Flight measurements of hinged-plate wing-spoiler hinge moments

Hinge moment of hinged-plate wing spoilers were measured during flight of a twin turboprop airplane modified by the addition of upper and lower wing-surface spoilers. The spoiler-actuating hydraulic cylinders were instrumented to measure the forces required to extend the spoiler panels. Those measurements were converted to moment coefficient form, and are presented as a function of spoiler deployment angle. The hinge-moment data were collected at three flight conditions: with flaps extended at approach speed; with flaps retracted at a low speed; and with flaps retracted at a high speed (C sub L = 1.4, 1.0, and 0.5). In general, the magnitude of measured spoiler hinge moments were lower than predicted. Furthermore, for upper surface spoilers with flaps extended, the hinge moments increased in a discontinuous manner between spoiler deflection 10 and 10.