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A unique exercise facility has been developed and used to simulate orbital extravehicular activity (EVA). The device incorporates an arm ergometer into a mechanism which places the subject in the zero-g neutral body posture. The intent of this configuration is to elicit muscular, cardiovascular, respiratory, and thermoregulatory responses similar to those observed during orbital EVA. Experiments done with this facility will help characterize the astronaut's dynamic heat balance during EVA and will eventually lead to the development of an automated thermal control system which would more effectively maintain thermal comfort.

The forming behavior of Al-Cu-Mg-Mn alloy 2024 sheets with fine, equiaxed and coarse, elongated grain structures was characterized in the O temper (fully annealed) and W temper (solution heat treated and quenched) conditions. The fine grained materials had better biaxial stretching capabilities in both tempers. The fine grained O temper also had superior drawing and plane strain stretching properties. For the O temper, conventional tensile forming indicators such as elongation and strain ratio, correlated with ball punch depth, forming limit strains and limiting draw ratio. Such correlations were not apparent in the W temper, however, nor could the two tempers be compared on the basis of tensile data alone.

The cost of development, qualification and certification of new engines has become an extremely high financial burden, both for Governments and private companies at a time when reducing expenditures, cutting research and development budgets, and restructuring organizations are the norm in aerospace industry. The Government acquisition strategy has encouraged contractors to form joint ventures or teaming arrangements in an attempt to glean the best expertise from two companies and then allow the two companies to compete for the production contracts. This concept was palatable and accepted by the industry in the past when they knew a production contract was in the offing. In today's declining defense budget (Figure 1) there is no certainty of production contracts. When the Government does fund a development program, funds are extremely limited. Similarly companies are selectively funding private development efforts. In both cases tight control of costs is a high priority.

A new oil-fringe imaging skin friction (FISF) technique to measure skin friction on wind tunnel models is presented. In the method used to demonstrate the technique, lines of oil are applied on surfaces that connect the intended sets of measurement points, and then a wind tunnel is run so that the oil thins and forms interference fringes that are spaced proportional to local skin friction. After a run the fringe spacings are imaged with a CCD-array digital camera and measured on a computer. Skin friction and transition measurements on a two-dimensional wing are presented and compared with computational predictions.

Mach-flow angularity probes were developed for use in scramjet flow path probe rakes. Prototype probes were fabricated to demonstrate the assembly processes (numerical control machining, furnace brazing, and electron beam welding). Tests of prototype probes confirmed the thermal durability margins and life cycle. Selected probes were calibrated in air at Mach numbers from 1.75 to 6.0. Acceptance criteria for the production probes stressed thermal durability and pressure (and, consequently, Mach number) measurement quality. This new water-cooled MFA probe has 0.397-cm shaft diameter and is capable of withstanding heat fluxes of 2.724 kW/cm2.

In a little over thirty-five years the Auxiliary Power Unit (APU) has evolved from a simple onboard source of starting energy to a flight-essential component for today's commercial transports engaged in Extended Range Twin Engine Operations (ETOPS). In the course of this transition, the APU has progressed from a simple turbomachine to one employing comparable technologies to similarly sized propulsion engines. Reliability, troubleshooting, maintainability, and similar characteristics critical to economical airline operation have necessitated progressively increased sophistication in the design and testing of APUs. Peculiar requirements to APUs, such as totally dependable starting at 40,000 feet and above when cold soaked to -65F exceed the challenges of most propulsion engine systems. This paper addresses the issues facing the APU designer, with particular reference to reliability and maintainability characteristics, major drivers for current APU designs.

Anticipated high agility aircraft will require pilot training and acceleration research to investigate the human capacity to function in the projected environment. Existing man-rated centrifuges and fixed-base simulators are capable of imposing only a portion of the entire envelope of accelerations, and often produce significant artifactual accelerations and illusions. Simulations and engineering analysis of a large radius track centrifuge indicate such a device could impose an acceleration environment suitable for training and research. The technology required for the concept is estimated to be feasible in the near future.

Historically, fusion of metals was accomplished through the use of heat. Cold fusion has become a reality with metal to metal fusion occurring at room temperature. The basics of this new technology which can be done in tank, brush or solid form is covered in this paper.

Multi-axis laser materials processing systems are having a significant impact on the way aircraft and turbine engine parts are being cut, drilled, and welded. The success of laser cutting, drilling and welding is based in the ability to concentrate laser energy into a small area and to produce features having narrow heat affected zones. Reduced tooling expense, fast turnaround, and flexibility for handling design changes and for economical small lot manufacturing are some of the benefits associated with laser processing of aerospace parts. For example, in replacing hand trimming, laser cutting has increased throughput for trimming a deep drawn gas turbine engine part from 18 pieces per day to 18 pieces in 30 minutes. For another company, laser cutting saved $75,000 in tooling expense for an application involving drilling of 3000-0.013 inch diameter holes in a 0.015 inch thick aircraft engine blade insert.

Recent computer-based improvements in excavator-type machines have addressed fuel economy and power delivery to the implement for various types of tasks. Although some developments have been made in task-specific bucket control, the basic pattern of hand control motions for operating these machines has remained little changed over many years. This paper reports on a hand control interface, its computer-based hydraulic control system and the results of human factors studies carried out on a Cat 215B-based log loader. By means of a set of real-time excavator simulator studies, a new approach to directing the control of the implement motion has been developed. A testbed machine was made available by Caterpillar and the control system was implemented on an excavator, a log loader and at present is also being implemented on a feller-buncher. A commercial version of the concept has also been successfully implemented on grapple yarders.

