Installation of a High-Reduction-Ratio Transmission in the UH-1 Helicopter

Abstract : The report presents the results of an engineering design study to determine the feasibility of utilizing a high-speed roller gear transmission in a turbine-powered helicopter drive system. In such a transmission, the total speed reduction from the engine power turbine to the main rotor is through one bevel gear stage and a single 'planetary' stage. The salient advantages of this concept are derived from the use of pitch-line rollers in lieu of antifriction bearings in the 'planetary' stage. The study was directed toward the design of an optimized system adaptable to the UH-1 helicopter. Five different roller gear planetary systems were devised and analyzed during this refinement period. Manufacturing tolerance requirements commensurate with reliable operation were also determined. The primary study criteria were cost, weight, efficiency, and reliability as compared to the existent UH-1 system.