The F-15 Eagle

An F-15C Eagle during a training exercise over the Pacific Ocean, close to Okinawa, 1994. This plane wsa operating out of Kadena Air Base, Japan and was of the 18th Wing, 5th Air Force. (A)

The Eagle

An F-15C Eagle on September 12th, 2006, awaiting an in-air refueling from a KC-135 Stratotanker of the 909tth Air Refueling Squadron. This particular plane was operating out of Kadena Air Force Base, Japan. (B)

The McDonnell Douglas F-15 Eagle has come to be renown as, and perhaps synonymous with, an extremely capable modern jet fighter. Its capacity for air-to-air, and later, air-to-ground combat has led to numerous victories over decades of conflicts.

But there is much more to know about the F-15 Eagle — from its technical capabilities to its gravity-defying performance in-air, the F-15 has plenty of impressive qualities you may never have heard about. Here are five facts about the F-15 Eagle.

1. The F-15 was developed as an air-superiority fighter.

A USAF F-15C Eagle flies over Northern Iraq in December 1998, during a patrol operation. (C)

In the early to mid-1960s, jet fighters such as the U.S. Air Force’s (USAF) F-105 Thunderchief were large, fast, and heavy aircraft designed for multiple combat uses over long ranges.

These aircraft came to be equipped with such features as long-range radar, radar-guided missiles, and large arrays of conventional bombs. In the case of the F-105, this was at times in excess of 12,000 pounds.

The USAF F-105D Thunderchief in flight, location and date unknown. This fighter-bomber was built by Republic Aviation and was prevalent in USAF use in the early and mid-1960s. (D)

Though these features would make the F-105 good for low-altitude bombing and ground attacks, it had its vulnerabilities. It was not as capable in air-to-air combat as it was attacking ground units, and needed escort for ground-attack missions.

When two F-105s were lost to MiG-17s (an outdated enemy aircraft model) over Vietnam on April 4^th 1965, this underscored the need for more capable air-to-air fighters.

As far the remainder of the Vietnam conflict was concerned, the General Dynamics F-111 Aardvark and the McDonnell Douglas F-4 Phantom II served as the American military’s primary high-powered, high-speed, multi-purpose combat jets.

A USAF McDonnell Douglas F-4 Phantom II in flight over Vietnam during the Vietnam War, ca. 1967 to 1973. This particular plane was part of the 8th Tactical Fighter Wing, 435th Tactical Fighter Squadron, shown here approaching a Boeing KC-135A Stratotanker for in-air refueling. (E)

The F-4 could engage in air-to-air combat – whereas the F-111 was not designed to do so. Both, however, were capable of carrying heavy loads (18,000 to over 31,000 pounds) of ordinance – including (in the F-4’s case) long-range guided air-to-air missiles.

However, even the nature of these newer airplanes was argued by USAF and Pentagon-adjacent figures like Col. John Richard Boyd, Pierre Sprey, Charles Meyers Jr., and Thomas P. Christie (collectively, and informally, known as the “Fighter Mafia”) as being somewhat impractical in air-to-air combat situations.

Col John R. Boyd (1927 – 1997), a former USAF military pilot and Pentagon consultant who advocated for USAF use of smaller, lighter, more maneuverable fighter jets in the 1960s and 1970s. He is shown here as a pilot during his service during the Korean War (1950 – 1953). (F)

Thus, Boyd and his contemporaries argued for the construction of somewhat smaller, lighter, more manueverable fighter jets with less emphasis on top speeds and long-range radar capablilites. These new fighters, they argued, would be able to handle subsonic air-to-air combat at a closer range, as well as be produced in greater numbers.

Roughly at the same time, the USAF and the U.S. Navy were at odds over what a jet fighter intended for both branches would look like. The USAF had been looking for a more manueverable aircraft, while the Navy looked for a more long-range aircraft capable of interception and defensive roles.

Robert McNamara (the then-U.S. Secretary of Defense) stated on February 14^th, 1961 that both branches should work together to develop one aircraft to satisfy all of these combat needs. The resulting aircraft, the F-111 Aardvark, was a result of what was called the Tactical Fighter Experimental (TFX) Program.

The F-111 Aardvark, one of the USAF’s primary fighter jets in the latter Vietnam War, flies over the North Sea, date unknown. (G)

As the 1960s progressed, however, branch-specific experimental programs continued. The USAF’s “F-X” program, for example, worked to develop an airplane to satisfy the USAF’s jet fighter combat needs.

