Refine Your Search

Search Results

Technical Paper

Biodegradable Fluids for Axial Piston Pumps & Motors - Application Considerations

1991-04-01
910963
The use of environmentally acceptable hydraulic fluids in mobile machines is becoming more prevalent worldwide, as a way to reduce the pollution of the environment. These fluids are biodegradable, and therefore do not damage the forests, soil, or ground water when accidentally leaked from hydraulic powered machinery. There are three types of environmentally acceptable hydraulic fluids currently available. These fluids are either vegetable oil based, synthetic polyglycol based, or synthetic ester based. Each of these fluids has characteristics that differ from conventional mineral oil. This paper discusses the characteristics of the various types of environmentally acceptable hydraulic fluids, and application considerations for their use with heavy duty axial piston pumps and motors. The selection of an environmentally acceptable fluid for new machine use, as well as for conversion of existing mineral oil equipped machines is discussed.
Technical Paper

The Development of Environmentally Acceptable Hydraulic Oil Formulations

1991-04-01
910965
In the automobile and earthmoving market place, consumer pressure is creating a demand for more environmentally considerate products. One aspect of this definition is biodegradability. In the forestry and farming industries where lubricant losses and spillages are recognised as a significant potential hazard, the use of these products is now widespread and in terms of environmental protection, the benefits are multiple. This paper discusses technical developments based on vegetable oils, including an assessment of additive requirements to meet performance needs. It also reviews necessary work to define other aspects of performance.
Technical Paper

Biodegradable and Nontoxic Hydraulic Oils

1991-04-01
910964
Abstract In response to the growing industry interest in environmentally acceptable (EA) lubricants, a hydraulic oil development program was initiated with these express objectives: Define the environmental impact and performance expectations for a lubricant used in applications where inadvertent leakage to the environment may occur. Develop a new product which degrades rapidly and is nontoxic to fish while providing satisfactory field performance in severe applications. This paper will first review the current regulatory initiatives and proposed ecotox test requirements for this class of lubricant. In addition, ecotox data for the candidate fluids will be presented along with recommendations aimed at more clearly defining the test requirements and limits. Lubricant performance data, including laboratory evaluation and field experience, for a vegetable-based hydraulic fluid will be presented, identifying both performance strengths and weaknesses.
Technical Paper

Shaft Seals-Trends and Developments for Off Highway Heavy Equipment Applications

1991-04-01
910966
The paper will review existing seals used in off-highway heavy equipment, both radial lip seal applications and face type seal applications in general use on track vehicles. With the trend towards improved reliability and durability, together with the never ending quest for quality and product improvements, the paper will discuss a number of seal development programs which will result in products that meet the new and projected future requirements for seals from the off-highway heavy equipment manufacturers.
Technical Paper

In-Flight Off-Surface Flow Visualization Using Infrared Imaging

1991-04-01
911006
Abstract A flight test investigation was conducted to evaluate an infrared (IR) imaging technique to visualize off-surface flow phenomena. A single-engine, general-aviation airplane was equipped with an IR imaging system that viewed the region around the left wingtip. Vortical flow at the wingtip was seeded with sulfur hexafluoride, a gas with strong infrared absorbing and emitting characteristics. Different terrain and sky backgrounds were evaluated for their effect on IR images of vortical flow. The best IR images were obtained with a clear sky background. The results of the investigation indicate that IR flow visualization compliments existing smoke generator methods for off-surface flow visualization.
Technical Paper

Aerodynamic Performance of Wing-Body Configurations and the Flying Wing

1991-04-01
911019
An elementary analysis has been made of generic wing-body configurations with variable volume allotment in wing and body, for constant total useful volume, including the all-wing configuration. These aircraft were compared on the basis of the Lift-to-Drag (L/D) ratio, for specified flight conditions. In addition the parameter ML/D for constant corrected thrust has been optimized, resulting in certain combinations of altitude and speed for maximum specific range (if corrected TSFC = constant). Finally, the effect of volume allotment on L/D for given engine size was studied. It has been found that in many cases optimum volume allotments indicate that wing-body combinations are to be favored. Only in the case of relatively low Mach numbers and high-altitude flight the flying wing outperforms conventional aircraft, but it will generally require larger engines.
Technical Paper

Garrett TPF351-20 Engine Flight Test and Ground Test Performance

1991-04-01
911011
The Garrett TPF351-20 engine design program was initiated in October of 1987. The engine was selected by Embraer to power the CBA123 “Vector”, a high-speed commuter “pusher” aircraft. The first engine test was successfully completed on May 19, 1989, nineteen months after design initiation. Subsequent testing has been done on indoor and outdoor propeller test stands at Garrett test facilities. Additionally, testing was successfully completed on Garrett's Boeing 720 flying test bed in July of 1990. An aggressive aircraft test program on the first prototype CBA123 aircraft in Sao Jose dos Campos, Brazil, also began in July of 1990. This was soon followed by a flight of the aircraft to the Farnborough Air Show in September of the same year. This paper describes this test program and some unique features used to expedite the program.
Technical Paper

