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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 127 records · Page 7

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NASA NTRS1981

Space shuttle solid rocket booster sting interference wind tunnel test analysis

Wind tunnel test results from shuttle solid rocket booster (SRB) sting interference tests were evaluated, yielding the general influence of the sting on the normal force and pitching moment coefficients and the side force and yawing moment coefficients. The procedures developed to determine the sting interference, the development of the corrected aerodynamic data, and the development of a new SRB aerodynamic mathematical model are documented.

Conine, B.↗

NASA NTRS1981

Research developing closed loop roll control for magnetic balance systems

Computer inputs were interfaced to the magnetic balance outputs to provide computer position control and data acquisition. The use of parameter identification of a means of determining dynamic characteristics was investigated. The thyraton and motor generator power supplies for the pitch and yaw degrees of freedom were repaired. Topics covered include: choice of a method for handling dynamic system data; applications to the magnetic balance; the computer interface; and wind tunnel tests, results, and error analysis.

Covert, E. E.↗

NASA NTRS1980

Selected advanced aerodynamics and active controls technology concepts development on a derivative B-747

The feasibility of applying wing tip extensions, winglets, and active control wing load alleviation to the Boeing 747 is investigated. Winglet aerodynamic design methods and high speed wind tunnel test results of winglets and of symmetrically deflected ailerons are presented. Structural resizing analyses to determine weight and aeroelastic twist increments for all the concepts and flutter model test results for the wing with winglets are included. Control law development, system mechanization/reliability studies, and aileron balance tab trade studies for active wing load alleviation systems are discussed. Results are presented in the form of incremental effects on L/D, structural weight, block fuel savings, stability and control, airplane price, and airline operating economics.

Source record↗

NASA NTRS1982

Some observations of separated flow on finite wings

Wind tunnel test results for aspects of flow over airfoils exhibiting single and multiple trailing edge stall 'mushroom' cells are reported. Rectangular wings with aspect ratios of 4.0 and 9.0 were tested at Reynolds numbers of 480,000 and 257,000, respectively. Surface flow patterns were visualized by means of a fluorescent oil flow technique, separated flow was observed with a tuft wand and a water probe, spanwise flow was studied with hot-wire anemometry, smoke flow and an Ar laser illuminated the centerplane flow, and photographs were made of the oil flow patterns. Swirl patterns on partially and fully stalled wings suggested vortex flow attachments in those regions, and a saddle point on the fully stalled AR=4.0 wing indicated a secondary vortex flow at the forward region of the separation bubble. The separation wake decayed downstream, while the tip vortex interacted with the separation bubble on the fully stalled wing. Three mushroom cells were observed on the AR=9.0 wing.

Winkelmann, A. E.↗

NASA NTRS1982

Plume/flowfield jet interaction effects on the Space Shuttle Orbiter during entry

A comparison of wind tunnel test results with actual flight test data from the performance of the Orbiter Reaction Control System during the STS-1 and -2 flights is presented. Jet interaction phenomena were modeled analytically and a decision was made to develop a jet interaction scaling parameter from empirical measurements wherever possible. A number of different scaling parameters resulted, and errors bounds were determined for tunnel-to-tunnel differences, model to tunnel differences, balance accuracy, real gas effects, varying nozzle configurations, and angle of sideslip. Flight test data has concentrated on the lateral/directional jet interaction of the aft yaw jets, which operate almost continuously from entry down to Mach 1 conditions. A discussion of rolling moments, side forces, and results of usage of the aft pitch and roll jets indicates an underprediction of the side force and yawing moment and overprediction of pitch and roll jet effects.

Kanipe, D. B.↗

NASA NTRS1985

Prediction of wing aeroelastic effects on aircraft lift and pitching moment characteristics

The distribution of flight loads on an aircraft structure determines the lift and pitching moment characteristics of the aircraft. When the load distribution changes due to the aeroelastic response of the structure, the lift and pitching moment characteristics also change. Some estimate of the effect of aeroelasticity on stability and control characteristics, particularly lift and pitching moment, is required for use in aircraft simulation models for evaluation of flight characteristics. This presentation outlines a procedure to incorporate aeroelastic effects into lift and pitching moment data from wind tunnel tests. Results are presented which were obtained from applying this procedure to an aircraft with a very flexible transport-type research wing. The procedure described is generally applicable to all types of aircraft.

