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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Electrical emissions of airplanes flying in electrified clouds and their effect on airplane measurements of cloud electric fields

The signature of the cloud electric field components deduced from measurements made with electric field meters carried on airplane penetrating electrified clouds is often complex, especially when the airplane experiences strong electrical charging. However, simple electric field variations were obtained for penetrations involving severe charging of the airplane on flights over KSC on 19 Aug. 1989. During these episodes of severe electrical charging, the airplane typically became negatively charged as it approached a region of negative cloud charge and then became positively charged as it receded from the cloud charge. The charge acquired by the airplane within the cloud was so large that the electric fields at the faces of the mills mounted on the fuselage were as large as for an ambient electric field of 60 to 80 kV/m. However, the deduced electric field components perpendicular to the direction of flight, to which these mills respond, were only about 5 to 10 kV/m. The variation of the deduced ambient field component in the direction of flight was antisymmetric about the charge region for these penetrations. Analysis of these results suggest that intense plumes of electric charge were emitted from the airplane and that the electric field associated with these plumes overcame the electric field due to the cloud charge at the tail-mounted field mill. As a consequence, the deduced component of the ambient electric field in the direction of flight was severely distorted. These findings emphasize the need for careful evaluation of airplane electric field measurements and of the need for further work on techniques for improving the measurements.

Jones, James J.↗
NASA NTRS1961

Calculated Normal Load Factors on Light Airplanes Traversing the Trailing Vortices of Heavy Transport Airplanes

Results are presented of normal-load-factor calculations made for a lightnormal-category airplane and a light transport-category airplane traversing the trailing vortices generated by each of three heavy transport airplanes. With each light airplane, the normal load factors were determined for several penetration paths lying i n a plane perpendicular to the trailing vortices and for three center-of-gravity locations and velocities. Also determined for the light normal-category airplane were the elevator deflections required to maintain 1 g flight and the vertical displacements of the airplane from the prescribed penetration paths while transversing the vortices.

McGowan, William A.↗
NASA NTRS1961

Summary of V-G and VGH Data Collected on Lockheed Electra Airplanes During Airplane Operations

Data obtained by NASA VGH and V-G recorders on several Lockheed Electra airplanes operated over three domestic routes have been analyzed to determine the in-flight accelerations, airspeed practices, and landing accelerations experienced by this particular airplane. The results indicate that the accelerations caused by gusts and maneuvers are comparable to corresponding results for piston-engine transport airplanes. Oscillatory accelerations (apparently caused by the autopilot or control system) appear to occur about one-tenth as frequently as accelerations due to gusts. Airspeed operating practices in rough air generally follow the trends shown by piston-engine transports in that there is no significant difference between the average airspeed in rough or smooth air. Placard speeds were exceeded more frequently by the Electra airplane than by piston-engine transport airplanes. Generally, the landing-impact accelerations were higher than those for piston-engine transports.

Jewel, Joseph W., Jr.↗
NASA NTRS1955

Supplementary Investigation in the Langley Free-Spinning Tunnel of a 1/20-Scale Model of the Douglas XF4D-1 Airplane Including Spin-Recovery Parachute Tests of the Model Loaded to Simulate the Douglas F5D-1 Airplane

A supplementary investigation has been conducted in the Langley 20-foot free-spinning tunnel of a l/20-scale model of the Douglas XF4D-1 airplane to determine the effect of only neutralizing the rudder for recovery from an inverted spin, and the effect of partial aileron deflection with the spin for recovery from an erect spin. An estimation of the size parachute required for satisfactory recovery from a spin with the model ballasted to represent the Douglas F5D-1 (formerly the Douglas XF4D-2) airplane was also made. Results of the original investigation on the XF4D-1 design are presented in NACA RM SL50K30a. The results indicated that satisfactory recoveries from inverted spins of the airplane should be obtained by rudder neutralization when the longitudinal stick position is neutral or forward. Recoveries from erect spins from the normal-spin control configuration should be satisfactory by full rudder reversal with simultaneous movement of the ailerons to two-thirds with the spin. For the parachute tests with the model loaded to represent the F5D-1 airplane, the tests indicated that a 16.7-foot-diameter hemispherical-tail parachute (drag coefficient of 1.082 based on the projected area) with a towline 20.0 feet long (full- scale values) should be satisfactory for an emergency spin-recovery device during demonstration spins of the airplane.

