![]() The answer–somewhat lost in history–is that the color reduces reflections during night flying. Why, you may ask, are so many cockpit surfaces black (a long-time complaint of mine)? The ideal method would take the form of an inexpensive (about $25) reflective solar blanket wrapped around all window surfaces. To really reduce solar loading during storage, the panel’s reflective surface should be outside the aircraft’s thermal containment envelope. These panels reflect a small portion of the IR radiation back through the window, but heat still builds up in the cockpit, as the panels serve mainly to prevent ultraviolet (UV) damage to panel-top upholstery. The use of "remove before flight" reflective panels inside the cockpit windows during storage is a classic case in point. But they generally are ineffective due to poor understanding of thermodynamics and the root causes of heating. Many techniques are employed to address the cockpit heating and light saturation problem. This makes them hard to read in bright light and creates a circular design problem with no solution, as increasing brightness also increases heat from the display. Heat also causes dramatically reduced brightness from light emitting diode (LED) displays–typically, to less than 40 to 50 percent of the design value. As small aircraft shift to LCD displays, this issue becomes much more important. Prolonged heating leads to irreversible darkening of the LCD nematic fluid. This situation involves all small aircraft but is particularly acute with helicopters, which typically have more overhead glass.Ĭonsiderable solar radiation over a long period of time can destroy many liquid crystal displays (LCDs). It also contributes significantly to increased pilot stress during flight. ![]() ![]() The greenhouse effect of the windowed cockpit and dark surfaces leads to premature equipment damage and an uncomfortable operating environment. In southerly regions, the temperatures can reach a scorching 70 degrees C (158 degrees F), the upper operating limit for many avionics items. Live testing shows the surface temperature inside a sealed aircraft cockpit parked on the ramp routinely passes the 60-degree C (140-degree F)–threshold of pain for human tissue. These factors produce a hot ambient environment for avionics and instruments that can easily exceed DO-160D environmental specifications (high-temperature operating limits) before a system is switched on. In small single-engine aircraft, heat also builds up because of conduction and reradiation from the front bulkhead and engine. By midday, the IR accumulation, combined with the considerable internal heat generation from stack-mounted avionics and instruments, quickly raises the temperature of surfaces and areas behind the panels to dangerous levels. Matte black cockpit surfaces act as near-perfect infrared (IR) accumulators. It is physically cramped but visually open, with as much window space as possible, since the point of being airborne is often to observe.īecause of their large overhead window areas, many cockpits suffer from solar accumulation, which causes heat-loading problems. ![]() Few working environments impose as many irritating problems as the aircraft cockpit. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |