Evaluation of Pylon Focusing for Reduced Helicopter Vibration.
Abstract
A wind tunnel model test program was conducted to investigate the effectiveness of a focused isolation system in reducing the transmission of rotor-induced vibratory loads for a four-bladed hingeless rotor. The model consisted of a four-bladed hingeless rotor and a simulated transmission mounted on a focal isolation system having pitch and roll degrees of freedom. Analytical considerations indicate that there is no single focus which will simultaneously isolate both hub moments and inplane loads. For the four-bladed hingeless rotor with large vibratory hub moments, the optimum focus lies close to the combined rotor/transmission center of gravity. Model test results indicated two configurations with reasonable moment isolation. One was an upward focus near the combined rotor/transmission center of gravity. The second, which had an effective downward focus, produced high lateral and longitudinal loads. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1979
- Accession Number
- ADA069712
Entities
People
- Domonique Reed
- R. Gabel
Organizations
- Boeing Rotorcraft Systems