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T700

The Comanche [canclled in 2005] was powered by two Light Helicopter Turbine Engine Co. (LHTEC) T800-801 engines. Its advanced 1440 SHP engines enabled it to maintain sufficient speed to keep up with the more powerful AH-64 series Apache. The Comanche had a crusing speed of 161 knots (185 mph) and a dash speed of 172 knots (198 mph).

In response to the relatively high cost of forging turbine components, powdered metal (PM) was investigated as a possible lower cost alternative. Development of PM disks was conducted as part of the U.S. Army's T800 program with great success. The use of PM provided the potential to reduce material and machining cost by progressing to a near net shape forging.

Comanche's all-composite fuselage sides were flat and canted and rounded surfaces are avoided by use of faceted turret and engine covers. The Comanche's head-on RCS is 360 times smaller than the AH-64 Apache, 250 times less than the smaller OH-58D Kiowa Warrior, and 32 times smaller than the OH-58D's mast-mounted sight.

The Comanche only radiates 25% of the engine heat of current helicopters, a critical survivability design concern in a low-flying tactical scout helicopter. The Comanche is the first helicopter in which the infrared (IR) suppression system is integrated into the airframe. This innovative Sikorsky design feature provides IR suppressors that are built into the tail-boom, providing ample length for complete and efficient mixing of engine exhaust and cooling air flowing through inlets above the tail. The mixed exhaust is discharged through slots built into an inverted shelf on the sides of the tail-boom. The gases are cooled so thoroughly that a heat-seeking missile cannot find and lock-on to the Comanche.

The RAH-66 Comanche was a multi-mission aircraft optimized for the critical battlefield mission of tactical armed reconnaissance. It was to provide a globally self-deployable attack platform for light/contingency forces. Comanche was to provide the solution to reconnaissance deficiencies of no night/adverse weather/high/hot/stand-off capability and was a component on the digitized battlefield in winning the information war. The Comanche was the Army's technology leader and provides significant horizontal technology transfer within the Army and DoD.

In 1984, Allison and Garrett formed the Light Helicopter Turbine Engine Company (LHTEC), a partnership that won the Army's contract to develop an engine that would power the Comanche helicopter. The team approached MANPRINT integration principles with vigor and developed a program organization where communication, commitment, feedback and user influence prevailed on the designers.

This approach resulted in a capable and highly supportable engine, the T800, which surpassed all Army reliability and maintainability requirements. In contrast with predecessor engines, the T800 requires fewer personnel to perform flight-line maintenance. User training requirements are also significantly reduced. LHTEC's approach resulted in numerous innovative solutions to field maintenance and support challenges. For example, only six common handtools are needed to perform user-level maintenance, translating into a 76 percent reduction in depot tool inventories.

The human requirement for the T800 engine used in the Comanche helicopter called for no increase in aptitude (from its predecessor engine-the T700 in the OH-58 helicopter) and to reduce the number of maintainers. The resulting HSI effort reduced organizational tool kits from 64 to eight-a substantial accomplishment. The reduction also included a reduction in the number of maintenance tasks. Finally, the manpower manhours were reduced by 14 percent and the reliability of the system was increased.

The LHX program received approval by Defense Department officials in FY88 to begin its demonstration/validation phase in early FY 89. Intended to replace the tactically inferior AH-1 Cobra, OH-6 Cayuse, and the OH-58 Kiowa, the LHX was to perform armed reconnaissance and light attack missions and complement the larger and more powerfully armed AH-64 Apache. Developers aimed to obtain a maximum empty weight of 7,500 pounds and a cost limit of $7.5 million per aircraft in FY 88 dollars. Powered by two 1,200 shaft horsepower T800 engines, the LHX had two crewmen but the capability of one-person operation.

By 1992 the aircraft's T800 engine requirde a power upgrade of about 12 percent to compensate for increases in the Comanche's weight. The cost for the engine modification, was approximately $200 million over 6 years. When the demonstration/validation/prototype contract was awarded in April 199 1, the Army's empty weight goal for the Comanche was 7,500 pounds, and the engine was designed to power an aircraft weighing up to 8,138 pounds. The Army subsequently determined that it was necessary to increase the engine horsepower to allow for (1) additional equipment, (2) the Longbow system, and (3) possible weight growth.

Light Helicopter Turbine Engine Co., a partnership between Allison Engine/Rolls Royce-Indianapolis, and Allied Signal/Honeywell-Phoenix, Indianapolis, Ind., was awarded a $12,025,366 modification to cost-plus-fixed-fee contract DAAJ09-92-C-0453, on Feb. 25, 2000. The requirement is for the efforts required that will lead to the Pre-Production Qualification Program for the T800 engine in support of the Comanche Airframe Program. These efforts will maintain current air vehicle support without interruption ensuring continuous development of the T800 engine in order to meet the Comanche Program Manager Office schedule. Such efforts include, but are not limited to, engineering design, fabrication, test validation, administration, cost benefit analysis, and life cycle cost (trade) studies. Work will be performed in Indianapolis, Ind. (50%), and Phoenix, Ariz. (50%), and is expected to be completed by Oct. 31, 2000. Contract funds will not expire at the end of the current fiscal year. This is a sole source contract initiated on Feb. 28, 1991. The U.S. Army Aviation & Missile Command, St. Louis, Mo., is the contracting activity.

Light Helicopter Turbine Engine Co., Indianapolis, Ind., was awarded on 31 May 2001 an initial $8,499,998 as part of a $17,000,000 modification (because this is an undefinitized contract action, only 50% is being awarded at this time) to cost-plus-fixed-fee contract DAAJ09-92-C-0453. This requirement is for the efforts necessary to extend the current T800 contract that will lead to the Pre-Production Qualification Program for the T800 engine in support of the Comanche Airframe Program. These efforts will maintain current air vehicle support without interruption, ensuring continuous development of the T800 engine in order to meet the Comanche Program Management Office scheduled delivery date of the engine in July 2003. Such efforts include, but are not limited to, engineering design, fabrication, test validation, administration, cost benefit analysis and life cycle cost studies. Work will be performed in Indianapolis, Ind. (50%), and Phoenix, Ariz. (50%), and is expected to be completed by Oct. 31, 2001. Contract funds will not expire at the end of the current fiscal year. This is a sole source contract initiated on May 7, 2001. The U.S. Army Aviation & Missile Command, Redstone Arsenal, Ala., is the contracting activity.




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