Dragonflies are dramatic, successful aerial predators, notable for their flight agility and endurance. Further, they are highly capable of low-speed, hovering and even backwards flight. While insects have repeatedly modified or reduced one pair of wings, or mechanically coupled their fore and hind wings, dragonflies and damselflies have maintained their distinctive, independently controllable, ...

Recent work on flapping hawkmoth models has demonstrated the importance of a spiral 'leading-edge vortex' created by dynamic stall, and maintained by some aspect of spanwise flow, for creating the lift required during flight. This study uses propeller models to investigate further the forces acting on model hawkmoth wings in 'propeller-like' rotation ('revolution'). Steadily revolving model haw...

The generation of a finite element based structural model of a small, flexible unmanned aircraft is presented. The paper focuses on obtaining a simple model suitable for control design based on a two step procedure. In an initial step, static and dynamic tests of the wings are conducted. These experiments give first estimates of the material properties (e.g., stiffness) of the aircraft. A finit...

The importance of house fly (Musca domestica L) wings in mechanical transmission of bacteria was studied. A droplet of phosphate-buffered saline containing Vibrio cholerae was rolled along one wing of each house fly. None adhered to the wings but small proportions of the bacterium were isolated from about half the wings. Vibrio cholerae was spread onto the ventral wing surfaces of each unconsci...

The aerodynamic characteristics of the wings and body of a dragonfly and of artificial wing models were studied by conducting two types of wind-tunnel tests and a number of free-flight tests of gliders made using dragonfly wings. The results were consistent between these different tests. The effects of camber, thickness, sharpness of the leading edge and surface roughness on the aerodynamic cha...

Adults, particularly males, of a papilionid butterfly, Papilio machaon hippocrates, emit a fairly strong scent perceivable by humans. We have identified a variety of volatile compounds (hydrocarbons, alcohols, aldehydes, ketones, esters, and so on) from the wings and bodies of both sexes of the butterfly. Male wings secreted n-dodecane, linalool and geranylacetone as major components together w...

In this paper we examine the design of metallic and composite aircraft wings in order to assess how the use of composites modifies the trade-off between structural weight and drag. In order to perform this assessment, we use a gradient-based aerostructural design optimization framework that combines a high-fidelity finite-element structural model that includes panel-level design variables with ...

In aerospace engineering, high-order computational fluid dynamics (CFD) solvers suitable for three-dimensional unstructured meshes are less developed than expected. The Runge–Kutta discontinuous Galerkin (RKDG) finite element method with compact weighted essentially non-oscillatory (WENO) limiters is one of the candidates, which might give solutions on meshes. this article, we provide an effici...