22,490 research outputs found
Stability and performance characteristics of a fixed arrow wing supersonic transport configuration (SCAT 15F-9898) at Mach numbers from 0.60 to 1.20
Tests on a 0.015 scale model of a supersonic transport were conducted at Mach numbers from 0.60 to 1.20. Tests of the complete model with three wing planforms, two different leading-edge radii, and various combinations of component parts, including both leading- and trailing-edge flaps, were made over an angle-of-attack range from about -6 deg to 13 deg and at sideslip angles of 0 deg and 2 deg
The EET Horizontal Tails Investigation and the EET Lateral Controls Investigation
In the energy efficient transport (EET) Horizontal Tails Investigation, aerodynamic data were measured for five different horizontal tails on a full span model with a wide body fuselage. Three of the horizontal tails were low tail configurations and two were T tail configurations. All tails were tested in conjunction with two wings, a current wide body wing and a high aspect ratio supercritical wing. Local downwash angles and dynamic pressures in the vicinity of the tails were measured using a yaw head rake. The results provide a comparison of the aerodynamic characteristics of the two wing configurations at trimmed conditions for Mach numbers between 0.60 and 0.90. In the EET Lateral Controls Investigation, the control effectiveness of a conventional set of lateral controls was measured over a Mach number range from 0.60 to 0.90 on a high aspect ratio supercritical wing semispan model. The conventional controls included a high speed aileron, a low speed aileron, and six spoiler segments. The wing was designed so that the last 25% of the chord is removable to facilitate testing of various control systems. The current status and an indication of the data obtained in these investigations are presented
Experimental Results of Winglets on First, Second, and Third Generation Jet Transports
Results of wind tunnel investigations of four jet transport configurations representing both narrow and wide-body configurations and also a future advanced aerodynamic configuration are presented including performance and wing root bending moment data. The effects of winglets on the aerodynamic characteristics throughout the flight envelope were studied. The results indicate that winglets improved the cruise lift to drag ratio between 4 and 8 percent, depending on the transport configuration. The data also indicate that ratios of relative aerodynamic gain to relative structural weight penalty for winglets are 1.5 to 2.5 times those for wing-tip extensions. Over the complete range of flight conditions, winglets produce no adverse effects on buffet onset, lateral-directional stability, and aileron control effectiveness
Effect of an alternate winglet on the pressure and spanwise load distributions of a first generation jet transport wing
Pressure and spanwise load distributions on a first-generation jet transport semispan model at subsonic speeds are presented. The wind tunnel data were measured for the wing with and without an alternate winglet. The results show that the winglet affected outboard wing pressure distributions and increased the spanwise loads near the tip
Effect of winglets on a first-generation jet transport wing. 1: Longitudinal aerodynamic characteristics of a semispan model at subsonic speeds
The effects of winglets and a simple wing-tip extension on the aerodynamic forces and moments and the flow-field cross flow velocity vectors behind the wing tip of a first generation jet transport wing were investigated in the Langley 8-foot transonic pressure tunnel using a semi-span model. The test was conducted at Mach numbers of 0.30, 0.70, 0.75, 0.78, and 0.80. At a Mach number of 0.30, the configurations were tested with combinations of leading- and trailing-edge flaps
Effect of Winglets on a First-Generation Jet Transport Wing. 2: Pressure and Spanwise Load Distributions for a Semispan Model at High Subsonic Speeds
Pressure and spanwise load distributions on a first-generation jet transport semispan model at high subsonic speeds are presented for the basic wing and for configurations with an upper winglet only, upper and lower winglets, and a simple wing-tip extension. Selected data are discussed to show the general trends and effects of the various configurations
Intracellular rols7 mRNA localization and the importance of Barren for mitosis in the embryonic myogenesis of Drosophila melanogaster
The body wall musculature of the D. melanogaster larva is a highly ordered assembly of striated myotubes that are formed by fusion of myoblasts, much like the skeletal muscle fibres of vertebrates. In this study, the embryonic development of this musculature is used as a genetic model system for myogenesis, muscle regeneration and related processes.
Rols7 is a crucial protein in the signal transduction chain that controls the Actin filament branching necessary for myoblast fusion. In somatic muscle founder cells, the rols7 mRNA shows intracellular localization into one or more patches near the cell surface. This thesis demonstrates that the rols7 transcript’s 3’ untranslated region is necessary for its localization. A reporter mRNA with this trailer region as well as the 5’ untranslated region gets intracellularly localized in a way seemingly identical to the wild type pattern, even in the absence of native rols transcripts.
