A first order model of a variable camber wing for a civil passenger aircraft.

摘要

This work presents the development, implementation and analysis of a rst orderudmodel of a variable camber wing. An aerodynamic model of a homogeneous wingudemploying variable camber actuation was developed based on the vortex latticeudmethod and was applied to the approach and landing phases (low speed, steadyudstate, high angle of attack) of a civil transport aircraft. The aerodynamic modeludwas shown to predict the lift curve well up to the stall angle of attack of 18 . Audnovel way of varying the camber across the wing span was presented which uses audparameter de ning the NACA 5 series camber line to provide a means of smoothlyudchanging the camber at a speci c span location combined with a linear variationudof the parameter along the span. This provided a model of a homogeneous wingudcapable of smooth continuous changes in shape. The lift distribution along theudspan of the variable camber wing clearly demonstrated smoothness with none of theuddiscontinuities caused by conventional ailerons. The camber control e ectiveness wasudshown to be 44% less than that of conventional ailerons which is partly attributed toudthe linear variation in camber along the span. It was shown that the variable camberudhas even less coupling with the longitudinal aerodynamics than do conventionaludailerons and that the coupling with both yaw and side force appears smaller. Audstrip theory model was developed based on the typical section in aeroelasticity withudtwo degrees of freedom: heave and twist. It was assumed that the camber actuationudmechanism holds the wing perfectly rigid once the desired camber is reached. Theuddiscrete model was veri ed against a continuous cantilever beam. The discrete modeludof the Citation V wing was found to have natural bending and torsion frequenciesudof approximately 8 Hz and 5 Hz respectively which lie in the expected range forudlight civil passenger jets. The stability of the system in response to aircraft angle ofudattack and variable camber inputs was evaluated both with and without the presenceudof aerodynamic damping in the model. The stability of the system was found touddepend on the amount of aerodynamic damping present.