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A low pressure axial fan for benchmarking numerical methods in the field of aerodynamics and aeroacoustics is presented. The generic fan for this benchmark is a typical fan to be used in commercial applications. The design procedure was according to the blade element theory for low solidity fans. A wide range of experimental data is available, including aerodynamic performance of the fan (fan characteristic curve), fluid mechanical quantities on the pressure and suction side from laser Doppler anemometer (LDA) measurements, wall pressure fluctuations in the gap region and sound characteristics on the suction side from sound power and microphone array measurements. The experimental setups are described in detail, as to ease reproducibility of measurement positions. This offers the opportunity of validating aerodynamic and aeroacoustic quantities, obtained from different numerical tools and procedures.

A low pressure axial fan for benchmarking numerical methods in the field of aerodynamics and aeroacoustics is presented. The generic fan for this benchmark is a typical fan to be used in commercial applications. The design procedure was according to the blade element theory for low solidity fans. A wide range of experimental data is available, including aerodynamic performance of the fan (fan characteristic curve), fluid mechanical quantities on the pressure and suction side from laser Doppler anemometer (LDA) measurements, wall pressure fluctuations in the gap region and sound characteristics on the suction side from sound power and microphone array measurements. The experimental setups are described in detail, as to ease reproducibility of measurement positions. This offers the opportunity of validating aerodynamic and aeroacoustic quantities, obtained from different numerical tools and procedures.

In this work, a newly developed iced-aircraft modeling tool is applied to wings, engine inlets, and helicopter rotors. The tool is based on a multiscale-physics, unstructured finite-volume CFD approach and is applicable to general purpose aircraft icing applications. The present approach combines an Eulerian-based droplet-trajectory solver that is loosely coupled, in a time-accurate manner, to a surface-film and ice-evolution model. The goal of the model is to improve the fidelity of ice accretion modeling on dynamic geometries and for three-dimensional ice shapes typical of helicopter rotors. The numerical formulation is discussed and presented alongside 2D and 3D static validation cases, and dynamic helicopter rotors. The present results display good validation for predicting ice shape on a variety of geometries, and a strong initial capability of modeling ice forming on helicopters in forward flight.

ANY aggregation of parts assembled to obtain a mechanical result is a series of compromises. The relative importance of the objectives governs the nature of the compromise. The major objectives to be considered in the design of airplane engines are (1) Reliability (2) Small weight per horsepower (3) Economy of fuel and oil consumption (4) Carburetion that permits of easy starting; maximum power through a range of 30 per cent of the speed range; and idling at one-quarter maximum speed without danger of stalling (5) Ability to deliver full power through a small speed range without excessive vibration (6) Complete local cylinder-cooling under conditions of high mean effective pressure (7) Compactness The automobile engine must have (1) Reliability (2) Silence (3) Carburetion that accomplishes proper and even firing in all cylinders under varying throttle conditions, through speeds covering more than 90 per cent of the speed range of the engine.

The characteristics of turbines for turbojet and space power plant applications are compared on the basis of power requirement trends, working fluids, materials, and system requirements. The differences in Brayton and Rankine cycles, the requirements of the cycles imposed on turbines, and typical losses inherent in present low power space turbines are discussed. A comparison is made of representative present and future turbines for turbojet and space power applications. Future large space turbines will parallel the performance and design techniques of high performance gas turbines. Some of the design techniques of steam turbines can also be used because of experience with wet vapor and long endurance. The future goals and problem areas of turbojet and space turbines are shown.

The Near Infrared Camera and Multi Object Spectrometer (NICMOS) was installed in the Hubble Space Telescope in February 1997. Shortly thereafter, the instrument experienced a thermal short in its solid nitrogen dewar system which will shorten its useful life significantly. A reverse Brayton cycle mechanical refrigerator will be installed during the third servicing mission (SM3) to provide cooling for the instrument, and thereby extend its life. A Capillary Pump Loop (CPL) and radiator system has been designed, built and tested to remove up to 500 watts of heat from the mechanical cooler and its electronics. This paper will describe the CPL system in detail and present the results of the extensive testing and qualification program.

