F-15SE Silent Eagle Fighter fails. The F-15EX Eagle II was the result

Summary and key points: The F-15 Eagle, known for its 100 confirmed kills without loss, remains a legendary fighter platform. Designed to counter the Soviet MiG-25 Foxbat, it evolved into several successful variants such as the F-15E Strike Eagle. In 2009, Boeing introduced the F-15SE Silent Eagle, featuring internal weapons bays and a reduced radar signature, aiming to bridge traditional features with emerging stealth technologies.

-Despite initial interest, it was considered unsuitable for modern threats.

-Elements of the Silent Eagle were later integrated into the F-15EX II, a non-stealth fighter that excels in payload delivery and could complement fifth-generation platforms.

The F-15 Silent Eagle: The forgotten stealth variant of a legend

The F-15 Eagle is widely regarded as one of the most legendary fighter aircraft to ever fly the skies. With an astonishing record of 100 confirmed kills against zero losses, this American-made jet is a combat-tested fighter with an undefeated track record.

Although the Eagle platform has been around for nearly five decades, some of its derivatives have not been so lucky. When the F-15SE Silent Eagle was conceived in 2009, designers envisioned the aircraft as a bridge between traditional features and emerging stealth technologies in the modern era. Ultimately, however, the introduction of more advanced fifth-generation platforms would prevent the Silent Eagle from ever entering service.

The Eagle: An Overview

As the arms race between the United States and the USSR gathered pace in the 1960s, aerial innovation was perhaps at its peak. When the Soviet Union introduced its Mikoyan-Gurevich MiG-25 Foxbat fighter toward the end of the decade, U.S. officials were deeply concerned about the platform’s perceived capabilities.

Interestingly, the Foxbat’s speed was seen as a major threat, especially after Israeli radar operators discovered a Foxbat flying at the enormous speed of Mach 3.2 (times the speed of sound), which would have been faster than other NATO jets could manage. To combat this competition, the “fighter mafia” was formed under the leadership of mathematician John Boyd and was tasked with designing a lightweight day fighter that could guarantee air superiority for the service.

Major manufacturers including General Dynamics, North American Rockwell, McDonnell Douglas and Fairchild all submitted proposals for fighter aircraft to achieve this goal. Ultimately, McDonnell was selected as the winner by the Air Force, resulting in the creation of the F-15 Eagle.

The Eagle was originally conceived as a single-seat variant platform, followed by the TF-15 two-seat variant, powered by the Pratt & Whitney F1000 engines. These subsequent F-15A and F-15B variants were equipped with the M61 Vulcan cannon in place of the planned 25 mm Ford-Philco GAU-7 cannon.

Later, modified versions of the F-15C and F-15D were introduced, featuring the Production Eagle Package improvements, including additional internal fuel storage and a higher maximum takeoff weight. Armament improvements were also incorporated into future Eagle variants, including the addition of a programmable armament control set capable of advanced versions of the AIM-7, AIM-9, and AIM-120A missiles.

The F-15 Strike Eagle and the F-15 Silent Eagle

Perhaps the most successful Eagle variant is the F-15E Strike Eagle, which first flew in 1986. This rugged aircraft can carry a munitions load of nearly 25,000 pounds, including radar-homing and infrared-guided air-to-air missiles. In addition, the Strike Eagle can deliver the B61-12 nuclear weapon. Based on the effectiveness of this variant, Boeing recognized the need to reduce the Eagle’s radar return in hopes of convincing foreign customers that the Eagle could still be relevant even if it wasn’t stealthy.

The Silent Eagle variant was introduced by Boeing in 2009, with several significant changes that Sandboxx News outlined: “The result was an F-15 that looked very much like a stripped-down old one, but with some very significant changes. Most noticeably, the 750-gallon conformal fuel tanks were removed from the fighter’s fuselage and replaced with new conformal weapons bays (CWBs) that were very similar in external design to the fuel tanks they replaced. This allowed the Silent Eagle to carry its firepower internally like 5th generation fighters, eliminating the radar return caused by external munitions, while maintaining a similar aerodynamic profile to the service-proven Strike Eagle.”

Based on these impressive specifications, several foreign countries were initially interested in purchasing the Silent Eagle variant, including South Korea and Saudi Arabia. Ultimately, however, the aircraft was not deemed capable enough to survive in emerging threat climates.

Despite the variant’s cancellation, some of its components and designs have been incorporated into the latest Eagle iteration. The F-15EX II does not compromise payload for survivability, as it can fire significantly further than any of its counterparts, making it a potentially critical asset to the USAF. For this reason, many analysts consider the Eagle II to be an improved and modernized version of the proposed Silent Eagle fighter. Like the latter platform, the Eagle II lacks stealth.

Still, this fighter could still remain relevant alongside fifth-generation platforms or even the Air Force’s upcoming Next Generation Air Dominance (NGAD) fighter.

About the Author: Maya Carlin

Maya CarlinNational Security Writer at The National Interest, is an analyst at the Center for Security Policy and a former Anna Sobol Levy Fellow at IDC Herzliya in Israel. She has contributed to many publications, including The National Interest, Jerusalem Post, and Times of Israel. You can follow her on Twitter: @MayaCarlin.

Image: Creative Commons.