TY  - BOOK
AU  - Brentner, Kenneth S.
TI  - Prediction of helicopter rotor discrete frequency noise: a computer program incorporating realistic blade motions and advanced acoustic formulation / 
U1  - 629.13436 
PY  - 1986///
CY  - Virginia
PB  - National Aeronautics and Space Administration
KW  - Aeronautics
KW  - Airplaines
KW  - Helicopter
N1  - NASA Technical Memorandum 87721
ER  -