Search Results

THE performance characteristics of various devices applicable for jet directional control, lift augmentation, and VTOL-STOL studied at the NACA Lewis Laboratory are discussed, including jet deflection devices applicable to the conventonal round nozzle and novel nozzle configurations. The results indicate that many of the deflection devices applicable to conventional nozzles can readily be used for directional control or lift augmentation. Other deflection devices, such as movable plug, internal flap, cylindrical thrust reverser, swiveled primary with fixed shroud, and 90 deg side-bleed nozzle, are limited in application to jet directional control or aircraft trim because the loss in axial thrust for a given deflection force is prohibitive or the maximum deflected force obtainable is limited.

In a 2-year program sponsored by SJAC, an aqueous electroplating process using alkaline Zn-Ni with trivalent chromium post treatment is under evaluation for high strength steel for aircraft application as an alternative to cadmium. Commercial Zn-15%Ni rack/barrel plating solutions are basis for plating aircraft parts or fasteners. Brightener was reduced from the original formula to form porous plating that enables bake-out of hydrogen to avoid hydrogen embrittlement condition. Properties of the deposit, such as appearance, adhesion, un-scribed corrosion resistance, and galvanic corrosion resistance in contact with Al alloy, were evaluated. Coefficient of friction was compared with Cd plating by torque-tension measurements. Evaluation of the plating for scribed corrosion resistance, primer adhesion, etc. will continue in FY2007.

In spite of environmental issues related to cadmium and its electroplating process, electroplated cadmium is still extensively used in the aerospace and defense sectors. This trend is likely to continue especially for high strength steels because cadmium provides the best known corrosion and embrittlement protection for this application. Consequently, the environmental concerns related to the cadmium electroplating have been addressed using an alternative Zero-waste Physical Vapor Deposition (Z-PVD). This method does not use liquids, it recycles cadmium in situ, and is free of hydrogen embrittlement. The Z-PVD process is now in commercial production for the aerospace fasteners. The quality of the coatings has been at least equal to that of the electroplated cadmium.

The commercial aviation currently accounts for roughly 2.5 % of the global CO2 emissions and around 3.5% of world warming emissions, taking into account non CO2 effects on the climate. Its has grown faster in recent decades than the other transport modes (road, rail or shipping), with an average rate of 2.3%/year from 1990 to 2019, prior to the pandemic. Moreover, its share of Greenhouse (GHG) emissions is supposed to grow, with the increasing demand scenario of air trips worldwide. This scenario might threaten the decarbonization targets assumed by the aviation industry, in line with the world efforts to minimize the climate effects caused by the carbon emissions. In this context, hydrogen is set as a promising alternative to the traditional jet fuel, due to its zero carbon emissions.

This paper describes the ZENITH Nano-Satellite cum planetary atmospheric entry vehicle, called CanSat, the first Nano-Satellite project that has been developed by Delhi Technological University (Formerly Delhi College of Engineering), India. The satellite will function for monitoring the concentrations of various gases in the atmosphere. For this, the satellite consists of arduino microcontroller interfaced with the various Micro-electromechanical system (MEMS) gas sensors for measuring the concentrations of various gases such as carbon dioxide, carbon monoxide, methane, nitrous oxides, ozone, etc. The data obtained from the CanSat will be transmitted to the ground station where all the data will be stored and also the locations will be stored using GPS sensor. The academic goal of this project is to recruit students to the field of space science and technology.

The AS6224 specification covers environment resistant, permanent insulation repair sleeves for repairing different types of insulation damages of wire or cable jackets in installed applications. The repair sleeve is intended to repair damaged primary wire or cable jacket covers where the shielding and wire conductors are not damaged.

To recommend supplementary design criteria to enhance the endurance, reliability, and dependability of transport aircraft wheels and brakes.

To recommend supplementary design criteria to enhance the endurance, reliability, and dependability of transport aircraft wheels and brakes.

The paper presents an extensive assessment of the hygroscopic characteristics of a number of alternative jet fuel blends. These are blended with conventional Jet A-1 to conform with current aviation standards at a 50:50 ratio by volume, except for DSHC (Direct Sugar to Hydrocarbon), which is blended at 10% DSHC and 90% Jet A-1. Given the lack of information available on the water solubility of alternative jet fuels, an effective analysis of experimental data about this characteristic in six different alternatives was performed. These included four ASTM approved alternatives (two Fischer-Tropsch (FT) synthetics from coal and natural gas, one HEFA (Hydroprocessed Esters and Fatty Acids) derived from camelina and DSHC. An extra two alternatives currently under consideration for ASTM approval were also tested; ReadiJet and an ATJ (Alcohol to Jet).

This paper presents results of new development work carried out in the context of the Water Conditioning Assembly (WCA) which is part of the Liquid Management Section (LMS) of the Hermes Environmental Control and Life Support Subsystem (ECLSS) (see ref [1] and [2]). Its task is to condition and monitor the quality of highly pure water which has been produced in two fuel-cell stacks by the oxidation of hydrogen. This water will be used for different cooling elements (e.g. water evaporator, water sublimator) and as potable water for drinking and food purposes. The assembly consists mainly of: a hydrogen separator, providing for removal of dissolved and gaseous residual hydrogen from the fuel-cell water.

To recommend supplementary design criteria to enhance the endurance, reliability, and dependability of transport aircraft wheels and brakes.

The paper presents the results of the visual investigations of the working fluid vapour and non-condensible gaseous impurities interaction in low temperature heat pipe (LTHP) condensation zone. The effect of the transferred heat flow amount on the vapour and non-condensible gaseous impurity (NCG) separation is established. The obtained dependance allows to determine the minimal amount of the transferred heat flow from which the vapour and NCG will be dinamic mixed and the temperature profile will be simmetry in the heat pipe condensation zone. Water, ethanol, acetone, Freon-11 were used as the working fluid, while air, argon and helium as NCG.

The solution to the problem of establishing the value of the maximum stress in a uniform cylinder with fixed ends, subjected to a unit step change in pressure is presented. It is shown that the ratio of the maximum transient stress to the steady-state stress is a monotonically decreasing function of the damping ratio of the shell. The stress ratio approaches a value of 2 as the damping ratio and the parameter ψ, defined as

WHILE the centrifugal supercharger is excellently suited to aviation service and to relatively constant-speed, diesel-engine service, Mr. Pigott states, it is not of value for cases of considerable variation in speed where full boost is required at all speeds. The Roots-type blower, the author says further, has had a justified development for low-pressure boost, but is not valuable for compression ratios much in excess of 1.6 because it has no adiabatic compression. The vane-type supercharger, while it has an adiabatic compression, as so far developed appears to the author to be somewhat complex in structure, requires internal lubrication, and has not yet shown satisfactory efficiency compared to other types. The Elliott-Lysholm screw-type and the new P. L. internal-gear type appear to him, however, to give great promise for satisfactory supercharging at the higher pressures beyond the range of the Roots type, and appear to be the best present line of development.