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  • 1
    Publication Date: 2019-06-28
    Description: The thrust efficiency and vectoring performance of a convergent-divergent nozzle were investigated at static conditions in the model preparation area of the Langley 16-Foot Transonic Tunnel. The diamond-shaped nozzle was capable of varying the internal contour of each quadrant individually by using cam mechanisms and retractable drawers to produce pitch and yaw thrust vectoring. Pitch thrust vectoring was achieved by either retracting the lower drawers to incline the throat or varying the internal flow-path contours to incline the throat. Yaw thrust vectoring was achieved by reducing flow area left of the nozzle centerline and increasing flow area right of the nozzle centerline; a skewed throat deflected the flow in the lateral direction.
    Keywords: Aerodynamics
    Type: NASA-TP-3628 , NAS 1.60:3628 , L-17570
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  • 2
    Publication Date: 2019-06-28
    Description: A static (wind-off) test was conducted in the static test facility of the Langley 16-foot Transonic Tunnel to evaluate the vectoring capability and isolated nozzle performance of the proposed thrust vectoring system of the F/A-18 high alpha research vehicle (HARV). The thrust vectoring system consisted of three asymmetrically spaced vanes installed externally on a single test nozzle. Two nozzle configurations were tested: A maximum afterburner-power nozzle and a military-power nozzle. Vane size and vane actuation geometry were investigated, and an extensive matrix of vane deflection angles was tested. The nozzle pressure ratios ranged from two to six. The results indicate that the three vane system can successfully generate multiaxis (pitch and yaw) thrust vectoring. However, large resultant vector angles incurred large thrust losses. Resultant vector angles were always lower than the vane deflection angles. The maximum thrust vectoring angles achieved for the military-power nozzle were larger than the angles achieved for the maximum afterburner-power nozzle.
    Keywords: AERODYNAMICS
    Type: NASA-TM-4359 , L-17002 , NAS 1.15:4359
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  • 3
    Publication Date: 2019-06-28
    Description: An investigation has been conducted to evaluate the effects of several geometric parameters on the internal performance of rectangular thrust-reverser ports for nonaxisymmetric nozzles. Internal geometry was varied with a test apparatus which simulated a forward-flight nozzle with a single, fully deployed reverser port. The test apparatus was designed to simulate thrust reversal (conceptually) either in the convergent section of the nozzle or in the constant-area duct just upstream of the nozzle. The main geometric parameters investigated were port angle, port corner radius, port location, and internal flow blocker angle. For all reverser port geometries, the port opening had an aspect ratio (throat width to throat height) of 6.1 and had a constant passage area from the geometric port throat to the exit. Reverser-port internal performance and thrust-vector angles computed from force-balance measurements are presented.
    Keywords: AERODYNAMICS
    Type: NASA-TM-89061 , L-16211 , NAS 1.15:89061
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  • 4
    Publication Date: 2019-06-28
    Description: A static test was conducted in the static test facility of the Langley 16 ft Transonic Tunnel to evaluate the effects of post exit vane vectoring on nonaxisymmetric nozzles. Three baseline nozzles were tested: an unvectored two dimensional convergent nozzle, an unvectored two dimensional convergent-divergent nozzle, and a pitch vectored two dimensional convergent-divergent nozzle. Each nozzle geometry was tested with 3 exit aspect ratios (exit width divided by exit height) of 1.5, 2.5 and 4.0. Two post exit yaw vanes were externally mounted on the nozzle sidewalls at the nozzle exit to generate yaw thrust vectoring. Vane deflection angle (0, -20 and -30 deg), vane planform and vane curvature were varied during the test. Results indicate that the post exit vane concept produced resultant yaw vector angles which were always smaller than the geometric yaw vector angle. Losses in resultant thrust ratio increased with the magnitude of resultant yaw vector angle. The widest post exit vane produced the largest degree of flow turning, but vane curvature had little effect on thrust vectoring. Pitch vectoring was independent of yaw vectoring, indicating that multiaxis thrust vectoring is feasible for the nozzle concepts tested.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2813 , L-16389 , NAS 1.60:2813
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  • 5
    Publication Date: 2019-06-28
    Description: Dynamic pressure loads were obtained on 1/12 scale models of the F-15B production aircraft and the F-15 S/MTD experimental aircraft with rectangular nozzles and canards. Flight Mach numbers from 0.51 to 1.20 were studied for aircraft angles of attack from 0 to 10 deg and nozzle pressure ratios from 1.00 to 5.09. The results show that dynamic levels are lower in the internozzle region of twin rectangular nozzles than are levels found with twin axisymmetric nozzles. At other locations, the levels associated with both geometries are of the same order of magnitude when normalized by aircraft dynamic Q. At Mach number of 0.51, the loads spectrum is dominated by plume shock noise processes for both geometries. Above Mach 0.51, this mechanism is associated with either vortex bursting from a forward location or turbulent boundary layer separation over the nozzle external flaps. At supersonic speeds both geometries show significantly decreased load levels.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 90-1910
    Format: text
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  • 6
    Publication Date: 2019-06-28
    Description: The performance of a three-dimensional Navier-Stokes solution technique in predicting the transonic flow past a nonaxisymmetric nozzle was investigated. The investigation was conducted at free-stream Mach numbers ranging from 0.60 to 0.94 and an angle of attack of 0 degrees. The numerical solution procedure employs the three-dimensional, unsteady, Reynolds-averaged Navier-Stokes equations written in strong conservation form, a thin layer assumption, and the Baldwin-Lomax turbulence model. The equations are solved by using the finite-volume principle in conjunction with an approximately factored upwind-biased numerical algorithm. In the numerical procedure, the jet exhaust is represented by a solid sting. Wind-tunnel data with the jet exhaust simulated by high pressure air were also obtained to compare with the numerical calculations.
