SEARCH · Search NASA

Results for “AIRPLANES - PERFORMANCE”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10

All sources NASA NTRS DOE OSTI

NASA NTRS1935

A flight investigation of the effect of mass distribution and control setting on the spinning of the XN2Y-1 airplane

The investigation of the effect of mass distribution on the spinning of airplanes initiated with tests on the NY-1 airplane has been continued by tests on another airplane in order to increase the scope of the information and to observe particularly the behavior of an airplane that shows considerable change in sideslip angle for its various conditions of spinning. The XN2Y-1 naval training biplane was used for the present tests in which changes of ballast along the longitudinal and lateral axes and changes of aileron, stabilizer, and elevator settings were made. The effects of these changes on the steady spin were measured in flight.

Scudder, N F↗

NASA NTRS1937

The effect of lateral controls in producing motion of an airplane as computed from wind-tunnel data

This report presents the results of an analytical study of the lateral controllability of an airplane in which both the static rolling and yawing moments supplied by the controls and the reactions due to the inherent stability of the airplane have been taken into account. The investigation was undertaken partly for the purpose of coordinating the results of a long series of wind-tunnel investigations with phenomena observed in flight tests; for this reason a hypothetical average airplane, embodying the essential characteristics of both wind-tunnel models and the full-size test airplanes, was assumed for the study.

Weick, Fred E↗

NASA NTRS1937

Flight measurements of the dynamic longitudinal stability of several airplanes and a correlation of the measurements with pilots' observations of handling characteristics

The dynamic longitudinal stability characteristics of eight airplanes as defined by the period and damping of the longitudinal oscillations were measured in flight to determine the degree of stability that may be expected in conventional airplanes. An attempt was made to correlate the measured stability with pilots' opinions of the general handling characteristics of the airplanes in order to obtain an indication of the most desirable degree of dynamic stability. The results of the measurements show that the period of oscillation increases with speed. At low speeds a range of periods from 11 to 23 seconds was recorded for the different airplanes. At high speeds the periods ranged from 23 to 64 seconds. The damping showed no definite trend with speed.

Soule, Hartley A↗

NASA NTRS1937

Spinning Characteristics of the XN2Y-1 Airplane Obtained from the Spinning Balance and Compared with Results from the Spinning Tunnel and from Flight Tests

Report presents the results of tests of a 1/10-scale model of the XN2Y-1 airplane tested in the NACA 5-foot vertical wind tunnel in which the six components of forces and moments were measured. The model was tested in 17 attitudes in which the full-scale airplane had been observed to spin, in order to determine the effects of scale, tunnel, and interference. In addition, a series of tests was made to cover the range of angles of attack, angles of sideslip, rates of rotation, and control setting likely to be encountered by a spinning airplane. The data were used to estimate the probable attitudes in steady spins of an airplane in flight and of a model in the free-spinning tunnel. The estimated attitudes of steady spin were compared with attitudes measured in flight and in the spinning tunnel. The results indicate that corrections for certain scale and tunnel effects are necessary to estimate full-scale spinning attitudes from model results.

Bamber, M J↗

NASA NTRS1940

Free-Spinning Wind-Tunnel Tests of a Low-Wing Monoplane with Systematic Changes in Wings and Tails V : Effect of Airplane Relative Density

The reported tests are a continuation of an NACA investigation being made in the free-spinning wind tunnel to determine the effects of independent variations in load distribution, wing and tail arrangement, and control disposition on the spin characteristics of airplanes. The standard series of tests was repeated to determine the effect of airplane relative density. Tests were made at values of the relative-density parameter of 6.8, 8.4 (basic), and 12.0; and the results were analyzed. The tested variations in the relative-density parameter may be considered either as variations in the wing loading of an airplane spun at a given altitude, with the radii of gyration kept constant, or as a variation of the altitude at which the spin takes place for a given airplane. The lower values of the relative-density parameter correspond to the lower wing loadings or to the lower altitudes of the spin.