Eckstrom, C. V.↗

NASA NTRS1986

Wind tunnel test of a model rotor with a free-tip

A model helicopter rotor with a free tip was tested in a wind tunnel to show the effect of the free tip on rotor performance and oscillatory loads. The free-tip rotor has blade tips that are free to pitch independently of the remainder of the blade. A nearly constant pitching moment is applied to the tip so the tip will produce a nearly steady lift around the azimuth. The aerodynamic development of the free tip is reviewed. The development process concentrated on configuring the tip to have the capability of fast response to angle-of-attack perturbations. Wind tunnel test results show the free-tip rotor configuration requires less power than a fixed-tip configuration in forward flight. In addition, the free tip causes substantial reduction in blade-flapwise vibratory loads. However, blade-chordwise loads were increased. Pitch-link vibratory loads were also reduced by the free-tip configuration. Discussion is presented on the reasons that the use of the free tip caused reduced power and smaller vibratory loads.

Stroub, R. H.↗

NASA NTRS1986

Prediction of wing aeroelastic effects on aircraft lift and pitching moment characteristics

The distribution of flight loads on an aircraft structure determine the lift and pitching moment characteristics of the aircraft. When the load distribution changes due to the aeroelastic response of the structure, the lift and pitching moment characteristics also change. An estimate of the effect of aeroelasticity on stability and control characteristics is often required for the development of aircraft simulation models of evaluation of flight characteristics. This presentation outlines a procedure for incorporating calculated linear aeroelastic effects into measured nonlinear lift and pitching moment data from wind tunnel tests. Results are presented which were obtained from applying this procedure to data for an aircraft with a very flexible transport type research wing. The procedure described is generally applicable to all types of aircraft.

Eckstrom, Clinton V.↗

NASA NTRS1987

Prediction of wing aeroelastic effects on aircraft life and pitching moment characteristics

Eckstrom, Clinton V.↗

NASA NTRS1990

Static Wind-Tunnel and Radio-Controlled Flight Test Investigation of a Remotely Piloted Vehicle Having a Delta Wing Planform

At the request of the United States Marine Corps, an exploratory wind-tunnel and flight test investigation was conducted by the Flight Dynamics Branch at the NASA Langley Research Center to improve the stability, controllability, and general flight characteristics of the Marine Corps Exdrone RPV (Remotely Piloted Vehicle) configuration. Static wind tunnel tests were conducted in the Langley 12 foot Low Speed Wind Tunnel to identify and improve the stability and control characteristics of the vehicle. The wind tunnel test resulted in several configuration modifications which included increased elevator size, increased vertical tail size and tail moment arm, increased rudder size and aileron size, the addition of vertical wing tip fins, and the addition of leading-edge droops on the outboard wing panel to improve stall departure resistance. Flight tests of the modified configuration were conducted at the NASA Plum Tree Test Site to provide a qualitative evaluation of the flight characteristics of the modified configuration.

Yip, Long P.↗

NASA NTRS1990

Wind-tunnel and flight-test investigation of the exdrone remotely piloted vehicle configuration

At the request of the United States Marine Corps, an exploratory wind-tunnel and flight test investigation was conducted by the NASA Langley Research Center to improve the stability, controllability, and general flight characteristics of the Marine Corps Exdrone RPV (Remotely Piloted Vehicle) configuration. Static wind tunnel tests were conducted to identify and improve the stability and control characteristics of the vehicle. The wind-tunnel test resulted in several configuration modifications which included increased elevator area, increased vertical tail area and moment arm, increased rudder area and aileron area, the addition of vertical wing-tip fins, and the addition of leading-edge droops on the outboard wing panel to improve the stall departure resistance. Flight tests of the modified configuration were conducted at the NASA Plum Tree Test Site to provide a qualitative evaluation of the flight characteristics of the modified configuration.

Yip, Long P.↗

NASA NTRS1990

An experimental study to improve Space Shuttle approach and landing performance

Experiments have been conducted by engineers at NASA's Lyndon B. Johnson Space Center to study the effects of modifications to the base area of the Space Shuttle Orbiter on approach and landing performance. A candidate configuration, the 'OMS plate', has been chosen for further study based on wind tunnel test results. This modification consists of a curved plate which extends the length of the upper portion of the Orbiter base. The addition of this plate reduces Orbiter base drag by up to 16 percent and has positive effects on performance. An aerodynamic model including the effects of these modifications has been produced for use in Space Shuttle landing simulations.

Meyerson, Robert E.↗

NASA NTRS1991

Status of heavy rain tests

The heavy rain effects program is presented in the form of the view-graphs. The following topics are covered: rain effects on airfoil performance; two-phase flow dynamics; wind tunnel test results; issues; large-scale results; and summary.

