Under a contract awarded in August 1972, Boeing Vertol designed and delivered three prototypes to compete UTTAS program. 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, the SH-60B, won the Navy contract, and the civil orders received were canceled. Three aircraft were built and a further two were cancelled and not completed. An attack helicopter design, using the YUH-61's dynamic system, was proposed for the Advanced Attack Helicopter competition, much as the dynamic system of the earlier UH-1 Iroquois had been adapted into the AH-1 Cobra gunship, but did not make the downselect that resulted in the Bell YAH-63 and Hughes YAH-64 being built. The Boeing Vertol AAH design was unique in that the crew were seated in a laterally staggered tandem configuration.
Design
The YUH-61 was designed to meet the UTTAS requirements for improved reliability, survivability and lower life-cycle costs, resulting in features such as dual-engines with improved hot and high altitude performance, and a modular design ; run-dry gearboxes; ballistically tolerant, redundant subsystems ; crashworthy crew and troop seats; dual-stage oleomainlanding gear; ballistically tolerant, crashworthy main structure; quieter, more robust main and tail rotor systems; and a ballistically tolerant, crashworthy fuel system. Transport aboard the C-130 limited the UTTAS cabin height and length. This also resulted in the main rotor being mounted very close to the cabin roof. While Sikorsky chose a fully articulated rotor head with elastomeric bearings, Boeing Vertol chose a rigid main rotor design, based upon technology supplied by MBB, which was partnered with Boeing Vertol at the time. Boeing Vertol also selected to use a tricycle 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 thrust produced by the tail rotor was directed away from the vertical stabilizer, while the Sikorsky's flowed around it..
Variants
Model 237: naval version of the YUH-61 for the USN's LAMPS II competition and lost out to Sikorsky SH-60 Seahawk; no models built
Model 179: civilian 14–20 passenger utility helicopter later canceled; 1 model built
