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9-726: In support of the LHX program, the United States Army started the Advanced Composite Airframe Program (ACAP) to develop an all-composite helicopter fuselage. In February 1981, contracts were awarded to Sikorsky (for the Sikorsky S-75 ) and Bell Helicopter (for the Bell D-292 ). An Army Aviation Mission Area Analysis, completed in 1982, identified deficiencies in current materiel and doctrine that needed to be addressed to meet

18-478: The Boeing-Sikorsky and Bell-McDonnell Douglas teams received contracts for their designs. The Bell-McDonnell Douglas design featured ordnance carriage within a combined wing/ sponson and instead of a tail rotor used a NOTAR ducted exhaust system. The Boeing-Sikorsky design carried ordnance within upward swinging gull-wing doors in the sides of the fuselage and featured a fenestron tail rotor. The program's name

27-466: The box . The Army solidified requirements too early without sufficient risk management . A single-crew version was an early requirement, but depended upon successful development of a risky electronic package. Early concepts included both utility and scout/attack versions, but by 1988, the utility concept was dropped. A Request for proposals for the new helicopter type was released in June 1988. In October 1988,

36-430: The first time in 27 July 1984. The S-75 mated an entirely new composite airframe with the twin turboshaft engines, transmission, and main and tail rotors of Sikorsky's S-76A civil transport helicopter. The S-75's floors, roof and most exterior surfaces were of more ballistically-resistant Kevlar , while most of the aircraft's basic load-bearing structure was built of graphite or a graphite/ epoxy blend. The machine

45-667: The requirements of the new Airland Battle Doctrine. The specific material deficiencies were to be resolved through the LHX program. In 1982, the U.S. Army started the Light Helicopter Experimental (LHX) program to replace the UH-1 , AH-1 , OH-6 , and OH-58 helicopters. In August 1986, the Defense Science Board review revealed that the Army suffered from stovepiping in a program development sense, and could not think outside

54-572: The rising projected cost of production, changing aviation mission of the Army (refusal to consider the changing threat environment), lack of sufficient funding for other critical aviation needs, the lack of achieving reduced risk of certain key technologies, and chronic groupthink . Sikorsky S-75 The Sikorsky S-75 was a proof-of-concept all-composite helicopter . Sikorsky Aircraft used all- composite materials to replace metal to provide greater strength, lighter weight, lower manufacturing costs, and reduce maintenance costs. The Sikorsky S-75

63-546: Was changed to Light Helicopter (LH) in 1990. In April 1991, the Boeing-Sikorsky team was selected as the contest winner and received a contract to build four prototypes. Also that month, the helicopter was designated " RAH-66 Comanche " by the Army. In March 2004, the Army Chief of Staff terminated the Comanche program. The termination happened for several reasons; among them were unrealistic and unachievable overarching requirements,

72-546: Was developed under the US Army's Advanced Composite Airframe Program (ACAP), the goal of which was the development of an all-composite helicopter fuselage, lighter and less costly to build than predominantly metal airframes in support of the Light Helicopter Experimental (LHX) program. In February 1981, contracts were awarded to Sikorsky and Bell Helicopter , with Bell submitting its Model D292 . The S-75 flew for

81-477: Was equipped with specially designed impact-resistant crew and passenger seats and high-strength pneumatic shock absorbers on its fixed tricycle landing gear, in keeping with the Army's requirement that the ACAP aircraft meet or exceed all existing military crashworthiness standards. The aircraft was flown by two pilots, and could carry up to six passengers in the 100-cubic-foot (2.8 m ) rear cabin. The S-75 underwent

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