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This paper deals with the performance prediction of one member of a family of thrust producing intermittent combustion engines, namely the pulsejet. The first part is concerned with formulating basic concepts of how pulsejets work. It describes the different methods of providing intake valving action and derives theory to demonstrate the operation of the aerodynamic tuned valve in particular. The second part is concerned with devising a computer program to simulate and predict the performance of valveless pulsejets. The program is based on the method of characteristics for calculating unsteady gas flow. Theories and techniques are given to handle the major problems associated with this application. These problems include the large range of discontinuous temperature and entropy, flow through an area discontinuity and the calculation of mean thrust.

Field studies of agricultural airplane operations indicated that airplane design parameters significantly affected aircraft productivity. Limitation of material discharge rate, while still securing uniform distribution pattern of ejected material, appeared to be a serious factor in restricting markets and holding down productivity. A computer program was written to explore possible gains from optimizing design parameters in a given market, to determine improvements which would result from extending the range of design parameters, and to study the effects of different operating procedures. The program actually “flies” an airplane through all steps of a mission. A mission is defined as a complete working day from preparation for first take-off to shutting down after last landing. All flight operations are defined in terms of airplane specifications and design parameters.

A general computer program has been developed for analytic fatigue crack growth. It is designed so that the user does not need to have an extensive background in Fracture Mechanics Theory. This FORTRAN program can analyze the growth of most common types of cracks and accounts for the transition from part-thru to completely thru-the-thickness crack. The input loading may be a mission profile or arbitrary cyclic stresses with or without concentrated loads and may be repeated a number of times. There are built-in corrections for geometry, plastic-zone size, plane-stress vs. plane-strain and applicability of Linear-Elastic-Fracture-Mechanics, and there are options available for crack growth rate calculations, retardation models and plastic zone corrections.

This paper describes a computational technique for prediction of the flow and thermal environment in the Space Shuttle Solid Rocket Motor field joint cavities. The SRM field joint hardware has been tested with a defect in the insulation. Due to this defect, the O-ring gland cavities are pressurized during the early part of the ignition. A computer model has been developed to predict the flow and thermal environment through the simulated flaw, during the pressurization of the field joint. The transient mass, momentum, and energy conservation equations in the flow passage in conjunction with the thermodynamic equation of state are solved by a fully implicit iterative numerical procedure. Since this is a conjugate flow and heat transfer problem, wall temperatures are calculated by solving the one-dimensional transient heat conduction equation in the solid along with the other governing equations. The pressure and temperature predictions have been compared with the test data.

This paper develops a set of seven general equations which describe various portions of a standard engine performance chart. A regression analysis technique is then employed to evaluate the constants in these equations which identifies them to a particular engine. Computer programs which employ this technique are provided. A final program is provided which utilizes the equations to yield a value of brake horsepower for an input of any combination of RPM, manifold air pressure, air temperature, and pressure altitude.

In the design of fluid systems plumbing for aircraft engines, the designer is continually challenged by the problem of component location and routing. In order to achieve accessibility and maintainability, and to avoid physical interferences, plumbing design is accomplished through extensive graphical projection and mockups. The solution to this problem must also satisfy tubing stress limits, resonant frequencies, bracket or clamping positions available and future space requirements. To facilitate and expedite this design procedure a digital computer technique has been developed which determines the clearances between tubing and other engine components. Though not a substitute for graphical projection, this program provides a means for accurate checking for interference. It also serves a valuable purpose in the storage of previous or alternate plumbing routing arrangements for comparison.

The technological advances which have been made in the computer hardware industry, from interactive computer graphics systems to numerically controlled manufacturing and inspection machines, has resulted in major changes in the impeller design process. The contents of this paper describes an “Interactive CAD/CAM Geometric Modeling System for Impellers” developed to integrate aerodynamic design, mechanical design, structural and dynamics analysis, manufacturing and quality assurance into an integrated CAD/CAM impeller system. The system allows for more design and analysis iterations to take place in a short time frame, resulting in optimized impeller designs. The system also reduces the lead time required for part fabrication and inspection from many months to a few weeks.

This paper discusses the pioneering efforts of General Electric Co. to develop and operate a computer based Technical Information Center in its Flight Propulsion Div. This system is aimed at providing discriminating technical information services directed to the individual needs of a large body of engineering users. Operation of the GE Automatic Information Retrieval System and its application are described from the user's viewpoint. What a technically competent information service, using a large electronic computer as a major tool, means to its engineering users and their management in terms of cost, effectiveness, and efficiency is considered.

In 1999, the Cargo Airlines Association and the Federal Aviation Administration conducted an operational evaluation of Cockpit Display of Traffic Information (CDTI) and Automatic Dependent Surveillance - Broadcast technologies at the Airborne Express Airpark in Wilmington, Ohio. Thirteen aircraft of various types flew multiple flight patterns during the morning and the afternoon of a single day and were assigned to either a CDTI or baseline (no CDTI) condition. New computerized analysis techniques were developed to examine routinely recorded air traffic control flight data. This paper describes those techniques in detail, as well as the results of the analysis. Methods such as those described here will be increasingly important as new technologies are developed and evaluated operationally.

In today’s aircraft design, more and more attention is paid to the conceptual and preliminary design stages in order to increase the capability of choosing a design that will be successful. Therefore, the decisions made during these design phases play a central role in determining the success of a design. Decision making techniques at these stages, must manage multiple, conflicting criteria and capture associated uncertainties. The method presented in this study was developed from Joint Probability Decision Making (JPDM), a probabilistic multiple criteria decision making technique. The proposed method eliminated the limitations that JPDM has by utilizing Utility Functions to represent the decision maker’s preference. An advanced rotorcraft concept selection problem is performed in order to demonstrate the improvements, and the results obtained from the proposed method and the JPDM technique are compared with each other.

