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The search for ever-lower emission technology for future generations of aircraft engines is actively progressing on both sides of the Atlantic. Tucked away on a modest-size stand at this year’s Farnborough International Airshow was a highly varied collection of unconventional engine technology displays – a clear indication of radical innovation already being investigated as a part of Ultimate, the European Horizon 2020 research and innovation project.

In part two of a two-part series, Richard Gardner discusses various aerospace propulsion innovations and continued work by aerospace engineers and scientists to advance aircraft engine technologies to increase efficiency and lower emissions.

Aircraft potable (drinking) water systems haven’t changed significantly in the last half-century. These systems consist of cylindrical water tanks pressurized by bleed air from the jet engines, with insulated stainless steel distribution lines. What has changed recently is the increase in the possibility of aircraft picking up contaminated drinking water at foreign and domestic stops. Customer awareness of these problems has also changed - to the point where having reliable drinking water is now a competitive issue among airlines. Old style potable water systems that are used on modern aircraft are high maintenance and exacerbate the growth of microbes because the water is static much of the time. The integrity of some pressurized water tanks are also a concern after years of use. Cost-effective mechanical and biological solutions exist that can significantly reduce the amount of chemicals added and provide good potable water.

On January 14, 2004 President George W Bush outlined a new vision for NASA that has humans venturing back to the moon by 2020. With this ambitious goal, new tools and models have been developed to help define and predict the amount of space radiation astronauts will be exposed to during transit and habitation on the moon. A representative scenario is used that includes a trajectory from LEO to a Lunar Base, and simplified CAD models for the transit and habitat structures. For this study galactic cosmic rays, solar proton events, and trapped electron and proton environments are simulated using new dynamic environment models to generate energetic electron, and light and heavy ion fluences. Detailed calculations are presented to assess the human exposure for transit segments and surface stays.

The scope of this Standard is the definition of the response of a numerically controlled machine to a valid sequence of records made up of 32 bit binary words or ASCII text strings. The Standard defines the structure of these records and of the 32 bit binary words or ASCII text strings which make up the records. This standard addresses the control of machines capable of performing 2, 3, 4, and 5 axis motion of an active tool (mill, laser, pen, etc.) relative to a part, and those capable of 2 and 4 axis tool motion relative to a rotating part (turning machines), including parallel tool slide sets capable of concurrent (merged) motion.

The need to improve quality while reducing cost in aerospace manufacturing is requiring new manufacturing methods and processes. Advanced technologies, such as 3D Image Metrology, offer great potential to lean manufacturing, if properly integrated into the production process. Over the last years 3D Image Metrology has developed a level of performance, which make it ideally suited for this purpose. These capabilities include the automatic in-process inspection of tools and parts before machining, machine control for highly accurate positioning during the machining operation, and in-process inspection during machining. This offers jig-less assembly, lower inventory, faster part throughput, and many more advantages.

New approaches to problems such as noise, temperature control of accessories and equipment in the nacelle, as well as improved safety features, are necessary in a modern high by-pass engine installation. The means of supporting the engine, cowling design, and maintainability features combine to improve the state of the art that a more economic airplane will result.

The Automated Spar Assembly Tool (ASAT II) at the Everett, Washington, 777 Boeing manufacturing facility could be the largest automated fastening cell in the commercial aircraft industry. Based on the success of the ASAT I, Boeing's 767 spar assembly tool, the 285-foot long ASAT II cell was needed to accurately position and fasten the major spar components (chords and web), then locate and fasten over 100 components (ribposts and stiffeners) to assemble the 777 forward and rear wing spars. From its inception in 1990 to the first drilled hole in January 1993 and through two years of spar production, the more advanced ASAT II has proven to be a greater success than even its 767 ASAT I predecessor. This massive automated fastening system consistently provides accurate hole preparation, inspection, and installation of three fastener types ranging from 3/16 inches to 7/16 inches in diameter.

In the frame of the CRYOSYSTEM A-phase study financed by the European Space Agency, AIR LIQUIDE (France) and ORBITAL HYDRAULIC-BREMEN (Germany) have been studying a -183°C freezer to be used on-board the International Space Station for freezing and storing biological samples.

U S Army tactical vehicles are equipped with a wide range of electrical and electronic equipment to support a variety of missions. This equipment typically requires AC input power with varying voltage, power and phasing requirements. Presently, separate inverters with different voltage, power, and phase ratings are necessary to power the equipment, which imposes maintenance and support problems during field deployments. Avionic Instruments Inc. has developed a scalable inverter system that operates from 28V vehicular power and provides outputs that can easily be configured for a variety of load requirements.

This paper presents an application of Bayesian Belief Networks for modeling the uncertainty in aircraft safety diagnostics. Belief networks or influence diagrams represent possible means to efficiently model uncertain causal relationships among components of a system. HUGIN is a software for the construction of knowledge based systems based on Bayesian networks. A HUGIN prototype is dicussed to illustrate how a Bayesian approach could be used to support the decision search routine of aircraft safety inspectors when diagnosing equipment of subsystem malfunctions. The example focuses on diagnostic procedures for assessing aircraft tire condition.

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.

This paper discusses various engine installations in Naval aircraft, looking especially at their costs of maintenance. Fuel systems, fuel control systems, and several engine accessories are discussed for present and future engines. It is concluded that simple, reliable equipment is necessary to keep aircraft in the air instead of in maintenance areas on the ground.

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.

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.

Airline tenants at Dallas/Fort Worth International Airport (DFW Airport) use deicing/anti-icing chemicals, as may be needed, to maintain wintertime operations. DFW Airport has implemented best management practices for pollution prevention measures relating to deicing/anti-icing activities. However, as the planes leave the deicing pads, deicing/anti-icing fluids can drip from the planes onto the runways, taxiways, and ramp areas. As planes take off, the fluids can also shear off onto Airport property. During winter storm events, these deicing/anti-icing fluids are flushed off the runways, etc., with the stormwater. Stormwater containing deicing/anti-icing fluids can discharge through outfalls into Trigg Lake located in the southwestern part of the DFW Airport property.

More realistic training for flight crews would not only be beneficial but could be instrumental in the reduction of incidents and accidents, as well as the casualties caused by accidents. Modern equipment and technology are a plus, but they are not necessary for the application of realistic training, when realistic means any training that can provide flight crews with the necessary practical knowledge and skill to deal effectively with real world situations. Examples of this are provided.