F-15 series fighter aircraft

Originally designed as a high-end United States Air Force fighter strictly for air-to-air use, the F-15 Eagle aircraft has become a family, with multiple mission variants, upgrades, and export versions.
For the pure air superiority versions, first the F-15A/B and then the F-15C/D, the first of the pair is the single-seat version and the second a two seat; the two seat is used for training, proficiency testing, and similar requirements. All ground attack variants, beginning with the F-15E Strike Eagle, are two seat, with a pilot and weapons systems officer (WSO).
Within major version levels such as A/B, there are a series of numbered incremental upgrades called blocks.
Air-to-Air
The air-to-air version has gone through multiple upgrades. Besides the USAF, it is operated by:
- Israel
- Japan (F-15J license-built local manufacturing). Some are used for radar reconnaissance
- Saudi Arabia
Air-to-Ground
Originally built, over the protests of some Air Force officers with an informal motto of "not a pound for air to ground", as a high-performance attack aircraft retaining air combat capability, the Strike Eagle has been extremely successful. In many demanding missions, it outperforms the F-16 Fighting Falcon, which had been seen as the low-end, primarily air-to-ground version. This is not to say, however, that the F-16 is not a highly effective aircraft, and the F-16 and F-15E form a low/high mix that provides air planners with additional flexibility.
Foreign versions include:
- F-15I (Israel): Basically the same as the U.S. version, with the exception of using a domestic radar warning receiver rather than the AN/ALR-56
- F-15K (South Korea): many advances in electronics, including head-mounted sights and a wider range of missiles, including AGM-84 Harpoon anti-shipping missiles and the SLAM land attack version of the AGM-84.
- F-15S (Saudi Arabia): a basic F-15E, but with reduced performance in some of the ground attack radar modes
- F-15SG, formerly F-15T (Singapore)
Speculative version
Boeing, now the manufacturer, has developed a F-15 Silent Eagle variant, which is considerably stealthier than the basic F-15; it is intended primarily for the export market as an alternative to the F-35 Joint Strike Fighter and the F-22 Raptor.