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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Load distribution on a close-coupled wing canard at transonic speeds

This paper reports on a wind-tunnel test where load distributions were obtained at transonic speeds on both the canard and wing surfaces of a closely-coupled wing-canard configuration. The investigation included detailed component and configuration arrangement studies to provide insight into the various aerodynamic interference effects for the leading-edge vortex flow conditions encountered. Data indicate that increasing the Mach number from 0.70 to 0.95 caused the wing leading-edge vortex to burst over the wing when the wing was in the presence of the high canard. For some of the outboard span locations, the leading-edge vortex reattachment streamline intersects the wing trailing edge inboard of these span locations, thus, the Kutta condition was not satisfied. In general, the effect of adding a canard was to reduce the lift inboard and somewhat increase the lift outboard similar to the trends that would have been expected had the flow been attached.

Gloss, B. B.↗
NASA NTRS1932

Span-Load Distribution as a Factor in Stability in Roll

This report gives the results of pressure-distribution tests made to study the effects on lateral stability of changing the span-load distribution on a rectangular monoplane wing model of fairly thick section. Three methods of changing the distribution were employed: variation in profile along the span to a thin symmetrical section at the tip, twist from +5 degrees to -15 degrees at the tip, and sweepback from +20 degrees to -20 degrees. The tests were conducted in a 5-foot closed-throat atmospheric wind tunnel. The investigation shows the following results: (1) change in profile along the span from the NACA-84 at the root to the NACA-M2 at the tip considerably reduces lateral instability, but also reduces the general effectiveness of the wing. (2) washout up to 11 degrees progressively reduces maximum lateral instability. (3) transition from sweepforward to sweepback gradually reduces the useful angle-of-attack range, but has no clearly defined effect on maximum lateral instability.

Knight, Montgomery↗
NASA NTRS1978

Effects of laminar flow control on the performance of a large span-distributed-load flying-wing cargo airplane concept

The effects of laminar flow control (LFC) on the performance of a large span-distributed-load flying-wing cargo airplane concept having a design payload of 2.669 MN and range of 5.93 Mm were determined. Two configurations were considered. One employed laminarized flow over the entire surfaces of the wing and vertical tails, with the exception of the estimated areas of interference due to the fuselage and engines. The other case differed only in that laminar flow was not applied to the flaps, elevons, spoilers, or rudders. The two cases are referred to as the 100 percent and 80 percent laminar configurations, respectively. The utilization of laminar flow control results in reductions in the standard day, sea level installed maximum static thrust per engine from 240 kN for the non-LFC configuration to 205 kN for the 100 percent laminar configuration and 209 kN for the 80 percent case. Weight increases due to the LFC systems cause increases in the operating empty weights of approximately 3 to 4 percent. The design takeoff gross weights decrease approximately 3 to 5 percent. The FAR-25 takeoff field distances for the LFC configurations are greater by about 6 to 7 percent. Fuel efficiencies for the respective configurations are increased 33 percent and 23 percent.

Jernell, L. S.↗
NASA NTRS1978

Design of a large span-distributed load flying-wing cargo airplane with laminar flow control

A design study was conducted to add laminar flow control to a previously design span-distributed load airplane while maintaining constant range and payload. With laminar flow control applied to 100 percent of the wing and vertical tail chords, the empty weight increased by 4.2 percent, the drag decreased by 27.4 percent, the required engine thrust decreased by 14.8 percent, and the fuel consumption decreased by 21.8 percent. When laminar flow control was applied to a lesser extent of the chord (approximately 80 percent), the empty weight increased by 3.4 percent, the drag decreased by 20.0 percent, the required engine thrust decreased by 13.0 percent, and the fuel consumption decreased by 16.2 percent. In both cases the required take-off gross weight of the aircraft was less than the original turbulent aircraft.