Klinar, Walter J.↗
NASA NTRS1990

Shuttle Laser Technology Experiment Facility (LTEF)-to-airplane lasercom experiment: Airplane considerations

NASA is considering the use of various airplanes for a Shuttle Laser Technology Experiment Facility (LTEF)-to-Airplane laser communications experiment. As supporting documentation, pertinent technical details are included about the potential use of airplanes located at Ames Research Center and Wallops Flight Facility. The effects and application of orbital mechanics considerations are also presented, including slant range, azimuth, elevation, and time. The pros and cons of an airplane equipped with a side port with a bubble window versus a top port with a dome are discussed.

Kalil, Ford↗
NASA NTRS1922

Testing airplanes in flight: determining position of resultant of action of air and longitudinal stability of an airplane at different angles of attack

Measurements made during flight with the triple recording device which gives the horizontal and vertical speeds of an airplane and the angle it makes with the horizon, render it possible to calculate its lift, its drag, and R the resultant of the action of the air both in magnitude and direction, but with these data alone, it is impossible to determine the position of this resultant in the plane of symmetry of the airplane. We will also see how we may determine the position of R during flight and then calculate the variations in the stability of an airplane.

STABILITY, LONGITUDINAL↗
NASA NTRS1923

Tests on an airplane model, AEG D I of the Allgemeine Elektricitats Gesellschft, A-G, airplane construction section conducted at the Gottingen Model Testing Laboratory for Aerodynamics

Tests were carried out in the small wind tunnel of the Gottingen establishment on a complete model of the AEG D I airplane. The agreement between the model and the complete airplane applies particularly to the wings, which have ribs cut out of sheet metal and built up in exactly the same manner as in the actual airplane. Various series of tests were carried out with this model in which one or the other of the control surfaces were adjusted to various angles, while the others remained in their neutral positions. During the first three series of tests, the stabilizer was set at a positive angle of 3 degrees, 45' relative to the axis of the engine crankshaft, after which further tests at a 6 degree 30' we made. Finally, the model was tested with the tail group removed. With the elevators set in the prescribed positions, the lift, the drag, and the moments about an axis passing through the center of gravity and perpendicular to the plane of symmetry were measured. All three sets of readings are given as absolute coefficients. Where one of the other control surfaces was deflected from its normal position, the moment produced by that adjustment of the surface was also measured.

Munk, Max↗
NASA NTRS1949

Investigations on the stability, oscillation, and stress conditions of airplanes with tab control. Second partial report : application of the solutions obtained in the first partial report to tab-controlled airplanes.

The first partial report, FB 2000, contained a discussion of the derivation of the equations of motion and their solutions for a tab-controlled airplane; the results obtained there are now to be applied to the longitudinal motion of tab-controlled airplanes. In view of the abundance of structural factors and aerodynamic parameters, a general discussion of the problems is unfeasible. Thus it is demonstrated on the basis of examples what stability, oscillation, and stress conditions are to be expected for tab-controlled airplanes. (author)

Filzek, B↗
NASA NTRS1957

The frequency content of the control input and airplane response obtained during service operations of fighter airplanes

The frequency content of the control input and resulting airplane motions is presented as power spectral densities for one operational flight of the fighter airplane (Republic F-84G). The frequency content, which is described by the shape of the spectrum, may be useful in providing inputs for the design of power control systems. For normal load factors, the results presented for the operational flight considered are in general agreement with the results of more complete data on three fighter airplanes (Republic F-84G, Republic F-84F, and North American F-86A) . The frequency content for the three control positions was similar and the frequency content for the three angular velocities was also similar when normalized by dividing the mean-square value.

