F-15E Strike Eagle
Although the slogan of the F-15's original design team was "Not a pound for air-to-ground," the F-15 has long been recognized as having superior potential in the ground attack role. In 1987 this potential was realized in the form of the F-15E Strike Eagle. The F-15E became the newest fighter in Tactical Air Command when the 405th Tactical Training Wing, Luke Air Force Base, Ariz., accepted delivery of the first production model in April 1988. The 4th Fighter Wing at Seymour Johnson Air Force Base, N.C., was the first operational F-15E Strike Eagle wing in the Air Force.
While new to the operational inventory, F-15E Strike Eagles were among the first airframes tasked to react to events in the Persian Gulf in August 1990. The 4th Fighter Wing deployed two F-15E squadrons to Southwest Asia in August and December of that year, and spearheaded an attack on Iraqi forces Jan. 16, 1991. The war was brought to a swift and successful conclusion in late February 1991.
Unlike previous models, the F-15E uses two crew members, a pilot and a weapon systems officer. The two engine dual role fighter capable of speeds up to MACH 2.5. It is capable of carrying an external payload of up to 24,500 pounds, to include fuel tanks, weapons pylons, missiles, and bombs. The maximum takeoff weight ofthe F- 15E is 81,000 pounds. The basic empty weight is 36,500 pounds. Considered to be the most advanced tactical fighter aircraft in the world, the F-15E is the fifth version of the Eagle to come off the McDonnell Douglas assembly line in St. Louis, Mo., since 1972. While retaining the best features of its predecessors, the "E" model is equipped with an array of new avionics and electronics systems.
The mission of the Strike Eagle is as succinct as that of its air-to-air cousin: to put bombs on target. While previous models of the Eagle are assigned air-to-air roles, the "E" model is a dual-role fighter. It has the capability to fight its way to a target over long ranges, destroy enemy ground positions, and fight its way back out. The F-15E performs day and night all weather air-to-air and air-to-ground missions including strategic strike, interdiction, OCA and DCA. Although primarily a deep interdiction platform, the F-15E can also perform CAS and Escort missions. The F-15E is especially configured for the deep strike mission, venturing far behind enemy lines to attack high value targets with a variety of munitions.
The Strike Eagle accomplishes this mission by expanding on the capabilities of the air superiority F-15, adding a rear seat WSO (Weapon Systems Operator) crewmember and incorporating an entirely new suite of air-to-ground avionics.
One of the most important additions to the F-15E is the rear cockpit, reserved for a weapon systems officer (WSO). On four television-like screens, the WSO can display information from the radar, electronic warfare or infrared sensors, monitor aircraft or weapon status and possible threats, select targets, and use an electronic "moving map" to navigate. Two hand controls are used to select new displays and to refine targeting information. Displays can be moved from one screen to another, chosen from a "menu" of display options.
In addition to three similar screens in the front seat, the pilot has a tranparent glass screen (head-up display) at eye level that displays vital flight and tactical information. The pilot doesn't need to look down into the cockpit, for instance, to check weapon status. At night, the screen is even more important because it displays a video picture, generated by the forward-looking infrared (FLIR) sensor, that is nearly identical to a daylight view of the world.
Strike Eagles are equipped with LANTIRN, enhancing night PGM delivery capability. The F-15E outbord and inboard wing stations and the centerline can be loaded with various armament. The outboard wing hardpoint are unable to carry heavy loads and are assign for ECM pods. The other hardpoints can be employed for various loads but with the use of multiple ejection racks (MERs). Each MER can hold six Mk-82 bombs or "Snakeye" retarded bombs, or six Mk 20 "Rockeye" dispensers, four CBU-52B, CBU- 58B, or CBU-71B dispensers, a single Mk-84 (907 kg) bomb F- 15E can carry also "smart" weapons, CBU-10 laser quided bomb based on the Mk 84 bomb, CBU-12, CBU-15, or another, laser, electro-optical, or infra-red guided bomb (including AGM-G5 "Maverick" air-to-ground) missiles. For air-to-ground missions, the F-15E can carry most weapons in the Air Force inventory. Italso can be armed with AIM 7F/M Sparrows, AIM-9M Sidewinders, and AIM-120 advanced medium range air-to-air missiles (AMRAAM) for the air-to-air role. The "E" model also has an internally mounted 20mm gun which can carry up to 450 rounds.
Advanced avionics systems give the F-15E the capability to fight at low altitude, day or night, and in bad weather. An inertial navigation system, developed by Honeywell, uses a laser gyro to continuously monitor the aircraft's position and provide information to the central computer and other systems, including a digital moving map in both cockpits.
