The name of Fifth generation fighter refers to a classification that, although in principle is quite broad and diffuse, denotes those planes developed for military purpose and are the most advanced as of 2015. The plans contain all the technological advances in sensors and systems added up to the previous fourth-generation and incorporates new ones. The terms are not well-established as well as the criteria but some American companies developing the models have sometimes mentioned some of them. For example, they require an almost complete stealth aspect even when carrying weapons (which implicitly requires an internal weapons bay), a low profile to be detected by radar, special air-frames that have high-performance and resistance as well as unique and modern avionics. In addition,the computer systems should be among the most advanced ones and integrate a networking capability to create a perfect environment in the battlefield and early enemy detection features.
Although the only publicly reported fifth-generation fighters that have been tested for combat are the F-22 Raptor and the F-35 Lightning II (A,B), there are serious competitors at different stages of development (although they might have been already tested for combat in secret) such as HAL AMCA – India, Shenyang J-31 (F-60) – China, HAL Sukhoi PMF/FGFA – India and Russia, TbAI TFX / F-X – Turkey, Mitsubishi ATD-X (Shinshin) – Japan, KAI KF-X – South Korea, Lockheed Martin F-35 Lightning II (C) – USA, Sukhoi PAK FA (T-50) – Russia and Chengdu J-20 (Black Eagle) – China.
The described fifth-generation jet fighters need a special engine with high-performance and requirements. In the case of American fighters, there are only two that have these features called Pratt & Whitney F119 and the Pratt & Whitney F135 that is installed in the F-35. An alternative engine, the General Electric/Rolls-Royce F136 was under development for several years but it was cancelled by the developers by the end of 2011. There are however works for the engines of the F-35C which are still under development. The Chinese fighters entirely depend on the Russian engines but they are complicated and expensive to build so the Russian side is also under pressure to deliver them and are falling short in the development of the latest models and improvements for these jet engines.
The origins of the stealth technology to develop stealth fighters can be found here:
I am collecting information about the latest stealth / fifth generation jet fighters and creating a database. For each model, the preliminary information can be found as follows:
F-35A Lightning II
F-35B Lightning II
F-35C Lightning II
Shenyang J-31 (F-60)
HAL Sukhoi PMF/FGFA
TbAI TFX / F-X
Mitsubishi ATD-X (Shinshin)
Sukhoi PAK FA (T-50)
Chengdu J-20 (Black Eagle)