Little progress made in weapons bay development
F-15 Silent Eagle
By Lee Tae-hoon
Industry insiders raised questions Wednesday about whether U.S. aerospace giant Boeing will fulfill its pledge to offer F-15 Silent Eagles (F-15 SEs) with an internal weapons bay and twin canted tails, two of the core technologies for stealth jets, to Seoul.
A source familiar with Boeing’s plan to modify its F-15s said little progress has been made in the making of the F-15SE, especially in the development of its conformal weapons bay (CWB), which allows the aircraft to carry weapons internally.
“Only 10 percent of work has been completed for the research and development of the F-15SE’s conformal weapons bay,” the informed industry source said.
The Korea Aerospace Industries (KAI) has been carrying out research and development of the F-15 SE’s internal weapons bay, a crucial stealth feature, since signing a memorandum of understanding (MOU) with Boeing in 2010.
The CWB, a common characteristic of aircraft with low visibility, was a compulsory requirement to enter Korea’s FX-III bid, the country’s third and last phase of a program to procure advanced jets.
Seoul, however, has decided to remove the prerequisite to allow more companies to enter the competition, according to Noh Dae-lae, the commissioner of the Defense Acquisition Program Administration (DAPA).
Boeing, which has sold 61 F-15Ks to Korea since 2002, pledged to develop the F-15SE for international customers, including Seoul, by upgrading its F-15 Strike Eagle upon unveiling its concept for the semi-stealth aircraft in March 2009.
An industry source said Beoing has yet to determine whether to push the development of 15-degree outward-canted V-tails, which it proposed to include when the company first announced the F-15SE.
He said Boeing is expected to propose canted vertical tails as an upgrade option to Korea.
Boeing sought to cant the vertical tails of the F-15 outward to reduce the combat aircraft’s radar signature and increase aerodynamic efficiency, but announced it would suspend the development of the new feature in 2010.
Other industry officials noted that it will be physically impossible for Boeing to complete the development of the CWB and canted tails by the end of October this year when Seoul plans to finalize the deal after three to four months of evaluations and negotiations. “Boeing will most likely change their offer. They won’t offer the Silent Eagle,” a senior official of Lockheed Martin, which is competing with Boeing and the European Aeronautic Defense and Space Company (EADS) for the FX-III bid, said asking for anonymity.
“They are going to offer the F-15K because that’s the only plane they can deliver by 2016.”
DAPA officials warned that Boeing may enter the FX-III race after minor upgrades to the F-15K, such as installing Active Electronically Scanned Array (AESA) radars, but the airplane’s stealth capability remains a crucial factor in deciding which new fighter jets will be purchased.
“Boeing may compete in the FX-III race without having to complete its development of the CWB or canted vertical tails, but it should bear in mind that Korea is eyeing to acquire advanced jets, rather than outdated ones,” a senior DAPA official said.
DAPA is expected to issue a request for proposal on Jan. 30 without the requirements of the conformal weapons bay and a specific target value for the radar cross section of the plane.
FX-3차 사업에 F-15 스텔스 버전인 F-15SE (사일런트 이글)을 가지고 출사표를 던진 보잉사가 Conformal Weapons Bay (내부무기탑재실) 등 스텔스 핵심기술 개발에 있어 진행 정도가 매우 부진한 것으로 들어났다.
한 업계 관계자는 스텔스의 핵심기술인 내부무기탑재실에 대한 “연구 및 개발의 경우 10% 정도 진척된 상태”라고 전했다.
한국항공우주산업(KAI)은 보잉사와 F-15 사일런트 이글(F-15SE)의 내부무기탑재실의 설계, 개발, 생산 협력에 관한 합의각서(MOA)를 2010년 체결 후 내부무기탑재실에 대한 연구 및 개발을 수행하고 있다.
한 업계 관계자에 의하면 보잉은 사일런트 이글의 경우 수직꼬리 날개를 15도 외각으로 기울여 레이더 반사 면적을 줄이려는 계획을 가지고 있었으나 이마저 개발 진행 여부가 불확실 한 실정이어서 이를 한국에 옵션사항으로 제시하게 될 거라 말했다.
이에 대해 록히드 마틴 관계자는 보잉이 사일런트 이글을 2016까지 만들어 한국 공군에 납품한다는 것은 현실적으로 불가능하며, FX 3차 사업을 수주하게 되더라도 보잉사는 결국 F-15의 성능을 약간 업그레이드 해 납품할 수 밖에 없을 거라 주장했다.
방사청 관계자는 이에 대해 보잉이 F-15K를 가지고 FX 3차에 뛰어드는 것은 최근 군요구성능(ROC)를 낮추어 문제가 없을 수 있다 볼 수도 있지만 스텔스 기능이 있는 신형 전투기를 확보한다는 공군의 입장에는 크게 변화가 없어 이는 사실상 무리수라 보여진다 말했다.