F-15 Eagle

 

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The F-15 Eagle is beyond any doubt one of the most famous air superiority fighters of the second half of the Cold War, and a worthy successor of the also famous McDonnel Douglas F-4 Phantom. For instance, its predecessor was designed to be a fighter with attack capabilities for any weather condition, and the same concept was taken into account when developing the Eagle, only that it was intended mainly for air superiority. Interestingly, and despite the F-4 being a naval plane for most of the part, the F-15 would be a combat eagle on use by the USAF. There is also another thing both planes have in common, despite being the Phantom already in combat and the Eagle yet to be developed: the Vietnam War. As it happens, high number of casualties made the US Navy and the Air Force, along with the influence of Secretary of State Robert McNamara, to look for new models to replace the existing ones, including the Phantom. The introduction of the Mig 25 Foxbat provided the final argument in favour of the development of a new aircraft for air superiority. And with while the Navy would ultimately incorporate the Grumman F-14 Tomcat, the USAF decided to go for its own fighter, resulting in the F-15, being the counterpart of the Tomcat and taking the Mig-25 as inspiration in terms of performance, to say the least.

The F-15 Eagle is single-seat – or double seat in tandem in certain versions – twin-engine all-weather tactical fighter/air superiority fighter with attack and bombing capabilities, with cantilever shoulder-mounted wings. As it was briefly mentioned, the Vietnam War gave way for its requirement given the high losses to soviet-made aircraft (often old models) back in 1964, with 1968 being the year of requirements issuing and 1969 the year when development of the Eagle began. The main requirement was for the new fighter to be of air superiority and having secondary attack capacities. McDonnell Douglas was the company that awarded the requirements, thus developing the Eagle from the abovementioned year and flying the first prototype in 1972. NASA, in addition, came to take active part in the development of the F-15, especially on its mission requirements, at the same time of the development by the industry contractors.

The Eagle became to be one of the most advanced fighters of the times, clearly fulfilling its mission as it is considered the best air superiority fighter. The secret of its effectiveness and resilience lies on its structure, which is made of metal and then titanium at most of its components, and the empennage made of composite materials – twin aluminium/composite material honeycomb – and the vertical stabilizers made of boron-composite skin. This allowed the tails and the rudders to be very thin yet resistant. The wing also plays its role in bestowing the flying and combat capabilities of the F-15, as this has a cropped delta shape with a leading-edge sweepback of 45 degrees. There are no leading-edge flaps, and the trailing edge – or posterior area of the wing – is having ailerons and a simple high-lift flap. As a result, the wing’ low loading allows the F-15 to be very manoeuvrable without sacrificing speed in the process. The powerplant (two Pratt & Whitney F100-PW-100 turbofans engines with afterburners) and the avionics also play a role in providing the F-15 with its exceptional qualities: The former by bestowing speeds of up to 2.5 Mach and a good time/altitude ratio, the latter by allowing the crew to track and engage targets at distanced up to 160 km (87 miles) and targets at very low and high altitudes.

The F-15 has proven to be a platform capable of receiving structural and avionics/electronics improvements, further enhancing its combat and flight capabilities, with new radars, computers, weapons controls and armament type, powerplants (Pratt & Whitney F-100-PW-220), warning and navigation systems. The F-15 could even receive low visibility technologies, proving the adaptability and capacity of the aircraft to incorporate the latest technologies, as it is the case of the proposed F-15SE Silent Eagle, where its weapons carrying capabilities are proposed to be equally upgraded. This version could co-operate with 5th generation air assets, let alone to almost operate like one.

The F-15 has witnessed action not only in the air campaigns waged by the USA in the Middle East, the Balkans and Central Asia, but also with other air forces, being the Israeli Air Force where the F-15 have had similar combat intensity, and the Saudi Air Force making some considerable use of their F-15s. With the USAF, the F-15 on its different configurations achieved air superiority by shooting down many air assets of Iraq in air-to-air combats or in the ground, as well as to inflict a serious damage to Iraqi military and governmental infrastructure, contributing at a great extend to the sound victory of the Coalition in 1991. The F-15 even managed to destroy a low flying helicopter with a laser guided bomb. The F-15 kept a watch in enforcing the established no-fly zones after this conflict. The Balkans were another scenario where the F-15s made their presence to be felt, by pounding Serbian ground targets and even scoring 4 enemy kills (Serbian Mig-29s). The Second Iraq War, Afghanistan and strikes against ISIS saw the F-15E mainly in action, attacking important targets on these three scenarios, and even providing Close Air Support (CAS) for the troops in the ground.

With the Israeli Air Force, it achieved its first air-to-air kill, establishing then Israeli air superiority over the skies of Lebanon and against Syrian air assets. It had seen use also as a long-range striker and as a platform for attacking specific targets. Saudi Arabia also had some air kills in the 80’s and during Operation Desert Storm, using the F-15s nowadays to strike important targets in Yemen.

As of now, the F-15 is still in service and production (by Boeing, as McDonnell Douglas was absorbed by this company), with the USAF considering to operate with this fighter until 2025 or 2040 at the latest, and production to be maintained until 2019. So far, 1074 units have been produced (by 2012).