Lovell, W. A.↗
NASA NTRS1947

Flight Investigation on a Fighter-type Airplane of Factors which Affect the Loads and Load Distributions on the Vertical Tail Surfaces During Rudder Kicks and Fishtails

Results are presented of a flight investigation conducted on a fighter-type airplane to determine the factors which affect the loads and load distributions on the vertical tail surfaces in maneuvers. An analysis is made of the data obtained in steady flight, rudder kicks, and fishtail maneuvers. For the rudder kicks, the significant loads were the "deflection load" resulting from an abrupt control deflection and the "dynamic load" consisting of a load corresponding to the new static equilibrium condition for the rudder deflected plus a load due to a transient overshoot. The minimum time to reach the maximum control deflection attainable by the pilot in any flight condition was found to be a constant. In the fishtail maneuvers, it was found that the pilot tends to deflect the rudder in phase with the natural frequency of the airplane. The maximum loads measured in fishtails were of the same order of magnitude as those from a rudder kick in which the rudder is returned to zero at the time of maximum sideslip.

Boshar, John↗
NASA NTRS2011

On-Orbit Evaluation of a New Treadmill Harness for Improved Crewmember Comfort and Load Distribution

The current design of the International Space Station (ISS) Treadmill Harness has been reported to cause pain and discomfort to crewmembers during exercise. The Harness Station Development Test Objective (SDTO) provided participating crewmembers (n = 6) with a new harness design, the "Glenn Harness," to evaluate for comfort and loading as compared to the current Treadmill Harness. A novel suite of load-sensing instrumentation was developed to noninvasively measure load distribution and provided a first-ever quantification of actual dynamic loads during treadmill exercise. In addition, crew debriefs provided feedback on harness preference and overall impressions. Conclusions: Post-flight analysis in returned Glenn Harnesses (n = 3) showed minimal wear and tear. Four of the six subjects found the Glenn Harness to be more comfortable in this on-orbit, side-by-side comparison as measured by the crew comfort questionnaire and crew debriefs. Specific areas for improvement have been identified, and forward recommendations will be provided to the Human Research Program. The protocol developed for the SDTO provided valuable insight into crew comfort issues, design improvements, and loading preferences for exercise harnessing, which lays the groundwork for better harnessing systems and training protocols.

Perusek, G. P.↗
NASA NTRS1930

Span Load Distribution on Two Monoplanes Wing Models as Affected by Twist and Sweepback

The results presented in this note show the effect of twist and sweepback on the span load distribution over two monoplane wing models. The tests were made in the Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. The data are taken from the results of an investigation dealing primarily with lateral stability. As presented, they are suitable as an aid in the structural design of certain monoplane wings.

Knight, Montgomery↗
NASA NTRSDate not supplied

Effects of Trailing Edge Thickness and Blade Loading Distribution on the Aerodynamic Performance of Simulated CMC Turbine Blades

The aerodynamic performance of three blade sets that represent the geometric manufacturing constraints of Ceramic Matrix Composite (CMC) blades was measured experimentally in a large-scale transonic turbine blade cascade. The trailing edge thicknesses of CMC blades are anticipated to be significantly larger than those of current state-of-the-art metallic blades. The blades tested in the current study had trailing edge thicknesses of 5%, 7%, and 9% relative to the blade axial chord. The three blade sets were designed with matching throat dimensions, so the blade loading distributions were varied to retain similar overall loading levels. Data were acquired at four Reynolds numbers, covering a factor of six range. All data were acquired at the design isentropic exit Mach number of 0.74. Measurements include blade loading and five-hole probe surveys at two downstream stations. The effects of inlet turbulence intensity were also quantified. Total pressure loss data were integrated to determine overall loss levels for each of the three measured blade passages. Excellent periodicity was noted. For low inlet turbulence levels, losses were surprisingly lower for the thickest trailing edge at low Reynolds numbers, but were highest at the maximum Reynolds number. In general, losses were found to scale well with Reynolds number, although front loading was found to significantly reduce the sensitivity of loss to Reynolds number. For high inlet turbulence intensity, losses were found to scale with trailing edge thickness as expected, and the Reynolds number sensitivity was reduced for all three blade sets. Loss levels at the highest Reynolds number were comparable at low and high inlet turbulence intensity levels.