At the heart of the F-15E is the APG-70 radar. In the air-to-air mode, the APG-70 can provide range, altitude, airspeed, and other information on aircraft at ranges exceeding 100 miles. The Hughes Aircraft Company APG-70 radar system allows aircrews to detect ground targets from longer ranges. For example, the crew can pick out bridges and airfields on the radar display from more than 80 miles away, while at closer ranges targets as small as vehicles can be easily detected. One feature ofthis system is that after a sweep of a target area, the image on the screen can be frozen while the radar itself is turned off to avoid enemy detection systems. The APG-70 can produce near photo quality images of the ground by using synthetic aperture radar (SAR) technology. SAR imaging is made possible by enhancing the radar returns received from the process known as the Doppler Shift. One job of the APG-70 is to locate aircraft flying close to the ground while the F-15E is flying well above them (20,000 - 30,000 feet above them for example). A pulse radar looking down on the earth would see EVERYTHING -- mountains, buildings, lakes, and the aircraft. This would make it difficult (or impossible) to find an aircraft flying at low altitude. A continuous wave radar (or other radar using Doppler technology) will only "see" objects that are moving (the radar's computer will filter out the speed of the F-15E). Thus, the Doppler shift gives advanced radars like the APG-70 the ability to see aircraft flying at very low altitudes.
As of 2005 there were 224 USAF F-15E aircraft in service worldwide. The radars were, on average, 22 years old and are experiencing problems in reliability, diminishing manufacturing sources, and increasing radar sustainment costs. The goal of the F-15E Radar Modernization Program (RMP) is to affordably upgrade the F-15E radar system to significantly improve Reliability, Maintainability + Supportability (RM+S), maintain APG-70 operational capability, and lay the groundwork for future network-centric warfare requirements. Our plan is to leverage existing COTS/GOTS radar systems technology from already developed systems (examples include F/A-18E/F (APG-79), F/A-22 (APG-77) and F-35 (APG-81)). By emphasizing reuse and integration of existing technologies, the F-15E RMP approach will keep the program development risks low and development costs at a fraction of similar fighter radar improvement programs. The F-15E RMP will combine developmental and operational test activities to reduce schedule and cost. Using existing technologies will increase parts commonality across aircraft platforms, significantly improving supply chain management and reducing spares inventory and depot repair level costs. The modernized radar's open architecture and standard interfaces will facilitate technology insertion, technology refresh and component improvement. This upgraded radar will be an important component of Combat Identification (CID) and Theater Air and Missile Defense (TAMD) Families of System.
As of June 2005 the F-15 Systems Group Wright-Patterson AFB anticipated award of two separate contracts under the F-15E Radar Modernization Program. The first contract was for execution of the System Development and Demonstration (SDD) phase of the F-15E RMP. Major SDD tasks will include design, development, full weapon system integration and test of a radar system that meets the requirements documented in the Capability Development Document (CDD), into the F-15E Weapon System. The Capability Development Document (CDD) for the F-15E Radar Modernization Program had been approved by the Joint Requirements Oversight Council. After successful completion of both SDD and Milestone C, a production contract will be awarded for both Low Rate Initial Production (LRIP) and procurement of the first lots of production hardware. As part of any production contract(s), the government will also purchase training support for Organizational-Level (O- level) maintenance personnel, training equipment upgrades, test equipment for an Interim Contractor Support (ICS) capability, and three years of ICS support. If the decision is made to provide long term support via an organic depot, the government may also decide to procure depot support equipment at this time. The Milestone C decision will also address timing of "break out" procurement of subsequent radar production lots. Projected contract award dates are no later than FY09 for SDD and FY10/11 for LRIP.
Considered the cream ofthe new avionics crop is the Low-Altitude Navigation and Targeting Infrared for Night (LANTIRN) system manufactured by Martin Marietta. The system consists of two pods attached to the exterior of the aircraft. The navigation pod contains terrain-following radar which allows the pilot to safely fly at a very low altitude following cues displayed on his head up display (HUD). This system also can be coupled to the aircraft's auto pilot to provide "hands off' terrain-following capability.
The second pod, the targeting pod, contains a laser designator and a tracking system that mark an enemy for destruction from as far away as 10 miles. Once tracking has been started, targeting information is automatically handed offto infrared air-to-surface missiles or laser-guided bombs.
