The analysis of vibration characteristics including the natural frequencies and mode shapes for various shaped composite wings with tip mass and engine has been performed using the finite element method based on the shear deformable theory. The present analysis presents the effect of sweptback angle, fiber orientation and aspect ratio of a composite wing, which is composed of graphite/epoxy laminate adapted in symmetric stacking sequence, on vibration characteristics. As the bending and torsional stiffness are changed due to geomerical shapes and varying directional stiffness of composite materials, the frequencies of two vibration modes approach each other. However, the frequencies do not cross each other. In case of [$\theta_2$/0]s tapered wing, bending-torsion modes are highly coupled in the range of 0°-15° for fiber orientation $\theta$. As $\theta$ increases from 0° to 90°, the lowest mode, which can always be characterized as the first bending, reduces due to the decrease in spanwise stiffness. This present finite element method which uses 8-node quadrilateral elements gives very accurate results.
