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NACA-TN-4117
Experimental investigation of lift, drag, and pitching moment of five annular airfoils
Year: 1957
Abstract: An investigation was carried out in the Langley stability tunnel to determine the lift, drag, and pitching-moment characteristics of a family of annular airfoils. The five annular airfoils had equal projected areas but had varying chords and diameters which covered aspect ratios of 1/3, 2/3, 1.0, 1.5, and 3.0.
The results showed that the effects of aspect ratio on the aerodynamic-center location were similar for annular and unswept airfoils and that annular airfoils had larger maximum lift-drag ratios below an aspect ratio of 2.4 than did plane rectangular airfoils with faired tips. The lift-curve slope was twice the lift curve slope for a plane unswept airfoil of the same aspect ratio, and the induced drag coefficient was one-half the induced drag coefficient of an elliptic airfoil. The characteristics of the flow in the wake of the annular airfoils having lower aspect ratios (1/3, 2/3, and 1.0) were similar to the wake characteristics of low-aspect-ratio or highly swept airfoils.
The results showed that the effects of aspect ratio on the aerodynamic-center location were similar for annular and unswept airfoils and that annular airfoils had larger maximum lift-drag ratios below an aspect ratio of 2.4 than did plane rectangular airfoils with faired tips. The lift-curve slope was twice the lift curve slope for a plane unswept airfoil of the same aspect ratio, and the induced drag coefficient was one-half the induced drag coefficient of an elliptic airfoil. The characteristics of the flow in the wake of the annular airfoils having lower aspect ratios (1/3, 2/3, and 1.0) were similar to the wake characteristics of low-aspect-ratio or highly swept airfoils.
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T17:54:37Z | |
| date available | 2017-09-04T17:54:37Z | |
| date copyright | 01/01/1957 | |
| date issued | 1957 | |
| identifier other | FHOUYDAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std/handle/yse/177692 | |
| description abstract | An investigation was carried out in the Langley stability tunnel to determine the lift, drag, and pitching-moment characteristics of a family of annular airfoils. The five annular airfoils had equal projected areas but had varying chords and diameters which covered aspect ratios of 1/3, 2/3, 1.0, 1.5, and 3.0. The results showed that the effects of aspect ratio on the aerodynamic-center location were similar for annular and unswept airfoils and that annular airfoils had larger maximum lift-drag ratios below an aspect ratio of 2.4 than did plane rectangular airfoils with faired tips. The lift-curve slope was twice the lift curve slope for a plane unswept airfoil of the same aspect ratio, and the induced drag coefficient was one-half the induced drag coefficient of an elliptic airfoil. The characteristics of the flow in the wake of the annular airfoils having lower aspect ratios (1/3, 2/3, and 1.0) were similar to the wake characteristics of low-aspect-ratio or highly swept airfoils. | |
| language | English | |
| title | NACA-TN-4117 | num |
| title | Experimental investigation of lift, drag, and pitching moment of five annular airfoils | en |
| type | standard | |
| page | 26 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1957 | |
| contenttype | fulltext |