Search Results

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.

“Spotlight on Design: Insight” features an in-depth look at the latest technology breakthroughs impacting mobility. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. As global concerns about the negative consequences of greenhouse gases on the environment increase, regulatory agencies around the world are taking serious steps to address the issue of tailpipe emissions In the episode “Fuel Efficiency: Fuel Economy Testing” (12:05), engineers at the EPA’s National Vehicle and Fuel Emissions Laboratory demonstrate how different vehicles are tested for emissions, and AVL’s technical team shows how accurate tailpipe emissions can be measured and reported.

This set includes: SAE International Journal of Aerospace March 2010 - Volume 2 Issue 1 SAE International Journal of Commercial Vehicles October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2 SAE International Journal of Engines October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2 SAE International Journal of Fuels and Lubricants October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2 SAE International Journal of Materials and Manufacturing October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2 SAE International Journal of Passenger Cars - Electronic and Electrical Systems October 2009 - Volume 2, Issue 1 SAE International Journal of Passenger Cars - Mechanical Systems October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2

Abstract The use of nanomaterials and nanostructures have been revolutionizing the advancements of science and technology in various engineering and medical fields. As an example, Carbon Nanotubes (CNTs) have been extensively used for the improvement of mechanical, thermal, electrical, magnetic, and deteriorative properties of traditional composite materials for applications in high-performance structures. The exceptional materials properties of CNTs (i.e., mechanical, magnetic, thermal, and electrical) have introduced them as promising candidates for reinforcement of traditional composites. Most structural configurations of CNTs provide superior material properties; however, their geometrical shapes can deliver different features and characteristics. As one of the unique geometrical configurations, helical CNTs have a great potential for improvement of mechanical, thermal, and electrical properties of polymeric resin composites.

Abstract More than a decade ago, we proposed combined use of direct injection (DI) and jet ignition (JI) to produce high efficiency, high power-density, positive-ignition (PI), lean burn stratified, internal combustion engines (ICEs). Adopting this concept, the latest FIA F1 engines, which are electrically assisted, turbocharged, directly injected, jet ignited, gasoline engines and work lean stratified in a highly boosted environment, have delivered peak power fuel conversion efficiencies well above 46%, with specific power densities more than 340 kW/liter. The concept, further evolved, is here presented for unmanned aerial vehicle (UAV) applications. Results of simulations for a new DI JI ICE with rotary valve, being super-turbocharged and having gasoline or methanol as working fuel, show the opportunity to achieve even larger power densities, up to 430 kW/liter, while delivering a near-constant torque and, consequently, a nearly linear power curve over a wide range of speeds.

Abstract While the design of nozzles for diatomic gases is very well established and covered by published works, the case of a diatomic gas dissociating to monatomic along a nozzle is a novel subject that needs a proper mathematical description. These novel studies are relevant to the definition of nozzles for gas-core Nuclear Thermal Rockets (NTR) that are receiving increased attention for the potential advantages they may deliver versus current generation rockets. The article thus reviews the design of the nozzles of gas-core NTR that use hydrogen as the propellant. Propellant temperatures are expected to reach 9,000-15,000 K. Above 1500 K, hydrogen begins to dissociate at low pressures, and around 3000 K dissociation also occurs at high pressures. At a given temperature, the lower the gas pressure the more molecules dissociate, and H2 → H + H. The properties of the gas are a function of the mass fractions of diatomic and monatomic hydrogen x H2 and x H = 1 − x H2.

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 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 A key problem of the construction of fully electric aircraft is the limited energy density of battery packs. It is generally accepted that this can only be overcome via new, denser battery chemistry together with a further increase in the efficiency of power utilization. One appealing approach for achieving the latter is using laser-assisted filler-based joining technologies, which offers unprecedented flexibility for achieving battery cell connections with the least possible electrical loss. This contribution presents our results on the effect of various experimental and process parameters on the electrical and mechanical properties of the laser-formed bond.

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 preliminary gas turbine combustor design process uses a huge amount of empirical correlations to achieve more optimized designs. Combustion efficiency, in relation to the basic dimensions of the combustor, is one of the most critical performance parameters. In this study, semi-empirical correlations for combustion efficiencies are examined and correlation coefficients have been revised using an experimental air-blasted tubular combustor that uses JP8 kerosene aviation fuel. Besides, droplet diameter and effective evaporation constant parameters have been investigated for different operating conditions. In the study, it is observed that increased air velocity significantly improves the atomization process and decreases droplet diameters, while increasing the mass flow rate has a positive effect on the atomization—the relative air velocity in the air-blast atomizer increases and the fuel droplets become finer.

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.

The scope of this document is to provide a guidance of the common contamination types and their concentrations in order to size FTIS components and characterize its performance on generic commercial aircraft.

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.

This document defines the technical guidelines for the safe integration, operation and maintenance, and for certification of Liquid Hydrogen Storage Systems (LHSS) in aircraft. This document also defines guidelines for safe refuelling operation of hydrogen for aircraft. This document does not address airport infrastructure, nor how the refuelling means is specified, except the provisions required for the safety of the aircraft refuelling operation.