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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Passenger ride comfort technology for transport aircraft situations

Research in ride comfort and of the resultant technology is overviewed. Several useful relations derived from the technology are: input environments to the vehicle; aircraft operations; and aircraft configurations. Input environments which influence the ride motion environment consist of naturally occuring phenomena such as gusts or turbulence and man generated phenomena such as trailing vortex wakes or runway roughness. Aircraft operations influence ride environments in the form of motions caused by maneuvers, of pressure changes caused by rapid descents, or of too high temperature. Aircraft configurations influence the ride environment by size and shape of external surfaces which generate aerodynamic perturbing forces; by onboard equipment, such as power plant noise and vibrations; and by passive equipment which directly interfaces the passengers such as marginal size seats with limited elbowroom and legroom.

Conner, W.↗
NASA NTRS1975

Some considerations in the design of transport aircraft /The W. Rupert Turnbull Lecture for 1975/

The slow landing speeds (30 mph, 65 mph) and light wing loading required for safety in the early days of aviation are shown to be irrelevant to safe landings of propeller-driven aircraft, while increases in wing loading and landing speed have been accompanied by improved safety records. This is attributed to length of runway and time available for approach maneuvers, plus immunity to wind gusts and turbulence conferred by higher wing loadings. Aerodynamical and mechanical aspects of safe landing are discussed, with no mention of instruments. Fuel savings achievable through high aspect ratio, variable sweep angle, and supercritical airfoils are also considered.

Jones, R. T.↗
NASA NTRS1976

Development, manufacturing, and test of graphite-epoxy composite spoilers for flight service on 737 transport aircraft

A total of 114 spoiler units were fabricated in a production shop environment, utilizing three graphite epoxy material systems. Production planning paper was generated for each spoiler unit to completely document each production step of each spoiler unit. The graphite epoxy skins were laid up on production tooling using both mechanical and hand layup techniques. Inspection techniques utilized MRB type assessment in the abscence of quality requirements. Each completed spoiler was subjected to ultrasonic inspection utilizing a multicolor recording system that documented each inspection result. In addition, one static test spoiler was sectioned after the test to examine the adhesive filleting to the honeycomb core. Visual examination of the cured adhesives showed excellent results.

Stoecklin, R. L.↗
NASA NTRS1977

Study of the impact of cruise speed on scheduling and productivity of commercial transport aircraft

A comparison is made between airplane productivity and utilization levels derived from commercial airline type schedules which were developed for two subsonic and four supersonic cruise speed aircraft. The cruise speed component is the only difference between the schedules which are based on 1995 passenger demand forecasts. Productivity-to-speed relationships were determined for the three discrete route systems: North Atlantic, Trans-Pacific, and North-South America. Selected combinations of these route systems were also studied. Other areas affecting the productivity-to-speed relationship such as aircraft design range and scheduled turn time were examined.

Bond, E. Q.↗
NASA NTRS1977

Flight service evaluation of Kevlar-49/epoxy composite panels in wide-bodied commercial transport aircraft

Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after three years' service, and found to be performing satisfactorily. There are six Kevlar-49 panels on each aircraft, including sandwich and solid laminate wing-body panels, and 150 C service aft engine fairings. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

Stone, R. H.↗
NASA NTRS1976

An automated procedure for preliminary design of primary structure for transport Aircraft

A multistation structural synthesis procedure, designed to perform structural sizing and detail design of boxbeam structure, is presented. The design procedure combines the use of an iterative sizing technique for distributing material to structural elements with a nonlinear programming technique to finding efficient structural element designs of a given weight. Constraints based on fatigue and fracture criteria and static strength criteria under multiple loading conditions are considered, as well as constraints on the upper and lower bounds of the actual design variables. Emphasis is placed on the overall design procedure and the technique used to include the fatigue and fracture criteria.

Kruse, G. S.↗
NASA NTRS1977

Recent ground-based and in-flight simulator studies of low-speed handling characteristics of supersonic cruise transport aircraft

Several advanced arrow-wing concepts have evolved from NASA's Supersonic Cruise Aircraft Research (SCAR) Program. Evaluations of the low-speed handling characteristics of these configurations have been conducted at Langley Research Center using a fixed-base ground simulator with a visual landing scene. A brief in-flight simulation program was also conducted using Calspan's Total In-Flight Simulator (TIFS) in order to provide: (1) points of reference for interpretation of the ground-simulator results, (2) data for control-system design tradeoffs, and (3) data on effects of real-world visual height cues and cockpit-motion cues not available in the fixed-base simulation. The more significant results of these studies are presented.

Grantham, W. D.↗
NASA NTRS1977

Application of powered lift and mechanical flap concepts for civil short-haul transport aircraft design

The objective of this paper is to determine various design and performance parameters, including wing loading and thrust loading requirements, for powered-lift and mechanical flap conceptual aircraft constrained by field length and community noise impact. Mission block fuel and direct operating costs (DOC) were found for optimum designs. As a baseline, the design and performance parameters were determined for the aircraft using engines without noise suppression. The constraint of the 90 EPNL noise contour being less than 2.6 sq km (1.0 sq mi) in area was then imposed. The results indicate that for both aircraft concepts the design gross weight, DOC, and required mission block fuel decreased with field length. At field lengths less than 1100 m (3600 ft) the powered lift aircraft had lower DOC and block fuel than the mechanical flap aircraft but produced higher unsuppressed noise levels. The noise goal could easily be achieved with nacelle wall treatment only and thus resulted in little or no performance or weight penalty for all studied aircraft.