Paul W Giel↗
NASA NTRSDate not supplied

Effects of Trailing Edge Thickness and Blade Loading Distribution on the Aerodynamic Performance of Simulated CMC Turbine Blades

The aerodynamic performance of three blade sets that represent the geometric manufacturing constraints of Ceramic Matrix Composite (CMC) blades was measured experimentally in a large-scale transonic turbine blade cascade. The trailing edge thicknesses of CMC blades are anticipated to be significantly larger than those of current state-of-the-art metallic blades. The blades tested in the current study had trailing edge thicknesses of 5%, 7%, and 9% relative to the blade axial chord. The three blade sets were designed with matching throat dimensions, so the blade loading distributions were varied to retain similar overall loading levels. Data were acquired at four Reynolds numbers, covering a factor of six range. All data were acquired at the design isentropic exit Mach number of 0.74. Measurements include blade loading and five-hole probe surveys at two downstream stations. The effects of inlet turbulence intensity were also quantified. Total pressure loss data were integrated to determine overall loss levels for each of the three measured blade passages. Excellent periodicity was noted. For low inlet turbulence levels, losses were surprisingly lower for the thickest trailing edge at low Reynolds numbers, but were highest at the maximum Reynolds number. In general, losses were found to scale well with Reynolds number, although front loading was found to significantly reduce the sensitivity of loss to Reynolds number. For high inlet turbulence intensity, losses were found to scale with trailing edge thickness as expected, and the Reynolds number sensitivity was reduced for all three blade sets. Loss levels at the highest Reynolds number were comparable at low and high inlet turbulence intensity levels.

Turbine↗
NASA NTRS1973

Space shuttle: An investigation of the load distribution over the SRB and external tank of a 0.004 scale model of the 049 space shuttle launch configuration

A study was conducted in a trisonic wind tunnel to determine the load distribution over the external tank and solid rocket boosters of the space shuttle launch configuration. The external tank was sting-supported and the solid rocket boosters and orbiter were mounted directly on the external tank. The external tank was, instrumented with 152 pressure orifices and the solid rocket boosters contained 78 orifices. The pressure data were obtained for various combinations of the three geometric components as the gap size between the external tank and the solid rocket boosters, angle of attack, and angle of sideslip were varied. Mach numbers ranged from 0.8 to 1.96.

Lott, R. A.↗
NASA NTRS1947

High-Speed Load Distribution of the Wing of a 3/16-Scale Model of the Douglas XSB2D-1 Airplane with Flaps Deflected

The tests reported herein were made for the purpose of determining the high-speed load distribution on the wing of a 3/16 scale model of the Douglas XSB2D-1 airplane. Comparisons are made between the root bending moment and section torsional moment coefficients as obtained experimentally and derived analytically. The results show good correlation for the bending moment coefficients but considerable disagreement for the torsional moment coefficients, the measured moments being greater than the analytical moments. The effects of Mach number on both the bending moment and torsional moment coefficients were small.

Barnes, Robert H.↗
NASA NTRS1947

High-Speed Load Distribution on the Wing of a 3/16-Scale Model of a Scout-Bomber Airplane with Flaps Deflected

The tests reported herein were made for the purpose of determining the high-speed load distribution on the wing of a 3/16 scale model of a scout-bomber airplane. Comparisons are made between the root bending-moment and section torsional-moment coefficients as obtained experimentally and derived analytically. The results show good correlation for the bending-moment coefficients but considerable disagreement for the torsional-moment coefficients.

