 2007 and made its first flight, a conventional take-off and landing, in June 2008. STOVL flights began in early 2009. An LRIP contract for six F-35B STOVL aircraft was placed in July 2008.
First flights of Lockheed’s F-35 variations
The F-35C took off on its first flight in November 2011. The F-35A fighter was delivered to Eglin Air Force Base in October 2011 and is under functional test; the F-35B was inaugurated in October 2011.
The first flight of the F-35 is powered by the GE Rolls-Royce F136 engine. Critical design review was completed in February 2008.
By the end of 2006, Australia, Canada, the Netherlands and the UK had signed the MoU for the F-35 Production, Sustainment and Follow-on Development (PSFD) phase.
Norway and Turkey (requirement 100 F-35A) signed in January 2007. Denmark and Italy (requirement 131 F-35A and B) signed in February 2007. In May 2008, Israel requested the sale of 25 F-35A aircraft with 50 options.
Participating nations were to sign up to the initial operation test and evaluation (IOT&E) phase by the end of February 2009. In October 2008, Italy announced that it intended not to participate in the IOT&E.
In September 2004, Lockheed Martin announced that, following concerns over the weight of the STOVL F-35B, design changes had reduced the aircraft weight by 1,225kg while increasing propulsion efficiency and reducing drag. The weight requirements will also call for a smaller internal weapons bay than on the other variants.
International orders and deliveries to forces in the UK, US and Canada
The USAF ordered 32 new F-35A aircraft in 2010. USMC ordered 16 F-35B aircraft and is considering more 13 more aircraft. The USN ordered seven F-35Bs aircraft in 2009, and 12 F-35s were delivered to the US in 2011.
The UK ordered two F-35B’s in 2009 and one F-35C in 2010. The Netherlands ordered three F-35A aircraft, one in 2010 and two in 2011. Australia decided to purchase 14 F-35A aircraft in October 2010.
Israel ordered 20 F-35I variant aircraft in 2010 following the Israeli Government’s decision to select the F-35 as its next-generation aircraft. In June 2011, the Norwegian Parliament unanimously approved the funding of four F-35 Lightning II training jets to stabilise Norway’s future air-combat capability requirements.
Canada also announced its choice of F-35 aircraft for its future fighter requirements. The Italian Parliament has approved the purchase of 131 F-35 aircraft and construction of a final assembly facility at Cameri Air Base.
Design differences between variants of the Joint Strike Fighter
In order to minimise the structural weight and complexity of assembly, the wingbox section integrates the wing and fuselage section into one piece. To minimise radar signature, sweep angles are identical for the leading and trailing edges of the wing and tail (planform alignment).
The fuselage and canopy have sloping sides. The seam of the canopy and the weapon bay doors are sawtoothed and the vertical tails are canted at an angle.
The marine variant of JSF is very similar to the air force variant, but with a slightly shorter range because some of the space used for fuel is used for the lift fan of the STOVL propulsion system.
The main differences between the naval variant and the other versions of JSF are associated with the carrier operations. The internal structure of the naval version is very strong to withstand the high loading of catapult-assisted launches and tailhook arrested landings.
The aircraft has larger wing and tail control surfaces for low-speed approaches for carrier landing. Larger leading edge flaps and foldable wingtip sections provide a larger wing area, which provides an increased range and payload capacity.
The canopy (supplied by GKN Aerospace), radar and most of the avionics are common to the three variants.
The centre fuselage assembling process includes loading of an all-composite air inlet duct into a special tooling structure called a jig, followed by 18 major steps such as bonding metal frames around the duct. The frames serve to brace and position the duct properly within the centre fuselage.
Cockpit and avionics systems from BAE Systems, Honeywell and Raytheon
L-3 Display Systems is developing the panoramic cockpit display system, which will include two 10in×8in active matrix liquid crystal displays and display management computer.
The following will also supply F-35 avionics systems:
- BAE Systems Avionics – side stick and throttle controls
- Vision Systems International (a partnership between Kaiser Electronics and Elbit of Israel) – advanced helmet-mounted display
- BAE Systems Platform Solutions – alternative design helmet-mounted display, based on the binocular helmet being developed for the Eurofighter Typhoon
- Ball Aerospace – communications, navigation and integration (CNI) integrated body antenna suite (one S-band, two UHF, two radar altimeter, three L-band antennas in each aircraft)
- Harris Corporation – advanced avionics systems, infrastructure, image processing, digital map software, fibre optics, high-speed communications links and part of the communications, navigation and information (CNI) system
- Honeywell – radar altimeter, inertial navigation / global positioning system (INS/GPS) and air data transducers
- Raytheon – 24-channel GPS with digital anti-jam receiver (DAR).
Weapons and armaments used on Lockheed Martin’s JSF
Weapons are carried in two parallel bays located in front of the landing gear. Each weapons bay is fitted with two hardpoints for carrying a range of bombs and missiles.
