The Lockheed Martin F-35 Lightning II

The Lockheed Martin F-35 Lightning II is a fifth-generation, single-seat, single-engine, stealth-capable military strike fighter, a multirole aircraft that can perform close air support, tactical bombing, and air superiority fighter missions. The F-35 has three different models; one is the conventional takeoff and landing variant, the second is short takeoff and vertical-landing variant, and the third is a carrier-based variant.

The F-35 is descended from the X-35, the product of the Joint Strike Fighter (JSF) program. Its development is being principally funded by the United States, with the United Kingdom, and other partner governments providing additional funding.[4] It is being designed and built by an aerospace industry team led by Lockheed Martin with Northrop Grumman and BAE Systems as major partners.[4] Demonstrator aircraft flew in 2000,[5] with the first flight on 15 DEC
An F-35 wind tunnel testing model in the Arnold Engineering Development Center's 16-foot transonic wind tunnel

The JSF program was created to replace various aircraft while keeping development, production, and operating costs down. This was pursued by building three variants of one aircraft, sharing 80% of their parts:

F-35A, conventional takeoff and landing (CTOL) variant.
F-35B, short-takeoff and vertical-landing (STOVL) variant.
F-35C, carrier-based (CV) variant.

The F-35 is being designed to be the world's premier strike aircraft through 2040. It is intended that its close and long-range air-to-air capability will be second only to that of the F-22 Raptor.[7] Specifically the F-35’s requirements are that it be: four times more effective than legacy fighters in air-to-air combat, eight times more effective in air-to-ground battle combat, and three times more effective in reconnaissance and suppression of air defenses. These capabilities are to be achieved while still having significantly better range and require less logistics support than legacy aircraft.[8]

Origins and selection
The Joint Strike Fighter evolved out of several requirements for a common fighter to replace existing types. The actual JSF development contract was signed on 16 November 1996.
The contract for System Development and Demonstration (SDD) was awarded on 26 October 2001 to Lockheed Martin, whose X-35 beat the Boeing X-32. DoD officials and British Minister of Defence Procurement Lord Bach, said the X-35 consistently outperformed the X-32, although both met or exceeded requirements. The designation of the fighter as "F-35" came as a surprise to Lockheed, which had been referring to the aircraft in-house by the designation "F-24".[9]

Design phase

The F-35 was in danger of missing performance requirements in 2004 because it weighed too much — reportedly, by 2,200 pounds (1,000 kg) or 8 percent. In response, Lockheed Martin added engine thrust and shed more than a ton by thinning the aircraft's skin; shrinking the weapons bay and vertical tails; rerouting some thrust from the roll-post outlets to the main nozzle; and redesigning the wing-mate joint, portions of the electrical system, and the portion of the aircraft immediately behind the cockpit.[10]

On 7 July 2006, the U.S. Air Force officially announced the name of the F-35: Lightning II,[11] in honor of Lockheed's World War II-era twin-prop P-38 Lightning[12] and the Cold War-era jet, the English Electric Lightning. English Electric Company's aircraft division was incorporated into BAC, a predecessor of F-35 partner BAE Systems. Other names previously listed as contenders were Kestrel, Phoenix, Piasa, Black Mamba and Spitfire II. Lightning II was also an early company name for the aircraft that became the F-22 Raptor.

Design

The F-35A being towed to its inauguration ceremony on 7 July 2006
The F-35 appears to be a smaller, slightly more conventional, one-engine sibling of the sleeker, two-engine F-22 Raptor, and indeed drew elements from it. The exhaust duct design was inspired by the General Dynamics Model 200, a 1972 VTOL aircraft designed for the Sea Control Ship.[13][verification needed] Lockheed teamed with the Yakovlev Design Bureau, developer of the Yakovlev Yak-141 "Freestyle", in the 1990s.[14][15] Stealth technology makes the aircraft difficult to detect as it approaches short-range tracking radar.
Some improvements over current-generation fighter aircraft are:
Durable, low-maintenance stealth technology;
Integrated avionics and sensor fusion that combine information from off- and onboard sensors to increase the pilot's situational awareness and improve identification and weapon delivery, and to relay information quickly to other command and control (C2) nodes;
High speed data networking including IEEE 1394b[16] and Fibre Channel.[17]

