6,991 research outputs found

    Effect of a simulated engine jet blowing above an arrow wing at Mach 2.0

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    The effects of a gas jet simulating a turbojet engine exhaust blowing above a cambered and twisted arrow wing were investigated. Tests were conducted in the Langley 4-foot supersonic pressure tunnel at a Mach number of 2.0. Nozzle pressure ratios from 1 to 64 were tested with both helium and air used as jet gases. The tests were conducted at angles of attack from -2 deg to 8 deg at a Reynolds number of 9,840,000 per meter. Only the forces and moments on the wing were measured. Results of the investigation indicated that the jet blowing over the wing caused reductions in maximum lift-drag ratio of about 4 percent for helium and 6 percent for air at their respective design nozzle pressure ratios, relative to jet-off data. Moderate changes in the longitudinal, vertical, or angular positions of the jet relative to the wing had little effect on the wing aerodynamic characteristics

    Summary of External-Store Drag

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    The drag problems associated with the addition of external stores to airplanes are reviewed. Current analytic techniques for estimating drag penalties associated with the addition of stores in both subsonic and supersonic flight are discussed. In subsonic flight, the drag penalty caused by the addition of external stores is shown to be a function of the type of store installation. In supersonic flight, the drag is shown to be a function of the type of store installation and also of the location of the store installation with respect to the rest of the airplane components. Special store arrangements and attention to the design of the store itself can reduce the drag penalty of the store installation

    Longitudinal aerodynamic characteristics of an elliptical body with a horizontal tail at Mach numbers from 2.3 to 4.63

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    Longitudinal aerodynamic characteristics of a configuration consisting of an elliptical body with an in plane horizontal tail were investigated. The tests were conducted at Mach numbers of 2.3, 2.96, 4.0, and 4.63. In some cases, the configuration with negative tail deflections yielded higher values of maximum lift drag ratio than did the configuration with an undeflected tail. This was due to body upwash acting on the tail and producing an additional lift increment with essentially no drag penalty. Linear theory methods used to estimate some of the longitudinal aerodynamic characteristics of the model yielded results which compared well with experimental data for all Mach numbers in this investigation and for both small angles of attack and larger angles of attack where nonlinear (vortex) flow phenomena were present

    Aerodynamic characteristics of a supersonic cruise airplane configuration at Mach numbers of 2.30, 2.96, and 3.30

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    An investigation was made in the Langley Unitary Plan wind tunnel at Mach numbers of 2.30, 2.96, and 3.30 to determine the static longitudinal and lateral aerodynamic characteristics of a model of a supersonic cruise airplane. The configuration, with a design Mach number of 3.0, has a highly swept arrow wing with tip panels of lesser sweep, a fuselage chine, outboard vertical tails, and outboard engines mounted in nacelles beneath the wings. For wind tunnel test conditions, a trimmed value above 6.0 of the maximum lift-drag ratio was obtained at the design Mach number. The configuration was statically stable, both longitudinally and laterally. Data are presented for variations of vertical-tail roll-out and toe-in and for various combinations of components. Some roll control data are shown as are data for the various sand grit sizes used in fixing the boundary layer transition location

    Mind the Gap? : An Intensive Longitudinal Study of Between-Person and Within-Person Intention-Behavior Relations

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    Acknowledgments This work was supported by the University of Konstanz, Germany. The first author was supported by a fellowship of the Swiss National Science Foundation (Fellowship P2ZHP1_155103).Peer reviewedPostprin

    A wind-tunnel investigation of sonic-boom pressure distributions of bodies of revolution at Mach 2.96, 3.83, and 4.63

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    Measurements of sonic boom pressure distribution of bodies of revolution at Mach 2.96, 3.83, and 4.63 in Unitary Plan wind tunne

    Surface pressure data for a supersonic-cruise airplane configuration at Mach numbers of 2.30, 2.96, 3.30

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    The tabulated results of surface pressure tests conducted on the wing and fuselage of an airplane model in the Langley Unitary Plan wind tunnel are presented without analysis. The model tested was that of a supersonic-cruise airplane with a highly swept arrow-wing planform, two engine nacelles mounted beneath the wing, and outboard vertical tails. Data were obtained at Mach numbers of 2.30, 2.96, and 3.30 for angles of attack from -4 deg to 12 deg. The Reynolds number for these tests was 6,560,000 per meter

    Advanced Analysis of Curved and Corrugated Titanium Aluminide Metal Intermetallic Laminates Utilizing Multi-Dimensional Finite Element Analysis

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    Titanium-aluminide (Al3Ti) is a high strength per density intermetallic compound that has fascinating implications in the realm of lightweight materials. Such a composite laminate can be thermally reacted from titanium and aluminum foils in an open air heated press. While maintaining many benefits of both materials, its inherent hardness and lack of ductility results in its inability to be conventionally formed into shapes after the reaction occurs. This project developed a method of manufacturing titanium/titanium-aluminide laminate composites in a corrugated geometry. Research and experimentation was conducted to determine the benefits of the curved material. The results suggest a possible change in manufacturing methodology from a sinusoidal corrugation to an angular corrugation

    School-based decision making (SBDM) councils and their efficacy and productivity as perceived by council members.

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    This study examined the perceptions of Kentucky SBDM council members concerning the productivity and efficacy of the councils. The major variables studied were council member position, council member demographic characteristics, perceived efficacy, and perceived productivity. The research data came from an already completed field survey. This study used the methods of descriptive analysis, causal-comparative analysis, and correlational/predictive research. Statistical procedures included calculation of means and standard deviations, as well as multivariate analysis of variance (MANOVA), ordinary least squares multiple regression, and random effects analysis of variance (ANOVA). The results of the study showed that, in general, council members had a positive perception of the productivity and efficacy of the councils. There were no differences between the perceptions of parents and principals, nor between principals and teachers/staff. There was, however, a difference between parents and teachers/staff in regards to efficacy, with parents revealing a higher rating than teachers. Although the difference was statistically significant, it was small in magnitude. Additional research explored the amount of variance in efficacy and productivity in relation to several predictor variables. The amount of variance in the average efficacy score could be predicted by the contrast between parents and principals/staff, relevant information, use of committees, and training activities. The amount of variance in the average productivity score could be predicted by the contrast between parents and Iteachers/staff, relevant information, use of committees, training activities, school level, and level of efficiency. Additionally, there were significant differences among schools both for teachers and for parents in regards to both efficacy and productivity
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