The McDonnell Douglas (now Boeing) F-15E Strike Eagle is an American all-weather multirole strike fighter derived from the McDonnell Douglas F-15 Eagle. Intended for the Dual-Role Fighter (DRF) program (initially called Enhanced Tactical Fighter), the F-15E was designed in the 1980s for long-range, high-speed interdiction without relying on escort or electronic-warfare aircraft. United States Air Force (USAF) F-15E Strike Eagles can be generally distinguished from other US Eagle variants by darker aircraft camouflage, conformal fuel tanks (CFTs) and LANTIRN pods mounted behind the engine intake ramps (although CFTs can also be mounted on earlier F-15 variants) and a tandem-seat cockpit.

Initially designed and manufactured by McDonnell Douglas, the F-15E first flew in 1986 and production continued under Boeing following the companies' merger in 1997. The aircraft became the USAF's primary strike fighter/interdictor starting near the end of the Cold War, gradually replacing the F-111 Aardvark. The Strike Eagle has been deployed for military operations in Iraq, Afghanistan, Syria, Libya, and Iran among others. During these operations, the strike fighter has carried out deep strikes against high-value targets and combat air patrols, and provided close air support for coalition troops. It has also been exported to several countries. The F-15E is expected to remain in USAF service until the 2030s. Enhanced versions of the design, called the F-15 Advanced Eagle, remain in production. , the F-15E is USAF's most capable tactical nuclear weapon delivery aircraft, able to carry up to five B61 Mod 12 nuclear bombs.

Development

Origins The McDonnell Douglas F-15 Eagle was introduced by the USAF to replace its fleet of McDonnell Douglas F-4 Phantom IIs. Unlike the F-4, the F-15 was designed for air superiority with little consideration for a ground-attack role; the F-15 Special Project Office opposed the idea of F-15s performing interdiction, giving rise to the phrase "Not a pound for air to ground."Davies and Dildy 2007, pp. 9, 15, 20, 35.

Despite a lack of official interest, McDonnell Douglas had quietly included a basic secondary ground attack capability in the F-15's design since the beginning and worked on an F-15-derived interdictor fighter. The company envisaged the aircraft as a replacement for the General Dynamics F-111 and the remaining F-4s, as well as to augment the existing F-15s.Donald 1995, p. 40. In 1978, the USAF initiated the Tactical All-Weather Requirement Study, which looked at McDonnell Douglas's proposal and other options such as the purchase of further F-111Fs, and then the Enhanced Tactical Fighter program. The studies recommended the F-15E as the USAF's future strike platform.Donald 1995, p. 42. In 1979, McDonnell Douglas and Hughes began a close collaboration on the development of the F-15E's potential air-to-ground capabilities.Davies 2003, pp. 15–16.

To assist in the F-15E's development, although not yet a program of record, McDonnell Douglas modified the second TF-15A prototype, AF serial number 71-0291, as a demonstrator. The aircraft, known as the Advanced Fighter Capability Demonstrator, first flew on 8 July 1980. It was previously used to test conformal fuel tanks (CFTs), initially designed for the F-15 under the designation "FAST Pack", with FAST standing for "Fuel and Sensor, Tactical. It was subsequently fitted with a Pave Tack laser designator targeting pod to allow the independent delivery of guided bombs.Jenkins 1997, p. 42. The demonstrator was displayed at the 1980 Farnborough Airshow.Donald 1995, p. 44.

Enhanced Tactical Fighter In March 1981, the USAF announced the Enhanced Tactical Fighter program to replace the F-111. The program was later renamed the Dual-Role Fighter (DRF) competition, while the Advanced Tactical Fighter looked at more advanced concepts. The ETF concept envisioned an aircraft capable of launching deep air interdiction missions without requiring additional support by fighter escort or jamming.Rininger 2009, pp. 85, 88. General Dynamics submitted the F-16XL, while McDonnell Douglas submitted the F-15E. The Panavia Tornado was also a candidate, but since the aircraft lacked a credible air-superiority fighter capability, coupled with the fact that it was not American-made, it was not seriously considered.

The DRF evaluation team, under the direction of Brigadier General Ronald W. Yates, ran from 1981 through 30 April 1983, during which the F-15E logged more than 200 flights, demonstrated a takeoff weight of more than , and validated 16 different weapons-carrying configurations.Donald 1995, p. 45. McDonnell Douglas, to assist 71-0291 in the evaluation, added to the program other F-15s, designated 78-0468, 80-0055, and 81-0063. The single-engined F-16XL was a promising design, which with its radically redesigned cranked-delta wing, greatly boosted performance; if selected, the single- and two-seat versions were to be designated F-16E and F-16F, respectively. On 24 February 1984, the USAF chose the F-15E; key factors in the decision were the F-15E's lower development costs compared to the F-16XL (US$270 million versus US$470 million), a belief that the F-15E had future growth potential, and possessing twin-engine redundancy.Jenkins 1998, p. 36.Ciborski, James R. "The F-15 Eagle: A Chronology." History Office, Aeronautical Systems Center, Air Force Materiel Command, Wright-Patterson AFB, Ohio, June 2002. The USAF was initially expected to procure 400 aircraft, a figure later revised to 392.