Full Authority Digital Electronic Control of Pratt and Whitney 305 Turbofan Engine

1991-04-01
911018
In the present competitive aerospace industry, there is an increased demand on performance and safe operation of the propulsion system in particular for commuter and business aircrafts. Pratt and Whitney Canada has developed the PW305 turbofan engine equipped with a Full Authority Digital Electronic Control (FADEC) to meet these demands. The control system is designed to provide optimum engine operation within safe limits, reduced pilot workload and high reliability over the whole flight envelope. This paper gives a general overview of the requirements, development, operability and performance of the PW305 propulsion system.
Technical Paper

Composite Prototype Aircraft Development A Method For Design, Fabrication and Test Training

1991-04-01
911015
The faculty and staff of the Raspet Flight Research Laboratory (RFRL) have concluded a project with an industrial customer to lead a group of engineers and technicians in a study of the “art” of developing a prototype composite aircraft. The objective was to produce a turbine powered, composite, pressurized, single-engine aircraft, which would introduce the team to the many aspects of a complex aircraft in a environment. The prototype Allison Soloy turbine conversion of the Beechcraft A-36 was chosen as the study aircraft. It was proposed that the A-36 structure be replaced with composite structures in three steps of increasing complexity. The sequence was to first design-build-test-fly the tail, then the wings, and finally the fuselage. To limit the difficulty of the project development and to allow a meaningful comparison between aluminum and composite structures, the configuration modifications were to be minor and to utilize existing RFRL Marvel II composite technology.
Technical Paper

Turboshaft Engine Development for Commercial Tiltrotor Aircraft

1991-04-01
911017
The civil aircraft market frequently employs propulsion systems originally developed and qualified for military aircraft applications. When this occurs, the civil sector benefits greatly from the lessons learned during the military engine development and qualification process. This paper presents the unique test experiences and lessons learned during development of the T406-AD-400 turboshaft engine that the GMA2100 turboprop, GMA3007 turbofan, and GMA1107 turboshaft engines will profit from for years to come. Some of these valuable T406 test experiences include: 1) development of engine attitude capabilities, 2) integration with a fly-by-wire control system, 3) incorporation of flight test experience into the engine design, and 4) utilization of unique test facilities.
Technical Paper

On the Feasibility of Small, Transcontinental Commuter Aircraft

1991-04-01
911023
Abstract Air travelers between medium sized coastal cities in the USA are faced with a major inconvenience: they are forced by existing airline schedules to make at least one stop in a major hub with a change of airplane and, sometimes even a change in air carrier. This inconvenience translates into lost time, missing of a connection due to delays and possible loss of luggage. These inconveniences could be alleviated if non-stop, coast-to-coast small jet commuters could be designed such that they can compete with the existing transcontinental transports on a DOC per passenger seat-mile basis. It is shown that significant advances in aerodynamic and propulsion design technology will be needed to enable the profitable development of such airplanes.
Technical Paper

Multi-Process Multi-Material Case Study

1991-04-01
911029
When GE Plastics entered the multi-process multi-material arena with the construction and installation of Alpha I in its Pittsfield, Mass. headquarters, it recognized that if plastics are to continue to provide revolutionary products, the industry must expand its thinking beyond current single process applications. Multi-process parts must be developed to demonstrate to the automotive industry a new generation of applications. The purpose of this paper is twofold: to explain the value of multi-process multi-material technology and to present an engineering analysis of the system which addresses design and processing questions.
Technical Paper

Design Developments for Advanced General Aviation Aircraft

1991-04-01
911022
Abstract The preliminary design studies are presented for an advanced general aviation aircraft. Advanced guidance and display concepts, laminar flow, smart structures, fuselage and wing structural design and manufacturing, and preliminary configuration design are topics to be discussed. This project was conducted as a graduate level design class under the auspices of the KU/NASA/USRA Advanced Design Program in Aeronautics. This paper will present the results obtained during the fall semester of 1990. The project will be continued into the spring semester of 1991.
Technical Paper

EICAS as a Modularized Aircraft System

1991-04-01
911028
Today's EICAS is required to functionally integrate a wide variety of systems and information and intelligently utilize this to enhance crew operations, maintenance operations, and aircraft availability. This is accomplished through a modular system architecture and LRU design which supports flexibility, growth, and uniqueness, and also recognizes the need to minimize the development costs during the design cycle of a new aircraft or major aircraft update.
Technical Paper