The LANTIRN system gives the F-15E unequaled weapons delivery accuracy during the day or night and in poor weather. According to the former commander of Tactical Air Command, Gen. Robert D. Russ, "Two F-15Es with four crew members and 12,000 pounds of conventional bombs will be able to do the same damage to a pinpoint target that only yesterday took eight F-4s, 16 crew members and 48,000 pounds of conventional bombs."
The F-15E Strike Eagle's tactical electronic warfare system [TEWS] is an integrated countermeasures system. Radar, radar jammer, warning receiver and chaff/flare dispenser all work together to detect, identify and counter threats posed by an enemy. For example, if the warning receiver detects a threat before the radar jammer, the warning receiver will inform the jammer of the threat. A Strike Eagle's TEWS can jam radar systems operating in high frequencies, such as radar used by short-range surface-to-air missiles, antiaircraft artillery and airborne threats. Current improvements to TEWS will enhance the aircraft's ability to jam enemy radar systems. The addition of new hardware and software, known as Band 1.5, will round out the TEWS capability by jamming threats in mid-to-low frequencies, such as long-range radar systems. The equipment went into full production in late 1999.
The cockpit design of the F-15E is one reason it is the most versatile and capable fighter flying today. Seven programmable multi-function displays provide the aircrew with a wealth of information that no aircraft flying today can match. Most functions can be controlled by switches on the throttles and the control stick (referred to as "HOTAS" or Hands On Throttle And Stick). This allows the pilot to control the aircraft's systems without having to remove his hands from the aircraft controls (a significant advantage in demanding phases of flight like an instrument approach in the weather.) The programmable nature of the multi-purpose displays is another outstanding feature that greatly aids the aircrew. For example, the WSO has four displays available in the rear cockpit. On a night low-level mission (using the Terrain Following Radar to fly 500 feet above the ground) most WSOs will have the following information on the displays: Terrain Following Radar, Heads-Up Display (HUD), Air-to-Air radar, Moving Map display. Since each display is programmable, the aircrew can program three separate displays on each multi-function display. Therefore, the WSO can have the engine display (providing the engines' "vital" signs) on the same screen as the Moving Map display. By moving a switch on the hand controller, the engine display replaces the Moving Map display. Hitting the switch again returns the multi-function display to the Moving Map (or the third option if one was programmed).
The F-15E is powered by two Pratt & Whitney F100-PW-220 engines which incorporate advanced digital technology for improved performance. For example, with a digital electronic engine control system, F-15E pilots can accelerate from idle power to maximum afterburner in under four seconds, a 40 percent improvement over the previous engine control system. Faster engine acceleration means quicker takeoffs and crisper response while maneuvering. Each engine can produce 25,000 pounds of thrust.
Each of the low-drag conformal fuel tanks that hug the F-15E's fuselage can carry 750 gallons of fuel. The tanks hold weapons on short pylons rather than conventional weapon racks, reducing drag, and further extending the range of the Strike Eagle. Conformal Fuel Tanks were introduced with the F-15C in order to extend the range of the aircraft. The CFTs are carried in pairs and fit closely to the side of the aircraft, with one CFT underneath each wing. By designing the CFT to minimize the effect on aircraft aerodynamics, much lower drag results than if a similar amount of fuel is carried in conventional external fuel tanks. This lower drag translate directly into longer aircraft ranges, a particularly desirable characteristic of a deep strike fighter like the F-15E. As with any system, the use of CFTs on F-15s involves some compromise. The weight and drag of the CFTs (even when empty) degrades aircraft performance when compared to external fuel tanks, which can be jettisoned when needed (CFTs are not jettisonable and can only be downloaded by maintenance crews). As a result, CFTs are typically used in situations where increased range offsets any performance drawbacks. In the case of the F-15E, CFTs allow air-to-ground munitions to be loaded on stations which would otherwise carry external fuel tanks. In general, CFT usage is the norm for F-15Es and the exception for F-15C/D's.
The Strike Eagle's flight control system is among the best flying today. It provides excellent handling characteristics throughout the F-15E's vast flight envelope. This remarkable system allows the F-15E to fly at speeds ranging from Mach 2.5 to airspeeds below 150 knots. In addition, it provides exceptional maneuverability. Like most systems on the F-15E, the flight control system has two separate systems for redundancy (either system is perfectly capable of flying the aircraft by itself). The hydromechanical system (mechanical controls that are hydraulically operated) and the Control Augmentation System (CAS) work together to provide manual and automatic control of the aircraft.