Construction of the first three F-15Es started in July 1985. The first of these, 86-0183, made its maiden flight on 11 December 1986. Piloted by Gary Jennings, the aircraft reached a maximum speed of Mach 0.9 and an altitude of 40,000 feet (12,000 m) during the 75-minute flight. This aircraft had the full F-15E avionics suite and the redesigned front fuselage, but not the aft fuselage and the common engine bay for more powerful Improved Performance Engine (IPE) variants of the Pratt & Whitney F100 or General Electric F110. The latter was featured on 86-0184, while 86-0185 incorporated all the changes of the F-15E from the F-15. On 31 March 1987, the first officially completed F-15E made its first flight.Rininger 2009, p. 89.

The first production F-15E was delivered to the 405th Tactical Training Wing, Luke Air Force Base, Arizona, in April 1988. Production continued into the 2000s with 236 produced for the USAF through 2001."Boeing F-15E Eagle." Jane's All the World's Aircraft, Jane's Information Group, 2010 (subscription article, dated 26 February 2010).

Upgrade programs and replacement

The F-15E was upgraded with the Raytheon AN/APG-82(V)1 Active Electronically Scanned Array (AESA) radar after 2007, and the first test radar was delivered to Boeing in 2010.Frost, Patricia. "Boeing Receives 1st F-15E Radar Modernization Program Test Asset from Raytheon." Boeing. Retrieved: 27 February 2012. It combines the processor of the APG-79 used on the F/A-18E/F Super Hornet with the antenna of the APG-63(V)3 AESA being fitted on the F-15C;Trimble, Stephen. "Raytheon claims AESA upgrade contract for F-15E." Flightglobal.com, 1 November 2007. it was named APG-63(V)4 until it received the APG-82 designation in 2009.Trimble, Stephen. "Raytheon trumps Northrop with new AESA designation." Flight Daily News, 17 June 2009. The new radar is to be part of the F-15E Radar Modernization Program,Frost, Patricia. "Boeing Selects Raytheon to Provide AESA Radar for U.S. Air Force F-15E Strike Eagles." Boeing, 1 November 2007. which also includes a wideband radome (enabling operation on more radar frequencies) and environment control and electronic warfare improvements."F-15E, B-1B Modernization and Upgrades." Defense Update, 23 July 2012. In 2015, Boeing and BAE Systems were awarded contracts to comprehensively upgrade of the electronic warfare system of all USAF F-15s, including the F-15E, with the AN/ALQ-250 Eagle Passive/Active Warning Survivability System (EPAWSS).Boeing, BAE To Develop New Electronic Warfare Suite for F-15 – Ainonline.com, 1 October 2015 The first F-15E retrofitted with EPAWSS was delivered in 2022.

Having a sturdier airframe rated for 8,000 hours of service life or up to 16,000 hours with proper depot maintenance programs, twice the lifetime of earlier variants, the F-15E is expected to remain in service past 2025. , the USAF's F-15E fleet had an average age of 21 years and an average airframe flying time of 6,000 hours. In 2012, the USAF was reportedly considering future options, with no replacement for the F-15E being slated at that time.USAF mulls options for replacement of Boeing F-15E Strike Eagle – Flightglobal.com, 13 December 2012.

The F-15E design would see some export success and Boeing continued developing upgrades for international customers. More radical upgrades to the air vehicle design resulted in the F-15 Advanced Eagle family that began with the F-15SA (Saudi Advanced) for the Royal Saudi Air Force, which first flew in 2013. It replaces the older hybrid electronic/mechanical system with a digital fly-by-wire control system that opens up two additional wing pylons and a revised wing structure for increased service life. The Advanced Eagle would have further developed variants with the F-15QA (Qatari Advanced) for the Qatar Emiri Air Force and the F-15EX Eagle II for the USAF. In FY 2020, USAF began procuring the F-15EX to replace the aging fleet of F-15C/D and supplement the F-22 Raptor to maintain air superiority fighter numbers, taking advantage of the existing export production line to quickly and affordably bring additional fighters into service; the F-15EX is also an option to replace the F-15E at a later time. Another choice is the F-35 Lightning II, set to replace other aircraft such as the F-16 Falcon; an F-35E variant was studied. Adding a second seat to the F-35 is complex and costly, especially to preserve its stealth profile; providing for greater range and payload would also be difficult tasks. Alternatively, the role could be covered by a combination of fighter and bomber aircraft, such as the B-21 Raider. The F-15E may also be replaced by a clean-sheet sixth-generation aircraft design.What will replace the F-15E Strike Eagle? – Flightglobal.com, 17 December 2012.

ALASA On 24 March 2014, Boeing won a $30.6 million contract from DARPA as part of the Airborne Launch Assist Space Access (ALASA) program. The goal of the program is to cut the cost of putting microsatellites into orbit by 66% through advances in launch systems. Under the 11-month contract, Boeing will build twelve launch vehicles, each with a payload capability up to . An ALASA vehicle is to be fitted under an F-15E, which will climb to 40,000 ft, then be released and fire its four engines to reach low-Earth orbit. Awarding the contract to Boeing would make use of the F-15E as the carriage vehicle, as previous design contracts had been given to Lockheed Martin to use the F-22 Raptor and Virgin Galactic to use their SpaceShip Two aircraft. DARPA had previously insisted they wanted to select an aircraft they would not need to modify heavily to carry and launch the ALASA payload.Boeing wins contract to design DARPA Airborne Satellite Launch Vehicle – Boeing press release, 27 March 2014 – Spacenews.com, 28 March 2014 The project was terminated in late 2015.

Design

Overview