A theoretical estimate of the effects of compressibility on the performance of a helicopter rotor in various flight conditions / Alfred Gessow and Almer D. Crim.
The effects of compressibility arising from high-tip-speed operation on the flapping, thrust, and power of a helicopter rotor over a wide range of forward fkight conditions are investigated by the use of numerical methods.
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| Format: | Government Document Book |
| Language: | English |
| Published: |
Washington, D.C. :
National Advisory Committee for Aeronautics,
1956.
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| Series: | Technical note (United States. National Advisory Committee for Aeronautics) ;
3798. |
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| Summary: | The effects of compressibility arising from high-tip-speed operation on the flapping, thrust, and power of a helicopter rotor over a wide range of forward fkight conditions are investigated by the use of numerical methods. For the particular set of airfoil characteristics used, the results indicated minor increases in rotor flapping and thrust arising from increasing rotor tip speed from 350 to 750 fps. The largest effect noted was an increase in profile-drag power on the advancing side of the disk that was proportional to the amount by which the blade-tip Mach number exceeded the drag-divergence Mach number. These effects of compressibility appeared to be independent of blade twist but are, of course, a function of the airfoil characteristics employed in the analysis. |
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| Item Description: | "October 1956." NACA TN Number 3798. |
| Physical Description: | 33 pages : illustrations ; 27 cm. |
| Bibliography: | Includes bibliographical references. |