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NACA-RM-L57B21
Jet effects on the drag of conical afterbodies for Mach numbers of 0.6 to 1.28
Year: 1957
Abstract: INTRODUCTION
Present-day jet-propelled aircraft capable of supersonic flight cruises at high subsonic speeds in order to achieve a significant operating range. Since afterburner operation is not required for the cruise condition, the exit area of the nozzle must be reduced to maintain propulsive efficiency. The reduction in nozzle exit area necessitates increased boattailing of the afterbody or a larger base annulus. These changes in the shape of the afterbody cm result in lower static pressures; thus, the drag of the afterbody increases and the range capabilities of the aircraft reduces.
The investigation reported herein is part of a study to determine the effects of a propulsive jet on the drag of the afterbody from which it issues through the speed range from subsonic to supersonic speeds. The initial part-of this study was concerned with jet effects on a cylindrical afterbody and is described in reference 1. The work of reference 2 and the present investigation were conducted concurrently and the conical afterbody configurations of the former are geometrically similar to the configurations of this investigation. Studies by other researchers have been conducted at transonic speeds and some of these are reported in references 3 to 6. Reference 3 presents data on conical and contoured afterbodies obtained in a perforated tunnel in addition to results from a study of boundary-layer and tunnel-wall effects on the data. Reference 6 is one of several reported studies of jet effects on the afterbody of rocket-launched free-flight models.
The present investigation was conducted in the Langley internal aerodynamics laboratory over a Mach number range of 0.6 to 1.28 at corresponding Reynolds number of 3.4 X 106 to 4.8 X 106 per foot. The conical afterbodies investigated had boattail angles of 3°, 5.6°, 8°, 16°, 30o, and 45° with ratios of the jet diameter to the base diameter of 0.65 and 0.75. Values of the ratio of the base diameter to the maximum diameter of these models were 0.55, 0.70, and 0.85. The jet total pressure ratio was varied from no jet flow to approximately 8 and the stagnation temperature of the issuing jet was approximately 70° F.
Present-day jet-propelled aircraft capable of supersonic flight cruises at high subsonic speeds in order to achieve a significant operating range. Since afterburner operation is not required for the cruise condition, the exit area of the nozzle must be reduced to maintain propulsive efficiency. The reduction in nozzle exit area necessitates increased boattailing of the afterbody or a larger base annulus. These changes in the shape of the afterbody cm result in lower static pressures; thus, the drag of the afterbody increases and the range capabilities of the aircraft reduces.
The investigation reported herein is part of a study to determine the effects of a propulsive jet on the drag of the afterbody from which it issues through the speed range from subsonic to supersonic speeds. The initial part-of this study was concerned with jet effects on a cylindrical afterbody and is described in reference 1. The work of reference 2 and the present investigation were conducted concurrently and the conical afterbody configurations of the former are geometrically similar to the configurations of this investigation. Studies by other researchers have been conducted at transonic speeds and some of these are reported in references 3 to 6. Reference 3 presents data on conical and contoured afterbodies obtained in a perforated tunnel in addition to results from a study of boundary-layer and tunnel-wall effects on the data. Reference 6 is one of several reported studies of jet effects on the afterbody of rocket-launched free-flight models.
The present investigation was conducted in the Langley internal aerodynamics laboratory over a Mach number range of 0.6 to 1.28 at corresponding Reynolds number of 3.4 X 106 to 4.8 X 106 per foot. The conical afterbodies investigated had boattail angles of 3°, 5.6°, 8°, 16°, 30o, and 45° with ratios of the jet diameter to the base diameter of 0.65 and 0.75. Values of the ratio of the base diameter to the maximum diameter of these models were 0.55, 0.70, and 0.85. The jet total pressure ratio was varied from no jet flow to approximately 8 and the stagnation temperature of the issuing jet was approximately 70° F.
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T18:43:23Z | |
| date available | 2017-09-04T18:43:23Z | |
| date copyright | 01/01/1957 | |
| date issued | 1957 | |
| identifier other | KBYIYDAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std;jsessionid=3826AF679D40527318548F1EFDEC014A/handle/yse/224819 | |
| description abstract | INTRODUCTION Present-day jet-propelled aircraft capable of supersonic flight cruises at high subsonic speeds in order to achieve a significant operating range. Since afterburner operation is not required for the cruise condition, the exit area of the nozzle must be reduced to maintain propulsive efficiency. The reduction in nozzle exit area necessitates increased boattailing of the afterbody or a larger base annulus. These changes in the shape of the afterbody cm result in lower static pressures; thus, the drag of the afterbody increases and the range capabilities of the aircraft reduces. The investigation reported herein is part of a study to determine the effects of a propulsive jet on the drag of the afterbody from which it issues through the speed range from subsonic to supersonic speeds. The initial part-of this study was concerned with jet effects on a cylindrical afterbody and is described in reference 1. The work of reference 2 and the present investigation were conducted concurrently and the conical afterbody configurations of the former are geometrically similar to the configurations of this investigation. Studies by other researchers have been conducted at transonic speeds and some of these are reported in references 3 to 6. Reference 3 presents data on conical and contoured afterbodies obtained in a perforated tunnel in addition to results from a study of boundary-layer and tunnel-wall effects on the data. Reference 6 is one of several reported studies of jet effects on the afterbody of rocket-launched free-flight models. The present investigation was conducted in the Langley internal aerodynamics laboratory over a Mach number range of 0.6 to 1.28 at corresponding Reynolds number of 3.4 X 106 to 4.8 X 106 per foot. The conical afterbodies investigated had boattail angles of 3°, 5.6°, 8°, 16°, 30o, and 45° with ratios of the jet diameter to the base diameter of 0.65 and 0.75. Values of the ratio of the base diameter to the maximum diameter of these models were 0.55, 0.70, and 0.85. The jet total pressure ratio was varied from no jet flow to approximately 8 and the stagnation temperature of the issuing jet was approximately 70° F. | |
| language | English | |
| title | NACA-RM-L57B21 | num |
| title | Jet effects on the drag of conical afterbodies for Mach numbers of 0.6 to 1.28 | en |
| type | standard | |
| page | 64 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1957 | |
| contenttype | fulltext |