Seidman, Oscar↗

NASA NTRS1940

Preliminary Investigation of the Flying Qualities of Airplanes

The National Advisory Committee for Aeronautics is undertaking an investigation of the flying qualities of airplanes. The work consists in the determination of the significant qualities susceptible of measurement, the development of the instruments required to make the measurements, and the accumulation of data on the flying qualities of existing airplanes, which data are to serve as a basis for quantitative specifications for the flying qualities of future designs. A tentative schedule of measurable flying qualities has been prepared and the instruments needed for their measurements have been assembled. A trial of the schedule and the instruments has been made using the Stinson SR-8e airplane. The results showed that, although the original schedule and instruments are basically satisfactory some further development is required to eliminate nonessential items and to expedite flight testing. The report describes and discusses the work done with this airplane.

Soule, H A↗

NASA NTRS1948

Correlation of the Drag Characteristics of a Typical Pursuit Airplane Obtained from High-Speed Wind-Tunnel and Flight Tests

In order to obtain a correlation of drag data from wind-tunnel and flight tests at high Mach numbers, a typical pursuit airplane, with the propeller removed, was tested in flight at Mach numbers up to 0.755, and the results were compared with wind-tunnel tests of a 1/3-scale model of the airplane. The tests results show that the drag characteristics of the test airplane can be predicted with satisfactory accuracy from tests in the Ames 16-foot high-speed wind tunnel of the Ames Aeronautical Laboratory at both high and low Mach numbers. It is considered that this result is not unique with the airplane.

Nissen, James M↗

NASA NTRS1949

Sound-Level Measurements of a Light Airplane Modified to Reduce Noise Reaching the Ground

An Army liaison-type airplane, representative of personal airplanes in the 150 to 200 horsepower class, has been modified to reduce propeller and engine noise according to known principles of airplane-noise reduction. Noise-level measurements demonstrate that, with reference to an observer on the ground, a noisy airplane of this class can be made quiet -- perhaps more quiet than necessary. In order to avoid extreme and unnecessary modifications, acceptable noise levels must be determined.

Vogeley, A W↗

NASA NTRS1950

Flight Investigation of the Effect of Various Vertical-Tail Modifications on the Directional Stability and Control Characteristics of a Propeller-Driven Fighter Airplane

A flight investigation was made to determine the effect of various vertical-tail modifications and of some combinations of these modifications on the directional stability and control characteristics of a propeller-driven fighter airplane. Six different vertical-tail configurations were investigated to determine the lateral-directional oscillation characteristics, the sideslip characteristics, the yaw due to ailerons in rudder-fixed rolls from turns and pull-outs, the trim changes due to speed changes, and the tim changes due to power changes. Results of the tests showed that increasing the aspect ratio of the vertical tail by 40 percent while increasing the area by only 12 percent approximately doubled the directional stability of the airplane. The pilots considered the directional characteristics of the airplane unsatisfactory with original vertical tail but satisfactory with the enlarged vertical tail. The ventral and dorsal fins tested had little effect on the directional stability of the airplane but were effective in eliminating rudder-force reversals in high-engine-power sideslips.

Johnson, Harold I↗

NASA NTRS1952

Flight investigation of the effect of control centering springs on the apparent spiral stability of a personal-owner airplane

Report presents the results of a flight investigation conducted on a typical high-wing personal-owner airplane to determine the effect of control centering springs on apparent spiral stability. Apparent spiral stability is the term used to describe the spiraling tendencies of an airplane in uncontrolled flight as affected both by the true spiral stability of the perfectly trimmed airplane and by out-of-trim control settings. Centering springs were used in both the aileron and rudder control systems to provide both a positive centering action and a means of trimming the airplane. The springs were preloaded so that when they were moved through neutral they produced a nonlinear force gradient sufficient to overcome the friction in the control surface at the proper setting for trim. The ailerons and rudder control surfaces did not have trim tabs that could be adjusted in flight.

