The design maybe 40 years old, but there is plenty of life left in the F-15 Eagle fighter. Boeing’s St. Louis factory is producing F-15Ks for South Korea and F-15SGs for Singapore, and current orders mean that the Eagle will be in production into 2012. Meanwhile, Boeing Defense, Space and Security (DSS) is maintaining the technology insertion program that has seen the F-15 remain a viable option in today’s tactical aircraft marketplace.

“We believe there’s a great market for us in the tac air business,” said Jeffrey Johnson, Boeing DSS’s vice president business development for Global Strike Systems. “We can give you a good price. We are truly combat-proven. We bring technologies today that the others hope to have in 10 years.”

This continued belief in the F-15 was justified by the type’s selection by South Korea and Singapore in the face of stiff competition from the Rafale and Typhoon. Singapore initially ordered 12 F-15SGs in late 2005, with an option for eight more that was exercised in October 2007, at which time four more were added to raise the total to 24. The first was rolled out on Nov. 3, 2008.

Deliveries began to Mountain Home U.S. Air Force Base in Idaho, where the RSAF will maintain up to 12 of the aircraft for roughly 25 years as a training detachment. The Peace Carvin V detachment was officially inaugurated on November 20 by Singapore’s deputy prime minister and defense minister, Teo Chee Hean. The detachment had been activated as the 428th Fighter Squadron of the USAF in October 2008, restoring the squadron number used previously by an RSAF F-16 training detachment at Holloman AFB (Peace Carvin III). The first F-15SGs are due to arrive in Singapore later this year, and all deliveries should be completed in 2011.

Singapore’s F-15SGs are the most advanced Eagles flying. They are fitted with Raytheon’s APG-63(V)3 AESA radar, and a navigation/targeting suite provided by Lockheed Martin. This comprises a LANTIRN navigation pod with terrain-following radar and forward-looking infrared, a Sniper XR EO/laser targeting pod, and the AAS-42 Tiger Eyes infrared search and track system. The IRST offers passive air-to-air detection and tracking functions, and is built into the pylon for the Sniper pod.

F-15SGs are believed to incorporate several key systems of Israeli origin, such as mission computer and electronic warfare system. They also have Link 16 data link and JHMCS helmet sights. Weaponry includes AIM-9X Sidewinder, AIM-120C AMRAAM, JDAM GPS-guided bombs and the AGM-154 standoff weapon.

Silent Eagle
Last March Boeing revealed the latest product of its continued investment in the Eagle design–the F-15SE Silent Eagle. Developed primarily with existing F-15 customers in mind, the F-15SE can be seen as offsetting some of the technology release and cost issues associated with acquisition of the F-22 and F-35.

As its name suggests, reducing radar signature is one of the key elements of the Silent Eagle program, which can be viewed as a menu of options for customers. In its full specification the F-15SE is envisioned as having extensive low observable treatments and RCS-reducing coatings, an AESA radar, new digital electronic warfare suite, new digital flight control system, conformal fuel tanks redesigned to accommodate weapons, and canted fins. The tail surfaces remain the standard F-15 units, but are angled out at 15 degrees to reduce RCS, requiring some internal structural redesign.

Known as conformal weapons bays, the new CFTs each have two separate weapons bays. They can accommodate AIM-9X and AIM-120C air-to-air missiles, or air-to-surface weaponry comprising one GBU-32 1,000-pound JDAM, two GBU-38 500-pound JDAMs or four small-diameter bombs.

With CWBs fitted and the other signature management measures applied, the F-15SE has a much-reduced radar cross section for “first-day” stealthy attacks. While Boeing concedes that it is not as stealthy as a true fifth-generation fighter such as the F-22, the F-15SE offers a considerable capability against intact air defense systems. When operations do not dictate low observability, the CWBs can be quickly replaced with standard CFTs, restoring the Eagle’s full stores-carrying capability.

Last fall Boeing conducted initial RCS tests of the Silent Eagle layout, using long-term testbed F-15E1 (the first F-15E Strike Eagle). The tests were conducted with standard upright fins. Boeing is now preparing F-15E1 for flight trials of the CWBs some time in the third quarter of the year. As well as in-flight bay door operations, the trials are scheduled to include a live missile launch, probably of an AIM-120.

While the Silent Eagle treatment is available for retrofit to existing F-15s, Boeing is seeking new-build business for the type, although current Eagle models remain available. A Silent Eagle option is to be proposed to South Korea for the third phase of its F-X fighter modernization plan, which is expected to total around 60 aircraft.

Another nation where the Silent Eagle may find an application is Japan. At present Boeing is proposing both F-15 and F/A-18 Super Hornet options to Tokyo, but that will reduce to one type after a formal RFP is issued, thought to be in the next month or so. Interest in new-build Eagles–possibly of the Silent variety–has also been reported from Saudi Arabia.