NACA Technical Notes

Tests of a partial-span model of a large bomber-type air1ane\ud were conducted to determine the. aerodynamic characteristics of the\ud wing equipped with full-span flaps and a retractable spoiler end\ud aileron lateral control system. The arrangement consisted of\ud (1) a double slotted flap extending over aproximate1y 86 percent of the wing semispan, (2) a 20-percent constant-percentage-chord\ud aileron extending from the outboard end of the flap to the wing tip,\ud and (3) a retractable spoiler, located at the 65-percent wing-chord\ud station and extending from approximately 63 percent of the wing\ud semispan to the wing tip. In addition, tests were made of a wing\ud vent (of 1 and 2 percent of the wing chord located directly behind\ud the spoiler), perforations in the spoiler, a blot or cut-out along\ud the lower edge of the spoiler and spoilers of various spans.\ud With full-span flaps deflected and with the 2-percent vent open\ud or closed the initial stalling of the wing occurred at the tips, but\ud with the vents closed there probably would be no appreciable loss in\ud lateral control until maximum lift was reached. The l-percent vent\ud increased the rolling effectiveness of the spoiler at small spoi1er \ud deflections, particularly at high angles of attack with flaps\ud deflected. With flaps deflected the 2-percent vent caused a large\ud reduction in both the wing lift and rolling effectiveness of the\ud spoiler at large angles of attack. However, at small angle of attack\ud the 2-percent vent increased the rolling effectiveness of the spoiler at small spoiler deflections. The simultaneous operation of the\ud spoiler and vent (in contrast to a vent fixed in the wing) would result\ud in a large increase in the effectiveness of the spoiler and would\ud avoid any loss in wing lift as in a fixed vent arrangement.\ud The tests of the spoiler modifications revealed that (1) the\ud spoiler perforations reduced the rolling-moment and yawing-moment\ud coefficients but caused the spoiler hinge-moment coefficients to become more positive; (2) the spoiler slot had no notable effect on\ud the rolling-moment and yawing-moment characteristics but produced\ud a positive increase in the spoiler hinge-moment coefficients at\ud large spoiler deflections; (3) the effects produced by the individual\ud modifications were additive when the various modifications were\ud combined. In general, progressively decreasing the spoiler span by\ud removing the segments from the inboard end of the spoiler caused a\ud decrease in rolling effectiveness approximately proportional to the\ud span of the segment