Aerodynamic and aeroelastic considerations of a variable-span morphing wing

Morphing concepts for air vehicles such as unmanned air vehicles (UAVs) have been a topic of current research interest in aerospace engineering. A morphing wing is a bird-like wing that has the ability of adapting to obtain better flight performance. One concept of morphing is the variable-span morphing wing (VSMW) in which the wingspan is varied to accommodate multiple flight regimes. In the present study, the advantages and disadvantages of a VSMW for a cruise type missile are discussed. The aerodynamic characteristics and the range of this morphing wing are analyzed as its wingspan is changed. The results of the analysis demonstrate an improvement in the aerodynamic characteristics of the VSMW, in the form of a reduction in the induced drag, resulting in an increase in range. As further discussed, the VSMW also provides an alternative method of controlling the roll motions of a bank-to-turn cruise missile. Compared to conventional roll control the variable span method provides an increase in roll control authority. Unfortunately, the aeroelastic characteristics of the VSMW become worse because the wing-root bending moment increases due to the wingspan increase.