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The C-17 airplane operates in some of the most challenging environments in the world including semi prepared runway operations (SPRO). Typical semi-prepared runways are composed of a compacted soil aggregate of sand, silt, gravel, and rocks. When the airplane lands or takes off from a semi-prepared runway, debris, including sand, gravel, rocks and, mud is kicked up from the nose landing gear (NLG) and the main landing gear (MLG) tires. As the airplane accelerates to takeoff or decelerates from landing touchdown, this airborne debris impacts the underbelly and any component mounted on the underbelly. The result is the erosion of the protective surface coating and damage to systems that protrude below the fuselage into the debris path. The financial burden caused by SPRO damage is significant due to maintenance costs, spares costs and Non-Mission Capable (NMC) time.

The paper presents the results of a CFD study for predictions of ventilation characteristics and convective heat transfer within the Shuttle Orbiter middeck cabin in the presence of seven suited crewmember simulation and Individual Cooling Units (ICU). For two ICU arrangements considered, the thermal environmental conditions directly affecting the ICU performance have been defined for landing operation. These data would allow for validation of the ICU arrangement optimization.

Environmental Control Systems (ECS) ducts on airplanes are primarily fabricated from aluminum or thermoset composites, depending on temperature and pressure requirements. It is imperative to fabricate lightweight, cost effective, durable, and repairable systems with minimal tooling. It is also important that the duct systems are easy to assemble even with alignment issues resulting from structural variations, tolerance accumulation, variation from thermal expansion of different materials, and inherent duct stiffness. These requirements create an opportunity and need for a technology that can address all of these issues, while increasing performance at the same time. This report provides a background on current ECS ducting systems.

Statistical Energy Analysis (SEA) is a very powerful tool in its ability to guide noise control package design in automobile, airplane and architectural systems. However transmission loss modeling in an SEA frame work has more to do with modeling of sound propagation through foam and fiber noise control materials than classical SEA power flow between groups of resonant modes. The transmission loss problem is reviewed in an SEA frame work with a focus on key paths and input parameter variations on predicted noise control package performance.

The robust stability of an active flexible wing section with leading- and trailing-edge control surfaces is further investigated via the μ-method. Motivated by a more detailed servo control dynamics, the two controllers K1 and K2, which command the deflections of the trailing-edge flap and the leading-edge flap respectively, are modeled as two second-order shock absorbers in this study. The nominal and robust stability margins, modal properties, critical flutter airspeeds and frequencies are computed to predict the flutter of a nonlinear aeroelastic system and to investigate the aeroservoelastic stability in the μ-framework. The simulation results are compared with the previous study of which the controllers were modeled as the simplified (first-order) shock absorbers. The improved sensitivity to detect the control-structure coupling is observed by applying the second-order shock absorbers in the ASE model.

There is an increasing demand in the aerospace industry for automated machinery that is portable, flexible and light. This paper will focus on a joint project between BROETJE-Automation and Boeing called the Universal Splice Machine (USM). The USM is a portable, flexible and lightweight automated drilling and fastening machine for longitudinal splices. The USM is the first machine of its kind that has the ability not only to drill holes without the need to deburr, (burrless drilling) but also to insert fasteners. The Multi Function End Effector (MFEE) runs on a rail system that is mounted directly on the fuselage using a vacuum cup system. Clamp up is achieved through the use of an advanced electromagnet. A control cart follows along next to the fuselage and includes an Automated Fastener Feeding System. This paper will show how this new advancement has the capabilities to fill gaps in aircraft production that automation has never reached before.

This study was designed to answer what percent of “required” traffic pilots acquire visually using the current “visual acquisition system” of windows, eyes and the Traffic Collision Avoidance System (TCAS). “Required Traffic” was defined as Air Traffic Control (ATC) calls to the research aircraft, TCAS Traffic Alerts and/or TCAS Resolution Advisories. The results of the approximately 40 hours of flight were that the majority of (“required”) traffic was NOT visually acquired (39% visually acquired; 61% not visually acquired). When traffic was identified to the pilots by more than one source, the visual acquisition rate was 58%. For validation purposes, an additional 10 hours of flight observations were made during revenue flights with a major airline. Flight test and airline observations were found to be comparable.