Weapons to be cleared for internal carriage include: JDAM (joint direct attack munition), CBU-105 WCMD (wind-corrected munitions dispenser) for the sensor-fused weapon, JSOW (joint stand-off weapon), Paveway IV guided bombs, small diameter bomb (SDB), AIM-120C AMRAAM air-to-air missile and Brimstone anti-armour missile; for external carriage: JASSM (joint air-to-surface stand-off missile), AIM-9X Sidewinder, AIM-132 ASRAAM and Storm Shadow cruise missile.
In September 2002, General Dynamics Armament and Technical Products was selected as the gun system integrator. General Dynamics was awarded a contract for the internally mounted 25mm GAU-22/A gun system for the air force CTOL variant in November 2008. General Dynamics is developing an external gun system for the carrier and marine variants.
Fire control and targeting technology on the F-35 Lightning II
Lockheed Martin Missile & Fire Control and Northrop Grumman Electronic Sensors and Systems are jointly responsible for the JSF electro-optical system. A Lockheed Martin electro-optical targeting system (EOTS) will provide long-range detection and precision targeting, along with the Northrop Grumman DAS (distributed aperture system) thermal imaging system.
EOTS will be based on the Sniper XL pod developed for the F-16, which incorporates a mid-wave third-generation FLIR, dual mode laser, CCD TV, laser tracker and laser marker. BAE Systems Avionics in Edinburgh, Scotland will provide the laser systems.
DAS consists of multiple infrared cameras (supplied by Indigo Systems of Goleta, California) providing 360° coverage using advanced signal conditioning algorithms. As well as situational awareness, DAS provides navigation, missile warning and infrared search and track (IRST). EOTS is embedded under the aircraft’s nose, and DAS sensors are fitted at multiple locations on the aircraft.
AESA radar from Northrop Grumman Electronic Systems
Northrop Grumman Electronic Systems is developing the advanced electronically scanned array (AESA) AN/APG-81 multi-function radar. The AN/APG-81AESA will combine an integrated radio frequency subsystem with a multifunction array.
The radar system will also incorporate the agile beam steering capabilities developed for the APG-77. Northrop Grumman delivered the first radar to Lockheed Martin in March 2005 for flight testing.
Integrated electronic warfare suite from BAE Systems IEWS
BAE Systems information & electronic warfare systems (IEWS) will be responsible for the JSF integrated electronic warfare suite, which will be installed internally and have some subsystems from Northrop Grumman. BAE is developing a new digital radar warning receiver for the F-35.
Systems and suppliers including Honeywell, Goodrich and Paker Aerospace
Other suppliers include:
- ATK Composites – upper wing skins
- Vought Aircraft Industries – lower wing skins
- Smiths Aerospace – electronic control systems, electrical power system (with Hamilton Sundstrand), integrated canopy frame
- Honeywell – landing system wheels and brakes, onboard oxygen-generating system (OBOGS), engine components, power and thermal management system driven by integrated auxiliary power unit (APU)
- Parker Aerospace – fuel system, hydraulics for lift fan, engine controls and accessories
- Moog Inc – primary flight control electrohydrostatic actuation system (EHAS), leading edge flap drive system and wing-fold system
- EDO Corporation – pneumatic weapon delivery system
- Goodrich – lift-fan anti-icing system
- Stork Aerospace – electrical wiring
Propulsion of the Joint Strike Fighter variation aricraft
Early production lots of all three variants will be powered by the Pratt and Whitney afterburning turbofan F-135 engine, a derivative of the F119 fitted on the F-22. Following production aircraft will be powered by either the F135 or the F-136 turbofan being developed by General Electric and Rolls-Royce. However, in the 2007 US Military Budget, published in February 2006, no funding was allocated for the development of the F-136 engine. The US Congress voted to restore funding for the F-136 in October 2006.
Each engine will be fitted with two BAE Systems full authority digital electronic control (FADEC) systems. Hamilton Sundstrand is providing the gearbox.
On the F-35B, the engine is coupled with a shaft-driven lift fan system for STOVL propulsion. The counter-rotating lift fan, developed by Rolls-Royce Defence, can generate more than 20,000lb of thrust. Doors installed above and below the vertical fan open as the fin spins up to provide vertical lift.
The main engine has a three-bearing swivelling exhaust nozzle. The nozzle, which is supplemented by two roll control ducts on the inboard section of the wing, together with the vertical lift fan provide the required STOVL capability.
Variants
F-35A
The F-35A is the conventional takeoff and landing (CTOL) variant intended for the USAF and other air forces. It is the smallest, lightest version and capable of 9 g, the highest of all variants.
Although the F-35A currently conducts aerial refueling via boom and receptacle method, the aircraft can be modified for probe-and-drogue refueling if needed by the customer. A drag chute pod can be installed on the F-35A, with the Royal Norwegian Air Force being the first operator to adopt it.
F-35B
The F-35B is the short takeoff and vertical landing (STOVL) variant of the aircraft. Similar in size to the A variant, the B sacrifices about a third of the A variant’s fuel volume to accommodate the SDLF. This variant is limited to 7 g. Unlike other variants, the F-35B has no landing hook. The “STOVL/HOOK” control instead engages conversion between normal and vertical flight.