The Navy, meanwhile, engaged in the “VFAX” program – which resulted in the development of their Grumman F-14 Tomcat. Both military branches, as it turns out, ended up making smaller, relatively lighter, more manueverable fighters in their respective programs.

By the late 1960s, the USAF’s “F-X” program was gearing to match (and surpass) the performance of the Soviet Union’s latest fighter, the MiG-25 – produced by Mikoyan-Gurevich – and unveiled in 1967.

A MiG-25 Foxbat-E jet in flight, 1985, location unknown. The MiG-25 was a late-1960s Soviet plane produced by Mikoyan-Gurevich. (H)

The MiG-25 was a two-engined, wide-winged, high-flying jet interceptor that could reach a top speed of Mach 2.83. It could reach a service ceiling of 67,900 to 78,740 feet, and was composed of parts made of mainly of stainless steel, rather than aluminum.

The F-X – and the resulting F-15 – would not be able to fly nearly as fast or high, but this corresponded with the USAF’s design request. The USAF requested the F-X to have a higher thrust-to-weight ratio (1:1, as opposed to the Mig-25’s roughly 1 : 2.5), a top speed of Mach 2.5, and takeoff weight of 40,000 pounds maximum.

The first F-15 prototype, location and date unknown, the McDonnell Douglas F-15A, specifically serial number 71-0280. (I)

Different companies – such as McDonnell Douglas, Fairchild Republic, General Dynamics, and North American Rockwell – submitted proposals for the F-X; the final proposal stage submissions occurred in June 1969.

On December 23^rd 1969, the USAF chose a McDonnell Douglas design for the F-X. The single-seated F-15A and the two-seated F-15B trainer were produced from 1972 to 1979.

The F-15A had a length of 63 feet, 9 inches, a width of 42 feet, 9.5 inches, and height of 18 feet, 5.5 inches. It had a maximum takeoff weight of 66,000 pounds, and could fly Mach 2.5 at 36,000 feet.

An F-15A Eagle at the National Museum of the U.S. Air Force, date unknown, in Dayton, Ohio. The F-15A, and its two-seated counterpart, the F-15B were produced from 1972 to 1979. (J)

The F-15C – a version with an improved computer, a system for flight overload (high G-force) warnings, a higher maximum takeoff weight, a reprogrammable APG-63/APG-70 radar, and improved interior and exterior fuel capacities – was produced from 1978 to 1985. Similarly, the two-seated version of the F-15C, the F-15D was produced over the same period of time.

An F-15C Eagle of the 48th Fighter Wing (based out of RAF Lakenheath, UK) flies away from a KC-135R Stratotanker after refueling in-air, location unknown, in April 1999. (K)

With the F-15C’s capacity to handle up to 9Gs, a top speed of Mach 2.5, ability to handle altitudes of up to 65,000 feet, a thrust-to-weight ratio of over 1.07, and an ability to carry various air-to-air missiles, the F-15 Eagle would perform exceptionally well in USAF use.

The F-15C would also excel in international use – with no air-to-air combat losses reported and numerous (greater than 100) air-to-air victories.

Later developments would include the F-15E Strike Eagle, a strike fighter (fighter-bomber) variant produced since 1985.

Still in service in some militaries today, the F-15 arguably has fulfilled its original intended role as an air-superiority fighter.

2. F-15s can fly twice the speed of sound.

A USAF F-15C flying out of Royal Air Force (RAF) Lakenheath, Suffolk, England, in November 2015. This plane was part of the USAF 48th Fighter Wing. (L)

The F-15A could fly Mach 2.5 at altitudes of 36,000 feet. This was 1,650 miles an hour, more than twice the speed of sound.

This was due to the double-engined design of the plane, carrying two Pratt & Whitney F100 (specifically the F100-PW-100) engines, with each axial turbofan engine capable of delivering 12,420 pounds of thrust (dry) or 14,670 pounds of thrust at full power. With the afterburner in action, each engine could deliver 23,830 pounds of thrust.

An F-15A Eagle of the 199th Air Fighter Squadron (Hawaii Air National Guard) flying, location unknown, in 2000. (M)

Strangely enough, though, Mach 2.5 wasn’t the fastest speed for a jet fighter ever – even at the time the F-15A was produced. This was by design, however, with the F-15 intended to reach air-superiority through its acceleration and greater agility over other contemporary jet fighter aircraft.

