Browse Topic: Thrust reversers
Turboprop aircraft have the capability of reversing thrust to provide extra stopping power during landing. Reverse thrust helps save the wear and tear on the brakes and reduces the landing distance under various conditions. The article explains a methodology to predict the disking drag (reverse thrust) from the Computational Fluid Dynamics (CFD) technique using Blade Element Momentum (BEM) theory and estimation of the same from high-speed taxiing trial (HSTT) and ground roll data for a turboprop aircraft using system identification techniques. One-dimensional kinematic equation was used for modeling the aircraft dynamics, and the error between measured and estimated responses was optimized using the Output Error Optimization Method (OEOM). The estimated propeller drag was matched with CFD predictions to arrive at a relation between the propeller blade pitch angle and throttle position. The present study also investigates the estimation of the braking friction coefficient from the taxiing data and the change in braking distance using different runway conditions and reverse thrust. The exact prediction and usage of the reverse thrust can mitigate the possibility of using extra landing aids like spoilers for a similar prototype under design and development.
This SAE Aerospace Information Report (AIR) provides information on aircraft cabin air quality, including: Origins of chemical airborne contaminants during routine operating and failure conditions. Exposure control measures, including design, maintenance, and worker training/education. This AIR does not deal with airflow requirements.
Nickel based superalloys have a wide range of applications due to high mechanical strength at high temperatures, fracture toughness and resistance to corrosion. However, because of their outstanding properties, it is considered as the difficult to machine materials. Inconel alloy X-750 is used extensively in rocket-engine thrust chambers. Airframe applications include thrust reversers and hot-air ducting systems along with large pressure vessels are formed from Inconel alloy X-750. Moreover, the comparative analysis of machinability aspect using coated carbide inserts is reported few. The current study explains the machinability investigation on Inconel alloy X-750 superalloys using coated carbides. To collect the experimental data, the L16 experimental design plan is used to experiment with a machining length of 40 mm. Four level of cutting speed (70,120,170,220 m/min), feed rate (0.1, 0.15, 0.2, 0.25 mm/rev) and cutting depth (0.3, 0.4, 0.5, 0.6 mm) are the cutting/machining parameters used. Cutting Forces, surface roughness, flank and crater wear are considered as target functions. With the application of response surface, coupled with desirability analysis, the optimal levels of the combination are determined. With determined optimal levels, tool life study has been carried out to compare the effectiveness of cutting inserts. Finally, the ranges for best cutting conditions are proposed for serial industrial production.
This specification covers a water-base cleaner in the form of a liquid.
Fanjet Evolution - the Next Steps Rolls-Royce is on a determined path to equip commercial airplanes over the coming decades with new engines that take advantage of engineering breakthroughs in materials and core architectures. The global aerospace sector has always represented the cutting edge of practical technology advancement. When the first military jet engines emerged in the post-war 1940s it was clear that commercial applications would soon follow. The leap in performance, payload capability, maintainability, and speed compared to the best that turbo-supercharged piston-engines could offer was truly revolutionary.
Coriolis Composites and SAFRAN Aircelle worked together on a thrust reverser component demonstrator made with carbon-fiber-reinforced plastic (CFRP) material and an AFP process. Complex composites structures are becoming more common, especially in aeronautics. Composites preforms can now be manufactured by automated processes, such as automated fiber placement (AFP) and automated tape laying (ATL), to achieve the expected production volumes. The AFP process is the most interesting since it can address complex double-curvature layup surfaces with good productivity rates and low material scrap, according to Coriolis Software. The main advantages of this technology are that material can be steered to address the problem of curvature, and fiber angular deviation from the engineering rosette can be easily managed. This opens interesting possibilities to optimize the design of composites structures and to change the current traditional “black metal” approach of design offices.
This SAE Aerospace Recommended Practice (ARP) establishes the processes to achieve and maintain the required cleanliness levels in flight vehicle hydraulic systems during fabrication, assembly and pre-flight functional tests. This recommended practice covers exclusion and removal primarily of solid contaminants that occur or are created during these successive steps. The flushing procedure for installed tubing is detailed. This ARP does not address contamination levels of hydraulic fluids as purchased, operation and maintenance of ground carts, details of component cleanliness or of contamination measurement. This ARP applies to military aircraft and helicopters designed to AS5440, commercial aircraft hydraulic systems designed to ARP4752 and commercial helicopter hydraulic systems designed to ARP4925.
