Development of Helicopter Transmission Components for the 1980S

New components and materials are being evaluated for application to the next generation of helicopter transmissions. Three types of involute gears standard spur, high contact ratio (HCR) spur, and double-helical (D-H) - are to be evaluated in direct comparison tests. These tests will evaluate the following parameters: noise, efficiency, scoring, pitting, bending, and loss-of-lubricant operation. The test program is not to be concluded until early 1981; however, calculated test results are discussed. All three types of gears are made of Carpenter EX-00053, a new, high-temperresistant, air-hardening, carburizing steel. The double-helical sun and planet gears are made in one piece by shaping, shaving, carburizing, and honing. In conjunction with the gear tests, three rolling bearing materials, ANS 6444 (CEVN 52100), ANS 6491 (DVN N-50), and silicon nitride will be compared. Additionally, an input spiral bevel pinion with integral ball bearing inner races and a minilube system will be evaluated.