Conlon, J. A.↗
NASA NTRS1978

Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after four years' service, and found to be performing satisfactorily. The Kevlar-49 components were all found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings. A concurrent investigation was conducted on Kevlar-49/epoxy coupons exposed to an outdoor environment over a three year period at various locations providing a variety of climatic conditions. Weight changes and retention of mechanical properties were determined after one and three years exposure. A net weight loss occurred due to ultraviolet effects on the unpainted specimens. Mechanical property retentions were satisfactory with most specimens retaining well over 80% of their original value.

Stone, R. H.↗
NASA NTRS1976

Flight service evaluation of an advanced composite empennage component on commercial transport aircraft. Phase 1: Engineering development

The empennage component selected for this program is the vertical fin box of the L-1011 aircraft. The box structure extends from the fuselage production joint to the tip rib and includes the front and rear spars. Various design options were evaluated to arrive at a configuration which would offer the highest potential for satisfying program objectives. The preferred configuration selected consists of a hat-stiffened cover with molded integrally stiffened spars, aluminum trussed composite ribs, and composite miniwich web ribs with integrally molded caps. Material screening tests were performed to select an advanced composite material system for the Advanced Composite Vertical Fin (ACFV) that would meet the program requirements from the standpoint of quality, reproducibility, and cost. Preliminary weight and cost analysis were made, targets established, and tracking plans developed. These include FAA certification, ancillary test program, quality control, and structural integrity control plans.

Ary, A.↗
NASA NTRS1977

The vehicle design evaluation program - A computer-aided design procedure for transport aircraft

The vehicle design evaluation program is described. This program is a computer-aided design procedure that provides a vehicle synthesis capability for vehicle sizing, external load analysis, structural analysis, and cost evaluation. The vehicle sizing subprogram provides geometry, weight, and balance data for aircraft using JP, hydrogen, or methane fuels. The structural synthesis subprogram uses a multistation analysis for aerodynamic surfaces and fuselages to develop theoretical weights and geometric dimensions. The parts definition subprogram uses the geometric data from the structural analysis and develops the predicted fabrication dimensions, parts material raw stock buy requirements, and predicted actual weights. The cost analysis subprogram uses detail part data in conjunction with standard hours, realization factors, labor rates, and material data to develop the manufacturing costs. The program is used to evaluate overall design effects on subsonic commercial type aircraft due to parameter variations.

Oman, B. H.↗
NASA NTRS1978

Operational requirements for flight control and navigation systems for short haul transport aircraft

To provide a background for evaluating advanced STOL systems concepts, a number of short haul and STOL airline operations in the United States and one operation in Canada were studied. A study of flight director operational procedures for an advanced STOL research airplane, the Augmented Wing Jet STOL Research Airplane, was conducted using the STOLAND simulation facility located at the Ames Changes to the advanced digital flight control system (STOLAND) installed in the Augmentor Wing Airplane are proposed to improve the mode sequencing to simplify pilot procedures and reduce pilot workload.

Morrison, J. A.↗
NASA NTRS1979

Assessment of state-of-the-art of in-service inspection methods for graphite epoxy composite structures on commercial transport aircraft

A survey was conducted to determine current in-service inspection practices for all types of aircraft structure and particularly for advanced composite structures. The survey consisted of written questionnaires to commercial airlines, visits to airlines, aircraft manufacturers, and government agencies, and a literature search. Details of the survey including visits, questions asked, a bibliography of reviewed literature and details of the results are reported. From the results, a current in-service inspection baseline and a preliminary inspection program for advanced composite structures is documented as appendices to the report.

Phelps, M. L.↗
NASA NTRS1979

Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after five years' service. There are six Kevlar-49 panels on each aircraft: a left-hand and right-hand set of a wing-body sandwich fairing; a solid laminate under-wing fillet panel; and a 150 C (300 F) service aft engine fairing. The fairings have accumulated a total of 40,534 hours, with one ship set having 16,091 hours service as of Feb. 11, 1979. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings.

Stone, R. H.↗
NASA NTRS1979

Lateral noise-attenuation results from flyovers of three transport aircraft

Lateral noise-attenuation data have been compiled in a one-third-octave-band analysis from an available set of flyover tests using DC-8, DC-9, and DC-10 aircraft. For an intermediate frequency range of 400 through 2000 Hertz the lateral noise has been approximately separated into its two components - the excess ground attenuation and the aircraft shielding attenuation. Both attenuation factors varied from a maximum at small elevation angles to zero at an elevation angle of approximately 40 degrees. The lateral attenuation in this range generally did not vary with frequency. For frequencies of 80 Hertz and lower, negative lateral attenuation values were obtained. For high frequencies, the data were not complete enough to generate definitive lateral attenuation curves.

Mashita, E. M.↗
NASA NTRS1980

Preliminary design of graphite composite wing panels for commercial transport aircraft

Subjectively assessed practical and producible graphite/epoxy designs were subjected to a multilevel screening procedure which considered structural functions, efficiency, manufacturing and producibility, costs, maintainability, and inspectability. As each progressive screening level was reviewed, more definitive information on the structural efficiency (weight), manufacturing, and inspection procedures was established to support the design selection. The configuration features that enhance producibility of the final selected design can be used as a generic base for application to other wing panel designs. The selected panel design showed a weight saving of 25 percent over a conventional aluminum design meeting the same design requirements. The estimated cost reduction in manufacturing was 20 percent, based on 200 aircraft and projected 1985 automated composites manufacturing capability. The panel design background information developed will be used in the follow-on tasks to ensure that future panel development represents practical and producible design approaches to graphite/epoxy wing surface panels.

Byers, B. A.↗