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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Advanced technology transport configuration.

Consideration of the compromises involved in advanced transport aircraft designs for Mach numbers approaching 1.0, to develop an environmentally acceptable and economically viable commercial transport. The impact of configuration constraints on a baseline aircraft is discussed, and details are given on the development of the aircraft from a wind tunnel model. The subjects covered also include the configuration cycle, aerodynamic and configuration concepts, full-scale aircraft characteristics, and an alternate aircraft configuration.

Williams, B.↗
NASA NTRS1972

Comparative performance of several SST configurations powered by noise limited turbojet engines

A simplified study was made in which the mission performances of three Mach 2.7 airplane configurations were compared. Both wing loading and size of the unaugmented turbojet engines were varied at different levels of suppressor technology. The lowest gross weight and the best return on investment were obtained with an advanced arrow wing configuration when a mission range of 4200 nautical miles was specified. This comparison was made for the takeoff noise levels specified in F.A.R. 36 using retractable jet noise suppressors assumed to be capable of 15 PNdb of suppression with only a 7.5-percent thrust loss. With less advanced suppressor technology, a modified delta configuration is a close competitor of the arrow wing. Despite its good takeoff characteristics, a swing-wing configuration was too structurally heavy to be competitive at F.A.R. 36 noise levels. Engine performance and weight commensurate with engine definition in 1975 were postulated.

Whitlow, J. B., Jr.↗
NASA NTRS1973

Overall fluctuating pressure levels on prospective space shuttle launch configurations at Mach numbers from 0.8 to 2.2

Overall fluctuating pressure levels of seven space shuttle launch configurations are presented. The model was a 4-percent-scale space shuttle vehicle, tested in both a 11- by 11-foot transonic wind tunnel and a 9- by 7-foot supersonic wind tunnel. Mach numbers varied from 0.8 to 2.2, and the angle of attack range was from -8 deg to 8 deg at angles of sideslip of -5 deg, and 5 deg. The model configurations included both series-burn and parallel-burn configurations, two canopy configurations, two positions of the orbiter nose relative to the HO tank nose and two HO tank nose-cone angles (15 deg and 20 deg). The fluctuating pressure levels are presented in three forms.

Dods, J. B., Jr.↗
NASA NTRS1972

EBF noise tests with engine under-the-wing and over-the-wing configurations

Noise tests of externally blown flaps with the engine under the wing and engine over the wing configurations were conducted. Flap noise data obtained on a TF-34 aircraft are discussed. Noise data obtained during a free-jet forward-speed-effect analysis are presented. Noise sources associated with upper surface flap blowing are described. Results of a small scale configuration screening study and some large scale model test data are analyzed. The noise data for the engine over wing configurations are compared with the engine under the wing configurations.

Dorsch, R. G.↗
NASA NTRS1974

Comparison of acoustic performance of five muffler configurations on a small helicopter

A field noise measurement program has been conducted on a standard Bell 47 series helicopter and on one that had been modified with specially designed, airframe-mounted mufflers to reduce the engine exhaust noise. The purpose of the study was to evaluate the acoustic performance of five experimental exhaust muffler configurations for a helicopter reciprocating engine in an operational environment. All muffler configurations produced beneficial engine exhaust noise reductions but some configurations were markedly better than others. Flyover noise results indicated that maximum overall noise reductions of approximately 8 db were obtained with the various mufflers. The rotor noise was judged to be the dominant noise component for the muffler-equipped helicopters whereas the engine noise was the dominant component for the basic configuration.

Pegg, R. J.↗
NASA NTRS1974

Analytical expressions for position error in triangulation solution of point in space for several station configurations

Analytical expressions are derived to first order for the rms position error in the triangulation solution of a point object in space for several ideal observation-station configurations. These expressions provide insights into the nature of the dependence of the rms position error on certain of the experimental parameters involved. The station geometries examined are: (1) the configuration of two arbitrarily located stations; (2) the symmetrical circular configuration of two or more stations with equal elevation angles; and (3) the circular configuration of more than two stations with equal elevation angles, when one of the stations is permitted to drift around the circle from its position of symmetry. The expressions for the rms position error are expressed as functions of the rms line-of-sight errors, the total number of stations of interest, and the elevation angles.

Long, S. A. T.↗
NASA NTRS1974

Investigations on an 0.030-scale space shuttle vehicle configuration 140A/B orbiter model in the Ames Research Center 9 by 7-foot supersonic wind tunnel (OA53B)

A wind tunnel test of an 0.030-scale space shuttle vehicle orbiter configuration 140A/B model was conducted in the Ames Research Center 9- by 7-foot supersonic wind tunnel. This part of test series OA53 was conducted at Mach numbers of 1.60 and 2.00 and at Reynolds numbers ranging from 1.0 million per foot to 4.0 million per foot. The objective was to establish and verify longitudinal and lateral-directional aerodynamic performance, stability, and control characteristics for the configuration 140A/B SSV orbiter. Reynolds number studies were performed on certain nominal control-setting configurations, and examinations were made of the incremental effects of an alternate wing leading-edge configuration and of a sealed elevon-split construction. Six-component force and moment data, base and cavity pressures, bodyflap, elevon, speedbrake, and rudder hinge moments, and vertical tail forces and moments were measured for the orbiter.

