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NACA-ARR-L4I12 REV A
Notes on the propeller and slipstream in relation to stability
Year: 1944
Abstract: INTRODUCTION
In reference 1, an analytical treatment is given of the effect of propeller operation on the pitching moments of single-engine monoplanes with flaps neutral. The analysis, which is based on simplifying assumptions, is accompanied by experimental data. In reference 2, the analysis and the experiments are extended to the case with flaps deflected. The present paper is intended to supplement and, to a small extent, to amend references 1 and 2. A short extension is added on lateral stability.
Some previous work on propeller "fin effect" (references 3 and 4) has been recast in simpler form with the thrust coefficient replacing the advance diameter coefficient as the independent variable. The new relation, which is more suitable for stability calculations, is presented herein together with charts for the side-force derivative cross-plotted from reference 3. Hereinafter, the term "normal-force derivative," which is applicable to propellers in both pitch and yaw, is used to replace the term "side-force derivative," which is associated with propellers in yaw.
The up wash or down wash from the wing influences the normal force in pitch. A graph is provided for estimating this change.
The propeller side-force factor was introduced in reference 5 as a criterion for extrapolating side-force charts for one propeller to apply to another propeller. A simpler approximate method that avoids graphical integration is provided herein for readily estimating the side-force factor for a given propeller.
Because the propeller yawing moment due to pitch - or, what is the same except for sign, the pitching moment due to yaw Cm has a small but appreciable effect on lateral trim, curves for Cm' have been computed from the formula of reference 3 and are presented herein.
A derivation in reference 4 has been extended to provide a relation for the side wash of the slipstream of an isolated propeller in yaw that differs from the one in common use (reference 6). A figure is included herein to show the improved agreement with experiment. The new side wash relation, which is applicable also to the down wash of an isolated propeller in pitch, is presented with graphs to provide ready evaluation of the side wash or down wash by use of the normal-force graphs of this paper
In reference 1, an analytical treatment is given of the effect of propeller operation on the pitching moments of single-engine monoplanes with flaps neutral. The analysis, which is based on simplifying assumptions, is accompanied by experimental data. In reference 2, the analysis and the experiments are extended to the case with flaps deflected. The present paper is intended to supplement and, to a small extent, to amend references 1 and 2. A short extension is added on lateral stability.
Some previous work on propeller "fin effect" (references 3 and 4) has been recast in simpler form with the thrust coefficient replacing the advance diameter coefficient as the independent variable. The new relation, which is more suitable for stability calculations, is presented herein together with charts for the side-force derivative cross-plotted from reference 3. Hereinafter, the term "normal-force derivative," which is applicable to propellers in both pitch and yaw, is used to replace the term "side-force derivative," which is associated with propellers in yaw.
The up wash or down wash from the wing influences the normal force in pitch. A graph is provided for estimating this change.
The propeller side-force factor was introduced in reference 5 as a criterion for extrapolating side-force charts for one propeller to apply to another propeller. A simpler approximate method that avoids graphical integration is provided herein for readily estimating the side-force factor for a given propeller.
Because the propeller yawing moment due to pitch - or, what is the same except for sign, the pitching moment due to yaw Cm has a small but appreciable effect on lateral trim, curves for Cm' have been computed from the formula of reference 3 and are presented herein.
A derivation in reference 4 has been extended to provide a relation for the side wash of the slipstream of an isolated propeller in yaw that differs from the one in common use (reference 6). A figure is included herein to show the improved agreement with experiment. The new side wash relation, which is applicable also to the down wash of an isolated propeller in pitch, is presented with graphs to provide ready evaluation of the side wash or down wash by use of the normal-force graphs of this paper
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NACA-ARR-L4I12 REV A
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T16:43:19Z | |
| date available | 2017-09-04T16:43:19Z | |
| date copyright | 01/01/1944 | |
| date issued | 1944 | |
| identifier other | VTUYYDAAAAAAAAAA.pdf | |
| identifier uri | https://yse.yabesh.ir/std/handle/yse/106540 | |
| description abstract | INTRODUCTION In reference 1, an analytical treatment is given of the effect of propeller operation on the pitching moments of single-engine monoplanes with flaps neutral. The analysis, which is based on simplifying assumptions, is accompanied by experimental data. In reference 2, the analysis and the experiments are extended to the case with flaps deflected. The present paper is intended to supplement and, to a small extent, to amend references 1 and 2. A short extension is added on lateral stability. Some previous work on propeller "fin effect" (references 3 and 4) has been recast in simpler form with the thrust coefficient replacing the advance diameter coefficient as the independent variable. The new relation, which is more suitable for stability calculations, is presented herein together with charts for the side-force derivative cross-plotted from reference 3. Hereinafter, the term "normal-force derivative," which is applicable to propellers in both pitch and yaw, is used to replace the term "side-force derivative," which is associated with propellers in yaw. The up wash or down wash from the wing influences the normal force in pitch. A graph is provided for estimating this change. The propeller side-force factor was introduced in reference 5 as a criterion for extrapolating side-force charts for one propeller to apply to another propeller. A simpler approximate method that avoids graphical integration is provided herein for readily estimating the side-force factor for a given propeller. Because the propeller yawing moment due to pitch - or, what is the same except for sign, the pitching moment due to yaw Cm has a small but appreciable effect on lateral trim, curves for Cm' have been computed from the formula of reference 3 and are presented herein. A derivation in reference 4 has been extended to provide a relation for the side wash of the slipstream of an isolated propeller in yaw that differs from the one in common use (reference 6). A figure is included herein to show the improved agreement with experiment. The new side wash relation, which is applicable also to the down wash of an isolated propeller in pitch, is presented with graphs to provide ready evaluation of the side wash or down wash by use of the normal-force graphs of this paper | |
| language | English | |
| title | NACA-ARR-L4I12 REV A | num |
| title | Notes on the propeller and slipstream in relation to stability | en |
| type | standard | |
| page | 27 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1944 | |
| contenttype | fulltext |