![]() The alternative is to isolate the window from any possible loads being transmitted by the aircraft. The window becomes a structural part of the front of the fuselage. If you want to make the window an integral part of the aircraft structure, then a bolted in design is the way to go because it transmits the aircraft loads right through the window. Boeing aircraft, on the other hand, are typically bolted-in designs. “The Airbus A320 and A340 are clamped-in design, without bolt holes. Others use a clamping system, both methods are equally reliable. Some aircraft windshields are fastened with bolts. Thickness gauges like 38 DL Plus are used for the above measurement. Additionally, manufacturers need to measure the soft PVB middle layer to ensure that it is within a specified thickness. Scratches in aircraft windshields are typically removed by polishing during routine maintenance, after which thickness measurement is required to ensure that windshield thickness has not been reduced below a specified minimum. (10 to 12.5 mm) thick and the soft inner layer about 0.050 in. The hard plastic layers are typically about 0.4 in. Multilayer plastic construction is commonly employed by the aerospace industry for air-craft windshields, in which two relatively thick layers of acrylic or a similar hard plastic are typically sandwiched around a thinner layer of a soft material such as polyvinyl butyral (PVB) which provides thermal stress relief. How are the Measurement of individual layers and total thickness in aircraft windshields done? hardened) glass along with an interlayer. In some cases, such as the Boeing 737 and Boeing 747, the windshield features two plies of tempered (i.e. Then, there’s a layer between them, made of urethane. The flight deck windshields are made with glass-faced acrylic - an outer layer of glass bonded to stretched acrylic. Therefore, a passenger plane windscreen is on average four times thicker than a car windscreen which is 0.23 inch thick. It varies between just under an inch to 1.2 inches. Whether it’s for a short, medium or long-haul aircraft, the range of windscreen thickness is the same. Such damage is the chief cause for removal of front windshields, and almost invariably occurs at the inner surface of the outermost ply and/or within the interlayer adjacent thereto. ![]() The environment to which such laminated windshields are exposed is severe and the outer surface, known as the face ply, is often damaged due to particulate impacts, scratching or bond failures (delaminations) at inter-layer interfaces and/or electrical faults in anti-icing heater coatings caused by cyclical thermally and mechanically induced stresses, moisture ingress and bond deterioration. ![]() This laminated structure provides high strength at reduced weight necessary for use in aircraft. Flight Deck Windshields Design and MaterialĪircraft windshields typically comprise a laminated structure consisting of layers of glass, acrylic or polycarbonate plastics, or combinations thereof bonded together by interlayers of polymeric bonding material. “ The windshields have to withstand all of that, and sometime more than that too”. Besides pressure, temperature control, and bird strike, aircraft windscreen area has to withstand chemical resistance to things like hydraulic fluid or jet fuel as well as abrasion including rust, snow, or rain erosion and the most dangerous the static electrical discharge (saint Elmos fire) / lightening. Number one, protect the crew from the outside harsh environment and number two allow the crew to see outside. There are two primary purposes for the windshields. Between the two, just incredibly sturdy windshield. On one side, there’s a warm, pressurized cabin where you can work and on the other, a world that would kill you in minutes if you were exposed to it. ![]() When you’re in flight-deck, the only thing separating pilots from the minus 56 degrees centigrade and unbreathable, thin air outside is an airplane cockpit windshield. ![]()
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