Nature of the sonic-boom problem.
Overall nature and problem of sonic boom, noting roles of aircraft design, aircraft operations and atmosphere effect
SONIC BOOM↗
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Thermal protection system X-15A-2 Design report
Ablative thermal protection system for X-15 aircraft operating at hypersonic speeds
Price, A. B.↗
Flight evaluation of angle of attack as a control parameter in general-aviation aircraft
Investigation of angle of attack information display for pilots to increase efficiency of general aviation aircraft operation
Enevoldson, E. K.↗
Practical engineering methods for predicting hot gas reingestion characteristics of V/STOL aircraft jet lift engines
Engineering methods for predicting temperatures and velocities in vicinity of vertical lift engines of jet V/STOL aircraft operating near ground
Gray, L.↗
Development of turbulence and wind shear models for simulator application
Evaluating analytical models of turbulence having non-Gaussian gusts distributions and effects of wind shear on aircraft operations
Fichtl, G. H.↗
A comparison of optimal and noise-abatement trajectories of a tilt-rotor aircraft
The potential benefits of flight path control to optimize performance and/or reduce the noise of a tilt-rotor aircraft operating in the takeoff and landing phases of flight are investigated. A theoretical performance-acoustic model is developed and then mathematically flown to yield representative takeoff and landing profiles. Minimum-time and minimum-fuel trajectories are compared to proposed noise-abatement profiles to assess the reductions in annoyance possible through flight path control. Significant reductions are feasible if a nearly vertical-takeoff flight profile is flown near the landing site; however, the time expended and fuel consumed increase.
Schmitz, F. H.↗
Community reaction to aircraft noise around smaller city airports
The results are presented of a study of community reaction to jet aircraft noise in the vicinity of airports in Chattanooga, Tennessee, and Reno, Nevada. These cities were surveyed in order to obtain data for comparison with that obtained in larger cities during a previous study. (The cities studied earlier were Boston, Chicago, Dallas, Denver, Los Angeles, Miami, and New York.) The purpose of the present effort was to observe the relative reaction under conditions of lower noise exposure and in less highly urbanized areas, and to test the previously developed predictive equation for annoyance under such circumstances. In Chattanooga and Reno a total of 1960 personal interviews based upon questionnaires were obtained. Aircraft noise measurements were made concurrently and aircraft operations logs were maintained for several weeks in each city to permit computation of noise exposures. The survey respondents were chosen randomly from various exposure zones.
Connor, W. K.↗
Reduction of wave drag by antisymmetric arrangement of wings and bodies.
The wave interference effects for bodies or wings in a mirror-symmetric arrangement, and in an antisymmetric arrangement are discussed. It is shown that while in the case of a mirror-symmetric arrangement large adverse interference effects can be observed, antisymmetric arrangements provide comparatively much smaller wave drags. The single continuous wing panels also adapt themselves more readily to varying angles of obliquity, and hence, to varying flight speeds. A detailed review is presented of the previous work on the aerodynamic properties and flight stability of oblique elliptic wing combinations. A possible mode of application of these combinations to transport aircraft operating at moderate supersonic speeds is suggested.
Jones, R. T.↗
Active controls - Changing the rules of structural design.
Approaches making use of aerodynamic surfaces in combination with advanced flight computers, and electrohydraulic systems could be used to improve economics of commercial aircraft operation, smooth the passenger's ride, reduce terminal-area noise, and ease terminal-area congestion. This emerging technology is becoming known as active controls technology. Maximum benefits from active controls can come only by considering controls early in the design cycle. Active controls can save weight by reducing the structural strength necessary. Some of the technical benefits of active controls would increase return on investment and raise profits. Details of a proposed active controls research program are discussed.
Hood, R. V.↗
Proceedings of the 8th Annual Conference on Manual Control
The volume presents recent developments in the field of manual control theory and applications. The papers give analytical methods as well as examples of the important interplay between man and machine, such as how man controls and stabilizes machine dynamics, and how machines extend man's capability. Included in the broad range of subjects are procedures to evaluate and identify display systems, controllers, manipulators, human operators, aircraft, and non-flying vehicles. Of particular interest is the continuing trend of applying control theory to problems in medicine and psychology, as well as to problems in vehicle control.