Catalytic combustion coupled with activated carbon and molecular sieve adsorbents is applicable to all areas of air and gas clean up ranging from high to low levels of pollutants and trace contaminants control in a spacecraft environment is of no exception. In this study we propose a combined activated charcoal and catalytic combustion system based on a 70 watt power input achieving 350°C, operating on a 6 hour per 24 hour day catalytic cycle with an actual flow of 10.6 l min-1 in a residual free volume of 60 m3.

DASH 47R is a cementitious composite initially formulated for use as an autoclave molding/tooling material. A unique matrix and aggregate system imparts unusually high strength and excellent vacuum integrity to DASH 47 at moderately high temperatures even though DASH 47 molds are cast at ambient temperature over commonly used pattern materials. This paper reviews the formulation and properties of DASH 47, and outlines its fabrication method and curing schedule for thin-shelled autoclave tools. In addition, examples of other molding applications for DASH 47 are shown in this paper.

This paper documents the design and validation of a closed cycle propulsion system suitable for use on the Perseus A high altitude research aircraft. The atmospheric science community is expected to be the primary user of this aircraft with initial missions devoted to the study of ozone depletion and global warming. To date large amounts of funding are not available to the atmospheric science community, so to be useful, the aircraft must satisfy stringent cost and performance criteria. Among these, the aircraft has to be capable of carrying 50 kg of payload to altitudes of at least 25km, have a initial cost in the $1-2M range, be capable of launch from remote sites, and be available no later than 1994. These operational criteria set narrow boundaries for propulsion system cost, complexity, availability, reliability, and logistical support requirements.

This paper describes the requirements, design, and early testing of a flight weight V/STOL clutch. A clutch is required between the combiner box and the forward or nose fan for some versions of V/STOL aircraft. This clutch has been designed to transmit 11,000 HP at fan drive speeds, and be capable of minimum engagement times and rapid cycling. This paper will cover the mechanical arrangement and control system of this clutch.

As mission length and the number and complexity of payload experiments increase, so does the probability of thermodegradation contingencies (e.g. fire, chemical release and/or smoke from overheated components or burning materials), which could affect mission success. When a thermodegradation event occurs on board a spacecraft, potentially hazardous levels of toxic gases could be released into the internal atmosphere. Experiences on board the Space Shuttle have clearly demonstrated the possibility of small thermodegradation events occurring during even relatively short missions. This paper will describe the Combustion Products Analyzer (CPA), which is being developed under the direction of the Toxicology Laboratory at Johnson Space Center to provide necessary data on air quality in the Shuttle following a thermodegradation incident.

In large scale industries attempts are continuously being made to automate assembly processes to not only increase productivity but also alleviate non-ergonomic tasks. However this is not always technologically possible due to specific joining challenges and the high number of special-purpose parts. For the riveting process, for example, semi-automated approaches represent an alternative to optimizing aircraft assembly and to reduce the exposure of workers to non-ergonomic conditions entailed by performing repetitive tasks. In [1], a semi-automated solution is proposed for the riveting process of assembling the section barrel of the aft section to its pressure bulkhead. The method introduced a dynamic task sharing strategy between human and robot that implements interaction possibilities to establish a communication between a human and a robot in Human-Robot-collaboration fashion.

A unique heat exchanger has been developed with potential applications for cooling high power density electronics and perhaps high energy laser mirrors. The device was designed to absorb heat fluxes of approximately 50 w/cm2 (158,000 Btu/hr.ft2) with a low thermal resistance, a high surface temperature uniformity and very low hydraulic pumping power. A stack of thin copper orifice plates and spacers was bonded together and arranged to provide liquid jet impingement heat transfer on successive plates. This configuration resulted in effective heat transfer coefficients, based on the prime surface, of about 85,000 w/m2 °C (15,000 Btu/hr.ft2 °F) and 1.8 watts (.002 HP) hydraulic power with liquid Freon 11 as coolant.

