The Boeing F-15SE Silent Eagle was a proposed upgrade of the F-15E strike fighter by Boeing using stealth features, such as internal weapons carriage and radar-absorbent material.
On 17 March 2009, Boeing first displayed an F-15SE demonstrator. The F-15SE was designed to use fifth-generation fighter technology, such as radar-absorbing materials, to significantly reduce its radar cross-section (RCS). It would have possessed a level of stealth that the U.S. government would have allowed for export, being optimized for air-to-air missions (against X-band radars) and much less effective against ground radars (which use other frequencies). Different levels of RCS reduction were studied, and Boeing stated that this stealth will only be in the range of fifth-generation aircraft such as the F-35 Lightning II from the frontal aspect.
Unique features to the F-15SE were the conformal weapons bays (CWB) that would have replaced the conformal fuel tanks (CFT) to hold weapons internally – thus reducing fuel capacity – and the twin vertical tails canted outward 15° to reduce RCS. Weapons can also be carried externally on hardpoints under each wing. New build F-15SEs were to be lighter and more fuel efficient than Strike Eagle conversions due to the canted tails, fly-by-wire controls, and digital electronic warfare equipment; enabling two additional weapons stations on the wings. The aircraft was to have a Raytheon active electronically scanned array radar, and a new BAE Systems EW system.
In March 2009, Boeing formally launched the F-15SE for international sales; it was aimed at F-15 users such as Israel, Saudi Arabia, Japan, and South Korea. Boeing estimated the unit cost as approximately US$100 million, including spares and support; its lower cost compared to fifth generation fighters was intended to appeal to the export market. In 2009, Boeing began tentative talks with South Korea over the Silent Eagle, but was unable to market it to international customers without an export license from the US government. Boeing filed for an export license in early 2010, and received it in July 2010. In August 2010, clearance was granted to export the F-15SE's RCS treatments and EW suite to South Korea.
During August and September 2009, Boeing evaluated an F-15E with different radar absorbent coatings to select a coating. The first production F-15E (86-0183) was modified to the F-15E1 configuration to serve as a demonstrator. It first flew on 8 July 2010 with a left-side CWB, and on 20 July 2010 launched an AMRAAM from a CWB.
Boeing sought other companies to be risk-sharing partners to reduce development costs. In November 2010, Boeing signed an agreement with Korea Aerospace Industries for KAI to design and manufacture the F-15SE's CWB. KAI had previously produced wings and forward fuselages for F-15K and F-15SG. On January 2012, The Korea Times reported that only 10% of the design work on the CWB had been completed, and that development of the canted vertical tails had been suspended in 2010. However, Boeing had stated that development continued with scale model wind tunnel tests scheduled for spring 2012.
Israel held several discussions over the F-15SE as an alternative to the F-35 Lightning II. In August 2010, Israel opted to buy the F-35. In 2015, Israel requested a squadron of F-15s based on the Silent Eagle standard.
In South Korea's F-X III fighter program, the F-15SE was bid against the F-35 and Eurofighter Typhoon. Existing F-15s were used for a fly-off against the Typhoon, and an F-35 flight simulator. On 18 August 2013, the South Korean Defense Acquisition Program Administration (DAPA) announced that the F-15SE as the only remaining candidate; the F-35 being too costly and the Typhoon disqualified for bidding flaws. On 24 September 2013, the defense ministry rejected the award, saying that a new competition would be held. On 22 November 2013, it was reported that South Korea will purchase the F-35A. Boeing had shifted from the F-15SE to the "Advanced F-15".
Basic specifications listed are for the F-15E Strike Eagle, on which the F-15SE is based.