Gerotor motors have been in the rotary power transmission market for over 35 years. Rolland Nielson reviewed their usage and potential in his 1977 SAE 770771 paper (1) which was written 20 years after Lynn Charleston introduced the first hydraulic motor based on the principle of the orbiting rotor and stationery stator. Fifteen years prior to Nielson's paper, Hollis and Harvey White introduced valve plate commutation for this orbiting rotor and stationary stator gerotor motor. Also, ten years prior in 1967 Ross Gear, TRW, added stators with rollers to the orbiting rotor, statonery stator, and valve plate commutation gerotor motor. Gerotor motors of today have become the hydraulic motor power source of choice by providing performance, quality, and price to satiate the challenges of today's highly stressed managers, design engineers and CEO's with world wide markets for their products.

This article introduce a kind of displacement sensor and the matching circuits with it. The sensor can be used to measure the displacement of cartridge insert valve in the medium of pressure with amplitude ranged from 0 Mpa to 32 Mpa.

The engine performance, combustion characteristics and the effect of injection timing differences of a prechamber-type diesel engine operated by Diesel-fuel and methanol were investigated. When the Diesel-fuel is used as a pilot fuel, the ignition lag was mainly controlled by the Diesel-fuel. The maximum thermal efficiency occurs with the optimum main methanol injection timing. The optimum methanol injection timing is about 2 to 3 degrees crank angle before the ignition, as methanol vapor is required for smooth combustion. This was determined from results showing that the methanol combustion was initiated by flame propagation from the combustion of Diesel-fuel. It is advantageous that parts of the Diesel-fuel and methanol sprays be mixed.

The paper* describes the analysis of experimental results of a laboratory flow apparatus used to measure the energy released during premixed combustion at atmospheric pressure in near quiescent air. The flow apparatus, described in a parallel paper, has the means to provide air temperatures in the range between 800 and 950° K. An infrared radiation detector and a photodiode sensitive to radiation in the visible range of the electromagnetic spectrum monitor the events taking place inside the combustion chamber through a sapphire lens. A beam splitter permits simultaneous observation of the combustion events by both sensors. The difference in response times between the two sensors offers information about the non-luminous premixed combustion. Four fuels, No. 2-D diesel fuel, a 50/50% volumetric mixture of diesel fuel and sunflower oil, neat sunflower oil, and neat high oleic safflower oil were used.

The paper* describes the design and operation of a laboratory combustion chamber used to study the energy released during the premixed burning phase of diesel combustion. The flow apparatus operates at atmospheric pressure and has the means to provide near quiescent air at temperatures in the range between 800 and 950° K which is the typical temperature range at the end of compression stroke in a diesel engine. A rotary injection pump with a trigger mechanism delivers equal amounts of fuel to an injector, which sprays it into the constantly replenished supply of fresh, hot air for combustion. An infrared radiation detector and a photodiode sensitive to radiation in the visible range of the electromagnetic spectrum monitor the events taking place inside the combustion chamber through a sapphire lens. A beam splitter permits simultaneous observation of the combustion events by both sensors.

Field tests for a variety of fuels on different tractor engines were carried out during the summers of 1981 through 1986. Fuels tested included alkali refined and winterized sunflower oil blended with diesel fuel, crude degummed sunflower oil blended with diesel fuel, high oleic safflower oil blended with diesel fuel, methylester of sunflower oil, or soybean oil. Blends of either 25% vegetable oil and 75% diesel fuel or 50% vegetable oil and 50% diesel fuel were used. Methylesters were not blended with diesel fuel. The manufacturers that participated in the project were John Deere, J.I. Case and Allis Chalmers. The project indicated that farm diesel tractors can be operated on any of the fuels that were tested. Care should be taken, however, since some signs of premature engine problems were observed. In general, continued use of these fuels cannot be recommended at this time.

Two unmanned vehicles were designed for agricultural and off-highway use. The vehicles lack a cockpit and related accessories. They are initially guided by a video-assisted remote control system - a self-guiding system, which consists of an RF-based positioning system and a digital guidance module, is under development. Both vehicles are propelled by hydrostatic drives and hub motors. Traction is provided either by rubber tracks or a four-wheel-drive/four-wheel-steering system. The vehicles combine very low weight, small dimensions and agility with high drawbar pull and rough terrain capability. They offer potential for a high degree of automation and precision especially in agricultural use.

Kubota introduced a 14.9kw(20HP) multi-purpose compact tractor in 1989. This tractor was developed to perform light duty applications requiring loader, backhoe, and scraper capabilities as well as operations that require a 3-point hitch or a rear PTO. The design of tractor, loader, and backhoe was originally targeted to be especially suitable for agricultural and light duty industrial applications. The effort was to improve operating efficiency, ease of operation, and operator comfort. “AUTORETURN” system was adapted into the backhoe. Electro-hydraulic control technology reduces the need for operator skills. The detailed description of this technology as applied to multi-purpose compact tractor is described in the body of this report.

The J I Case Company recently introduced a new series of Maxxum tractors (Figure 1). The product line now offers 60, 67, 75, and 84 PTO kW versions. The all new 84 kW version features a new fuel delivery system providing both greater power and reduced exhaust emissions. The powertrain also features increased capacity components required for the reliability of the increased power, 84 kW model. The new series incorporates numerous customer requested improvements of the 5100 Series, including increased comfort, convenience, and visibility features such as swivel seat, in-cab remote coupler flow controls, fender mounted hitch controls and all glass doors.

The product line of 4WD tractors offered by John Deere has been updated as part of the continuous improvement process to meet customer needs and provide a product with maximum value to our customers. The new model lineup is 250, 300, 350 and 400 engine HP. Per customer requests a new model has been added to the prior model lineup at 350 HP. The new models expand the usage of electronic engine control, enhance the engine power curves for increased productivity, provide improved operator comfort, enhance conveniences available to the operator, provide added improvements for serviceability and revises the options available for the customer so that he can purchase the product of maximum value for his needs.