The rols7 mRNA is shown to be intracellularly localized in the circular and longitudinal visceral muscle founder cells as well; in the latter it forms spots close to the tips of the spindle-shaped cells, near the expected sites of cell-cell fusion.
At least for this latter cell type it can be suspected that rols7 mRNA localisation facilitates protein localisation and eventually myoblast fusion by preforming the Rols7 protein’s distribution pattern.
In search of previously unknown factors involved in myogenesis, the muscle phenotype of the EMS-induced mutant line E831 is analyzed. As the cause for the disturbed arrangement of the embryonic body wall musculature a nonsense mutation of the Condensin subunit barren is identified. Cap-G, another Condensin subunit, is found to show a phenotype very similar to that of barren.
While in a barren mutant both muscle founder cells and fusion competent myoblasts seem to get specified, muscle identity genes are expressed irregularly in a manner that corresponds to the perturbation of the muscle pattern.
In every cell, the Condensin complex fulfills a variety of essential functions. To help clarify whether the muscle phenotype is connected to Condensin’s regulatory role during interphase or its function in chromosome segregation during mitosis,
the time point at which Barren is needed in the musculature has to be identified.
To this end, the Gal4-UAS system is used to express a barren rescue construct. Gal4 drivers are found to rescue the phenotype only if they express Barren considerably before the final cell division that gives rise to the muscle founder
cells. This finding suggests that the muscle phenotype is caused by a mitotic defect. The mechanism behind the loss of muscle identity appears to be a phenomenon related to the genomic instability of cancer cell lines
Effect of winglets on a first-generation jet transport wing. 5: Stability characteristics of a full-span wing with a generalized fuselage at high subsonic speeds
The effects of winglets on the static aerodynamic stability characteristics of a KC-135A jet transport model at high subsonic speeds are presented. The investigation was conducted in the Langley 8 foot transonic pressure tunnel using 0.035-scale wing panels mounted on a generalized research fuselage. Data were taken over a Mach number range from 0.50 to 0.95 at angles of attack ranging from -12 deg to 20 deg and sideslip angles of 0 deg, 5 deg, and -5 deg. The model was tested at two Reynolds number ranges to achieve a wide angle of attack range and to determine the effect of Reynolds number on stability. Results indicate that adding the winglets to the basic wing configuration produces small increases in both lateral and longitudinal aerodynamic stability and that the model stability increases slightly with Reynolds number. The winglets do increase the wing bending moments slightly, but the buffet onset characteristics of the model are not affected by the winglets
Aileron effectiveness for a subsonic transport model with a high-aspect-ratio supercritical wing
Aileron effectiveness for a subsonc energy efficient transport (EET) model with a high aspect ratio supercritical wing was determined in the 8-foot transonic pressure tunnel. Data are presented for ailerons located at three positions along the wing span. The ailerons were designed as a preliminary active control concept with gust load alleviation, maneuver load alleviation, and flutter suppression systems. A linear variation of rolling moment coefficient with angle of attack for individual and multiple aileron deflections at Mach numbers up to 0.81 is indicated. For Mach numbers greater than 0.81, the rolling moment coefficient data become nonlinear with increasing angle of attack. At Mach numbers near the design value increased aileron effectiveness resulted from aft transition locations, which produced relatively thin boundary layers and greater effective aileron deflections. Individual aileron deflections on the right wing panel produced only small effects on yawing moment and side force coefficients
Effect of aileron deflections on the aerodynamic characteristics of a semispan model of a subsonic energy-efficient transport
An investigation was conducted in the Langley 8 Foot Transonic Pressure Tunnel to determine the effect of aileron deflections on the aerodynamic characteristics of a subsonic energy efficient transport (EET) model. The semispan model had an aspect ratio 10 supercritical wing and was configured with a conventionally located set of ailerons (i.e., a high speed aileron located inboard and a low speed aileron located outboard). Data for the model were taken over a Mach number range from 0.30 to 0.90 and an angle of attack range from approximately -2 deg to 10 deg. The Reynolds number was 2.5 million per foot for Mach number = 0.30 and 4 million per foot for the other Mach numbers. Model force and moment data, aileron effectiveness parameters, aileron hinge moment data, otherwise pressure distributions, and spanwise load data are presented
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