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Finding ways to reduce the amount of fuel burned per flight takes top priority in aircraft operations and design. Three experts show how the smallest on-board components can make a huge difference.

Simulation-based tolerance analysis is the accepted standard for dimensional engineering in aerospace today. Sophisticated 3D model-based tolerance analysis processes enable engineers to measure variation in complex, often large, assembled products quickly and accurately. Best-in-class manufacturers have adopted Quality Intelligence Management tools for collecting and consolidating this measurement data. Their goal is to completely understand dimensional fit characteristics and quality status before commencing the build process. This results in shorter launch cycles, improved process capabilities, reduced scrap and less production downtime. This paper describes how to use simulation-based approaches to correlate the theoretical tolerance analysis results produced during engineering simulations to actual as-built results. This allows engineers to validate or adjust as-designed simulation parameters to more closely align to production process capabilities.

Abstract The Naval Nose Landing Gear (NLG) structural assembly consists of components with complex structural geometry and critical functionalities. The landing gear components are subjected to high static and dynamic loads, so they must be appropriately designed, dimensioned, and made by materials with mechanical characteristics that meet high strength, stiffness, and less weight requirements. This article contributes to the shape, size, and material optimization for the NLG of a supersonic naval aircraft for the estimated static loads. The estimated modal frequency values of the NLG assembly using Finite Element Analysis (FEA) software were compared with available Ground Vibration Test data of an aircraft to literally prove the accuracy and suitability of finite element (FE) model that can be used for any further analysis.

Abstract It is reasonable to use a two-phase heat transfer loop (TPL) in a thermal control system (TCS) of spacecraft with large heat dissipation. One of the key elements of TPL is a heat-controlled accumulator (HCA). The HCA represents a volume which is filled with vapor and liquid of a single working fluid without bellows. The pressure in a HCA is controlled by the heater. The heat and mass transfer processes in the HCA can proceed with a significant nonequilibrium. This has implications on the regulation of TPL. This article presents a mathematical model of nonequilibrium heat and mass transfer processes in an HCA for microgravity conditions. The model uses the equations of mass and energy conservation separately for the vapor and liquid phases. Interfacial heat and mass transfer is also taken into account. It proposes to use the convective component k for the level of nonequilibrium evaluation.

Abstract ERRATUM

Abstract The use of simulation is a long-standing industry standard at every level of flight training. Historically, given the acquisition and maintenance costs associated with such equipment, full-motion devices have been reserved for advanced corporate and airline training programs. The Motion Cueing Seat (MCS) is a relatively inexpensive alternative to full-motion flight simulators and has the potential to enhance the fixed-base flight simulation in primary flight training. In this article, we discuss the results of an evaluation of the effect of motion cueing on pilot workload and performance during primary instrument training. Twenty flight students and instructors from a collegiate flight training program participated in the study. Each participant performed three runs of a basic circuit using a fixed-base Advanced Aviation Training Device (AATD) and an MCS.

Abstract Improving the energy performance of batteries can increase the reliability of electric aircraft. To achieve this goal, battery management systems (BMS) are required to keep the temperature within the battery pack and cells below the safety limits and make the temperature distribution as even as possible. Batteries have a limited service life as a result of unwanted chemical reactions, physical changes that cause the loss of active materials in the structure, and internal resistance increase during the charging and discharging cycle of the battery. These changes usually affect the electrical performance of batteries. Battery life can be increased only by reducing or preventing unwanted chemical reactions. Lithium-ion (Li-ion) batteries are a suitable option due to their high specific energy and energy density advantages. In this study, the necessity of heat management is emphasized. The discharge tests of the Li-ion battery provided 94.6 Wh under 10C and 90.9 Wh under 1C.

Abstract The prediction of mechanical elastic response of laminated hybrid polymer composites with basic carbon nanostructure, that is carbon nanotubes and graphene, inclusions has gained importance in many advanced industries like aerospace and automotive. For this purpose, in the current work, a hierarchical, four-stage, multilevel framework is established, starting from the nanoscale, up to the laminated hybrid composites. The proposed methodology starts with the evaluation of the mechanical properties of carbon nanostructure inclusions, at the nanoscale, using advanced 3D spring-based finite element models. The nanoinclusions are considered to be embedded randomly in the matrix material, and the Halpin-Tsai model is used in order to compute the average properties of the hybrid matrix at the lamina micromechanics level.

Abstract The vibration behavior of components exposed to aerodynamic loads must be taken into consideration when designing aerial vehicles. Numerical simulation plays a key role in developing more realistic analytical models for panel flutter analysis. The notable feature of the present research is the use of two methods for the aeroelastic analysis of two-dimensional curved panels with cylindrical bending. In the first approach, the finite volume method (FVM) is used for supersonic viscous flow and nonlinear structural model while full Navier-Stokes equations are discretized. In the second approach, the third-order nonlinear piston theory aerodynamics in addition to mechanical and thermal loads is assumed. Moreover, the semi-analytical weighted residual method for the nonlinear curved panel is utilized. These approaches are concurrently compared with each other for the first time. Furthermore, Hamilton’s principle is used and partial differential equations (PDEs) are derived.

This SAE Aerospace Recommended Practice (ARP) provides guidance to develop and assure validation and verification of IVHM systems used in autonomous aircraft, vehicles and driver assistance functions. IVHM covers a vehicle, monitoring and data processing functions inherent within its sub-systems, and the tools and processes used to manage and restore the vehicle’s health. The scope of this document is to address challenges and identify recommendations for the application of integrated vehicle health management (IVHM) specifically to intelligent systems performing tasks autonomously within the mobility sector. This document will focus on the core aspects of IVHM for autonomous vehicles that are common to both aerospace and automotive applications. It is anticipated that additional documents will be developed separately to cover aspects of this functionality that are unique to each application domain.