The development of new commercial airliners is a very risky proposition. To get it right, airframe manufacturers must balance new technologies and manufacturing methods with global participation and business considerations. The 787 is Boeing's popular new wide body aircraft incorporating state of the art composites design and manufacturing methods. But new technology alone is not enough. A new logistics system was needed to integrate global partners in order to fully benefit from new technologies. The Boeing 747-400 Dreamlifter is a special purpose 747-400 modified to transport Boeing 787 airplane components through various stages of manufacturing.

Excessive impact pressures can develop when an evacuated system is filled with liquid. Such a process is usually highly chaotic, especially when the system geometry is complex. Available computational methods by themselves cannot provide the necessary answers. The International Space Station (ISS) heat exchanger has a complex flow system, and a synthesis of computational and experimental methods was necessary to design the system. The FLOW-NET two-phase flow program was used to determine the range of loss coefficients and the liquid-vapor interface mass and energy transfer that would fit the measured impact pressures. These loss coefficients could then be used to compute the impact pressures for a design configuration similar to the one tested at a range of operating conditions.

A multi-element fixed control volume integrated air interchange system performance computer model has been developed and upgraded for the evaluation/assessment of atmospheric characteristics inside the crew compartments of the mated Orbiter and International Space Station (ISS). In order to ensure a safe, comfortable, and habitable environment for all the astronauts during the Orbiter/ISS docked period, this model was utilized to conduct the analysis for supporting the early ISS assembly missions. Two ISS assembly missions #2A and #4A were selected and analyzed.

The temperature and humidity of the air within the habitable areas of the International Space Station are controlled by a set of hardware and software collectively referred to as the Temperature and Humidity Control (THC) subassembly. This subassembly 1) controls the temperature of the cabin air based on a crew selected temperature, 2) maintains humidity within defined limits, and 3) generates a ventilation air flow which circulates through the cabin. This paper provides descriptions of the components of the THC subassembly, their performance ranges, and the control approach of the hardware. In addition, the solutions of the design challenges of maintaining a maximum case radiated noise level of NC 45, controlling the cabin air temperature to within ±2°F of a setpoint temperature, and providing a means of controlling microbial growth on the heat exchanger surfaces are described.

The patented (US 7,277,811 B1) Position Bar provides precise measurement, machining and drilling data for large Engineering and Tooling structure. The Position Bar also supports end item verification seamlessly in the same machining control code. Position Bar measurements are fast, accurate, and repeatable. The true centerline of the machine tool's spindle bearings are being measured to within .002 in a 20 foot cubic volume (20×20×20). True “I”, “J”, & “K” machine tool spindle positions are also precisely measured. Any Gantry or Post Mill Tool can be converted to a Coordinate Measurement Machine (CMM) with this laser tracker controlled Position Bar. Determinant Assembly (D.A.) holes, for fuselage and wing structures are drilled and then measured to within .006 in X, Y, & Z, over a 40 foot distance. Average laser tracker measurement time, per hole, is 2 seconds.

Modern aircraft are aerodynamically designed at the edge of flight stability and therefore require high-response-rate flight control surfaces to maintain flight safety. In addition, to minimize weight and eliminate aircraft thermal cooling requirements, the actuator systems have increased power-density and utilize high-temperature components. This coupled with the wide operating temperature regimes experienced over a mission profile may result in detrimental performance of the actuator systems. Understanding the performance capabilities and power draw requirements as a function of temperature is essential in properly sizing and optimizing an aircraft platform. Under the Air Force Research Laboratory's (AFRL's) Integrated Vehicle and Energy Technology (INVENT) Program, detailed models of high performance electromechanical actuators (HPEAS) were developed and include temperature dependent effects in the electrical and mechanical actuator components.

