Shape
The inlet cone is shaped so that the shock wave that forms on its apex is directed to the lip of the intake; this allows the engine to operate properly in supersonic flight. As speed increases, the shock wave becomes increasingly more oblique (the cone gets narrower). As a result, some inlet cones (for example, on the SR-71) are designed to move axially to maintain the shock-on-lip and allow efficient operation over a wider range of flight speeds. On MiG-21 this movement also makes the opening between the intake (diffusor) lip and the cone smaller, preventing the inside of the intake section from bursting open from dynamic air overpressure at the aircraft's highest speeds above Mach 2.
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Famous quotes containing the word shape:
“Thus when I come to shape here at this table between my hands the story of my life and set it before you as a complete thing, I have to recall things gone far, gone deep, sunk into this life or that and become part of it; dreams, too, things surrounding me, and the inmates, those old half-articulate ghosts who keep up their hauntings by day and night ... shadows of people one might have been; unborn selves.”
—Virginia Woolf (1882–1941)
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—William Shakespeare (1564–1616)
“Irish poets, learn your trade,
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—William Butler Yeats (1865–1939)