This paper attempts to assess the benefits of a unique distributed propulsion concept, known as the Multi-Gas Generator Fan (MGGF) system, over conventional turbofan engines on civilian vertical takeoff and landing (VTOL) applications. The MGGF-based system has shown the potential to address the fundamental technical challenge in designing a VTOL aircraft: the significant mismatch between the power requirements at lift-off/hover and cruise. Vehicle-level performance and sizing studies were implemented using the Grumman Design 698 tilt-nacelle V/STOL aircraft as a notional personal air vehicle (PAV), subjected to hypothetical single engine failure (SEF) emergency landing requirements and PAV mission requirements.

Hawker de Havilland has undertaken research to utilize the benefits of using industrial robots for high accuracy drilling and trimming of composite components in preparation for assembly. Central to this development is the metrology system used to provide online position and orientation feedback to the robot control. Feedback is required for both digital calibration of the robotic work cell and error correction for any robot deflection. This paper presents a comparative study between two off-the-shelf metrology technologies; one being Indoor Infrared Global Positioning System (IRGPS), and the other Laser Tracking. The experiments use the task of robotic drilling in carbon composites to evaluate the effectiveness and limitations of each metrology system by measure of achievable drilling accuracy and ease of application.

Drying is an important process, ubiquitous on earth, and in space applications it is an unavoidable aspect of advanced life support technology. We analyze several solid and liquid waste treatment processes that involve drying as a primary operation and consider factors such as energy use, volume, mass, crew time upstream relief and downstream burden. The entry points of resources such as electrical energy, thermal energy, mass influent and effluent and crew time are discussed in the context of a common drying schematic, compared using generalized flow diagrams, and a table is provided to grasp the relative magnitudes.

A number of specimen life performance tests were conducted on three test lubricants selected to demonstrate their gross ranking capabilities. The results indicated that the test rigs should be used only for gross ranking. A large difference in magnitude of life values were obtained even though agreement in gross ranking was obtained by three out of the five participating laboratories. Further testing is recommended under preselected test conditions and lubricants.

Eight fixed-wing reusable horizontal landing booster point design concepts are presented and compared on the basis of weight, cost, technical difficulty, and availability date. The eight vehicle types considered are all basically two-stage systems with a lifting body reusable second stage, with all vehicles normalized to place 40,000 lbs. payload in orbit. All flight vehicles are fully recoverable and capable of flying back and landing at the launch site. Vehicle types discussed are vertical take-off horizontal landing rockets, sled launched horizontal take-off rockets, runway launched horizontal take-off rockets, air breathing first stages, combined air breathing and rocket first stages, oxidizer collection concepts, supersonic combustion ramjets, and in-flight refueling vehicles. Each of these vehicle types is depicted in the paper and its design and performance characteristics are discussed.

The purpose of this study was to evaluate and identify the most effective techniques for self-guided remote training. Nine subjects were trained on the use of a personal videoconferencing system and the use of a Web-based multimedia program. Each subject performed two tasks with both training techniques: one assembly task and one instrumentation task. It was found that task times using the multimedia application were greater than the task times using videoconferencing. However, for complex tasks, participants preferred multimedia training. With multimedia, participants preferred to use video clips over diagrams and photos during assembly tasks. However, no preference was found during instrumentation tasks.

Cooperation between Russia and the United States on manned spaceflight has led to unprecedented openness, resulting in the ability to now compare the characteristics of environmental control/life support hardware selected to generate oxygen (O2) by water electrolysis for space station applications. This comparison in this paper focuses on the characteristics that have the greatest effect on the cost of assembling and maintaining the hardware in space: launch weight, volume, power consumption, resupply requirements and maintenance labor.