In the first half of the next century, Mankind will expand its sphere of existence to the Moon and space, and they will stand on Mars and study the other planets. Then, humans will inevitably be required to live for long periods, two years or more, in micro-gravity and/or low gravity environments. However, it is well known that such micro or low gravity environments adversely affect human physiology and psychology. The longer the period the greater such effects are and these can result in serious health problems. To improve living conditions in space by generating artificial gravity will be important to solving these problems.

A concept for a miniature, mechanically pumped two-phase cooling loop with high thermal performance was developed. In this feasibility study, a miniature, annular gear pump was inserted into the liquid line of a two-phase LHP-type loop architecture. In contrast to capillary-pumped systems, the functions of liquid pumping and evaporative heat transfer were separated and could be optimized independently. The cooling system was tested in terms of heat transport capability, performance and stability using water as the working fluid. The results show a high heat transfer coefficient of >11 W/(cm2K), a high heat transport capability of >70 W/cm2, and stable working behavior in all orientations. These results were obtained with a device using a simple loop architecture and an evaporator design that was not optimized for this kind of operation.

A concept of developing a regenerative water management system (RWMS) for first lunar base missions is reviewed. The principal feature of the concept proposed is the maximum possible unification of RWMS for long-duration orbiting station and a lunar base with due regard to possible modification of the hardware for lunar gravity conditions. The paper is based on the expertise in research, development, testing and flight operation of RWMS in Russia. An upgraded RWMS of the International Space Station may be used for first lunar missions.

A Programmable Advance Life Support System (ALSS) that can accommodate all the demand changes necessary for life support must be developed particularly for bioregenerative functions. We have previously developed the Gravity Independent Photosynthetic Growing System (GIPGS)-a versatile multi-crop growing system), Automatic Plant Growing and Harvest System (APGHS). -a self-regenerating continuous food production systems, and the Inflatable Self-sufficient Growth Bags (ISGB). These systems can accommodate production of many other crops such as wheat, rice, lettuce, komatsuna, tomato, cucumber, sprout crops and fermented foods which can be all prepackaged in self-contained growth bags. GIPGS is capable of growing different crops and crops in different stages simultaneously with a high density and high-energy efficiency, APGHS has auto crop management for perpetual food production and auto harvest systems. Programmable logic controllers control most of these hardware functions.

The End of Life phase of Aircraft is a relatively complex phase in life cycle of this product. The retired Aircrafts need to be parked in certain conditions. Some valuable parts are disassembled and the rest of them are dismantled. Materials are separated and upgraded, waste is burned or deserted and toxic materials restrained or incinerated. All of these activities should be performed in an ecologically right manner; however, collectively produced added values for all stakeholders need to be considered. This paper aims to provide a conceptual framework for value chain analysis of Aircraft recycling process in the context of sustainable development. The value chain related to recycling aircraft at the end of life was chosen to generate an in-depth analysis of the value chain, considering environmental and socio-economic concerns. The value chain framework for recycling of fleets is identified. The key processes with environmental and social impacts are determined.

This paper presents the results of an investigation to improve design/analysis techniques for aircraft hydraulic systems. A design/analysis tool was developed by integrating control-surface commands and loads obtained from Aircraft Dynamic Simulator Software (ADSS) with an enhanced version of the HYdraulic TRansient ANalysis (HYTRAN) program. Control-surface commands and loads from an ADSS simulation of a selected maneuver were used as dynamic input to the HYTRAN program so that the hydraulic system response could be predicted throughout the maneuver. Predicted hydraulic system pressures and control-surface positions from the HYTRAN simulation of the maneuver were compared to flight-test data and were found to be in excellent agreement. The successful coalescence of the two independent software programs gives engineers a concurrent design/analysis tool that can be used to optimize hydraulic system designs during the very early stages of design.

Future vehicle power systems must achieve greater flexibility and reliability than those used in previous generations. New functions that enhance safety, such as arc detection and wiring integrity verification, are essential for new systems. Embedded autonomous control, and fault correction can be built into Fault Tolerant Processors that integrate into a vehicle Open System Architecture. This approach will provide status and fault detection information to maintenance interfaces and provide fault correction. Safety is enhanced by the prevention of dangerous restarts from crew and personnel. The embedded features allow for pre-flight mission configuration to setup systems before takeoff and on-board and off-board maintenance control. This enables operators to evaluate power system health and history to help reduce turn around time.

A connectable/disconectable thermal interface has been developed for the constructable radiator system under development at NASA-Johnson Space Center. A contact heat exchanger approach which involves pressurized clamping of a segmented cylindrical heat exchanger on the outside of a round heat pipe evaporator section was designed, fabricated, and tested. Dry metal-to-metal contact conductance heat transfer is utilized. Test results have indicated excellent contact conductances of up to 8500 w/m2°c (1500 Btu/ft2°F) at 2000 kPa (300 psi) clamping force. The feasibility and fabricability of the design have been demonstrated.

Due to ongoing efforts by the aviation industry, much has been learned over the last several years regarding jet engine power loss and compressor damage events caused by the ingestion of high concentrations of ice crystal particles into the core flow path. Boeing has created and maintained a database of such ice crystal icing (ICI) events to aid in analysis and further study of this phenomenon. This article provides a general update on statistics derived from the Boeing event database, and provides more details on specific event clusters of interest. A series of three flight campaigns have, over the past five years, collected in-situ data in deep convective clouds that will be used for the assessment of the new FAA CFR Part 33 ice crystal environmental envelope Appendix D, and the equivalent EASA CS-25 Appendix P.