A first order model of a variable camber wing for a civil passenger aircraft.
Date
2012-09-13
Authors
Martindale, Tristan.
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Abstract
This work presents the development, implementation and analysis of a rst order
model of a variable camber wing. An aerodynamic model of a homogeneous wing
employing variable camber actuation was developed based on the vortex lattice
method and was applied to the approach and landing phases (low speed, steady
state, high angle of attack) of a civil transport aircraft. The aerodynamic model
was shown to predict the lift curve well up to the stall angle of attack of 18 . A
novel way of varying the camber across the wing span was presented which uses a
parameter de ning the NACA 5 series camber line to provide a means of smoothly
changing the camber at a speci c span location combined with a linear variation
of the parameter along the span. This provided a model of a homogeneous wing
capable of smooth continuous changes in shape. The lift distribution along the
span of the variable camber wing clearly demonstrated smoothness with none of the
discontinuities caused by conventional ailerons. The camber control e ectiveness was
shown to be 44% less than that of conventional ailerons which is partly attributed to
the linear variation in camber along the span. It was shown that the variable camber
has even less coupling with the longitudinal aerodynamics than do conventional
ailerons and that the coupling with both yaw and side force appears smaller. A
strip theory model was developed based on the typical section in aeroelasticity with
two degrees of freedom: heave and twist. It was assumed that the camber actuation
mechanism holds the wing perfectly rigid once the desired camber is reached. The
discrete model was veri ed against a continuous cantilever beam. The discrete model
of the Citation V wing was found to have natural bending and torsion frequencies
of approximately 8 Hz and 5 Hz respectively which lie in the expected range for
light civil passenger jets. The stability of the system in response to aircraft angle of
attack and variable camber inputs was evaluated both with and without the presence
of aerodynamic damping in the model. The stability of the system was found to
depend on the amount of aerodynamic damping present.