Campbell, John P↗

NASA NTRS1956

Effect of interaction on landing-gear behavior and dynamic loads in a flexible airplane structure

The effects of interaction between a landing gear and a flexible airplane structure on the behavior of the landing gear and the loads in the structure have been studied by treating the equations of motion of the airplane and the landing gear as a coupled system. The landing gear is considered to have nonlinear characteristics typical of conventional gears, namely, velocity-squared damping, polytropic air-compression springing, and exponential tire force-deflection characteristics. For the case where only two modes of the structure are considered, an equivalent three-mass system is derived for representing the airplane and landing-gear combination, which may be used to simulate the effects of structural flexibility in jig drop tests of landing gears. As examples to illustrate the effects of interaction, numerical calculations, based on the structural properties of two large airplanes having considerably different mass and flexibility characteristics, are presented.

Cook, Francis E↗

NASA NTRS1953

Review and investigation of unsatisfactory control characteristics involving in stability of pilot-airplane combination and methods for predicting these difficulties from ground tests

A number of examples are presented of control difficulties not completely covered by existing handling-qualities requirements. 520/3:*:These control difficulties appear to result from a tendency for dynamic instability of the combination of pilot, control system, and airplane. The unsatisfactory characteristics involved have been encountered most frequently with hydraulic-power control systems. The nature of the difficulties may range from a slight interference with the ability of the pilot to hold precisely straight and level flight to a dangerous tendency toward divergent short-period oscillations which require constant attention of the pilot to control. Tests of a bomber and a fighter airplane with experimental power control systems have been made to study this problem further. The results of the investigation show that control difficulties of the type considered have always been associated with a marked phase difference between the pilot's control force and the associated control-surface deflection. The presence of static friction in the control valves of hydraulic-power control systems was found to be the explanation for unsatisfactory characteristics in several airplanes equipped with such systems. The valve friction may cause a phase lag between the pilot's control force and the associated control-surface deflection approaching 180 degrees at small control deflections. Definite limits or simple rules for the tolerable amount of valve friction appear to be difficult to establish because of the large number of variables which may influence the problem.The control characteristics of the airplanes tested were strongly influenced by minor design details of the power control systems.

Phillips, William H↗

NASA NTRS1947

Langley Full-scale-tunnel Investigation of the Factors Affecting the Static Lateral-stability Characteristics of a Typical Fighter-type Airplane

The factors that affect the rate of change of rolling moment with yaw of a typical fighter-type airplane were investigated in the Langley full-scale tunnel on a typical fighter-type airplane.Eight representative flight conditions were investigated in detail. The separate effects of propeller operation, of the wing-fuselage combination, and of the vertical tail to the effective dihedral of the airplane in each condition were determined. The results of the tests showed that for the airplane with the propeller removed, the wing-fuselage combination had positive dihedral effect which increased considerably with increasing angle of attack for all conditions. Flap deflection decreased the dihedral effect of the wing-fuselage combination slightly as compared with that with the flaps retracted. Flap deflection resulted in negative dihedral effect due to the vertical tail. Propeller operation decreased the lateral stability parameter of the airplane for all the conditions investigated with larger decreases being measured for the flaps deflected conditions.

Lange, Roy H↗

NASA NTRS1994

Flight testing a propulsion-controlled aircraft emergency flight control system on an F-15 airplane

Flight tests of a propulsion-controlled aircraft (PCA) system on an F-15 airplane have been conducted at the NASA Dryden Flight Research Center. The airplane was flown with all flight control surfaces locked both in the manual throttles-only mode and in an augmented system mode. In the latter mode, pilot thumbwheel commands and aircraft feedback parameters were used to position the throttles. Flight evaluation results showed that the PCA system can be used to land an airplane that has suffered a major flight control system failure safely. The PCA system was used to recover the F-15 airplane from a severe upset condition, descend, and land. Pilots from NASA, U.S. Air Force, U.S. Navy, and McDonnell Douglas Aerospace evaluated the PCA system and were favorably impressed with its capability. Manual throttles-only approaches were unsuccessful. This paper describes the PCA system operation and testing. It also presents flight test results and pilot comments.