Cockpit
The F-35 features a full-panel-width "panoramic cockpit display (PCD)", with dimensions of 20 by 8 inches (50 by 20 centimeters).[18] A cockpit speech-recognition system (Direct Voice Input) is planned to improve the pilot's ability to operate the aircraft over the current-generation. The F-35 will be the first U.S. operational fixed-wing aircraft to use this system, although similar systems have been used in AV-8B and trialled in previous U.S. jets, particularly the F-16 VISTA.[19] In development the system has been integrated by Adacel Systems Inc with the speech recognition module supplied by SRI International.[20]
A helmet mounted display system (HMDS) will be fitted to all models of the F-35. While some fourth-generation fighters (such as the Swedish JAS 39 Gripen) have offered HMDS along with a head up display (HUD), this will be the first time in several decades that a front-line tactical jet fighter has been designed to not carry a HUD.[21]
The pilot flies the aircraft by means of a right-hand side-stick and left-hand throttle, both of which are supplied by BAE Systems.[22]
The Martin-Baker US16E ejection seat is used in all F-35 variants.[23] The US16E seat design balances major performance requirements, including safe terrain clearance limits, pilot load limits, and pilot size. It uses a twin-catapult system that is housed in side-rails.[24]

Sensors

EOTS under the nose of a mockup of the F-35.
The main sensor on board the F-35 is its AN/APG-81 AESA-radar, designed by Northrop Grumman Electronic Systems.[25] It is augmented by the Electro-Optical Targeting System (EOTS) mounted under the nose of the aircraft, designed by Lockheed Martin and BAE.[26] Further electro-optical sensors are distributed over the aircraft as part of the AN/AAS-37 system which acts as missile warning system and can aid in navigation and night operations.

Engines
Two different jet engines are being developed for the F-35; the Pratt & Whitney F135 and the General Electric/Rolls-Royce F136. The STOVL versions of both powerplants use the innovative Rolls-Royce LiftSystem, patented by Lockheed Martin and built by Rolls-Royce. This system is more like the Russian Yak-141 and German VJ 101D/E[27] than the preceding generation of STOVL designs, such as the Harrier Jump Jet.

The LiftSystem is composed of a lift fan, driveshaft, clutch, 2 roll posts and a "3 Bearing Swivel Module" (3BSM).[28] The 3BSM is a thrust vectoring nozzle which allows the main engine exhaust to be deflected downward at the tail of the aircraft. The lift fan near the front of the aircraft provides a counter-balancing thrust. Somewhat like a vertically mounted turboprop within the forward fuselage, the lift fan is powered by the engine's low-pressure (LP) turbine via a driveshaft and gearbox. Roll control during slow flight is achieved by diverting pressurized air from the LP turbine through wing mounted thrust nozzles called Roll Posts.[29]
The F-35B lift fan achieves the same 'flow multiplier' effect as the Harrier's huge, but supersonically impractical, main fan. Like lift engines, this added machinery is just deadweight during horizontal flight but provides a net increase in payload capacity during vertical flight. The cool exhaust of the fan also reduces the amount of hot, high-velocity air that is projected downward during vertical takeoff (which can damage runways and aircraft carrier decks). Though complicated and potentially risky, the lift system has been made to work to the satisfaction of DOD officials.

Armament

Weapons bay on a mock-up of the F-35.
The F-35 includes a GAU-22/A four-barrel 25 mm cannon.[30] The Cannon will be mounted internally with 180 rounds in the F-35A and fitted as an external pod with 220 rounds in the F-35B and F-35C.[31][32]

Internally (current planned weapons for integration), up to two air-to-air missiles and two air-to-ground weapons (up to two 2,000 lb bombs in A and C models; two 1,000 lb bombs in the B model) in the bomb bays.[33] These could be AIM-120 AMRAAM, AIM-132 ASRAAM, the Joint Direct Attack Munition (JDAM) — up to 2,000 lb (910 kg), the Joint Standoff Weapon (JSOW), Small Diameter Bombs (SDB) — a maximum of four in each bay, the Brimstone anti-armor missiles, Cluster Munitions (WCMD) and High Speed Anti-Radiation Missiles (HARM).[citation needed] The MBDA Meteor air-to-air missile is currently being adapted to fit internally in the missile spots and may be integrated into the F-35. The UK had originally planned to put up to four AIM-132 ASRAAM internally but this has been changed to carry 2 internal and 2 external ASRAAMs.[34] It has also been stated by a Lockheed executive that the internal bay will eventually be modified to accept up to 6 AMRAAMs. [35]

At the expense of being more detectable by radar, many more missiles, bombs and fuel tanks can be attached on four wing pylons and two wingtip positions. The two wingtip pylons can only carry AIM-9X Sidewinders, while the AIM-120 AMRAAM, Storm Shadow, Joint Air to Surface Stand-off Missile (JASSM) cruise missiles and 480 gallon fuel tanks can be carried in addition to the stores already integrated. An air-to-air load of eight AIM-120s and two AIM-9s is conceivable using internal and external weapons stations, as well as a configuration of six two thousand pound bombs, two AIM-120s and two AIM-9s.[33][36] With its payload capability, the F-35 can carry more air to air and air to ground weapons than legacy fighters it is to replace as well as the F-22 Raptor.[37