BOEING UNVEILS NEW VERSION OF F-15 FIGHTER JET Boeing's new F-15 seen as cheaper alternative to Lockheed's Joint Strike Fighter Tuesday March 17, 2009 4:34 PM EDT WASHINGTON (AP) -- Plane maker Boeing Co. Tuesday unveiled a prototype of a new version of its F-15 tactical fighter jet to sell to international customers in the Middle East and Asia Pacific.    The new jet, called the F-15 Silent Eagle, is largely designed for foreign governments as a competing plane against Lockheed Martin Corp.'s Joint Strike Fighter, also known as the F-35. Boeing is hoping that its new F-15 will appeal to countries who are interested in the F-35, but are concerned about its rising costs and lack of flexibility. "The F-15 Silent Eagle is designed to meet our international customers' anticipated need for cost-effective stealth technologies, as well as for large and diverse weapons payloads," said Mark Bass, F-15 Program vice president for Boeing, in a statement. The future of Boeing's St. Louis manufacturing facility, where the F-15 is built, has been uncertain since it lost the Joint Strike Fighter contest to Bethesda, Md.-based Lockheed. The new aircraft includes redesigned conformal fuel tanks that can be converted into internal weapons bay, as well as a digital electronic warfare system made by BAE Systems. The jet will also be able to carry air-to-air missiles and air-to-ground missiles. Boeing will also offer coatings and treatments to improve the stealth of the aircraft. The Chicago-based company plans to hold a flight test of the prototype by the first quarter of 2010. That will include a live missile launch. Lockheed's F-35 is designed to replace many of the current warplanes flown by the Marine Corps, Navy and Air Force. A total of 2,456 planes will be bought for roughly $300 billion, with another $760 billion expected to be required to maintain the planes during their lifespans, according to a recent report by the Government Accountability Office. The U.S is developing the plane with nations that include the United Kingdom, Australia and Italy, though the Pentagon has shouldered much of the funding. Shares of Boeing added 61 cents to close at $34.44.