Conceptual Design of a Starcar

1991-04-01
911021
This is the second report about a new program on personal aviation at The University of Arizona. The motive for the program is a belief that advanced information technologies like the Global Positioning System (GPS) have made possible a personal aviation system on a scale last imagined fifty years ago. Research on differential GPS for precision navigation is described briefly, but the report is mainly about design concepts for a Starcar, a transformer vehicle that functions as an automobile or airplane. A Starcar is a composition of three components: passenger module, road module, and sky module. The passenger and road module together make an automobile, and the passenger and sky module are an airplane. Because the road module does not fly, a Starcar in flight proves to be nearly as efficient as the best of modern kit airplanes.
Technical Paper

Pusher Turboprop Installation Technology for the Embraer CBA-123 Vector

1991-04-01
911030
In late 1987, the Garrett Engine Division of the Allied-Signal Aerospace Company contracted with Embraer of Sao Jose, Brazil to build a modern free-turbine turboprop to power the new 19-passenger CBA-123 commuter aircraft. Designated the TPF351-20, this 2100 thermodynamic shp turboprop was developed using proven components from other new engine designs. It was the first Garrett turboprop to incorporate full authority digital electronic control (FADEC) and provide advanced component technologies to yield optimum powerplant efficiencies. A great deal of effort was expended on maintainability features including individual mechanical component accessibility and FADEC diagnostic capabilities.
Technical Paper

Aerodynamic Impact of Deicing/Anti-Icing Fluids on Commuter Aircraft

1991-04-01
911026
To understand the aerodynamic impact of the ground deicing/anti-icing fluids on commuter aircraft, a wind tunnel test simulating takeoffs of a typical commuter aircraft was conducted at NASA LeRC IRT during early 1990. The results of the tests indicate that the fluids remain on the aerodynamic surfaces until well after the simulated takeoffs. Significant degradation on the maximum lift and climb gradient at climb out conditions were observed. The degradation in aerodynamic performance, especially at low temperature, indicates that many of the fluids tested were considered unacceptable relative to flight safety. However, increasing the time to rotation resulted in a substantial improvement in the aerodynamic performance to the extent that those fluids became acceptable.
Technical Paper

Aerodynamic Noise of Ground Vehicles

1991-04-01
911027
As engine, tire, and other automobile noise is reduced and as driving speeds increase, aerodynamic noise sources on ground vehicles are becoming relatively more important. They often dominate at cruise speeds of 65 mph. Aspiration and leak noise are strong sources but generally can be controlled by known methods. Turbulent pressure fluctuations due to separated and vortical flows are also strong sources. Much interior noise is caused by transmission of these external pressure fluctuations through windows and other surfaces. The paper presents the variety of aeroacoustic sources on automobiles and reviews the state of experimental data, of analysis methods, and noise reduction principles. A new correlation method for predicting external fluctuating pressures in separated regions is presented.
Technical Paper

Nonlinear Finite Element Analysis in the Closed Loop Seal Design Cycle

1991-04-01
910968
Both static and dynamic seals have been designed in the past, primarily on the basis of prior experience, part prototyping, and extensive experimental testing. But, with the advent of nonlinear Finite Element Analysis (FEA), the seal design process is changing from “Black Magic” to a more fundamental and scientific approach. The overall design cycle is shortened and testing parameters are explored and evaluated utilizing FEA. Correlation between FEA predictions and test results lead to a more optimal interconnection of material and design for sealing applications. This paper discusses two specific applications of nonlinear FEA involving an O-Ring and a U-Cup seal design. The evaluation of appropriate material constants for two elastomeric compounds and their direct applications in FEA models are discussed here with an experimental correlation.
Technical Paper

FKM and HSN Materials for Diesel Engine Cylinder Liner Seals

1991-04-01
910967
Abstract Diesel engine cylinder liner seals present an application environment difficult for many seal elastomers. These cylinder liner seals must resist high temperature oil from the crank case as well as water based coolants. High performance Nitrile materials have found application in this area due to their resistance to oil and to water and steam. However, Nitriles lack the long term heat resistance for long mileage applications in hotter running engines. Fluorocarbons generally have excellent resistance to oil and high temperatures but suffer from poor long term resistance to steam and water. This paper discusses Fluorocarbons recently developed with greatly improved steam resistance along with compression set resistant Highly Saturated Nitriles for these cylinder liner seal applications. Accelerated testing in application environments as well as methods for selecting the best material for the cylinder liner seal application will be discussed.
X