Mayer, John P↗
NASA NTRS2018

Managing Complex Airplane System Failures Through a Structured Assessment of Airplane Capabilities

This report describes an analysis of current transport aircraft system-management displays and the initial development of a set of display concepts for providing information about aircraft system status. The new display concepts are motivated by a shift away from the current approach to aircraft system alerting that reports the status of physical components, and towards displaying the implications for mission capability. Specifically, the proposed display concepts describe transport airplane component failures in terms of operational consequences of aircraft system degradations. The research activity described in this report is an effort to examine the utility of different representations of complex systems and operating environments to support real-time decision making during off-nominal situations. A specific focus is to develop display concepts that provide more highly integrated information to allow pilots to more easily reason about the operational consequences of the off-nominal situations. The work can also serve as a foundational element to autonomy-supported decision making since we are developing ideas for integrating information from the airplane and the operational environment to support decision making.

operational decision making↗
NASA NTRS1978

Flight comparison of the transonic agility of the F-111A airplane and the F-111 supercritical wing airplane

A flight research program was conducted to investigate the improvements in maneuverability of an F-111A airplane equipped with a supercritical wing. In this configuration the aircraft is known as the F-111 TACT (transonic aircraft technology) airplane. The variable-wing-sweep feature permitted an evaluation of the supercritical wing in many configurations. The primary emphasis was placed on the transonic Mach number region, which is considered to be the principal air combat arena for fighter aircraft. An agility study was undertaken to assess the maneuverability of the F-111A aircraft with a supercritical wing at both design and off-design conditions. The evaluation included an assessment of aerodynamic and maneuver performance in conjunction with an evaluation of precision controllability during tailchase gunsight tracking tasks.

Friend, E. L.↗
NASA NTRS1961

Analysis of a Pilot Airplane Lateral Instability Experienced with the X-15 Airplane

An analysis is made of a lateral-control problem in which the pilot, through normal application of control, induces divergent oscillations in bank angle. The problem, first encountered on the X-15 simulator and later confirmed in flight, is explained through the use of root-locus plots of the pilot-airplane combination in which the pilot is represented by a human transfer function. A parameter is developed which is useful for predicting the lateral-control problem and for showing the effect of the principal aerodynamic and inertial parameters. Also, means of determining regions in the flight envelope where the pilot-airplane would be susceptible to lateral instability are developed.

Taylor, Lawrence W., Jr.↗
NASA NTRS1972

A flight evaluation of a vectored thrust jet V/STOL airplane during simulated instrument approaches using the Kestrel (XV-6A) airplane

An in-flight investigation was made to determine the terminal-area operating problems of a vectored-thrust-jet vertical and short take-off landing (V/STOL) airplane under simulated instrument conditions. Handling-qualities data pertinent to the terminal-area approach and landing task are presented in the text, and additional documentation is included in the appendixes. Problems dealing with the cruise letdown to localizer capture, conversion to powered-lift flight, precise control of the glide slope, approach velocity or deceleration schedule, hover, and landing are discussed.

Morello, S. A.↗
NASA NTRS1924

Tests on a model of the D.F.W. airplane T-29 of the "Deutsche Flugzeug derke" (German airplane works)

Experiments similar to those carried out with the A.E.G (Allgemeine Elektrizitats-Gesellschaft) were made in the small wind tunnel of the Gottingen laboratory on a model of the D.F.W. airplane T-29. Three series of tests were carried out on the model with a velocity head (or dynamic pressure) of 5 kg/sq m (1.02 lb/sq ft), during which one of the movable surfaces was deflected at various angles, while both the others were retained in their central positions. Of special interest among the results of the tests is the different run of the elevating moments. The curves for the A.E.G. model, rising to the right, denote stability with the elevator locked, while the slight inclination to the left with the D.F.W model denotes a slight instability. For the maximum C(sub L) values, the stability of A.E.G. model continues to increase and the instability of the D.F.W. model is converted into stability. The rolling moments shown when the angular deflection of the ailerons is 0 degrees are due, in both series of tests, to the unequal distribution of the air velocity over the cross section of the wind tunnel, rather than to a lack of symmetry in the model.

Molthan, Wilhelm↗
NASA NTRS1925

The estimation of airplane performance from wind tunnel tests on conventional airplane models

Calculations of the magnitude of the correction factors and the range of their variations for wind tunnel models used in making aircraft performance predictions were made for 23 wind tunnel models. Calculated performances were compared with those actually determined for such airplanes as have been built and put through flight test. Except as otherwise noted, all the models have interplane struts and diagonal struts formed to streamwise shape. Wires were omitted in all cases. All the models were about 18 inches in span and were tested in a 4-foot wind tunnel. Results are given in tabular form.

Warner, Edward P↗