F-35C
The F-35C variant is designed for catapult-assisted take-off but arrested recovery operations from aircraft carriers. Compared to the F-35A, the F-35C features larger wings with foldable wingtip sections, larger wing and tail control surfaces for improved low-speed control, stronger landing gear for the stresses of carrier arrested landings, a twin-wheel nose gear, and a stronger tailhook for use with carrier arrestor cables. The larger wing area allows for decreased landing speed while increasing both range and payload. The F-35C is limited to 7.5 g.
F-35D
A study for a possible upgrade of the F-35A to be fielded by the 2035 target date of the USAF’s Future Operating Concept.
F-35I “Adir”
The F-35I Adir (Hebrew: אדיר, meaning “Awesome”, or “Mighty One”) is an F-35A with unique Israeli modifications. The US initially refused to allow such changes before permitting Israel to integrate its own electronic warfare systems, including sensors and countermeasures. The main computer has a plug-and-play function for add-on systems; proposals include an external jamming pod, and new Israeli air-to-air missiles and guided bombs in the internal weapon bays. A senior IAF official said that the F-35’s stealth may be partly overcome within 10 years despite a 30 to 40 year service life, thus Israel’s insistence on using their own electronic warfare systems. Israel Aerospace Industries (IAI) has considered a two-seat F-35 concept; an IAI executive noted: “There is a known demand for two seats not only from Israel but from other air forces”. IAI plans to produce conformal fuel tanks.
CF-35
The Canadian CF-35 is a proposed variant that would differ from the F-35A through the addition of a drogue parachute and may include an F-35B/C-style refueling probe. In 2012, it was revealed that the CF-35 would employ the same boom refueling system as the F-35A. One alternative proposal would have been the adoption of the F-35C for its probe refueling and lower landing speed; however, the Parliamentary Budget Officer’s report cited the F-35C’s limited performance and payload as being too high a price to pay. Following the 2015 Federal Election the Liberal Party, whose campaign had included a pledge to cancel the F-35 procurement, formed a new government and commenced an open competition to replace the existing CF-18 Hornet.
Specifications
| Crew | 1 |
| Length | 51.4 ft (15.7 m) |
| Wingspan | 35 ft (11 m) |
| Height | 14.4 ft (4.4 m) |
| Wing area | 460 sq ft (43 m2) |
| Empty weight | 29,300 lb (13,290 kg) |
| Gross weight |
49,540 lb (22,471 kg) |
| Max take off weight | 70,000 lb (31,751 kg) |
| Power plant (Dry thrust) |
1 × Pratt & Whitney F135-PW-100 afterburning turbofan, 28,000 lbf (120 kN) |
| Power plant (Thrust with afterburner) |
43,000 lbf (190 kN) |
| Maximum speed (Sea level) |
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| Maximum speed (High altitude) | Mach 1.6 |
| Combat radius |
669 nmi (770 mi, 1,239 km) |
| Ferry range |
1,500 nmi (1,700 mi, 2,800 km) |
| Service ceiling |
50,000 ft (15,000 m) |
| Rate of climb | |
| Wing loading | 107.7 lb/sq ft (526 kg/m2) |
| Thrust/weight | 1.13 |
| Design load factor | +9g |
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Avionics
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Armament
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Operators
- Royal Australian Air Force – 30 F-35A delivered by November 2020, of 72 ordered. A fourth squadron is planned to bring the eventual total to 100.
- Belgian Air Component – 34 F-35A planned
- Royal Danish Air Force – 27 F-35A planned
- Israeli Air Force – 26 delivered and operational (F-35I), from 50 ordered, and 75 planned.
- Italy
- Italian Air Force – 9 F-35As operational and 2 more on order with 17 more ordered for delivery up to 2019; up to 60 total planned.
- Italian Navy – 15 F-35Bs planned of which 1 delivered with 4 on order for delivery by 2019.
- Japan Air Self-Defense Force – 12 F-35As operational; with a total order of 147, including 42 F-35B variants.
- Royal Netherlands Air Force – 9 F-35As delivered and operational, from 46 ordered.
- Royal Norwegian Air Force – 25 F-35As delivered and operational, of which 7 are based in the US for training in May 2020 of 52 F-35As planned in total.
- Polish Air Force – 32 F-35As on order.
- Republic of Korea Air Force – 13 F-35As delivered out of 60 ordered.
- Republic of Korea Navy – about 20 F-35Bs planned.
- Republic of Singapore Air Force – up to 12 F-35Bs planned
- Turkish Air Force – 4 F-35As delivered to Luke Air Force Base for training. 30 were ordered, of up to 120 total planned. Future purchases have been banned by the U.S. with contracts canceled by early 2020.
- Royal Air Force and Royal Navy (joint operation) – 18 F-35Bs received, with 15 in the UK and the rest in the US, where they are used for testing and training. 42 (24 FOC fighters and 18 training aircraft) to be fast-tracked by 2023; 138 F-35s total planned, first 48 aircraft will be F-35B.
- United States
- United States Air Force – 229 F-35As delivered, 1,763 F-35As planned.
- United States Marine Corps – 57 F-35Bs delivered. 353 F-35Bs and 67 F-35Cs planned.
- United States Navy – 39 F-35Cs delivered, 273 F-35Cs planned.
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