Bezos, Gaudy↗

NASA NTRS1992

Full-scale high angle-of-attack tests of an F/A-18

This paper presents an overview of high angle-of-attack tests of a full-scale F/A-18 in the 80- by 120-Foot Wind Tunnel of the National Full-Scale Aerodynamic Complex at NASA Ames Research Center at Moffett Field, California. A production aircraft was tested over an angle-of-attack range of 18 to 50 deg and at wind speeds of up to 100 knots. These tests had three primary test objectives. Pneumatic and mechanical forebody flow control devices were tested at full-scale and shown to produce significant yawing moments for lateral control of the aircraft at high angles of attack. Mass flow requirements for the pneumatic system were found to scale with freestream density and speed rather than freestream dynamic pressure. Detailed measurements of the pressures buffeting the vertical tail were made and spatial variations in the buffeting frequency were found. The LEX fence was found to have a significant effect on the frequency distribution on the outboard surface of the vertical fin. In addition to the above measurements, an extensive set of data was acquired for the validation of computational fluid dynamics codes and for comparison with flight test and small-scale wind tunnel test results.

Meyn, Larry A.↗

NASA NTRS1935

Tests of Nacelle-Propeller Combinations in Various Positions with Reference to Wings VI : Wings and Nacelles with Pusher Propeller

This report is the sixth of a series giving wind tunnel tests results on the interference drag and propulsive efficiency of nacelle-propeller-wing combinations. The present report gives the results of tests of a radial-engine nacelle with pusher propeller in 17 positions with reference to a Clark Y wing; tests of the same nacelle and propeller in three positions with reference to a thick wing; and tests of a body and pusher propeller with the thick wing, simulating the case of a propeller driven by an extension shaft from an engine within the wing. Some preliminary tests were made on pusher nacelles alone.

Wood, Donald H↗

NASA NTRS1994

Design and fabrication of forward-swept counterrotation blade configuration for wind tunnel testing

Work performed by GE Aircraft on advanced counterrotation blade configuration concepts for high speed turboprop system is described. Primary emphasis was placed on theoretically and experimentally evaluating the aerodynamic, aeromechanical, and acoustic performance of GE-defined counterrotating blade concepts. Several blade design concepts were considered. Feasibility studies were conducted to evaluate a forward-swept versus an aft-swept blade application and how the given blade design would affect interaction between rotors. Two blade designs were initially selected. Both designs involved in-depth aerodynamic, aeromechanical, mechanical, and acoustic analyses followed by the fabrication of forward-swept, forward rotor blade sets to be wind tunnel tested with an aft-swept, aft rotor blade set. A third blade set was later produced from a NASA design that was based on wind tunnel test results from the first two blade sets. This blade set had a stiffer outer ply material added to the original blade design, in order to reach the design point operating line. Detailed analyses, feasibility studies, and fabrication procedures for all blade sets are presented.

Nichols, G. H.↗

NASA NTRS1996

In-Flight Rotorcraft Acoustics Program

A key part of NASA's aeronautics research is reducing noise to make helicopters and tiltrotors more acceptable to the public. The objective of the In-Flight Rotorcraft Acoustics Program (IRAP) is to acquire rotorcraft. noise data in flight for comparison to wind tunnel data. The type of noise of concern is "blade-vortex-interaction," or BVI, noise. Microphones on the wing tips and tail fin of the quiet NASA YO-3A Acoustics Research Aircraft measure BVI noise while the YO-3A descends in close formation with the helicopter or tiltrotor emitting the noise.The data acquired through IRAP is needed to validate wind-tunnel test results, or, where the results cannot be validated, to provide researchers with clues as to how to improve testing methods.

Peterson, Randall L.↗

NASA NTRS2003

A Conceptual Wing Flutter Analysis Tool for Systems Analysis and Parametric Design Study

An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate flutt er instability boundaries of a typical wing, when detailed structural and aerodynamic data are not available. Effects of change in key flu tter parameters can also be estimated in order to guide the conceptual design. This userfriendly software was developed using MathCad and M atlab codes. The analysis method was based on non-dimensional paramet ric plots of two primary flutter parameters, namely Regier number and Flutter number, with normalization factors based on wing torsion stiffness, sweep, mass ratio, taper ratio, aspect ratio, center of gravit y location and pitch-inertia radius of gyration. These parametric plo ts were compiled in a Chance-Vought Corporation report from database of past experiments and wind tunnel test results. An example was prese nted for conceptual flutter analysis of outer-wing of a Blended-Wing- Body aircraft.

Mukhopadhyay, Vivek↗