Smallest Airplane

Smallest Airplane
     
       
High altitude aircraft need to pressurize their cabins (pack more air in) in order to offset the decreased air density (and consequently the decreased amount of oxygen in the air) at the higher altitudes so passengers and crew can continue to breathe without the need for supplemental oxygen. The way they do this is by compressing the outside air and forcing it into the aircraft cabin thereby increasing air density and oxygen concentration. The increased pressure of this compressed air can create a force against the inside of the aircraft cabin, and windows, of up to around 8 pounds per square inch (though some newer airplane designs, such as the Boeing 787, use a slightly higher level of pressurization). The greater the surface area of a window, the greater the force of the cabin air pressure pushing against it and, consequently, the greater the likelihood of breaking out a window. By decreasing the surface area of the window, aircraft designers decrease the possibility of rupturing a window and losing cabin pressure. Hope that helps.

     The size and shape of the windows can weaken the fuselage structure. The first British jet airliner, the de Havilland Comet, began to experience sudden crashes from high altitude. After many tests, the engineers discovered that the large windown with square corners could cause a fatigue crack to develope in the sharp corner of the window. Fatigue was an unknown science at that time. They redesigned the windows to make the smaller with large round corners and the aircraft didn't have any more dramatic crashes.