Nichols, M. E.↗
NASA NTRS1974

Investigation of space shuttle launch vehicle external tank nose configuration effects (model 67-OTS) in the Rockwell International 7 by 7 foot trisonic wind tunnel (IA69)

Wind tunnel aerodynamic investigations were conducted on an 0.015-scale representation of the space shuttle launch configuration. The primary test objectives were to investigate shock wave formation and record the aerodynamic stability and control effects generated by a new external tank nose configuration (MCR 467) at a Mach number of 1.2. Schlieren photographs were taken at angles of attack of -4 deg, 0 deg, and 4 deg, beta = 0 deg with force and pressure data recorded over the alpha range of -4 deg equal to or less than alpha equal to or less than 4 deg at beta = + or - 4 deg. The launch configuration model, consisting of the VL70-00014OA/B Orbiter, the VL78-000041B ET, and the VL77-000036A SRBs, was sting mounted on a 2.5-inch Task type internal balance entering through the ET base region. Wing, body, and base pressure lines for all orifices were routed internally through the model to the sting support system. Parametric variation consisted only of altering the ET nose configuration.

Mennell, R.↗
NASA NTRS1975

Results of investigations of an 0.010-scale 140A/B configuration (model 72-OTS) of the Rockwell International space shuttle orbiter in the NASA/Langley Research Center unitary plan wind tunnel

Experimental aerodynamic investigations were conducted in the NASA/Langley unitary plan wind tunnel on a sting mounted 0.010-scale outer mold line model of the 140A/B configuration of the Rockwell International Space Shuttle Vehicle. The primary test objectives were to obtain: (1) six component force and moment data for the mated vehicle at subsonic and transonic conditions, (2) effects of configuration build-up, (3) effects of protuberances, ET/orbiter fairings and attach structures, and (4) elevon deflection effects on wing bending moment. Six component aerodynamic force and moment data and base and balance cavity pressures were recorded over Mach numbers of 1.6, 2.0, 2.5, 2.86, 3.9, and 4.63 at a nominal Reynolds number of 20 to the 6th power per foot. Selected configurations were tested at angles of attack and sideslip from -10 deg to +10 deg. For all configurations involving the orbiter, wing bending, and torsion coefficients were measured on the right wing.

Petrozzi, M. T.↗
NASA NTRS1975

Results of a space shuttle vehicle ferry configuration afterbody fairing optimization study using a 140A/B 0.0405-scale model orbiter (43-0) in the Rockwell International 7.75 by 11.0 ft low speed wind tunnel (OA124)

Experimental aerodynamic investigations were conducted on a dual-strut mounted 0.0405-scale representation of the 140A/B outer mold line space shuttle orbiter vehicle. The tests, conducted from 11 Oct., 1974 through 22 Oct., 1974, were primarily to investigate aerodynamic stability and control characteristics of the space shuttle orbiter ferry configuration. Four afterbody fairing configurations and various additions to them in the form of horizontal and ventral fins strakes and other aerodynamic protuberances were tested. Base line data on the basic orbiter with MPS nozzles and bodyflap were recorded. The drag of the optimum ferry configuration was increased to the level of the basic orbiter for possible flight test configurations by the addition of two sizes of perforated speed brakes on the tail cone surface.

Houlihan, S. R.↗
NASA NTRS1974

Space shuttle configuration accounting functional design specification

An analysis is presented of the requirements for an on-line automated system which must be capable of tracking the status of requirements and engineering changes and of providing accurate and timely records. The functional design specification provides the definition, description, and character length of the required data elements and the interrelationship of data elements to adequately track, display, and report the status of active configuration changes. As changes to the space shuttle program levels II and III configuration are proposed, evaluated, and dispositioned, it is the function of the configuration management office to maintain records regarding changes to the baseline and to track and report the status of those changes. The configuration accounting system will consist of a combination of computers, computer terminals, software, and procedures, all of which are designed to store, retrieve, display, and process information required to track proposed and proved engineering changes to maintain baseline documentation of the space shuttle program levels II and III.

Source record↗
NASA NTRS1975

Shadowgraphs of air flow over prospective space shuttle configurations at Mach numbers from 0.8 to 1.4

Shadowgraphs of five space shuttle launch configurations are presented. The model was a 4 percent-scale space shuttle vehicle, tested in the 11- by 11-foot Transonic Wind Tunnel at Ames Research Center. The Mach number was varied from 0.8 to 1.4 with three angles of sideslip (0 deg, 5 deg and -5 deg) that were used in conjunction with three angles of attack (4 deg, -4 deg, and 0 deg). The model configurations included both series-burn and parallel-burn configurations, two canopy configurations, two positions of the orbiter nose relative to the HO tank nose, and two HO tank nose-cones angles (15 deg and 20 deg). The data consist entirely of shadowgraph photographs.

