Low wing loading STOL transport ride smoothing feasibility study Final report
Low wing loading STOL transport ride smoothing using Boeing aircraft
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Measurements and analysis of vibration ride environments
Air transportation systems ride vibration environments in relation to human comfort
Catherines, J. J.↗
Riding and handling qualities of light aircraft: A review and analysis
Design procedures and supporting data necessary for configuring light aircraft to obtain desired responses to pilot commands and gusts are presented. The procedures employ specializations of modern military and jet transport practice where these provide an improvement over earlier practice. General criteria for riding and handling qualities are discussed in terms of the airframe dynamics. Methods available in the literature for calculating the coefficients required for a linearized analysis of the airframe dynamics are reviewed in detail. The review also treats the relation of spin and stall to airframe geometry. Root locus analysis is used to indicate the sensitivity of airframe dynamics to variations in individual stability derivatives and to variations in geometric parameters. Computer programs are given for finding the frequencies, damping ratios, and time constants of all rigid body modes and for generating time histories of aircraft motions in response to control inputs. Appendices are included presenting the derivation of the linearized equations of motion; the stability derivatives; the transfer functions; approximate solutions for the frequency, damping ratio, and time constants; an indication of methods to be used when linear analysis is inadequate; sample calculations; and an explanation of the use of root locus diagrams and Bode plots.
Smetana, F. O.↗
STOL ride quality criteria - Passenger acceptance.
The ability to mathematically model human reaction to variables involved in transportation systems offers a very desirable tool both for the prediction of passenger acceptance of proposed systems, and for establishing acceptance criteria for the system designer. As a first step in the development of a general model for STOL systems, a mathematical formulation is presented which accepts as inputs nine variables felt to be important in flight under STOL-type conditions and presents an index of human response as the output. The variables used are three linear motions, three angular motions, pressure, temperature and noise level. The results are used to establish specifications for stability augmentation systems to improve the ride quality of existing STOL aircraft.
Jacobson, I. D.↗
Ride Quality Criteria for Large Commercial Helicopters
A review of major ride-quality criteria used in the design of commercial helicopters, some of the limitations of these criteria, research programs conducted to better define these criteria, and some recommended research programs is presented. Primary emphasis is given to the question of noise and vibration criteria for passenger acceptance and comfort.
Schlegel, R. G.↗
Analytical and experimental evaluation of proposed ride comfort criteria
An exploratory study was conducted to evaluate the effectiveness of indices proposed by different investigators to relate vehicle vibrations to passenger comfort. The indices considered included criteria for sinusoidal vibrations, unweighted and weighted amplitude exceedance counts, the integral of the unweighted and weighted power spectral density and absorbed power. These functions were initially examined analytically to determine the manner in which they each weighed vibration amplitude and frequency. Similarities among them are noted. Index values were then computed from measured vibrations and compared with the associated comfort ratings. The data for these comparisons were obtained from ride comfort evaluations of passenger trains.
Vinje, E. W.↗
Marine vehicle ride quality
The effects of marine vehicle design on passenger exposure to vibration and discomfort are discussed. The ride quality of advanced marine vehicles is examined. as a basis for marine vehicle selection in modern water transport systems. The physiological effects of rough water on passengers are identified as requiring investigation in order to determine the acceptable limits.
Gornstein, R. J.↗
Ride quality research activities at NASA Langley Research Center
Ride quality research to determine criteria to describe vehicle performance characteristics which will insure passenger comfort is discussed. The manner in which disciplines of vehicle environmental dynamics, structural dynamics, and electromechanical measurements are combined to define passenger environments is described. The activities of many governmental and private agencies in the field of passenger comfort are examined.
Connor, A. B.↗
NASA ride quality program at the Flight Research Center
A flight test program to determine the effects of low frequency vibrations on passengers in short haul aircraft is discussed. The objective of the program is to accumulate flight test data on aircraft ride quality in terms of vehicle motion and acceleration and human responses. The subjects discussed are: (1) test procedures, (2) data processing, and (3) the program schedule.
Gee, S. W.↗
Exploratory tests of a simple aero-mechanical ride comfort system for lightly loaded aircraft
Some exploratory wind tunnel and radio-controlled free-flight tests were made with a small high-wing airplane model (1.23m wing span) to study the concept of a simple aero mechanical system intended to alleviate gust loads and improve ride comfort of lightly loaded aircraft. The system consisted essentially of the outer portions of each wing being hinged in the chordwise direction and connected directly to the wing flaps using internal counter weights to provide neutral mass balance. When the wing experienced a change in velocity or angle of attack, the movable wing panels, acting as sensors and flap actuators, deflected in response to the changes in lift on the wing. The corresponding movements of the interconnected flaps tended to reduce the changes in the wing lift.
