Engineering topics

Conner, D. W.

Publications and source records attributed to Conner, D. W..

At least 19 records

NASA NTRS1982

Characteristics of future aircraft impacting aircraft and airport compatibility

Results are reported of an opinion survey of selected individuals at the decision-making level within the five major manufacturers of transport aircraft in the United States and Europe. Opinions were obtained concerning both possible and probable existence of over 50 compatibility-related characteristics of transport aircraft in use in the years 1990, 2000, and 2010. The maximum size of aircraft is expected to increase, at a roughly uniform rate, to the year 2010 by 85 percent in passengers, 55 percent in airfreighter payload, and 35 percent in gross weight weight. Companion to the expected growth in payloads and gross weight was the identification of probable increases in aircraft geometrical dimensions and component capability, and use of fully double-decked passenger compartments. Wing span will increase considerably more than normally expected to provide wings of higher aspect ratio. New aircraft features coming into probable use include large turboprops, synthetic jet-A fuel, winglets, wake-vortex-reducing devices and laminar flow control. New operational concepts considered probable include steep approaches, high-speed turnoffs, and taxiway towing for the aircraft, plus passenger bypass of the terminal building, expedited handling of belly cargo and an intermodal cargo container for the payloads.

Conner, D. W.↗

NASA NTRS1980

Air cargo market outlook and impact via the NASA CLASS project

An overview is given of the Cargo/Logistics Airlift Systems Study (CLASS) project which was a 10 man-year effort carried out by two contractor teams, aimed at defining factors impacting future system growth and obtaining market requirements and design guidelines for future air freighters. Growth projection was estimated by two approaches: one, an optimal systems approach with a more efficient and cost effective system considered as being available in 1990; and the other, an evolutionary approach with an econometric behavior model used to predict long term evolution from the present system. Both approaches predict significant growth in demand for international air freighter services and less growth for U.S. domestic services. Economic analysis of air freighter fleet options indicate very strong market appeal of derivative widebody transports in 1990 with little incentive to develop all new dedicated air freighters utilizing the 1990's technology until sometime beyond the year 2000. Advanced air freighters would be economically attractive for a wide range of payload sizes (to 500 metric tons), however, if a government would share in the RD and T costs by virtue of its needs for a slightly modified version of a civil air freighter design (a.g. military airlifter).

Winston, M. M.↗

NASA NTRS1980

Passenger comfort technology for system decision making

Decisions requiring passenger comfort technology were shown to depend on: the relationship between comfort and other factors (e.g., cost, urgency, alternate modes) in traveler acceptance of the systems, serving a selected market require technology to quantify effects of comfort versus offsetting factors in system acceptance. Public predict the maximum percentage of travelers who willingly accept the overall comfort of any trip ride. One or the other of these technology requirements apply to decisions on system design, operation and maintenance.

Conner, D. W.↗

NASA NTRS1980

Technology requirements and readiness for very large aircraft

The technology requirements for designing, manufacturing and operating any vehicle depend largely on the configuration of that vehicle. Under the general heading of Very Large Aircraft (VLA), configurations are many and varied, so, therefore, are the technology requirements. The present work is limited to technology requirements of particular interest to VLA. While many are of common interest, a few technology requirements critical to specific VLA types are also covered. Addressed in turn are common VLA concerns and how they influence configurations and technology; the methodology followed in selecting requirements and assessing readiness; the resultant technology requirements and readiness; and some overall observations regarding technology areas judged to be particularly critical. Over 50 technology requirements are identified as unique or particularly critical to VLA. However, none of the requirements is considered to have an excellent state of technology readiness.

Conner, D. W.↗

NASA NTRS1980

Outlook for advanced concepts in transport aircraft

The present air transport system is expected to continue until the turn of the century, but significant technological advances will have been incorporated into the existing aircraft. With a few exceptions, such as the SST, the development of all-new transports will be inhibited by economic constraints. The outlook for advanced transport aircraft concepts in the 21st century indicates new vehicles may be developed, such as air cushion landing gears, away from the airport; flatbed transports, at the airport; and aerial relay transports, in the air. Some of the new technologies and vehicle configurations are discussed, and their impact on aircraft maintenance, airport runways, taxiways, and cargo loading facilities is examined.