Design

The F-15 is an all metal (later on aluminium) semi-monocoque fighter with a shoulder-mounted wing, powered by two engines: 2 Pratt & Whitney F-100-PW-100 (F-15A, F-15B and F-15C) or F-100-PW-220 (F-15DJ and F-15 J), or F-100-PW-229 (F-15E). Two engine air intakes are located at each side of the fuselage, starting from the half area of the cockpit with a intake ramp configuration. The wings have a characteristic shape of a cropped delta shape with a leading-edge sweptback of 45 degrees, starting at nearly half of the wing. It lacks of manoeuvring flaps at the leading edge, having only a simple high-lift flap and ailerons at the trailing edge. As the wing has a low loading with high thrust-to-weight ratio, the F-15 can perform tight turns without any loose of speed, capable also of sustaining high G forces. Noteworthy to point out that the airfoil thickness has a variation of 6% at the wing root, to 3% at the wingtip. The empennage is made out of metal, with the two vertical stabilizers made out of honeycomb twin aluminium and composite materials covered with boron-composite skin, allowing them to be thin but very resisting. This means that the F-15 has two tails, the same way as the Grumman F-14 and the Mig 25. The horizontal stabilizers also have a remarkable characteristic of their own, as they have dogtooth within their structural shape, being able to move independently thus increasing control. The aerodynamic brake is located on the top of the fighter’s structure, behind the cockpit. The landing gear is a retractable tricycle. Noteworthy to point out that the F-15E lack of the typical exhaust petals covering the engine nozzles.

The cockpit is placed high in the frontal part of the aircraft, featuring a one-piece windscreen and a large canopy, allowing a full 360 degrees visibility for the pilot. In most F-15 variants the canopy is designed for one pilot. However, the F-15B, F-15D, F-15DJ and F-15E have a canopy designed for a crew of two: a pilot and a weapons officer in the case of the F-15E, and the student and instructor in the case of the training versions.

The wings and the same structure of the fighter allows it to carry a large number of weaponry and other devices. Among the weaponry normally carried by the F-15, there are AIM-7F/M Sparrow, AIM-120 AMRAAM, AIM—9L/M Sidewinder, as well as the M61 Vulcan Gatling gun at the right wing root. Other armament the F-15 is usually armed with are a varied array of free-fall and directed bombs, rockets, air-ground or anti-ship missiles, such as the AGM-84K SLAM-ER, AGM-84H Harpoon Block II anti-ship missiles, AGM-158 Joint Air-to-Surface Standoff Missile JASSM, AGM-88 HARM anti-radar missiles, and AGM-154 JSOW missiles. ECM pods, external fuel tanks and low-drag conformal fuel tanks (CTFs), which are attached to the sides of the air intakes and cannot be dropped, are usually among the additional equipment carried by this fighter.

The avionics of the F-15 allow an optimal operationalization of the armament carried by this fighter, as well as its navigation and combat-electronic performance and multi-mission capabilities. Among the avionics of the F-15, it could be accounted: Heads Up Display (HUD), the advanced pulse-Doppler Raytheon radars APG-63 and APG-70, the AN/ASN-109 Inertial Guidance System, the Joint Helmet Mounted Cueing System (JHMCS), ECM pods, Hazeltine AN/APX-76 or Raytheon AN/APX-119 IFF device, Magnavox AN/ALQ-128 Electronic Warfare Warning Set (EWWS), Loral AN/ALR-56 radar warning receiver and a Northrop-Grumman Electronics System ALQ-135 internal counter-measures system. All of these comprise the electronic brain of the fighter, which in combination with the powerplant, the aerodynamics and the weapons systems, makes of the F-15 an outstanding air asset that can achieve supreme control over the skies it operates.

As the design of the F-15 allows adaptation and upgrades, all of the versions were receiving gradual upgrades in avionics and engines, being the F-15E the most prominent. Yet some versions operated by other air forces, such as the Israel Air Force and the Republic of Korea Air Force can receive electronic and avionics components developed by those nations, proving that the Eagle is entirely adaptable to receive technology other than of its country of origin. And its versatility allows combat conversions, explaining why a single airframe can have air superiority, attack or electronic warfare missions, deciding the outcome of any campaign either in the skies or the ground.

An Eagle Not to Mess With

The F-15 has proven to be a very powerful asset and a though adversary for those obliged to face it, feeling the powerful strike of the F-15. It has a suitable name that makes honour to its combat capabilities, which have been proven in action from the year it was unleashed. During the 1991 Gulf War and the aftermath, the F-15 achieved air superiority and delivered hard blows to the Iraqi military assets, by scoring 32 fixed-wing aircraft as confirmed kills (Iraqi fighters, fighter/bombers, transport airplanes and trainers that fell under the claws of the F-15), and 4 helicopters as kills. Many of these kills were achieved in air-to-air combats or simply by attacking the Iraqi air assets on the ground, being involved also in the hunt for valuable targets or by watching the skies over Iraq and the Balkans. In the hands of Israel and Saudi Arabia, the F-15 Eagle scored 41 and around 4-5 air kills respectively. With Israel, the F-15 left a deep impression on those that were targeted by its bombs. In the Balkans, the F-15 scored four air kills and equally contributed to pound the Serbian military facilities at Bosnia, Serbia and Kosovo.

The Eagle began the 21st century with more capabilities to increase its striking power, as well as seeing more combat in the light of the 9/11 attacks and the campaigns against terrorism. During the Second Iraq war of 2003, the Eagle once and again delivered precision strikes that decimated Iraq’s combat capacities. During the Afghan campaign, it attacked key Taliban and terrorist targets, at the point of even supporting the troops on the ground, and in recent years, it contributed at weakening the military power of Libya during its own Arab Spring, as well as striking important targets in the anti-terrorist campaign over Syria, Libya and Iraq. The F-15 Eagle has been on active duty basically during its entire operational life, being at the very first line.

The Eagle, as a last, could be able to destroy the eyes above the skies, as it was used for experimental tests where it fired a two-staged anti-satellite missile, proving capable for doing so. It has more than fulfilled the requirements set for its development after the nasty experiences of the Vietnam War, war that gave birth to one of the most powerful and memorable birds in all the history of aviation, being the Eagle a milestone by itself.