Hewes, D. E.↗
Development and application of ride-quality criteria
Ride quality vibration criteria applicable to the design and evaluation of air and surface transportation systems are described. Consideration is given to the magnitude of vehicle vibration experienced by the passenger, the frequency of vibration, the direction of vibration measurements are presented for a variety of air and surface transportation systems. In addition, simulator data on seat dynamics and passenger response are presented. Results suggest the relative merits of various physical descriptors and measurement locations for characterizing the vibration in terms suitable for the design and/or evaluation of transportation systems.
Stephens, D. G.↗
A model and predictive scale of passenger ride discomfort
A model to define the interrelationship of the various factors (vibratory and nonvibratory) important to passenger comfort, in realistic transport vehicle vibration environments was developed. The model represents: (1) a framework for the investigation of comfort within diverse transportation vehicles; (2) a mechanism for the development of a scale of comfort; (3) a mechanism through which design criteria can be obtained for improving the rideability of current and future transportation vehicles; and (4) a tool for obtaining information for the maximization of passenger ride quality, based upon sociological and psychological information. The application of the model is based upon the computational steps necessary for derivation of the comfort scale. The emphasis within the scale is upon the summation of comfort units; the summation being obtained through the use of appropriately determined factors, both within and between axes.
Dempsey, T. K.↗
Inflight data collection for ride quality and atmospheric turbulence research
A flight test program to investigate the effects of atmospheric turbulence on passenger ride quality in large, wide-body commercial aircraft was conducted. Data were collected on a series of flight on a Boeing 747 aircraft. Atmospheric and aircraft performance data were obtained from special sensors, as well as conventional instruments and avionics systems normally available. Visual observations of meteorlogical conditions encountered were manually recorded during the flights.
Kadlec, P. W.↗
Development and application of ride-quality criteria
A program for the development of ride-quality vibration criteria applicable to the design and evaluation of air and surface transportation systems is described. Consideration is given to the magnitude of vehicle vibration experienced by the passenger, the frequency of vibration, the direction of vibration, and the influence of seat dynamics on passenger response. Comparative vibration measurements are presented for a variety of air and surface transportation systems. In addition, simulator data on seat dynamics and passenger response are presented. Results suggest the relative merits of various physical descriptors and measurement locations for characterizing the vibration in terms suitable for the design and/or evaluation of transportation systems.
Stephens, D. G.↗
Discussion of an aeromechanical gust alleviation system to improve the ride comfort of light airplanes
A discussion of an on-going NASA research project of a gust alleviation system to improve the ride comfort of a light airplane is presented. The discussion includes a description of the proposed system which uses auxiliary aerodynamic surfaces to drive the trailing-edge flaps. The results of analytical work on the effects of the system on stability and effectiveness of the system are presented. Static wind-tunnel tests of the system installed in a 1/6-scale model of a popular light airplane are also described. Problem areas which may need future investigation are discussed.
Stewart, E. C.↗
Application of active control technology to aircraft ride smoothing
Prototype Ride Smoothing System (RSSs) were synthesized for flight testing aboard the National Aeronautics and Space Administration General Purpose Airborne Simulator (GPAS). The systems were designed to meet comprehensive criteria including passenger comfort and aircraft handling qualities considerations. System performance estimates based on analytic expressions were compared to estimates derived from digital calculations. The effect of RSSs on pilot workload during ILS approach in turbulence was examined in a fixed-base simulator. A limited number of flights were conducted to verify predicted RSS performance. Results of these experiments indicate that RSSs reduce pilot workload and increase passenger comfort while maintaining handling qualities.
Jacobson, I. D.↗
NASA/FRC wake turbulence flight test program: Ride quality aspects
To determine how much the ride quality of the Shuttle Carrier (Boeing 747) Aircraft is affected at various spoiler settings, the PEMS II (Portable Environmental Measuring System) was used to measure onboard motion during a test flight October 15, 1975. The PEMS II measures acceleration in the vertical, transverse and longitudinal directions as well as angular rates of pitch, roll, and yaw. The data acquired by this instrument, combined with an airline passenger comfort model, gives an indication of how passengers would react to the motion induced by flying in a vortex alleviation configuration.
Deptula, D. A.↗
Flight research experiments on ride quality
The results and analysis of several flight research experiments in ride quality are described. These tests were carried out aboard the NASA Flight Research Center, JetStar Aircraft equipped with the General Purpose Airborne Simulator; and aboard a specially instrumented Boeing 747 flown in actual commercial flight. The data was analyzed to determine appropriate models for subjective reaction to the motion environment. Specifically, vertical and transverse acceleration inputs and aircraft bank angle were studied along with duration of exposure.
Jacobson, I. D.↗