The Design Study On The Kinematical Mechanism Of Multi-Gap-Fowler-flap Of Large-scale Cargo Airplane

Wing flap, widely assembled in various kinds of airplanes, can increase lift force rapidly in a short time, for an aircraft taking off or landing, and also at some emergency situations. Multi-gap-Fowler-flap, while deflecting its rudders, simultaneously extends backwards by relatively large scope, which broaden the overall wing-camber and area, so that more additional lift could be attained through improving air-flow boundary layer. Compared with other types of the wing flaps, the effect of the Fowler-flap generating more additional lift has great superiority, and so the multi-gap-Fowler-flap has been used abroad for large or middle-scale cargo and transport airplanes. At home, the mechanisms of the Fowler-flaps are not yet made in-depth research up to now, because of relative late development of transport airplanes. At present, the domestic development of large-scale cargo airplane is getting urgent, such that the design methodology of the mechanisms of Fowler-wing flap must be investigated thoroughly as one of the critical technologies of developing large-scale cargo airplane.With the demands of designing the large-scale cargo airplane, in this thesis, many technical materials about the mechanisms of current wing flap types, of foreign transport airplanes are carefully studied at first, and the mechanical composition of three-gaps-Fowler-flap is summarized technically about its major basic components, prime mechanism (track), driving device, sub-flaps mechanism and the sub-flaps sequential control system. Based on the kinematical design criterion of equi-chord percent ratio and spatial rigid body guiding mechanism, Three theoretical design methods of arc track, non-arc track, and helical track are proposed in this thesis, meanwhile, different design methods about prime flap and sub-flap driving mechanisms are completed.Three cases of different three-gaps-Fowler-flap tracks are designed. For specified three work positions as design inputs, the thesis evaluates their geometrical movements of the prime and sub-flaps, and some reasonableness are shown in view of kinematical geometry. The work can provide further aerodynamic analysis with variable wing geometrical data. The comparison of the computational results of flap movements indicates that three operational positions of the wing flaps guided through the different tracks are nearly close to each other and the non-arc-track is better to guide the flaps to the original three positions exactly.