Conner, D. W.↗

NASA NTRS1980

Outlook for advanced concepts in transport aircraft

Air transportation demand trends, air transportation system goals, and air transportation system trends well into the 21st century were examined in detail. The outlook is for continued growth in both air passenger travel and air freight movements. The present system, with some improvements, is expected to continue to the turn of the century and to utilize technologically upgraded, derivative versions of today's aircraft, plus possibly some new aircraft for supersonic long haul, short haul, and high density commuter service. Severe constraints of the system, expected by early in the 21st century, should lead to innovations at the airport, away from the airport, and in the air. The innovations are illustrated by descriptions of three candidate systems involving advanced aircraft concepts. Advanced technologies and vehicles expected to impact the airport are illustrated by descriptions of laminar flow control aircraft, very large air freighters and cryogenically fueled transports.

Conner, D. W.↗

NASA NTRS1980

Technology requirements and readiness for very large aircraft

Common concerns of very large aircraft in the areas of economics, transportation system interfaces and operational problems were reviewed regarding their influence on vehicle configurations and technology. Fifty-four technology requirements were identified which are judged to be unigue, or particularly critical, to very large aircraft. The requirements were about equally divided among the four general areas of aerodynamics, propulsion and acoustics, structures, and vehicle systems and operations. The state of technology readiness was judged to be poor to fair for slightly more than one-half of the requirements. In the classic disciplinary areas, the state of technology readiness appears to be more advanced than for vehicle systems and operations.

Conner, D. W.↗

NASA NTRS1979

Multirole cargo aircraft options and configurations

The paper discusses multirole cargo aircraft options and configurations. It was shown that derivatives of current wide-body aircraft would be economically attractive through 2008, but new dedicated airfreighters incorporating 1990 technology would offer little or no economic incentive. Option studies indicate that Mach 0.7 propfans would be economically attractive in trip cost, aircraft price, and airline ROI; spanloaders would be lower priced with higher ROI, but would have a relatively higher trip cost because of aerodynamic inefficiencies. Finally, air cushion landing gear configurations are identified as an option for avoiding runway constraints on airport accommodation of very large airfreighters.

Conner, D. W.↗

NASA NTRS1979

Multirole cargo aircraft options and configurations

A future requirements and advanced market evaluation study indicates derivatives of current wide-body aircraft, using 1980 advanced technology, would be economically attractive through 2008, but new dedicated airfreighters incorporating 1990 technology, would offer little or no economic incentive. They would be economically attractive for all payload sizes, however, if RD and T costs could be shared in a joint civil/military arrangement. For the 1994-2008 cargo market, option studies indicate Mach 0.7 propfans would be economically attractive in trip cost, aircraft price and airline ROI. Spanloaders would have an even lower price and higher ROI but would have a relatively high trip cost because of aerodynamic inefficiencies. Dedicated airfreighters using propfans at Mach 0.8 cruise, laminar flow control, or cryofuels, would not provide any great economic benefits. Air cushion landing gear configurations are identified as an option for avoiding runway constraints on airport requirements and/or operational constraints are noted.

Conner, D. W.↗

NASA NTRS1979

Technology requirements and readiness for very large vehicles

Common concerns of very large vehicles in the areas of economics, transportation system interfaces and operational problems were reviewed regarding their influence on vehicle configurations and technology. Fifty-four technology requirements were identified which are judged to be unique, or particularly critical, to very large vehicles. The requirements were about equally divided among the four general areas of aero/hydrodynamics, propulsion and acoustics, structures, and vehicle systems and operations. The state of technology readiness was judged to be poor to fair for slightly more than one half of the requirements. In the classic disciplinary areas, the state of technology readiness appears to be more advanced than for vehicle systems and operations.