The hydromechanical system provides inputs to the three primary flight controls - ailerons, rudders, and the stabilator. The ailerons and rudders act fairly conventional (see Flight Controls ); however, the stabilator works in a manner unlike conventional stabilators. A conventional stabilator is used only for pitch control. The stab on the F-15E is used for pitch as well as roll. Example: When the pilot pulls aft on the stick, the stab acts conventionally and both stabs on each side of the aircraft move together (i.e. both trailing edges go up). When the pilot moves the stick to the left in the F-15E, the stabs will move in opposite directions (acting like ailerons) to help roll the aircraft. While simple in concept, the actual workings of the stab and ailerons are extremely complex due to the flight envelope of the Strike Eagle.
In most general aviation aircraft, the ailerons and elevators are controlled by the control wheel and the rudders by pedals. The Aileron-Rudder Interconnect (ARI) mechanically links the ailerons and rudders to the control stick. This system automatically applies rudder inputs to correspond with roll inputs requested by the pilot. In simple terms, it automatically deflects the rudder for coordinated turns. Flight above the speed of sound has a different set of rules. For one, very little rudder inputs are required (as a matter of fact, at high Mach numbers rudder inputs can cause structural failure); thus, the ARI disengages above Mach 1.0. Also, when landing in a cross-wind (a wind that is not directly aligned with the runway), rudder inputs can hinder techniques to counter the wind so the ARI is disabled when the wheels on the ground and the speed is above 50 knots.
The primary responsibilities of the Control Augmentation System (CAS) system are to provide increased stability (smoothing out turbulance) and to refine the flight control inputs from the pilot provided to the hydromechanical system. It is a fly-by-wire system that overlays the hydromechanical system. It incorporates a sophisticated flight control computer with numerous motion sensors to refine the inputs to the flight control surfaces to respond to the pilot's stick inputs. In other words, it precisely deflects the flight control surfaces to provide the pilot with exactly the inputs he requested based on the amount of force used to move the stick). Again, this system has several redundant systems built within it providing outstanding reliability. The CAS system is sub-divided into 3 systems - PITCH, ROLL, and YAW. (Note: The CAS system does not provide inputs to the ailerons, it uses only differential stab inputs to roll the aircraft. The hydromechanical system provides the only inputs to the ailerons).
The Defense Department sustained production of the F-15E by purchasing three aircraft in both FY 1998 and FY 1999. Without FY 1998 procurement, the F-15 production line would have closed in the absence of new foreign sales. These six additional aircraft, together with the six aircraft approved by Congress in FY 1997, sustained the 132-plane combat force structure until about FY 2016. In June 1999 Boeing delivered the first new F-15E Eagle since 1994 to the U.S. Air Force, the first of 17 F-15Es to be delivered through early 2000. These 17 aircraft were equipped with new advanced data processors, a new digital mapping system, provisions for an upgraded Programmable Armament Control System, expanded smart weapons carriage capability, and an embedded Global Positioning System/Inertial Navigation System for increased accuracy. Boeing had previously delivered 209 F-15Es to the US Air Force from 1987 through 1994.
In April 2001 the Boeing Company and the US Air Force finalized contract terms for 10 F-15E aircraft, which sustained production of the fighter into 2004. Boeing began building the planes with initial funding from the Air Force's fiscal year 2000 budget. The aircraft will have several upgrades that make them the most capable F-15Es delivered to date. The planes will be the 227th-236th F-15Es produced by Boeing. Deliveries start during the first half of 2002 and will extend through the last quarter of 2004. Valued at approximately $571.1 million, the contract covers airframes and certain other components. The Air Force purchased some items separately - such as engines - as it had in the past.
The fiscal year (FY) 05 effort of the F-15E Attrition Aircraft Program acquisition included the fabrication, assembly and delivery to the field of up to two (2) additional F-15E production aircraft as well as associated data and equipment, production- related sustaining, warranty, limited updates to technical orders, and long lead effort for up to four (4) additional F-15E production aircraft. The contract may also contain an option for up to four (4) of the F-15E production aircraft established by the long lead effort in FY05.
By 2007, 236 F-15E Strike Eagles had been delivered to the U.S. Air Force, and 72 F-15S derivatives had been delivered to Saudi Arabia. Also, Israel had received 25 F-15I Thunder strike fighters. In 2005, deliveries of 40 more-advanced versions, the F-15K, began to the Republic of Korea Air Force. And in 2009 Singapore received its first of twelve F-15SG. >On October 20, 2010 the Defense Security Cooperation Agency notified Congress today of a possible Foreign Military Sale to the Government of Saudi Arabia of 84 F-15SA Aircraft and the upgrade of the existing Royal Saudi Air Force (RSAF) fleet of seventy (70) F-15S multi-role fighters to the F-15SA configuration.
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