The power plant is the area in an aircraft where they are a lot of power conversion. The power plant is the core of the aircraft from energy point of view. The engines allow to take off but not only, it also provides energy to the aircraft from many different manners. They are electrical, hydraulic, mechanical, …. The power plant is definitively a power generator but also a power consumer. Since now some years, the power electronic technology is spread into the aircraft. One can say that some pedigree has been collected with this technology embedded to the aircraft. For the power plant domain, it is different. This technology is really not usual for use. Our environment is really not friendly and even if the integration of the power converters has been improved over the last years, there is not a lot of space around the engines. These are probably the mains reason of the low deployment of the power electronic in this domain but not only. The reliability of the thrust function is expected to be very high; of course, for safety point of view but also for cost point of view. However, the emergence of this technology for some functions close to the engine can be observed. In some areas, the hydraulic technology is replaced by the electrical one. The most outstanding one is probably the thrust reverser. This paper will provide the description of some powerplant functions that are now, or could be, supported by the power electronic technology. Weight, temperature, reliability, integration will be addressed. The future? To get the technologies that will allow to substantially reduce the fuel consumption.
The development of the microprocessor controlled power MOSFET switch, as a circuit protection device for aircraft electrical power systems, has led to significant improvements in packaging, performance and thermal efficiencies over traditional thermal/mechanical systems. The electronic circuit breaker (ECB) inherently provides multiple functions (protect, sense, diagnose, and control). Employing the ECB as a “live” switching element in the system for active control, provides for significant integration of functions, previously requiring separate LRUs, additional wiring and more power to operate. This paper proposes an optimized electrical power distribution via intelligent control of electronic circuit breakers to provide maximum integration of existing utility management functions (i.e. window heat, de-icing, thrust reversers, etc.), reduction in aircraft wiring, reduced system weight and complexity. Specific electronic power system architecture will be proposed as an example to serve as a point of comparison to legacy electrical systems, inclusive of specific sub-systems targeted for this integration. A balanced perspective on design, aircraft mechanical/electrical integration, pilot-interface, maintainability and certification will be presented.
Increased productivity is the focus of today's automation for composites made of carbon-fiber-reinforced plastics. As use of composites grows in the aerospace industry, so will automation used to create composite parts and structures. “There is a tremendous opportunity over the next decade for vastly increasing the amount of aerostructures produced with automated processing,” said Chris Red, an industry analyst with Composite Market Reports. He backs this statement with the company's recent study of the market for automated machinery. Addressed are technologies such as automated fiber placement (AFP) and automated tape layers (ATL).
Higher bypass ratios, chevrons, shape memory alloys, and improved aerodynamics are some of the advancing technologies that will help quiet aircraft, and thus help the environment. Achieving London airports' QC2 noise level for the Trent 900 to power the A380 demanded very close liaison between Rolls-Royce and Airbus. It saw the development of an effectively spliceless inlet and fan case acoustic system. Rolls-Royce was responsible for the engineering of the fan case and Airbus for the inlet. A systems approach was used to ensure that the combined effect gave lower engine noise. Walsh says that may not sound significant “but to achieve a uniform surface that would successfully attenuate fan noise was quite a mechanical challenge. Imperfections in the acoustic treatment with any joints can disrupt the sound field, which at some frequencies may create added noise. We managed to achieve the very high degree of homogeneity required-a spliceless intake system.” Attempting acoustic gains in the intake lip area also needs consideration with regard to any minus elements. “For example, we have to consider anti-icing/deicing aspects and we certainly must not degrade aerodynamic performance,” he said. A deep understanding of the physics of noise generation is essential, and the potential production solutions are being developed via extensive mathematical modeling and fan rig facility test work.
Simulation, testing reduce the size and number of in-flight problems. Flight tests remain an important aspect of aircraft development, but these real-life tests are changing as modeling, simulation, and hardware-in-the-loop (HIL) testing improve. These tests haven't yet been reduced to a way to confirm that simulations are correct, but improved pre-flight analysis has dramatically reduced the number and severity of problems that are discovered during open-air flights. “Simulation has significantly reduced the burden on open-air flight tests and immensely increased the confidence that we're ready to fly,” said Doug Pearson, Vice President for F-35 Integrated Test Force at Lockheed Martin.
This document recommends criteria for electronic displays on the flight deck of transport aircraft. Electronic displays include electronic flight instruments, alert displays, aircraft system displays and control/display units for flight management and radio management systems.
Much of the excitement surrounding such aircraft as the point-to-point 787, hub-to-hub A380, and 7X business jet is due to the application of new technologies. Aerospace is singing the body electric in 2005 with myriad new electrically activated systems that are now migrating, along with other technologies, from military aircraft to the civil sector. In addition to electric systems, other technologies finding wider application on today's aerospace and defense platforms include composite materials, digital design and manufacturing tools, and power plant improvements for better fuel consumption and lower emissions.
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