Dods, J. B., Jr.↗
NASA NTRS1975

An investigation of airflow over the aft portions of a variable sweep fighter configuration

An investigation of air flow over the aft portions of a variable sweep fighter aircraft configuration was made. Tests conducted in the unitary plan wind tunnel at Mach number 2.16 included measurements of forces, moments, and local static pressures as well as visual recordings of the air flow. An aerodynamic analytical prediction method was evaluated when used in data comparison at angles of attack of 0, 5, and 15 degrees. The results indicate that in supersonic flow the typical outboard located twin vertical tail arrangement tends to provide a more positive increment in normal-force on the afterbody fuselage and the horizontal tail than a single center-mounted vertical tail of similar planform shape. In addition, the results indicate that a method for aerodynamic analysis of wing-body-tail configurations currently available can provide reasonable estimates of pressure coefficient distributions on configurations in regions of complex supersonic flow. At this time, however, the available analytical method cannot adequately replace experimental wind tunnel tests for determining the supersonic flow environment of a given configuration.

Graves, E. B.↗
NASA NTRS1976

A low speed wind tunnel test of a 0.050 scale model of shuttle orbiter (model 089B) to investigate the longitudinal and lateral directional effects of canard and tail configurational modifications in the LTV LSWT (MA14)

A low speed wind tunnel test was conducted to determine the effects of 6 canard configurations on the 0.050 scale model of shuttle orbiter 089B. In addition, two horizontal tail configurations were tested at two positions on the model as were two wing configurations. Since this test was restricted to 103 runs, only a limited number of permutations of the configurational changes could be tested. The testing was done in the 15 by 20 foot section of the LSWT and consisted of pitch polars, one yawed polar and several yaw runs. The pitch polars encompassed an alpha range from 0 to 28 deg; the yawed polar was run at beta = +2 degrees and the yaw runs covered a beta range from -6 to +6 deg at angles-of-attack of 0, 4, 10, 16, and 20 deg.

Chambliss, E. B.↗
NASA NTRS1977

Supersonic aerodynamic characteristics of a series of wrap-around-fin missile configurations

A parametric study of wrap-around-fin missile configurations was conducted at Mach numbers from 1.60 to 2.86 in the Langley Unitary Plan wind tunnel. The fin configurations investigated included variations in chord length, leading edge sweep, thickness ratio, and leading edge shape. The investigation also included a smooth and a stepped-down afterbody required for flush retraction of the wrap-around-fin configuration. The investigation indicated no unusual longitudinal characteristics; however, all the wrap-around-fin configurations tested indicated erratic lateral behavior, particularly in the form of induced roll at zero angle of attack and irregular variations of roll with angle of attack and Mach number. The magnitude of rolling moment at an angle of attack of 0 deg is estimated to represent approximately 0.25 deg or less roll control deflection. The stepped-down afterbody has a marked effect on reducing the induced roll.

Fournier, R. H.↗
NASA NTRS1977

Low-speed power effects on advanced fighter configurations with two-dimensional deflected thrust

Wind-tunnel studies at the Langley Research Center have shown that significant increases in maximum lift coefficient and stability and decreases in drag due to lift are obtained when two-dimensional vectored thrust is used in conjuction with a close-coupled canard. The configuration tested was somewhat above the theoretical minimum drag due to lift because of the sharp leading edge on the biconvex airfoil used on the wing and canard. An effort to design a new configuration which will approach the minimum drag due to lift while maintaining high-lift configurations was completed. The resulting model will incorporate a realistic planform, airfoil section, and twist for a transonic maneuvering configuration.

Paulson, J. W., Jr.↗
NASA NTRS1977

Cold-air performance of a 12.766-centimeter-tip-diameter axial-flow cooled turbine. 3: Effect of rotor tip clearance on overall performance of a solid blade configuration

Two tip clearance configurations, one with a recess in the casing and the other with a reduced rotor blade height, were investigated at design equivalent speed over a range of tip clearance from about 2.0 to 5.0 percent of the stator blade height. The optimum configuration with a recess in the casing was the one where the rotor tip diameter was equal to the stator tip diameter (zero blade extension). For this configuration there was an approximate 1.5 percent decrease in total efficiency for an increase in tip clearance of 1 percent of stator blade height. For the reduced blade height configurations there was an approximate 2.0 percent decrease in total efficiency for an increase in tip clearance of 1 percent of stator blade height.

Haas, J. E.↗
NASA NTRS1977

Acoustical properties of materials and muffler configurations for the 80 by 120 foot wind tunnel

Techniques for measuring the impedance of the muffler configurations and of porous plates with grazing flow were investigated and changes in the configuration parameters to enhance acoustic performance are explored. The feasibility of a pulse reflection technique for measuring the impedance of built-up structures in situ was demonstrated. A second technique involving the use of an open-end impedance tube with grazing flow was used to obtain detailed design data for the perforated plate configuration. Acoustic benefits associated with configuration changes such as curving the baffles, spacing and staggering baffle partitions, and techniques for alleviating baffle self-generated noise are described.

Scharton, T. D.↗