Second generation jet fighters 1950s- 1960s)
The development of second-generation fighters was shaped by technological breakthroughs, lessons learned from the aerial battles of the Korean War, and a focus on conducting operations in a nuclear warfare environment. Technological advances in aerodynamics, propulsion and aerospace building materials permitted designers to experiment with aeronautical innovations, such as swept wings, delta wings, and area-ruled fuselages. Widespread use of afterburning turbojet engines made these the first production aircraft to break the sound barrier, and the ability to sustain supersonic speeds in level flight became a common capability amongst fighters of this generation.
Third-generation jet fighters ( 1960s -1970s)
The third generation witnessed continued maturation of second-generation innovations, but it is most marked by renewed emphases on maneuverability and traditional ground-attack capabilities. Over the course of the 1960s, increasing combat experience with guided missiles demonstrated that combat would devolve into close-in dogfights. Analog avionics began to be introduced, replacing older "steam-gauge" cockpit instrumentation. Enhancements to improve the aerodynamic performance of third-generation fighters included flight control surfaces such as canards, powered slats, and blown flaps. A number of technologies would be tried for Vertical/Short Takeoff and Landing, but thrust vectoring would be successful on the Harrier jump jet. .
Fourth-generation fighters continued the trend towards multirole configurations, and were equipped with increasingly sophisticated avionics and weapon systems. Fighter designs were significantly influenced by the Energy-Maneuverability (E-M) theory developed by Colonel John Boyd and mathematician Thomas Christie, based upon Boyd's combat experience in the Korean War and as a fighter tactics instructor during the 1960s. E-M theory emphasized the value of aircraft specific energy maintenance as an advantage in fighter combat. Boyd perceived maneuverability as the primary means of getting "inside" an adversary's decision-making cycle, a process Boyd called the "OODA loop" (for "Observation-Orientation-Decision-Action"). This approach emphasized aircraft designs that were capable of performing "fast transients" – quick changes in speed, altitude, and direction – as opposed to relying chiefly on high speed alone.
5th generation jet fighters (1990s to the present)
The end of the Cold War in 1991 led many governments to significantly decrease military spending as a "peace dividend". Air force inventories were cut, and research and development programs intended to produce what was then anticipated to be "fifth-generation" fighters took serious hits; many programs were canceled during the first half of the 1990s, and those which survived were "stretched out". While the practice of slowing the pace of development reduces annual investment expenses, it comes at the penalty of increased overall program and unit costs over the long-term. In this instance, however, it also permitted designers to make use of the tremendous achievements being made in the fields of computers, avionics and other flight electronics, which had become possible largely due to the advances made in microchip and semiconductor technologies in the 1980s and 1990s. This opportunity enabled designers to develop fourth-generation designs – or redesigns – with significantly enhanced capabilities. These improved designs have become known as "Generation 4.5" fighters, recognizing their intermediate nature between the 4th and 5th generations, and their contribution in furthering development of individual fifth-generation technologies.
Sixth generation jet fighters
A sixth generation jet fighter is a conceptual airplane expected to enter service in the United States Air Force and United States Navy in 2025–30 timeframe. With the Chinese Chengdu J-20 and the Russian-Indian Sukhoi PAK FA under development, the need for of a sixth generation fighter may be urgent for the US military. The USAF seeks new fighter for the 2030–50 period named the "Next Generation Tactical Aircraft"/"Next Gen TACAIR" The US Navy looks to replace its F/A-18E/F Super Hornets beginning in 2025 with the Next Generation Air Dominance air superiority fighter.
China's sixth-generation fighter aircraft design based on nuclear propulsion Design Notes:
Aerodynamic layout: The nose starts from the edge of a large increase lift, duck wings can be rotated 360 °. Inlet rectangular design, the fuselage back into the air. The main wing for the diamond-shaped, adjustable flaps and edges of the former, ① leading edge sweep angle of 40 ~ 50 °. Twin-tail camber is about 25 °.
Propulsion: there are two programs.
Program 1: a conventional propulsion, using thrust-weight ratio of 12 to 15 between the turbofan engines, no afterburner: we can use Mach 1.5 ~ 1.8 supercruise; with afterburner: the maximum can reach Mach 2.4.
Program 2: using nuclear propulsion, using the nuclear heating-fuel rocket engines to accelerate the use of nuclear reactors, heat working fluid, jet speed can reach 5 to 10 km/second or so; or use of nuclear rocket engines, from nuclear power industry after the electric field to accelerate ions quality..
Airborne Weapons: a main-deck fuselage belly and two vice-cabins. Shells buried in the main cabin 4 ~ 6 in the long-range air to air missiles, and its maximum striking distance of 200 ~ 400KM. Vice shells buried in the cabin two off-axis angle is ± 90 ° infrared imaging focal plane short-range combat missiles. Can be mounted satellite/TV/IR/laser-guided and anti-radiation weapons and open space.
Airborne equipment: the source fitted with multi-function phased-array radar and helmet sight, a rear mounted tail radar, with all the attacks, over the shoulder launch capabilities. Equipped with radar/UV/IR warning system, installation of a belly may be 360 ° rotating laser cannons, the tail with an active-defense network systems. With the formation of combat capability, and a strong command of active / passive electronic interference.
Range: If the use of the program one: a maximum range of 4000 ~ 5000KM, combat radius of 1500 ~ 2000KM, with aerial refueling capability. If the use of the program two: enabling ultra-long-range flight operations, a maximum range of 12000 ~ 15000KM, combat radius of 5000 ~ 6000KM, without aerial refueling.
Aircraft, the basic geometric dimensions and weight:
Length 15m Wingspan 10m High 3.5m Empty weight is about 13000 ~ 15000Kg Maximum Takeoff Weight Program 1: 30000 ~ 35000Kg Program 2: 22000 ~ 27000Kg (less nuclear fuel can be loaded fuel 7000Kg) Ceiling of about 18000m.
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