In comparison to the McDonnell Douglas F-4 Phantom II, for example, some pilots found the F-15’s propulsion system to be quite interesting. Firstly, the F-15 had two engines – something not common in many fighter jets of the time.

Also, some pilots noted the F-15 did not “bleed” off air speed – something that the F-4 Phantom II was reported to do. In speeds that mimicked the effect of multiple times the force of gravity (Gs) the Eagle would stay in fast, constant speed.

3. The F-15 can perform near-vertical takeoffs (and can climb vertically in-air).

An F-15D of the USAF 325th Fighter Wing ascends in a vertical climb and releases flares in 2004. This plane was operating out of Tyndall Air Force Base, Florida. (N)

Perhaps owing to its powerful two-engined configuration, the F-15 has the capability for vertical acceleration, a first for a U.S. jet fighter.

For example, the thrust-to-weight ratio of the F-15A – which is the comparison of the plane’s accelerative power to how heavy it is – is 1.17 : 1.

An F-15 Eagle of the 96th Test Wing, the 40th Flight Test Squadron in particular, operating out of Eglin Air Force Base, Florida, in October 2014. (O)

This thrust in the ratio (1.17), when compared to the weight (1), is higher than 1 : 1, which allows the airplane to accelerate in a vertical climb, even approaching near-vertical climbs shortly after takeoff.

4. The F-15 has a number of advanced flight technologies.

An F-15E Strike Eagle is being refueled by a KC-135 Stratotanker over the Atlantic Ocean in September 2012. (P)

The F-15 Eagle is not a simple fighter plane. Technologically, it has many systems for navigation, combat, jamming, communication, landing, in-air refueling, and radar surveillance.

Some of these systems include a Pulse-Doppler radar, specifically the AN/APG-63 and AN/APG-70 radar systems. These surveillance systems use electromagnetic waves on the microwave (X band) frequency to pick up targets.

The F-15 can communicate using UHF wavelengths, has a system for all-weather (day or night) landings, and navigate with the AN/ASN-109 – and inertial guidance system – that makes use of gyroscopes and accelerometers for flight position, orientation, and velocity information.

After an in-air refueling, location and date unknown, an F-15 Eag;le flies off. (Q)

Another advancement found in the F-15 – perhaps ubiquitous in modern-day fighter jets – is the Heads Up Display (HUD). The HUD projects light onto a transparent panel, displaying information for the pilot to see. In the case of the F-15A, the HUD was known the AVQ-20; it presented flight performance and target information.

5. Variants of the F-15 were produced for different purposes.

Examples of the different variants of the F-15 Eagle: two F-15C Eagles of the USAF 493rd Fighter Squadron in ht ebackground, and one F-15E Eagle of the 492nd Fighter Squadron, foreground, fly over Gloucestershire, England in July 2016. (R)

Different variants of the F-15 were produced since the fighter jet’s intial production in the early 1970s. The first variant produced was the F-15A, a single-seated version of the air superiority plane first flown on July 27^th, 1972 out of Edwards Air Force Base, California.

The F-15B was a two-seated training variant of the F-15A. The F-15A (with 384 instances made) and the F-15B (with 61 instances made) were produced by McDonnell Douglas from 1972 to 1979.

The F-15C was an advanced air superiority version of the F-15A, with widened fuel capacities, an increased maximum takeoff weight, and with some models equipped with an AN/APG-70 (also -63(V)1) reprogrammable radar.

The F-15D was a two-seated training version of the F-15C, produced along with the F-15C from 1979 to 1985. 483 instances of the F-15C were made – along with 92 instances of the F-15D.

The F-15E Strike Eagle was a two-seated, all-weather multi-role (designed for ground-attack missions, but also air-to-air capable) fighter.

An F-15E Strike Eagle of the USAF 4th Fighter Wing operates out of Seymour Johnson Air Force Base, North Carolina, August 2000. The F-15E Strike Eagle was an F-15 Eagle modified for ground-attack use, while retaining its air-to-air combat abilities. (S)

With the standard F-15’s Mach 2.5+ speeds, the F-15E has been used effectively in strike missions. From 1985 to 2001, a total of 236 instances of the F-15E have been produced.

Besides use in the USAF, variants of the F-15 have been used, or produced under contract, by countries such as South Korea, Israel, Japan, Saudi Arabia, and Singapore.

Sources / Photos

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