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Technical Paper

Development Testing of the New Generation of Large Jet Aircraft

The new generation of large transport aircraft require the utilization of improved development test techniques discussed in this paper to ensure timely and efficient development cycles. Although the development test program on the C-5, largest of today's airplanes, has not been completed, a comprehensive accumulation of significant data in all test phases and extensive experience in managing and conducting the testing of these huge transports have been obtained. The C-5 greatly advances the state-of-the-art, but more important to this presentation are the advancements in test techniques. Increased aircraft size and complexity require additional emphasis on early, valid planning for test facilities and support equipment. Improved techniques for data retrieval and additional sophistication in laboratory test loading systems are essential for efficient accomplishment of the program.
Technical Paper

Design and Certification of a Composite Control Surface

A graphite/epoxy composite rudder for the Gulfstream Aerospace G-III executive jet aircraft was designed, tested and certified by the Lockheed-Georgia Company. The design replaces a conventional skin-stiffened aluminum structure, and achieves a 50% increase in acoustic fatigue life with a 22% weight savings. The design incorporates an innovative rib cap design with greatly improved fatigue and damage resistance over conventional composite rib cap designs. Details of the design as well as the FAA certification plan are presented in this paper. The certification plan, based on FAA Advisory Circular No. 20-107 (Reference 1), outlined the design details as well as all requirements for element, component and full-scale testing. Both static and acoustic fatigue element and component tests were conducted, with applied impact damage representive of initially detectable damage levels that could be incurred in the rudder skins.
Technical Paper

Maintenance and Reliability Simulation Modeling for Airfreighters

A Maintenance and Reliability Simulation Model has been developed which can be used to evaluate and optimize the Maintainability and Reliability characteristics of an aircraft and the maintenance and logistic resources required to support the aircraft. The model is programmed to simulate any aircraft type or series. Its uniqueness to a specific design arises by virtue of the input data supplied to the “aircraft characteristics” segment of the model. The validity and accuracy of the model logic have been verified by simulating the maintenance operations of a fleet of aircraft being operated in scheduled service and comparing the model output with actual in-service reported data.
Technical Paper

The MAC MADAR System: An AIDS Model for Commercial Airlines

The growing body of technology relative to maintenance monitoring provides substantial evidence that on-condition maintenance will be a reality in the foreseeable future. The Military Airlift Command's MADAR (Malfunction Detection, Analysis, and Recording) System is emerging as the “missing link” which has heretofore retarded progress toward attainment of this increasingly-important goal. The key issue is real time response. Monitoring-system reliability, accuracy, and repeatibility are all of little consequence if the system output is not timely enough to assist the maintenance function. Recent use of communications links by some airlines to transmit recorded data to a centrally-based computer has reduced the time span between data generation and its availability for use. Nevertheless, the response time is still estimated to be somewhere between 5 and 24 hr.
Technical Paper

Advanced Technology for STOL Transports

From an analysis of a typical large airport and its growth problems, it is concluded that STOL aircraft systems are needed now-with or without high-speed ground transportation systems. It is also shown that the needed first-generation STOL aircraft can be in operation in 1975. These contemporary STOL aircraft will, however, be only a step in the evolution to improved aircraft of the future. The needs for technological improvements are discussed, and some new prospects in STOL technology are described.
Technical Paper

The Role of the Small Jet in the Airline Training Syllabus

During the early part of 1967 the Lockheed-Georgia Co. initiated a program to determine the feasibility of utilizing the Lockheed JetStar as a trainer for airline pilots in order to reduce the flight time required in line equipment. Most U.S. airlines were contacted; airlines, as well as FAA operations personnel, evaluated the airplane in flight as a trainer, and participated in developing the techniques to provide the most useful training. This paper summarizes the development of this program and presents some preliminary conclusions on the economic advantages gained from utilizing the small jet in the airline training syllabus. Some discussion of the future development of the small jet required to simulate such aircraft as the 747 and SST is also included.
Technical Paper

Powered Lift for Longer Field Lengths and Longer Missions?

It is hypothesized that the potential value of powered lift may be greater for transport applications requiring RTOL and CTOL field lengths than for those requiring STOL performance. Thus, it is implied that powered lift can be applied effectively to aircraft designed for medium and long haul, as well as short haul. This premise has been reached on the basis of observed trends in direct operating cost, mission fuel consumption, and, most significantly, community noise footprint areas for both powered lift and conventional mechanical flap configurations. Some pertinent results from recent NASA-sponsored configuration design and system studies for quiet short haul and fuel-conservative aircraft are discussed, and further data are developed to explore the potential value of incorporating powered lift concepts in advanced aircraft designs for medium and long haul applications.
Technical Paper

Advanced Structural Materials Application for High-Subsonic-Speed Transports

This paper describes the results of parametric design studies of the application of filamentary composite materials in the structure of high-subsonic-speed transport aircraft. System costs and weight savings are presented as a function of percent utilization of composite materials from zero to 80%. The weight savings potential of composites for direct material substitution and for resized aircraft show gains of up to 25 and 50%, respectively. The state-of-the-art in structural design, analysis, fabrication, and test is discussed. Structural design concepts are shown and test validation is given, along with cost analyses.
Technical Paper

Design Studies of Low-Noise Propulsive-Lift Airplanes

A review is presented of low-noise airplanes designed for operation in the 1980 time period. Aircraft with parametric engines covering a range of fan pressure ratios and noise levels were developed conceptually under contract with NASA Advanced Concepts and Missions Division, supported by the NASA Lewis Research Center contracts for the Quiet Clean STOL Experimental Engine (QCSEE) Study Program. Powered-lift concepts included externally blown flap, augmentor wing, internally blown flap, and over-the-wing upper surface blowing. Performance, sizing, and costs are described for 148 passenger airplanes with design field length varying from 2000-4000 ft. Techniques for reducing noise are evaluated in terms of aircraft performance, weight, and cost; experimental data on decayer nozzles are presented and assessed with respect to effectiveness in exhaust noise reduction and aircraft performance penalties.
Technical Paper

Soft and Rough Field Landing Gears

The frequent use of large transport aircraft on soft and rough airfields in or near battle zones requires that they be fitted with landing gears having increased capability for ground flotation and shock absorption. Design and parametric studies of aircraft landing gears show feasible approaches to the problems associated with soft and rough airfields. Landing gear concepts, analytical methods, and design parameters are presented for airplanes of 110,000–750,000 lb gross weight. Landing gear weights, sizes, and configurations are compared, and their soft and rough field capabilities are evaluated. Structural and dynamic aspects of rough field operations are discussed for bare soil fields and for fields covered with landing mats.