Barnes, Robert H.↗
NASA NTRS1974

Wind-tunnel investigation of aerodynamic load distribution on a variable-wing-sweep fighter airplane with a NASA supercritical airfoil

Wind-tunnel tests have been conducted at Mach numbers of 0.85, 0.88, and 0.90 to determine the aerodynamic load distribution for the 39 deg swept-wing configuration of a variable-wing-sweep fighter airplane with a NASA supercritical airfoil. Chordwise pressure distributions were measured at two wing stations. Also measured were the overall longitudinal aerodynamic force and moment characteristics and the buffet characteristics. The analysis indicates that localized regions of shock-induced flow separation may exist on the rearward portions of the supercritical wing at high subsonic speeds, and caution must be exercised in the prediction of buffet onset when using variations in trailing-edge pressure coefficients at isolated locations.

Hallissy, J. B.↗
NASA NTRS1989

Explicit modeling and computational load distribution for concurrent processing simulation of the space station

Two important aspects of concurrent processing under development at TRW are discussed. These are: (1) the derivation of explicit mathematical models of multibody dynamic systems, and (2) a balanced computational load distribution (BCLD) among loosely coupled computational units (processors) of a concurrent processing system. The developed methodologies are demonstrated by way of an application to the Phase 1 of the Space Station - a task being performed by TRW under NASA/JSC contract NAS9-17778. The mathematical model of the Space Station consists of three interconnected flexible bodies capable of undergoing large, rigid-body motion with respect to each other. Body 1 is the main central body and contains the pressurized modules inboard of the two Alpha gimbals. Bodies 2 and 3 are the starboard and port bodies connected to Body 1 at the Alpha gimbals and include all components on the transverse booms outboard of the Alpha gimbals (including the solar arrays). The control systems in the model maintain Body 1 in a prescribed 3-axis attitude control mode, while producing large-angle rotations of the flexible solar arrays to position them normal to the sun-line.

Gluck, R.↗
NASA NTRS1960

Effect of Body-Mounted Lateral Controls and Speed Brakes on the Aerodynamic Load Distribution over a 45 deg Swept Wing at Mach Numbers from 0.80 to 0.98

An investigation has been made in the Langley 16-foot transonic tunnel to determine the effect of body-mounted lateral controls and speed brakes on the aerodynamic load distribution over a swept wing. The lateral controls and speed brakes consisted of flat plates which rotated out of the side of the fuselage, were approximately perpendicular to the wing chord plane, and extended either above or below the chord plane. The wing had 45 deg sweep of the quarter-chord line, an aspect ratio of 3, a taper ratio of0.2, and 4-percent-thick airfoil section. Data were obtained at Mach numbers of 0.80, 0.94, and 0.98 fir angels of attack that usually ranged from about 0 deg to 21 deg. The results show that at the higher angles of attack a lower-surface body-mounted lateral control located along the wing trailing edge had higher effectiveness than a similar upper-surface control. Reduction in span from 0.3 to 0.2 of the wing semispan of an upper-surface body-mounted lateral control located along the wing trailing edge resulted in a less than proportiona1,change in control effectiveness.

West, F. E., Jr.↗
NASA NTRS1977

Load distributions on slender delta wings having vortex flow

Results obtained through application of potential-flow theory based on a suction flow analogy for incompressible flow are compared to attached-flow theory and to experimental data acquired for sharp-edged delta wings. The error incurred in predicting structural loads on the basis of attached-flow theory is investigated. Force and moment coefficients and load distributions are used in the comparisons. The root bending moment can be estimated by assuming vortex lift concentrated at the wing leading edge. While this may entail some error at large angles of attack (owing to inboard movement of the center of vortex lift), it may furnish an upper bound in evaluating results based on other theories.

Kuhlman, J.↗
NASA NTRS1935

The Influence of Tip Shape on the Wing Load Distribution as Determined by Flight Tests

Pressure measurements were made in flight on the right upper wing of an M-3 airplane. The effects of tip plan form, washout, and transverse camber were investigated with eight tip forms in unyawed conditions through the range of positive lift coefficients from zero lift to the stall. The conclusion is that the tip plan form does not influence the span distribution of the coefficients of normal force and moment. It is shown inferentially that temperature, humidity, and the aging of the wood and fabric wing structure used on the M-3 airplane have an appreciable influence on the load distribution.

Rhode, Richard V↗