Pew, R. W.↗
Some considerations for air transportation analysis to non-urban areas.
Review of some of the problems associated with air transportation to and from nonurban areas. While a significant proportion of public transportation needs of nonurban areas are met by aircraft, there are indications that improvement in air transportation service are called for and would be rewarded by increased patronage. However, subsidized local service carriers are attracted by large aircraft operation, and there is a tendency to discontinue service to low density areas. Prospects and potential means for reversing this trend are discussed.
Norman, S. D.↗
An evaluation of the relative fire hazards of jet A and jet B for commercial flight
The relative fire hazards of Jet A and Jet B aircraft fuels are evaluated. The evaluation is based on a consideration of the presence of and/or the generation of flammable mixtures in fuel systems, the ignition characteristics, and the flame propagation rates for the two fuel types. Three distinct aircraft operating regimes where fuel type may be a factor in fire hazards are considered. These are: (1) ground handling and refueling, (2) flight, and (3) crash. The evaluation indicates that the overall fire hazards for Jet A are less than for Jet B fuel.
Hibbard, R. R.↗
Sonic boom measurements from accelerating supersonic tracked sleds
Supersonic sled tests on the Sandia 1524-m (5000-ft) track generate sonic booms of sufficient intensity to allow some airblast measurements at distance scales not obtained from wind tunnel or flight tests. During acceleration, an emitted curved boom wave propagates to a caustic, or focus. Detailed measurements around these caustics may help to clarify the overpressure magnification which can occur from real aircraft operations. Six fixed pressure gages have been operated to document the general noise field, and a mobile array of twelve gages.
Reed, J. W.↗
A wind model for an elevated STOL-port configuration
Measurements of mean velocity magnitude and direction as well as three-dimensional turbulence intensity were made in the flow over a model of an elevated STOL-port. A 1:300 scale model was placed in a wind tunnel flow simulating the mean velocity profile and turbulence characteristics of atmospheric winds over a typical city environment excluding detailed wake structures of possible nearby buildings. Hot-wire anemometer measurements of velocity and turbulence were made along approach and departure paths of aircraft operating on the runway centerline and at specified lateral distances from the centerline. Approach flow directions simulated were 0 and 30 degrees to the runway centerline.
Peterka, J. A.↗
Helicopter gust response characteristics including unsteady aerodynamic stall effects
The results of an analytical study to evaluate the general response characteristics of a helicopter subjected to various types of discrete gust encounters are presented. The analysis employed was a nonlinear coupled, multi-blade rotorfuselage analysis including the effects of blade flexibility and unsteady aerodynamic stall. Only the controls-fixed response of the basic aircraft without any aircraft stability augmentation was considered. A discussion of the basic differences between gust sensitivity of fixed and rotary wing aircraft is presented. The effects of several rotor configuration and aircraft operating parameters on initial gust-induced load factor and blade vibratory stress and pushrod loads are discussed.
Arcidiacono, P. J.↗
Statistical analysis of general aviation VG-VGH data
To represent the loads spectra of general aviation aircraft operating in the Continental United States, VG and VGH data collected since 1963 in eight operational categories were processed and analyzed. Adequacy of data sample and current operational categories, and parameter distributions required for valid data extrapolation were studied along with envelopes of equal probability of exceeding the normal load factor (n sub z) versus airspeed for gust and maneuver loads and the probability of exceeding current design maneuver, gust, and landing impact n sub z limits. The significant findings are included.
Clay, L. E.↗
Powered wheel for aircraft
Single integral unit includes motor, gearbox, and clutch. Device has two-speed capability, fits within aerodynamic contours of aircraft, operates with onboard power source, does not interfere with normal landing gear functions, reduces use of regular brakes in congested areas, and provides locomotion and supplementary braking capability.
Long, M. J.↗
An adaptive learning control system for aircraft
A learning control system is developed which blends the gain scheduling and adaptive control into a single learning system that has the advantages of both. An important feature of the developed learning control system is its capability to adjust the gain schedule in a prescribed manner to account for changing aircraft operating characteristics. Furthermore, if tests performed by the criteria of the learning system preclude any possible change in the gain schedule, then the overall system becomes an ordinary gain scheduling system. Examples are discussed.
Mekel, R.↗