Applications Aircraft

Mechanical Drives. Mechanical drive gas turbines are widely used to drive pumps and compressors. Their application is widely used by offshore and petrochemical industrial complexes. These turbines must be operated at various speeds and thus usually have a gasifier section and a power section. These units in most cases are aero-derivative turbines, turbines, which were originally designed for aircraft application. There are some smaller frame type units, which have been converted to mechanical drive units with a gasifier and power turbine. 

The methacrylic polymer remains a useful glazing material. In aircraft applications it is used extensively on aircraft which fly at speeds less than Mach 1.0. They form the familar bubble body of many helicopters. On land, acrylic sheet is useful for coach roof lights, motor cycle windscreens and in do-it yourself cabins for tractors and earth-moving equipment. Injection mouldings are frequently used for plaques on the centre of steering wheels and on some fascia panelling. 

E. O. Dickerson and B. OiMartino, Off-Axis Strength and Testing of Filamentary Materials for Aircraft Application, in Advanced Fibrous Reinforced Composites, Vol. 10, Society of Aerospace Materials and Process Engineers, 1966, p. H-23. 

More specialised alloys are covered by the DTD and L series for aircraft applications and include the high strength Al-Zn-Mg alloys. The medium strength weldable Al-Zn-Mg compositions are finding increasing utility in engineering and a national specification may be anticipated in the near future. 

RICEWQ was the first model developed for agrochemical runoff from paddy fields, incorporating aircraft application, dissipation by drift, adhesion on leaf surfaces, and dissipation from the leaf surface in addition to the processes affecting degradation and transport in sediment and paddy water. An important parameter, desorption from sediment to paddy water, is not considered, although this is not as important as other parameters in paddy fields such as sedimentation rate, behavior of SS, etc. 

Until the late 1960s almost all tactical aircraft were largely titanium. Although titanium is relatively light, it is costly and has demanding production requirements so that its use was limited to moderate temperature aircraft applications. Today, most tactical aircraft have a sizable component that is polymeric, mainly composite. The Boeing F/A 18E/F and Lockheed F/A-22 have about 25%, by weight, composite material. It is projected that future military aircraft will have more than 35%i composite materials. 

The inability of the engine to produce a useful propulsive force at zero or low flight speeds necessitates the use of an auxiliary power plant to initially accelerate the vehicle to the required take-over speed of the ramjet. Such auxiliary power is also required for controlled landing of the vehicle. As a consequence the ramjet engine is not well-suited for conventional aircraft applications (with the exception of the helicopter) and the principal application of the engine appears to be further restricted to missiles or other similar vehicles of a one-flight expendable nature ... 

Unlike ductile metals, composite laminates containing fiber-reinforced thermosetting polymers do not exhibit gross ductile yielding. However, they do not behave as classic brittle materials, either. Under a static tensile load, many of these laminates show nonlinear characteristics attributed to sequential ply failures. One of the difficulties, then, in designing with laminar composites is to determine whether the failure of the first ply constitutes material failure, termed first-ply failure (FPF), or if ultimate failure of the composite constitutes failure. In many laminar composites, ultimate failure occurs soon after first ply failure, so that an FPF design approach is justified, as illustrated for two common laminar composites in Table 8.9 (see Section 5.4.3 for information on the notations used for laminar composites). In fact, the FPF approach is used for many aerospace and aircraft applications. 

The manufacture of secondary batteries based on aqueous electrolytes forms a major part of the world electrochemical industry. Of this sector, the lead-acid system (and in particular SLI power sources), as described in the last chapter, is by far the most important component, but secondary alkaline cells form a significant and distinct commercial market. They are more expensive, but are particularly suited for consumer products which have relatively low capacity requirements. They are also used where good low temperature characteristics, robustness and low maintenance are important, such as in aircraft applications. Until recently the secondary alkaline industry has been dominated by the cadmium-nickel oxide ( nickel-cadmium ) cell, but two new systems are making major inroads, and may eventually displace the cadmium-nickel oxide cell - at least in the sealed cell market. These are the so-called nickel-metal hydride cell and the rechargeable zinc-manganese dioxide cell. There are also a group of important but more specialized alkaline cell systems which are in use or are under further development for traction, submarine and other applications. 

