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NACA-RM-L55I20
Effect of large negative dihedral of the horizontal tail on longitudinal and lateral stability characteristics of a swept-wing configuration at transonic speeds
Year: 1955
Abstract: INTRODUCTION
The longitudinal instability that occurs for some swept-wing air planes operating at high lift coefficients has been found to result from flow separation on the wing or improper location of the horizontal tail or a combination of both conditions. Consequently, the use of various wing fixes has been studied in an attempt to alleviate wing-flow separation. The results of some of these studies are summarized in reference 1. Studies of horizontal tail location, such as references 1 and 2, have shown that the longitudinal stability of a model can be altered by the vertical location of the horizontal tail because of the variation of the down-wash throughout the flow field behind the wing.
The analysis in reference 2 of the flow in the vicinity of the horizontal-tail location behind a sweptback wing indicated that at high angles of attack the variation of down-wash with angle of attack over the outer sections of the tail span was such that the tail contribution to the longitudinal stability was favorable for the position below the extended wing-chord plane and behind a sweptback wing indicated that at high angles of attack the variation of down-wash with angle of attack over the outer sections of the tail span was such that the tail contribution to the longitudinal stability was favorable for the position below the extended wing-chord plane and destabilizing for the positions above the extended wing-chord plane. It should be possible therefore, in cases where a low tail location is impractical, to incorporate some of the advantages of a low tail by mounting the tail in a higher position and incorporating negative dihedral.
During a recent low-speed investigation in the Langley 19-foot pressure tunnel, of a swept-wing fighter model equipped with wing fences and a modified leading edge outboard of the fences, it was found that longitudinal instability occurred at high lift coefficients. Various horizontal-tail arrangements were tried to improved the stability. One arrangement consisted of setting the horizontal tail with 22° of negative dihedral which gave some improvement in stability in the high lift range.
However, it was of interest to determine the effects of a horizontal tail with negative dihedral on the stability characteristics of the model at transonic speeds. Therefore, a study was made of a similar swept-wing fighter airplane model with wing fixes in the Langley 16-foot transonic tunnel to determine the effect on the longitudinal and lateral stability. Characteristics of a 40° swept horizontal tail set with 221/2°of negative dihedral. The data for the model without a horizontal tail, with a straight horizontal tail, and with a negative-dihedral horizontal tail are presented in this paper for a mach number range from 0.80 to 1.05 and for a range of angles of attack and of side-slip.
The longitudinal instability that occurs for some swept-wing air planes operating at high lift coefficients has been found to result from flow separation on the wing or improper location of the horizontal tail or a combination of both conditions. Consequently, the use of various wing fixes has been studied in an attempt to alleviate wing-flow separation. The results of some of these studies are summarized in reference 1. Studies of horizontal tail location, such as references 1 and 2, have shown that the longitudinal stability of a model can be altered by the vertical location of the horizontal tail because of the variation of the down-wash throughout the flow field behind the wing.
The analysis in reference 2 of the flow in the vicinity of the horizontal-tail location behind a sweptback wing indicated that at high angles of attack the variation of down-wash with angle of attack over the outer sections of the tail span was such that the tail contribution to the longitudinal stability was favorable for the position below the extended wing-chord plane and behind a sweptback wing indicated that at high angles of attack the variation of down-wash with angle of attack over the outer sections of the tail span was such that the tail contribution to the longitudinal stability was favorable for the position below the extended wing-chord plane and destabilizing for the positions above the extended wing-chord plane. It should be possible therefore, in cases where a low tail location is impractical, to incorporate some of the advantages of a low tail by mounting the tail in a higher position and incorporating negative dihedral.
During a recent low-speed investigation in the Langley 19-foot pressure tunnel, of a swept-wing fighter model equipped with wing fences and a modified leading edge outboard of the fences, it was found that longitudinal instability occurred at high lift coefficients. Various horizontal-tail arrangements were tried to improved the stability. One arrangement consisted of setting the horizontal tail with 22° of negative dihedral which gave some improvement in stability in the high lift range.
However, it was of interest to determine the effects of a horizontal tail with negative dihedral on the stability characteristics of the model at transonic speeds. Therefore, a study was made of a similar swept-wing fighter airplane model with wing fixes in the Langley 16-foot transonic tunnel to determine the effect on the longitudinal and lateral stability. Characteristics of a 40° swept horizontal tail set with 221/2°of negative dihedral. The data for the model without a horizontal tail, with a straight horizontal tail, and with a negative-dihedral horizontal tail are presented in this paper for a mach number range from 0.80 to 1.05 and for a range of angles of attack and of side-slip.
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T16:22:46Z | |
| date available | 2017-09-04T16:22:46Z | |
| date copyright | 01/01/1955 | |
| date issued | 1955 | |
| identifier other | TQSWXDAAAAAAAAAA.pdf | |
| identifier uri | https://yse.yabesh.ir/std/handle/yse/86072 | |
| description abstract | INTRODUCTION The longitudinal instability that occurs for some swept-wing air planes operating at high lift coefficients has been found to result from flow separation on the wing or improper location of the horizontal tail or a combination of both conditions. Consequently, the use of various wing fixes has been studied in an attempt to alleviate wing-flow separation. The results of some of these studies are summarized in reference 1. Studies of horizontal tail location, such as references 1 and 2, have shown that the longitudinal stability of a model can be altered by the vertical location of the horizontal tail because of the variation of the down-wash throughout the flow field behind the wing. The analysis in reference 2 of the flow in the vicinity of the horizontal-tail location behind a sweptback wing indicated that at high angles of attack the variation of down-wash with angle of attack over the outer sections of the tail span was such that the tail contribution to the longitudinal stability was favorable for the position below the extended wing-chord plane and behind a sweptback wing indicated that at high angles of attack the variation of down-wash with angle of attack over the outer sections of the tail span was such that the tail contribution to the longitudinal stability was favorable for the position below the extended wing-chord plane and destabilizing for the positions above the extended wing-chord plane. It should be possible therefore, in cases where a low tail location is impractical, to incorporate some of the advantages of a low tail by mounting the tail in a higher position and incorporating negative dihedral. During a recent low-speed investigation in the Langley 19-foot pressure tunnel, of a swept-wing fighter model equipped with wing fences and a modified leading edge outboard of the fences, it was found that longitudinal instability occurred at high lift coefficients. Various horizontal-tail arrangements were tried to improved the stability. One arrangement consisted of setting the horizontal tail with 22° of negative dihedral which gave some improvement in stability in the high lift range. However, it was of interest to determine the effects of a horizontal tail with negative dihedral on the stability characteristics of the model at transonic speeds. Therefore, a study was made of a similar swept-wing fighter airplane model with wing fixes in the Langley 16-foot transonic tunnel to determine the effect on the longitudinal and lateral stability. Characteristics of a 40° swept horizontal tail set with 221/2°of negative dihedral. The data for the model without a horizontal tail, with a straight horizontal tail, and with a negative-dihedral horizontal tail are presented in this paper for a mach number range from 0.80 to 1.05 and for a range of angles of attack and of side-slip. | |
| language | English | |
| title | NACA-RM-L55I20 | num |
| title | Effect of large negative dihedral of the horizontal tail on longitudinal and lateral stability characteristics of a swept-wing configuration at transonic speeds | en |
| type | standard | |
| page | 26 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1955 | |
| contenttype | fulltext |