Burcham, F. W., Jr.↗

NASA NTRS1995

Rapid Airplane Parametric Input Design (RAPID)

RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool ADIFOR to the grid generation program. The output of ADIFOR is a new source code containing the old code plus expressions for derivatives of specified dependent variables (grid coordinates) with respect to specified independent variables (design parameters). The RAPID methodology and software provide a means of rapidly defining numerical prototypes, grids, and grid sensitivity of a class of airplane configurations. This technology and software is highly useful for CFD research for preliminary design and optimization processes.

Smith, Robert E.↗

NASA NTRS1944

A Theoretical Investigation of Longitudinal Stability of Airplanes with Free Controls Including Effect of Friction in Control System

The relation between the elevator hinge moment parameters and the control forces for changes in forward speed and in maneuvers is shown for several values of static stability and elevator mass balance. The stability of the short period oscillations is shown as a series of boundaries giving the limits of the stable regions in terms of the elevator hinge moment parameters. The effects of static stability, elevator moment of inertia, elevator mass unbalance, and airplane density are also considered. Dynamic instability is likely to occur if there is mass unbalance of the elevator control system combined with a small restoring tendency (high aerodynamic balance). This instability can be prevented by a rearrangement of the unbalancing weights which, however, involves an increase of the amount of weight necessary. It can also be prevented by the addition of viscous friction to the elevator control system provided the airplane center of gravity is not behind a certain critical position. For high values of the density parameter, which correspond to high altitudes of flight, the addition of moderate amounts of viscous friction may be destabilizing even when the airplane is statically stable. In this case, increasing the viscous friction makes the oscillation stable again. The condition in which viscous friction causes dynamic instability of a statically stable airplane is limited to a definite range of hinge moment parameters. It is shown that, when viscous friction causes increasing oscillations, solid friction will produce steady oscillations having an amplitude proportional to the amount of friction.

Greenberg, Harry↗

NASA NTRS1996

Development and Flight Test of an Augmented Thrust-Only Flight Control System on an MD-11 Transport Airplane

An emergency flight control system using only engine thrust, called Propulsion-Controlled Aircraft (PCA), has been developed and flight tested on an MD-11 airplane. In this thrust-only control system, pilot flight path and track commands and aircraft feedback parameters are used to control the throttles. The PCA system was installed on the MD-11 airplane using software modifications to existing computers. Flight test results show that the PCA system can be used to fly to an airport and safely land a transport airplane with an inoperative flight control system. In up-and-away operation, the PCA system served as an acceptable autopilot capable of extended flight over a range of speeds and altitudes. The PCA approaches, go-arounds, and three landings without the use of any non-nal flight controls have been demonstrated, including instrument landing system-coupled hands-off landings. The PCA operation was used to recover from an upset condition. In addition, PCA was tested at altitude with all three hydraulic systems turned off. This paper reviews the principles of throttles-only flight control; describes the MD-11 airplane and systems; and discusses PCA system development, operation, flight testing, and pilot comments.

Burcham, Frank W., Jr.↗

NASA NTRS1996

Advanced Configurations for Very Large Subsonic Transport Airplanes

Recent aerospace industry interest in developing a subsonic commercial transport airplane with 50 percent greater passenger capacity than the largest existing aircraft in this category (the Boeing 747-400 with approximately 400-450 seats) has generated a range of proposals based largely on the configuration paradigm established nearly 50 years ago with the Boeing B-47 bomber. While this basic configuration paradigm has come to dominate subsonic commercial airplane development since the advent of the Boeing 707/Douglas DC-8 in the mid-1950's, its extrapolation to the size required to carry more than 600-700 passengers raises several questions. To explore these and a number of related issues, a team of Boeing, university, and NASA engineers was formed under the auspices of the NASA Advanced Concepts Program. The results of a Research Analysis focused on a large, unconventional transport airplane configuration for which Boeing has applied for a patent are the subject of this report. It should be noted here that this study has been conducted independently of the Boeing New Large Airplane (NLA) program, and with the exception of some generic analysis tools which may be common to this effort and the NLA (as will be described later), no explicit Boeing NLA data other than that published in the open literature has been used in the conduct of the study reported here.

McMasters, John H.↗