Conner, D. W.↗

NASA NTRS1979

Technology requirements and readiness for very large vehicles

Common concerns of very large vehicles (VLV) in the areas of economics, transportation system interfaces, and operational problems are reviewed with respect to the influence of these factors on aircraft configurations and technolgoy. Fifty-four technology requirements for VLVs have been identified and rated with regard to technology readiness. The requirements were about equally divided among the four general areas of aero/hydrodynamics, propulsion and acoustics, structures, and vehicle systems and operations. None of the requirements were considered to have an excellent technology readiness.

Conner, D. W.↗

NASA NTRS1978

Passenger ride quality in transport aircraft

Quantitative relationships are presented which can be used to account for passenger ride quality in transport aircraft. These relations can be used to predict passenger comfort and satisfaction under a variety of flight conditions. Several applications are detailed, including evaluation of use of spoilers to attenuate trailing vortices, identifying key elements in a complex maneuver which leads to discomfort, determining noise/motion tradeoffs, evaluating changes in wing loading, and others. Variables included in the models presented are motion, noise, temperature, pressure, and seating.

Jacobson, I. D.↗

NASA NTRS1978

CTOL concepts and technology development

Various developments in the Aircraft Energy Efficiency (ACEE) program are discussed. Terminal-area operations are considered with emphasis on the Terminal Configured Vehicle program. Consideration is also given to aircraft systems studies and economics (including noise reduction programs), coal-derived fuels for aviation systems (including LH2-fueled aircraft), and transport-aircraft concepts (including laminar flow control).

Conner, D. W.↗

NASA NTRS1976

Active controls for ride smoothing

Active controls technology offers great promise for significantly smoothing the ride, and thus improving public and air carrier acceptance, of certain types of transport aircraft. Recent findings which support this promise are presented in the following three pertinent areas: (1) Ride quality versus degree of traveler satisfaction; (2) significant findings from a feasibility study of a ride smoothing system; and (3) potential ride problems identified for several advanced transport concepts.

Conner, D. W.↗

NASA NTRS1976

Passenger ride comfort technology for transport aircraft situations

A brief overview is given of NASA research in ride comfort and of the resultant technology. Three useful relations derived from the technology are presented together with five applications of these relations to illustrate their effectiveness in addressing various ride comfort situations of passenger transports.

Conner, D. W.↗

NASA NTRS1975

Nonmotion factors which can affect ride quality

Data pertaining to nonmotion factors affecting ride quality of transport aircraft were obtained as part of NASA in-house and sponsored research studies carried out onboard commuter-airline and research aircraft. From these data, quantitative effects on passenger discomfort of seat width, seat legroom, change in cabin pressure, and cabin noise are presented. Visual cue effects are also discussed.

Conner, D. W.↗

NASA NTRS1975

Potential benefits to short-haul transports through use of active controls

The potential applications of active controls are examined for improving the characteristics of transport type aircraft used in short-haul service ( 1,000-kilometer range capability). The types of aircraft to meet future needs (quiet operation, congestion alleviation, fuel conservation, operating economy, and traveler acceptance) are identified as helicopters for shorter stage lengths and fixed wing aircraft of reduced field-length capability for longer stage lengths. Likely uses for active controls for these aircraft are examined regarding payoffs which can be expected and problems and constraints which must be dealt with. Uses showing significant benefits include augmented stability and control, gust-load alleviation, and ride smoothing. Gust-load alleviation is particularly effective for low-wing-loading aircraft employing conventional lift. Ride-smoothing systems are indicated to be the furthest advanced and ready for production commitment for those applications where they can be shown to have payoff.

Conner, D. W.↗

NASA NTRS1972

Status of STOL ride quality and control

A STOL ride-control development program has been initiated with the objective of generating ride-control technology through development and evaluation of an active control system specifically designed to provide ride smoothing on a STOL vehicle. Although much can be learned through analysis, there are deficiencies in technology for translating analysis results into operating hardware. The general approach being followed is to select an existing STOL vehicle for trial and then carry out a study to establish feasibility of a control system or systems to smooth the ride and generate system trade-off data.

Conner, D. W.↗