    Keywords: AERODYNAMICS
    Type: NASA-TM-4111 , L-16516 , NAS 1.15:4111
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  • 7
    Publication Date: 2019-06-28
    Description: An investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to determine the flow-turning capability and the nozzle internal performance of an axisymmetric convergent-divergent nozzle with post-exit vanes installed for multiaxis thrust vectoring. The effects of vane curvature, vane location relative to the nozzle exit, number of vanes, and vane deflection angle were determined. A comparison of the post-exit-vane thrust-vectoring concept with other thrust-vectoring concepts is provided. All tests were conducted with no external flow, and nozzle pressure ratio was varied from 1.6 to 6.0.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2800 , L-16371 , NAS 1.60:2800
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  • 8
    Publication Date: 2019-06-28
    Description: Extensive research programs conducted at the Langley Research Center have shown that thrust vectoring can be provided by multifunction (nonaxisymmetric) nozzles. Most of this research has been conducted on pitch vectoring at both static and forward flight conditions. Recent efforts have been aimed at evaluating yaw vectoring concepts at static (wind off) conditions. This paper summarizes results for three different twin-engine fighter configurations tested over a Mach number range of 0.15 to 2.47 at angles of attack up to 35 deg. The objective of these investigations was to determine the multiaxis control power characteristics provided by thrust vectoring. All three configurations employed two-dimensional convergent-divergent nozzles which provided pitch vectoring by differential deflection of the upper and lower nozzle divergent flaps. Three different means of yaw vectoring were tested: (1) a translating nozzle sidewall; (2) yaw flaps located in the nozzle sidewalls; and (3) canted nozzles. These investigations were conducted in the Langley 16-Foot Transonic Tunnel and the Lewis 10 x 10-Foot Supersonic Tunnel. Longitudinal and direction control power from thrust vectoring was greater than that provided by aerodynamic control effectors at low speed or at high angles of attack.
    Keywords: AIRCRAFT STABILITY AND CONTROL
    Type: AIAA PAPER 86-1779
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  • 9
    Publication Date: 2019-06-28
    Description: An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine thrust vectoring capability of subscale 2-D convergent-divergent exhaust nozzles installed on a twin engine general research fighter model. Pitch thrust vectoring was accomplished by downward rotation of nozzle upper and lower flaps. The effects of nozzle sidewall cutback were studied for both unvectored and pitch vectored nozzles. A single cutback sidewall was employed for yaw thrust vectoring. This investigation was conducted at Mach numbers ranging from 0 to 1.20 and at angles of attack from -2 to 35 deg. High pressure air was used to simulate jet exhaust and provide values of nozzle pressure ratio up to 9.
    Keywords: AERODYNAMICS
    Type: NASA-TM-4155 , L-16563 , NAS 1.15:4155
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  • 10
    Publication Date: 2019-06-28
    Description: Transonic wind tunnel tests are conducted to determine the flow-turning capabilities and nozzle internal performance of axisymmetric and nonaxisymmetric nozzles employing postexit vanes for multiaxis thrust-vectoring. The geometric parameters investigated for the axisymmetric nozzle installation were number of vanes, vane curvature, vane location relative to nozzle exit, and vane deflection angle; for the nonaxisymmetric cases, the parameters were vane planform and curvature, nozzle type, and nozzle exit aspect ratio. Nozzle pressure ratio was varied from 1.5 to 6.0, using high pressure air.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 87-1834
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