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Some of the methods used for experimental detection and examination of wake vortices are presented. The aim of the article is to provide the reader a brief overview of the available methods. The material is divided into two major sections, one dealing with methods used primarily in the laboratory, and the second part devoted to those used in field operations. Over one hundred articles are cited and briefly discussed.

Metal cutting is a substantial constituent of airframe manufacturing. During the past several decades, it has evolved significantly. However, most of the changes and improvement were initiated by the machine tool industry and cutting tool industry, thus these new technologies is generally applicable to all industries. Among them, few are developed especially for the airframe manufacture. Therefore, the potential of high efficiency could not be fully explored. In order to deal with severe competition, the aerospace industry needs improvement with a focus on achieving low cost through high efficiency. The direction of research and development in parts machining must comply with lean manufacturing principles and must enhance competitiveness. This article is being forwarded to discuss the trend of new developments in the metal cutting of airframe parts. Primary driving forces of this movement, such as managers, scientists, and engineers, have provided significant influence to this trend.

The work presented in this paper is part of a long-term research program to explore methods for improving bleed air system performance. Another objective of this research is to provide detailed experimental data for the development and validation of simulation tools used in the design and analysis of bleed air systems. A business jet wing was equipped with an inner-liner hot air ice protection system and was extensively instrumented for documenting system thermal performance. The wing was tested at the NASA Glenn Icing Research Tunnel (IRT) for representative in-flight icing conditions. Data obtained include bleed air supply and exhaust flow properties, wing leading edge skin temperatures, temperatures and pressures in the interior passages of the bleed air system, flow properties inside the piccolo tube, photos of run back ice shapes and ice shape traces. Selected experimental results for a warm hold icing condition are presented in this paper.

Drilling is one of the most widely applied manufacturing operations. Millions of holes are drilled today in manufacturing industries especially in aerospace industry where high quality holes are essential. Rejection and rework rate of the products because of the bad hole is quite high. In this research graphite/honeycomb composite material and aluminum sheet metal has been used. The results show that drill geometry, speed and feed rate have substantial effects on the hole quality and also there was gradual variation of the thrust and lateral forces with feed rates.

In this research helical Carbon Nanotubes (CNTs) with various weight percentages as an additional reinforcement were used. The objective was to investigate the effectiveness of helical geometries of the CNTs to form interlocking mechanisms with the resin and the traditional microfiber reinforcements to improve the overall performance of the composite structures and assemblies. In this study, ASTM D2344/2344M-16 is used to study the short beam strength of the laminated nanocomposites and evaluate the benefit of the mechanically interlocked helical CNTs reinforcement. Overall, three sets of composite laminates (i.e., with neat epoxy, and with two different wt% of Helical CNTs reinforced epoxy) were fabricated per ASTM standard D2344/2344M-16. Adequate test specimens were prepared and then they were tested per ASTM standard. The test results were analyzed and evaluated to determine the effects of helical CNTs on short beam strength of the laminated nanocomposites.

Global warming concerns are stimulating accelerated research and development of alternative fuels and propulsion systems for automobiles. The potential application of these emerging technologies to airplanes is reviewed. Preliminary designs of zero greenhouse gas emission airplanes using hydrogen fuel and either internal combustion or fuel cell-electric motor propulsion are presented for a wide body jet transport, medium jet transport, business jet, and single engine propeller airplane. The hydrogen fueled internal combustion engine airplanes offer the easiest path to zero emissions, but the greater efficiency of the fuel cell airplanes allows designs requiring substantially less fuel. The single engine propeller airplane is the easiest to modify for hydrogen fuel, because of the relatively high mass and volume of the engine being replaced. Technology improvements needed to make zero emission airplanes viable are suggested.