This Aerospace Information Report (AIR) is a historical technical record describing procedures, required continuous sampling conditions, and instrumentation for the measurement of non-volatile particle number and mass concentrations from the exhaust of aircraft gas turbine engines. Procedures are included to calculate sampling loss performance. This AIR is not intended for in-flight testing, nor does it apply to engine operating in the afterburning mode.

This Aerospace Information Report is a historical technical record of the initial document detailing the measurement of non-volatile particle emissions at the exit plane of aircraft gas turbine engines. This methodology was adopted by ICAO into Annex 16 Vol II and updated into Aerospace Recommended Practice ARP6320.

Future updates of this document may include explanations of the reasoning and assumptions used to develop this measurement methodology.

This Aerospace Informational Report (AIR) provides guidance on using environmental, electrochemical, and electrical resistance measurements to monitor environment spectra and corrosivity of service environments, focusing on parameters of interest, existing measurement platforms, deployment requirements, and data processing techniques. The sensors and monitoring systems provide discrete time-based records of 1) environmental parameters such as temperature, humidity, and contaminants; 2) measures of alloy corrosion in the sensor; and 3) protective coating performance in the sensor. These systems provide measurements of environmental parameters, sensor material corrosion rate, and sensor coating condition for use in assessing the risk of atmospheric corrosion of the structure.

The SAE E-32 Committee is requested to develop standards for Commercial Aircraft Engine Monitoring to support the Continued Airworthiness of aircraft in general, with particular emphasis on the ETOPS (Extended Operations) to support the regulations. 14CFR A33.3 (c) ETOPS Requirements. For an applicant seeking eligibility for an engine to be installed on an airplane approved for ETOPS, the Instructions for Continued Airworthiness must include procedures for engine condition monitoring. The engine condition monitoring procedures must be able to determine prior to flight, whether an engine is capable of providing, within approved engine operating limits, maximum continuous power or thrust, bleed air, and power extraction required for a relevant engine inoperative diversion. For an engine to be installed on a two-engine airplane approved for ETOPS, the engine condition monitoring procedures must be validated before ETOPS eligibility is granted.

The ARP shall cover the objectives and activities of Verification & Vallidation Processes required to assure high quality and/or criticality level of an IVHM Systems and Software.

The processes outlined in this document cover the entire aircraft for both commercial and military applications. In addition to on-board systems, it covers on-ground elements as well. The practical application of this standardized process is detailed in the form of a checklist. As in all HM-1 documents, the scope of this document covers sensing and acquisition systems, typically on board, data transmission systems and processes, methods and hardware for data analysis, and finally, maintenance actions. The on-board aspects relating to safety of flight, pilot notification, etc., are addressed by the other SAE Committees standards and documents. To help explain the process and the use of the checklist, some high-level use cases related to maintenance credit applications are included.

This SAE Aerospace Standard describes the system used by passenger boarding stairs (PBS) mobile passenger boarding ramps (PBS) and boarding bridges (PBB) to inform on-board cabin crew about the docking status of the PBS/PBR/PBB and whether it is positioned such that it is safe to open the aircraft door. Current practice calls for the PBS/PBR/PBB operator to knock on the aircraft door to inform the cabin crew that it is safe to open the aircraft door. New technologies being incorporated into PBS/PBR/PBB such as remote control systems and autonomous driving vehicles are entering the market. As such, new/updated controls and/or procedures are necessary to ensure continuing safe operations.

Verification of landing gear design strength is accomplished by dynamic and static test programs. This is essentially a verification of the analytical procedures used to design the gear. An industry survey was recently conducted to determine just what analysis and testing are currently being applied to landing gear. Timing in relation to first flight of new aircraft was also questioned. Opinions were solicited from designers of the following categories and/or types of aircraft: a Military - Large Land Based (Bomber) b Military - Small Land Based (Fighter) c Military - Carrier Based (Navy) d Military - Helicopter (Large) e Military - Helicopter (Small-attack) f Commercial - Large (Airliner) g Commercial - Small (Business) h USAF (WPAFB) - Recommendations It is the objective of this AIR to present a summary of these responses. It is hoped that this summary will be useful to designers as a guide and/or check list in establishing criteria for landing gear analysis and test.

The purpose of this SAE Aerospace Information Report (AIR) is to provide information that would be useful to potential users/operators and decision makers for evaluating and quantifying the benefits of an Engine Monitoring Systems (EMS) versus its cost of implementation. This document presents excerpts from reports developed to analyze “actual aircraft cost/benefits results”. These are presented as follows: a First, to outline the benefits and cost elements pertaining to EMS that may be used in performing a cost versus benefits analysis. b Second, to present considerations for use in conducting the analysis. c Third, to provide examples of analyses and results as they relate to the user/operator and decision-maker community. The document encompasses helicopters and fixed wing aircraft and distinguishes between civilian and military considerations.

The purpose of this SAE Aerospace Information Report (AIR) is to provide information that would be useful to potential users/operators and decision makers for evaluating and quantifying the benefits of an Engine Monitoring Systems (EMS) versus its cost of implementation. This document presents excerpts from reports developed to analyze "actual aircraft cost/benefits results". These are presented as follows: a. First, to outline the benefits and cost elements pertaining to EMS that may be used in performing a cost versus benefits analysis. b. Second, to present considerations for use in conducting the analysis. c. Third, to provide examples of analyses and results as they relate to the user/operator and decision-maker community. The document encompasses helicopters and fixed wing aircraft and distinguishes between civilian and military considerations.