became known to western allies, though officially the aircraft's designation remained Yak-41M within the Soviet military. In 1991 Lockheed-Martin entered into partnership with Yakovlev to further develop an aircraft they had always known as the Yak-141. Largely as a result of this agreement, by 1992 Yakovlev changed the aircraft's designation to Yak-141 for the two flyable prototypes. Series production in Russia could further change the designation. Cooperation with Lockheed Following the announcement by the CIS in September 1991 that it could no longer fund development of the Yak-41M, Yakovlev entered into discussions with several foreign partners who could help fund the program. Lockheed Corporation, which was in the process of developing the X-35 for the US Joint Strike Fighter program, stepped forward, and with their assistance aircraft 48-2 was displayed at the Farnborough Airshow in September 1992. Yakovlev announced that they had reached an agreement with Lockheed for funds of $385 to $400 million for three new prototypes and an additional static test aircraft to test improvements in design and avionics. Planned modifications for the proposed Yak-41M included an increase in STOL weight to 21,500 kg (47,400 lb). One of the prototypes would have been a dual-control trainer. Though no longer flyable, both 48-2 and 48-3 were exhibited at the 1993 Moscow airshow. The partnership began in late 1991, though it was not publicly revealed by Yakovlev until 6 September 1992, and was not revealed by Lockheed until June 1994. Variants Yak-41 The two flying prototypes and ground test article. Yak-41M Proposed production aircraft with large LERXs (leading-edge root extensions) and other improvements, particularly in the avionic suite. Yak-43 (Izdeliye 201) A proposed development of the Yak-41M 'Freehand' equipped with Kuznetsov NK-321 engines. Yak-141 Designation originally applied to a single Yak-41 for disinformation and propaganda purposes when registering records with the FAI (Fédération Aéronautique Internationale) and later for promotional purposes by Yakovlev. Operators Soviet Navy Soviet Naval Aviation Surviving aircraft Yak-41M (s/n 48-2, call sign "75") is on display at the Central Air Force Museum at Monino. The aircraft is displayed in its 1992 livery with olive/grey camouflage markings. Yak-41M (s/n 48-3, call sign "77") is on display at the Yakovlev OKB Museum. The aircraft is displayed in its 1992 livery with olive/grey camouflage markings and "141" painted in white in place of the former call sign. Specifications (Yak-41) See also References External links Walkaround Yak-41 from Monino Museum (Russia)