The time-space resolution that may be achieved with filter sampling techniques is dependent on the collection rate, limit of detection, and ambient concentrations. In aircraft applications, filters are typically operated at high flows (100-500 L/min) to maximize the mass accumulation rate. At these flow rates, sampling times on the order of 20 to 30 min are generally sufficient for measurement of substances in the urban troposphere. For sampling in the upper troposphere or in areas remote from pollutant sources, collection times of several hours may be necessary to obtain measurable quantities of material. 

The operating principle of the CSIRO (Australian Commonwealth Scientific and Industrial Research Organization) King probe (Particle Measuring Systems Inc., Boulder, Colorado) is similar in concept to that of the Johnson-Williams probe. The King probe measures the amount of power necessary to maintain a heated wire at a constant temperature, whereas the Johnson-Williams probe measures the change in resistance due to cooling of the wire by water evaporation. The probe consists of a heated coil of wire that is maintained at a constant temperature. The amount of excess power required to maintain the wire at this temperature when it is impacted by water droplets is measured and is proportional to the cloud liquid water content. The nominal response time of the instrument is 0.05 s, and it has an accuracy of 20%. This instrument uses less power than a Johnson-Williams probe, an important consideration in aircraft applications. 

New alloys, such as aluminum-lithium alloys for aircraft applications that will permit 7 to 10% weight reduction per aircraft. 

Medium-molecular-weight PMTFPS with vinyl or hydroxyl end blocks are used for adhesives and sealants. They are cured either at ambient temperature (RTV-room temperature vulcanization) or at elevated temperature. One-part moisture-activated RTV sealants have been available commercially for many years. Because of then-very high resistance to jet engine fuels, excellent flexibility at very low temperatures, and high thermal stability, they have been used in both military and civilian aerospace applications.78 Two-part, heat-cured fluorosilicone sealants have been used in military aircraft applications and for sealing automotive fuel systems.79 Special class of fluorosilicone sealants are channel sealants or groove injection sealants, sticky, puttylike compounds, which do not cure. They are used to seal fuel tanks of military aircraft and missiles.75... 

This anhydrous zinc borate was also claimed to improve the stability of a halogen-free polyamide containing aluminum diethylphosphinate, a new halogen-free flame retardant developed by Clariant.69 For aircraft applications, this zinc borate alone is also reported to be effective in reducing the HRR of polyetherketones and polysulfones (Table 9.7).70... 

Victrex PEEK is available in different viscosity grades suitable for extrusion processes, powder coating and compression moulding. PEEK 150P (Mw -40000 g/mol, d2.oc = 1.32 g/cm3, Tg = 147°C, Tm = 345°C), a coarse powder, presents the lowest viscosity grade and is the most suitable for potential aircraft applications. 

Deng et al. (8) investigated the tensile properties of PEEK/MWCNTs, and found increases in the elastic modulus and yield strength at temperatures above and below Tg at 25°C, the tensile modulus increased by -90% for composites including 15 wt% MWCNTs, and the increment reached -160% at 200°C. According to those results, the improvement of MWCNTs in the mechanical behaviour of the matrix is more effective at higher temperatures. Experimental results do confirm that the overall mechanical performance of PEEK/CNT nanocomposites is well above the required for potential aircraft applications. 

These properties explain why titanium steel is so desirable for spacecraft and aircraft applications. In fact, much of the titanium sold is used in aerospace applications. Titanium alloys are used in the airframes (bodies) and engines of aircraft and spacecraft. 

The combination of processability and performance has driven significant growth in thermoset applications where dimensional stability and accuracy are critical. For example, thermosets (usually UV or e-beam cured) are the materials of choice as the medium for rapid prototyping. Similarly, the combination of processability, dimensional stability, and strength have driven the use of thermosets for automotive components, structural members in aircraft, and braking systems in both automotive and aircraft applications. 

Because of these factors, the lubrication requirements of aircraft are generally very critical. Only in a few cases can lubricants developed for non-aircraft applications be used satisfactorily in aircraft. This has not always been the case the mineral oil or castor oil lubricants used in the earliest aircraft were all standard automotive or marine products. 

There are many components on an aircraft that require lubrication where it is impractical to use liquid lubricants, for instance, spoilers, ailerons, rudders, undercarriage, doors and certain engine components. Greases are used extensively in aircraft applications, particularly for the lubrication of airframe components. 

Completed analysis of power density and performance for aircraft applications (NASA funded)... 

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