The International Space Station (ISS) IATCS (Internal Active Thermal Control System) includes two internal coolant loops that use an aqueous based coolant for heat transfer. A silver salt biocide was used initially as an additive in the coolant formulation to control the growth and proliferation of microorganisms in the coolant loops. Ground-based and in-flight testing has demonstrated that the silver salt is rapidly depleted and not effective as a long-term biocide. Efforts are now underway to select an alternate biocide for the IATCS coolant loop with greatly improved performance. An extensive evaluation of biocides was conducted to select several candidates for test trials.

The OVERFLOW chimera grid Navier Stokes code was used to analyze a wide variety of airplane configurations. The code performed reliably and was found to have comparable accuracy to the structured grid code TLNS3D. It is easier to develop overlapping grid blocks to represent a complex configuration than it is to develop grid blocks that must abut one another. The process is inherently modular. One can add or subtract components like tip-lights, compound winglets, struts, nacelles, tails and fairings at will. The gain in grid simplicity is offset by the complication in specifying block connectivity, however. The overset blocks are typically of better quality, but there is a drawback in that it is not always possible to guarantee flux conservation. The recent development of software for automatic connectivity holds promise for the routine use of OVERFLOW by design engineers.

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.

Out-of-round holes are formed as a result of tool motion during drilling. Tool vibration is driven by radial and tangential forces on the primary and secondary cutting edges. These forces in turn depend on the chip loads on each cutting edge, which in turn depend on the position of the tool at the current time and at the time of the previous tooth passage. A preliminary analysis based on balancing the cutting forces and the bending forces on the tool, shows that the characteristic frequencies of motion of the tool in the tool frame are near 3/rev, 5/rev, 7/rev etc. (corresponding to 2/rev, 4/rev, 6/rev) in the workpiece frame. These motions are consistent with the tool motion and hole form errors commonly observed on the shop floor. We will describe procedures for measuring the dependence of cutting forces on chip load, the development of simple equations for lateral motion of the tool, and solutions for the tool's behavior.

Decades ago our innovative grandfathers developed the first automated riveting machines based on hard automation using kinematics and tools attached to a C-frame. The C-frame serves multiple functions: First, it holds the upper and lower tools in fixed positions relative to each other; second, it translates upper active tooling forces to the lower tool; and third, it embraces the part placed between the upper and lower tool. C-frames and newly developed yoke, ring and gantry machines, used for low level (first, second) fuselage and wing assembly are growing in size to exorbitant proportions to satisfy requirements of larger and larger structures. High costs are dictated by massive kinematics and complex controls that provide stability, precision, and process speed. All this is mainly needed because we have to carry mechanical forces around the part, from upper to lower tool along the C-frame, gantry, yoke, bridge, etc.

Fabrication and assembly of the majority of control surfaces for Boeing’s 777X airplane is completed at the Boeing Defense, Space and Security (BDS) site in St. Louis, Missouri. The former 777 airplane has been revamped to compete with affordability goals and contentious markets requiring cost-effective production technologies with high maturity and reliability. With tens of thousands of fasteners per shipset, the tasks of drilling, countersinking, hole inspection, and temporary fastener installation are automated. Additionally and wherever possible, blueprint fasteners are automatically installed. Initial production is supported by four (4) Electroimpact robotic systems embedded into a pulse-line production system requiring strategic processing and safeguarding solutions to manage several key layout, build and product flow constraints.

Jet fighter missions have been known to last extended period of time. The need for a comfortable and safe seat has become paramount considering that fact that uncomfortable seats can lead to numerous health issues. Several health effects like numbness, pressure sore, low back pain, and vein thrombosis have been associated with protracted sitting. The cushion, and of late the installation rail angle are the only components of the ejection seat system that can be modified to reduce these adverse effects. A comprehensive static comfort evaluation study for ejection seats was conducted. It provides comparison between a variety of operational and prototype cushions (baseline cushion, honeycomb and air-cushion) and three different installation rail angles (14°, 18°, and 22°). Three operational cockpit environment mockups with adjustable installation rail angle were built. Ten volunteer subjects, six females and four males, ages 19 to 35, participated in the seat comfort evaluation.