The original F-15 Eagle proved surprisingly adaptable when the Air Force sought to place it in other roles.

When McDonnell Douglas first conceived of the F-15 in the late 1960s, they had one, and only one, purpose: to create the world’s best air superiority fighter. When the F-15A and B variants entered service in the mid-1970s, they embodied that design philosophy, incorporating powerful twin engines, a massive thrust-to-weight ratio, and a radar built only for finding other aircraft. In short, the original F15s were built strictly for air superiority, and had virtually no use beyond that—“without a pound for ground,” as the saying went.

But by the early 1980s, the US Air Force’s doctrine was shifting. Vietnam had demonstrated the value of precision munitions and the need for deep-interdiction capability against Warsaw Pact forces. The result was a demand for multirole strike aircraft that could carry heavy ordnance loads behind enemy lines—and fight against other aircraft once it got there. The Air Force’s existing options were insufficient. The F-111 Aardvark, though groundbreaking in its day, was aging. The venerable F-4 Phantom was still a speed demon, but no longer a dominant platform. So the Air Force looked to the F-15, which had clean aerodynamics, huge fuel capacity, and redundant systems—giving it potential for a strike aircraft function. But the F-15 was a pure dogfighter. How would a bomber’s mission capacity be grafted onto a myopic air superiority platform?

The F-15E Strike Eagle’s Specifications

• Year Introduced: 1988
• Number Built: ~236
• Length: 63 ft 9 in (19.43 m)
• Wingspan: 42 ft 10 in (13.05 m)
• Weight (MTOW): ~81,000 lb (36,700 kg)
• Engines: Two Pratt & Whitney F100-PW-229 afterburning turbofans (~29,000 lbf each)
• Top Speed: ~Mach 2.5 (~1,650 mph / 2,655 km/h) at altitude
• Combat Radius: ~600–1,000 mi (965–1,610 km), depending on mission profile, fuel state, and loadout
• Service Ceiling: ~60,000 ft (18,300 m)
• Loadout: One 20 mm M61A1 Vulcan cannon; up to ~23,000 lb (≈10,400 kg) of external stores including AIM-120 AMRAAM and AIM-9 Sidewinder air-to-air missiles and a wide mix of air-to-ground ordnance (AGM-65 Maverick, AGM-88 HARM, GBU-10/12/24 laser-guided bombs, JDAMs, JSOWs), plus targeting/recce pods and conformal fuel tanks
• Aircrew: 2 (pilot and weapon systems officer)

Transforming the F-15 Into the F-15E

The transformation began with the F-15D, the F-15’s two-seat trainer variant. Engineers realized that the F-15D’s second cockpit seat could be reimagined for a weapons system officer rather than an instructor pilot. This was the inception of the F-15E, which would feature two crew members sharing an integrated digital mission suite.

The airframe would need to be changed, however—strengthened dramatically, with thicker longhorns, beefed-up bulkheads, and reinforced landing gear so that the jet could carry three times the external load of the original F-15. Where the F-15C’s belly had held only air-to-air missiles, the E included additional fuel tanks flush against the fuselage, giving the jet almost double the range without substantially affecting its aerodynamic efficiency. Hardpoints were added under the wing and the fuselage, capable of hefting laser-guided GBU-10s and later JDAMs and JSOWs. Under the nose, engineers installed the then-new LANTIRN system, two pods that facilitated night and low-altitude attacks. One of the pods housed a terrain-following radar, which would allow the F-15E to race a hundred feet above the ground at 500 knots (575 mph). The second pod carried a forward-look infrared sensor and laser designator for guiding precision strikes in darkness or bad weather. 

The F-15’s power plant was upgraded. Replacing the older versions were new Pratt & Whitney F100-PW-229 engines, offering a remarkable 29,000 pounds of thrust each. Avionics were fully digitized: multi-function displays replaced the outdated analog dials of the C-variant, while the radar gained synthetic-aperture modes for ground mapping. And importantly, the mission computer was upgraded to allow for the fusion of data for simultaneous air-to-air and air-to-ground operations. 

The transformation was profound, and the F-15E made for a remarkable strike aircraft, proving itself in combat during Operation Desert Storm. The F-15E still serves today, a testament to how solid and versatile the original F-15 platform was—even though it was designed solely to be the world’s best dogfighter.

About the Author: Harrison Kass

Harrison Kass is a senior defense and national security writer at The National Interest. Kass is an attorney and former political candidate who joined the US Air Force as a pilot trainee before being medically discharged. He focuses on military strategy, aerospace, and global security affairs. He holds a JD from the University of Oregon and a master’s in Global Journalism and International Relations from NYU.

Image: Shutterstock / A Periam Photography.

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