| YUH-61 | |
|---|---|
 Boeing Vertol YUH-61A | |
| General information | |
| Type | Utility transport helicopter |
| Manufacturer | Boeing Vertol |
| Status | Program terminated |
| Primary user | United States Army |
| Number built | 3 |
| History | |
| First flight | 29 November 1974 |
TheBoeing Vertol YUH-61 (company designationModel 179) is a twin turbine-engined, medium-lift, military assault/utilityhelicopter. The YUH-61 was the runner-up in theUnited States ArmyUtility Tactical Transport Aircraft System (UTTAS) competition in the early 1970s to replace theBell UH-1 Iroquois helicopter. At the end of the flyoff program,Sikorsky Aircraft was awarded a contract to develop and build itsUH-60A entry.
Under a contract awarded in August 1972, Boeing Vertol designed and delivered three prototypes to compete UTTAS program.[1] When Boeing Vertol failed to win the Army competition, it pinned its hope on winning civil orders and the US Navy's LAMPS III program. In the end, a variant of the Sikorsky design, theSH-60B, won the Navy contract, and the civil orders received were canceled.[1]
Three aircraft were built and a further two were cancelled and not completed. An attack helicopter design, using the YUH-61's dynamic system (engines, rotor systems and gearboxes), was proposed for theAdvanced Attack Helicopter (AAH) competition, but did not make the downselect that resulted in theBell YAH-63 andHughes YAH-64 being built. The Boeing Vertol AAH design was unique in that the crew were seated in a laterally staggered tandem configuration.[2]
The YUH-61 was designed to meet the UTTAS requirements for improvedreliability,survivability and lowerlife-cycle costs, resulting in features such as dual-engines with improvedhot and high altitude performance, and amodular design (reduced maintenance footprint); run-drygearboxes;ballistically tolerant, redundant subsystems (hydraulic, electrical andflight controls);crashworthy crew (armored) and troop seats;dual-stage oleo mainlanding gear; ballistically tolerant, crashworthy main structure; quieter, more robustmain andtail rotor systems; and aballistically tolerant, crashworthyfuel system.[3]
Transport aboard theC-130 limited the UTTAS cabin height and length.[4] This also resulted in the main rotor being mounted very close to the cabin roof.
While Sikorsky chose a fully articulated rotor head withelastomeric bearings, Boeing Vertol chose a rigid main rotor design, based upon technology supplied byMBB, which was partnered with Boeing Vertol at the time.[5] Boeing Vertol also selected to use atricycle landing gear and a pusher tail rotor, as opposed to the tail wheel configuration and canted tractor tail rotor that Sikorsky chose, meaning that the vector of lift produced by the tail rotor was directed towards the vertical stabilizer, while the Sikorsky's was away from it.
Two of the three aircraft (73-21656 and 73-21658) built are preserved at theUnited States Army Aviation Museum inFort Novosel,Alabama.[citation needed]
Data from Modern Military Aircraft[1]
General characteristics
Performance
Aircraft of comparable role, configuration, and era
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